GET https://kbin.spritesserver.nl/index.php/u/@blarbasaurus@lemmy.world/top

Response
200 OK
IP
216.73.216.163
Profiled on
Token
7b5321

Security

Token

There is no security token.

Firewall

main Name
Security enabled
Stateless

Configuration

Key Value
provider security.user.provider.concrete.app_user_provider
context main
entry_point App\Security\KbinAuthenticator
user_checker App\Security\UserChecker
access_denied_handler (none)
access_denied_url (none)
authenticators 
[
  "two_factor"
  "remember_me"
  "App\Security\KbinAuthenticator"
  "App\Security\FacebookAuthenticator"
  "App\Security\GoogleAuthenticator"
  "App\Security\GithubAuthenticator"
  "App\Security\KeycloakAuthenticator"
]

Listeners

Listener Duration Response 
Symfony\Component\Security\Http\Firewall\ChannelListener {#723
  -map: Symfony\Component\Security\Http\AccessMap {#722 …}
  -logger: Monolog\Logger {#783 …}
  -httpPort: 80
  -httpsPort: 443
}
 0.00 ms (none) 
Symfony\Component\Security\Http\Firewall\ContextListener {#706
  -tokenStorage: Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorage {#1017 …}
  -sessionKey: "_security_main"
  -logger: Monolog\Logger {#783 …}
  -userProviders: Symfony\Component\DependencyInjection\Argument\RewindableGenerator {#705 …}
  -dispatcher: Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcher {#747 …}
  -registered: false
  -trustResolver: Scheb\TwoFactorBundle\Security\Authentication\AuthenticationTrustResolver {#780 …}
  -sessionTrackerEnabler: Symfony\Component\Security\Core\Authentication\Token\Storage\UsageTrackingTokenStorage::enableUsageTracking(): void {#703 …}
}
 33.56 ms (none) 
Symfony\Component\Security\Http\Firewall\AuthenticatorManagerListener {#584
  -authenticatorManager: Symfony\Component\Security\Http\Authentication\AuthenticatorManager {#595 …}
}
 0.00 ms (none) 
Scheb\TwoFactorBundle\Security\Http\Firewall\TwoFactorAccessListener {#582
  -twoFactorFirewallConfig: Scheb\TwoFactorBundle\Security\TwoFactor\TwoFactorFirewallConfig {#842 …}
  -tokenStorage: Symfony\Component\Security\Core\Authentication\Token\Storage\UsageTrackingTokenStorage {#1018 …}
  -twoFactorAccessDecider: Scheb\TwoFactorBundle\Security\Authorization\TwoFactorAccessDecider {#581 …}
}
 0.06 ms (none) 
Symfony\Component\Security\Http\Firewall\AccessListener {#579
  -tokenStorage: Symfony\Component\Security\Core\Authentication\Token\Storage\UsageTrackingTokenStorage {#1018 …}
  -accessDecisionManager: Symfony\Component\Security\Core\Authorization\TraceableAccessDecisionManager {#937 …}
  -map: Symfony\Component\Security\Http\AccessMap {#722 …}
}
 0.00 ms (none) 
Symfony\Component\Security\Http\Firewall\LogoutListener {#786
  -tokenStorage: Symfony\Component\Security\Core\Authentication\Token\Storage\UsageTrackingTokenStorage {#1018 …}
  -options: [
    "csrf_parameter" => "_csrf_token"
    "csrf_token_id" => "logout"
    "logout_path" => "app_logout"
  ]
  -httpUtils: Symfony\Component\Security\Http\HttpUtils {#841 …}
  -csrfTokenManager: Symfony\Component\Security\Csrf\CsrfTokenManager {#1015 …}
  -eventDispatcher: Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcher {#747 …}
}
 0.00 ms (none)

Authenticators

No authenticators have been recorded. Check previous profiles on your authentication endpoint.

Access Decision

affirmative Strategy
# Voter class
1 
"Symfony\Component\Security\Core\Authorization\Voter\AuthenticatedVoter"
2 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
3 
"Symfony\Component\Security\Core\Authorization\Voter\RoleHierarchyVoter"
4 
"Symfony\Component\Security\Core\Authorization\Voter\ExpressionVoter"
5 
"App\Security\Voter\EntryCommentVoter"
6 
"App\Security\Voter\EntryVoter"
7 
"App\Security\Voter\MagazineVoter"
8 
"App\Security\Voter\MessageThreadVoter"
9 
"App\Security\Voter\MessageVoter"
10 
"App\Security\Voter\NotificationVoter"
11 
"App\Security\Voter\OAuth2UserConsentVoter"
12 
"App\Security\Voter\PostCommentVoter"
13 
"App\Security\Voter\PostVoter"
14 
"App\Security\Voter\UserVoter"

Access decision log

# Result Attributes Object
1 DENIED ROLE_USER 
null
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
 ACCESS ABSTAIN 
"Symfony\Component\Security\Core\Authorization\Voter\RoleHierarchyVoter"
 ACCESS DENIED 
"App\Security\Voter\EntryCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MagazineVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageThreadVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\NotificationVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\OAuth2UserConsentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\UserVoter"
 ACCESS ABSTAIN
Show voter details
2 DENIED moderate 
Proxies\__CG__\App\Entity\Entry {#1621
  +user: Proxies\__CG__\App\Entity\User {#2333 …}
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: Proxies\__CG__\App\Entity\Image {#2043 …}
  +domain: Proxies\__CG__\App\Entity\Domain {#2139 …}
  +slug: "Did-I-damage-my-crystal"
  +title: "Did I damage my crystal?"
  +url: "https://discuss.tchncs.de/pictrs/image/cf713e59-9c8f-43c3-a378-afc038e56ab2.png"
  +body: """
    I bought a random cheap crystal oscillator off AliX. It was advertised as a “constant temperature crystal reference”.\n
    \n
    I also didn’t know what voltage it took. I found a photo of a similar one which apparently needed 12 V. However, smoke started coming out when I tried 12 V.\n
    \n
    It seems to oscillate OK on 5 V though. However, it seems to be fluctuating in frequency, and I don’t know if this is normal, or whether I have damaged it.
    """
  +type: "image"
  +lang: "en"
  +isOc: false
  +hasEmbed: true
  +commentCount: 2
  +favouriteCount: 5
  +score: 0
  +isAdult: false
  +sticky: false
  +lastActive: DateTime @1687940429 {#2162
    date: 2023-06-28 10:20:29.0 +02:00
  }
  +ip: null
  +adaAmount: 0
  +tags: null
  +mentions: null
  +comments: Doctrine\ORM\PersistentCollection {#2225 …}
  +votes: Doctrine\ORM\PersistentCollection {#2231 …}
  +reports: Doctrine\ORM\PersistentCollection {#2229 …}
  +favourites: Doctrine\ORM\PersistentCollection {#2252 …}
  +notifications: Doctrine\ORM\PersistentCollection {#2189 …}
  +badges: Doctrine\ORM\PersistentCollection {#2311 …}
  +children: [
    App\Entity\EntryComment {#1613
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1621 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: null
      +root: null
      +body: "Assuming that this is a 10MHz reference, at the extreme your reference is 0.003Hz off from nominal (3e-10, or 0.3ppb error). It varies by 0.08ppb in the plot. IDK what it is that you bought (TCXO, OCXO, whatever), but that's rather impressive stability. Depending on what type of oscillator it is you can expect a temperature coefficient anywhere in the several ppm to 0.1ppb. Do you know by how much the ambient temperature (or even better, the oscillator temperature) changed over the duration of the plot? I don't work with temperature-compensated oscillators very often, but I don't see an issue here."
      +lang: "en"
      +isAdult: false
      +favouriteCount: 8
      +score: 0
      +lastActive: DateTime @1687940430 {#1552
        date: 2023-06-28 10:20:30.0 +02:00
      }
      +ip: null
      +tags: null
      +mentions: [
        "@Sexton01@discuss.tchncs.de"
      ]
      +children: Doctrine\ORM\PersistentCollection {#1556 …}
      +nested: Doctrine\ORM\PersistentCollection {#1604 …}
      +votes: Doctrine\ORM\PersistentCollection {#1619 …}
      +reports: Doctrine\ORM\PersistentCollection {#1701 …}
      +favourites: Doctrine\ORM\PersistentCollection {#1687 …}
      +notifications: Doctrine\ORM\PersistentCollection {#1689 …}
      -id: 4720
      -bodyTs: "'0.003':14 '0.08':27 '0.1':68 '0.3':21 '10mhz':6 '3e-10':19 'ambient':77 'anywher':62 'assum':1 'better':81 'bought':38 'chang':85 'coeffici':61 'compens':99 'depend':48 'durat':88 'error':23 'even':80 'expect':58 'extrem':10 'hz':15 'idk':32 'impress':46 'issu':109 'know':72 'much':75 'nomin':18 'ocxo':40 'often':102 'oscil':53,83,100 'plot':31,91 'ppb':22,28,69 'ppm':66 'rather':45 'refer':7,12 'see':107 'sever':65 'stabil':47 'tcxo':39 'temperatur':60,78,84,98 'temperature-compens':97 'type':51 'vari':25 'whatev':41 'work':95"
      +ranking: 0
      +commentCount: 0
      +upVotes: 0
      +downVotes: 0
      +visibility: "visible             "
      +apId: "https://lemmy.world/comment/587266"
      +editedAt: null
      +createdAt: DateTimeImmutable @1687911492 {#1620
        date: 2023-06-28 02:18:12.0 +02:00
      }
      +"title": 4720
    }
  ]
  -id: 469
  -titleTs: "'crystal':5 'damag':3"
  -bodyTs: "'12':39,49 '5':57 'advertis':12 'alix':9 'also':20 'appar':37 'bought':2 'cheap':5 'come':44 'constant':15 'crystal':6,17 'damag':81 'didn':21 'fluctuat':65 'found':29 'frequenc':67 'howev':41,60 'know':23,72 'need':38 'normal':76 'ok':55 'one':35 'oscil':7,54 'photo':31 'random':4 'refer':18 'seem':52,62 'similar':34 'smoke':42 'start':43 'temperatur':16 'though':59 'took':27 'tri':48 'v':40,50,58 'voltag':25 'whether':78"
  +cross: false
  +upVotes: 0
  +downVotes: 0
  +ranking: 1687924184
  +visibility: "visible             "
  +apId: "https://discuss.tchncs.de/post/341517"
  +editedAt: null
  +createdAt: DateTimeImmutable @1687902184 {#2143
    date: 2023-06-27 23:43:04.0 +02:00
  }
  +__isInitialized__: true
   …2
}
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryVoter"
 ACCESS DENIED 
"App\Security\Voter\MagazineVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageThreadVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\NotificationVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\OAuth2UserConsentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\UserVoter"
 ACCESS ABSTAIN
Show voter details
3 DENIED edit 
Proxies\__CG__\App\Entity\Entry {#1621
  +user: Proxies\__CG__\App\Entity\User {#2333 …}
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: Proxies\__CG__\App\Entity\Image {#2043 …}
  +domain: Proxies\__CG__\App\Entity\Domain {#2139 …}
  +slug: "Did-I-damage-my-crystal"
  +title: "Did I damage my crystal?"
  +url: "https://discuss.tchncs.de/pictrs/image/cf713e59-9c8f-43c3-a378-afc038e56ab2.png"
  +body: """
    I bought a random cheap crystal oscillator off AliX. It was advertised as a “constant temperature crystal reference”.\n
    \n
    I also didn’t know what voltage it took. I found a photo of a similar one which apparently needed 12 V. However, smoke started coming out when I tried 12 V.\n
    \n
    It seems to oscillate OK on 5 V though. However, it seems to be fluctuating in frequency, and I don’t know if this is normal, or whether I have damaged it.
    """
  +type: "image"
  +lang: "en"
  +isOc: false
  +hasEmbed: true
  +commentCount: 2
  +favouriteCount: 5
  +score: 0
  +isAdult: false
  +sticky: false
  +lastActive: DateTime @1687940429 {#2162
    date: 2023-06-28 10:20:29.0 +02:00
  }
  +ip: null
  +adaAmount: 0
  +tags: null
  +mentions: null
  +comments: Doctrine\ORM\PersistentCollection {#2225 …}
  +votes: Doctrine\ORM\PersistentCollection {#2231 …}
  +reports: Doctrine\ORM\PersistentCollection {#2229 …}
  +favourites: Doctrine\ORM\PersistentCollection {#2252 …}
  +notifications: Doctrine\ORM\PersistentCollection {#2189 …}
  +badges: Doctrine\ORM\PersistentCollection {#2311 …}
  +children: [
    App\Entity\EntryComment {#1613
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1621 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: null
      +root: null
      +body: "Assuming that this is a 10MHz reference, at the extreme your reference is 0.003Hz off from nominal (3e-10, or 0.3ppb error). It varies by 0.08ppb in the plot. IDK what it is that you bought (TCXO, OCXO, whatever), but that's rather impressive stability. Depending on what type of oscillator it is you can expect a temperature coefficient anywhere in the several ppm to 0.1ppb. Do you know by how much the ambient temperature (or even better, the oscillator temperature) changed over the duration of the plot? I don't work with temperature-compensated oscillators very often, but I don't see an issue here."
      +lang: "en"
      +isAdult: false
      +favouriteCount: 8
      +score: 0
      +lastActive: DateTime @1687940430 {#1552
        date: 2023-06-28 10:20:30.0 +02:00
      }
      +ip: null
      +tags: null
      +mentions: [
        "@Sexton01@discuss.tchncs.de"
      ]
      +children: Doctrine\ORM\PersistentCollection {#1556 …}
      +nested: Doctrine\ORM\PersistentCollection {#1604 …}
      +votes: Doctrine\ORM\PersistentCollection {#1619 …}
      +reports: Doctrine\ORM\PersistentCollection {#1701 …}
      +favourites: Doctrine\ORM\PersistentCollection {#1687 …}
      +notifications: Doctrine\ORM\PersistentCollection {#1689 …}
      -id: 4720
      -bodyTs: "'0.003':14 '0.08':27 '0.1':68 '0.3':21 '10mhz':6 '3e-10':19 'ambient':77 'anywher':62 'assum':1 'better':81 'bought':38 'chang':85 'coeffici':61 'compens':99 'depend':48 'durat':88 'error':23 'even':80 'expect':58 'extrem':10 'hz':15 'idk':32 'impress':46 'issu':109 'know':72 'much':75 'nomin':18 'ocxo':40 'often':102 'oscil':53,83,100 'plot':31,91 'ppb':22,28,69 'ppm':66 'rather':45 'refer':7,12 'see':107 'sever':65 'stabil':47 'tcxo':39 'temperatur':60,78,84,98 'temperature-compens':97 'type':51 'vari':25 'whatev':41 'work':95"
      +ranking: 0
      +commentCount: 0
      +upVotes: 0
      +downVotes: 0
      +visibility: "visible             "
      +apId: "https://lemmy.world/comment/587266"
      +editedAt: null
      +createdAt: DateTimeImmutable @1687911492 {#1620
        date: 2023-06-28 02:18:12.0 +02:00
      }
      +"title": 4720
    }
  ]
  -id: 469
  -titleTs: "'crystal':5 'damag':3"
  -bodyTs: "'12':39,49 '5':57 'advertis':12 'alix':9 'also':20 'appar':37 'bought':2 'cheap':5 'come':44 'constant':15 'crystal':6,17 'damag':81 'didn':21 'fluctuat':65 'found':29 'frequenc':67 'howev':41,60 'know':23,72 'need':38 'normal':76 'ok':55 'one':35 'oscil':7,54 'photo':31 'random':4 'refer':18 'seem':52,62 'similar':34 'smoke':42 'start':43 'temperatur':16 'though':59 'took':27 'tri':48 'v':40,50,58 'voltag':25 'whether':78"
  +cross: false
  +upVotes: 0
  +downVotes: 0
  +ranking: 1687924184
  +visibility: "visible             "
  +apId: "https://discuss.tchncs.de/post/341517"
  +editedAt: null
  +createdAt: DateTimeImmutable @1687902184 {#2143
    date: 2023-06-27 23:43:04.0 +02:00
  }
  +__isInitialized__: true
   …2
}
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryVoter"
 ACCESS DENIED 
"App\Security\Voter\MagazineVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageThreadVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\NotificationVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\OAuth2UserConsentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\UserVoter"
 ACCESS ABSTAIN
Show voter details
4 DENIED moderate 
Proxies\__CG__\App\Entity\Entry {#1621
  +user: Proxies\__CG__\App\Entity\User {#2333 …}
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: Proxies\__CG__\App\Entity\Image {#2043 …}
  +domain: Proxies\__CG__\App\Entity\Domain {#2139 …}
  +slug: "Did-I-damage-my-crystal"
  +title: "Did I damage my crystal?"
  +url: "https://discuss.tchncs.de/pictrs/image/cf713e59-9c8f-43c3-a378-afc038e56ab2.png"
  +body: """
    I bought a random cheap crystal oscillator off AliX. It was advertised as a “constant temperature crystal reference”.\n
    \n
    I also didn’t know what voltage it took. I found a photo of a similar one which apparently needed 12 V. However, smoke started coming out when I tried 12 V.\n
    \n
    It seems to oscillate OK on 5 V though. However, it seems to be fluctuating in frequency, and I don’t know if this is normal, or whether I have damaged it.
    """
  +type: "image"
  +lang: "en"
  +isOc: false
  +hasEmbed: true
  +commentCount: 2
  +favouriteCount: 5
  +score: 0
  +isAdult: false
  +sticky: false
  +lastActive: DateTime @1687940429 {#2162
    date: 2023-06-28 10:20:29.0 +02:00
  }
  +ip: null
  +adaAmount: 0
  +tags: null
  +mentions: null
  +comments: Doctrine\ORM\PersistentCollection {#2225 …}
  +votes: Doctrine\ORM\PersistentCollection {#2231 …}
  +reports: Doctrine\ORM\PersistentCollection {#2229 …}
  +favourites: Doctrine\ORM\PersistentCollection {#2252 …}
  +notifications: Doctrine\ORM\PersistentCollection {#2189 …}
  +badges: Doctrine\ORM\PersistentCollection {#2311 …}
  +children: [
    App\Entity\EntryComment {#1613
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1621 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: null
      +root: null
      +body: "Assuming that this is a 10MHz reference, at the extreme your reference is 0.003Hz off from nominal (3e-10, or 0.3ppb error). It varies by 0.08ppb in the plot. IDK what it is that you bought (TCXO, OCXO, whatever), but that's rather impressive stability. Depending on what type of oscillator it is you can expect a temperature coefficient anywhere in the several ppm to 0.1ppb. Do you know by how much the ambient temperature (or even better, the oscillator temperature) changed over the duration of the plot? I don't work with temperature-compensated oscillators very often, but I don't see an issue here."
      +lang: "en"
      +isAdult: false
      +favouriteCount: 8
      +score: 0
      +lastActive: DateTime @1687940430 {#1552
        date: 2023-06-28 10:20:30.0 +02:00
      }
      +ip: null
      +tags: null
      +mentions: [
        "@Sexton01@discuss.tchncs.de"
      ]
      +children: Doctrine\ORM\PersistentCollection {#1556 …}
      +nested: Doctrine\ORM\PersistentCollection {#1604 …}
      +votes: Doctrine\ORM\PersistentCollection {#1619 …}
      +reports: Doctrine\ORM\PersistentCollection {#1701 …}
      +favourites: Doctrine\ORM\PersistentCollection {#1687 …}
      +notifications: Doctrine\ORM\PersistentCollection {#1689 …}
      -id: 4720
      -bodyTs: "'0.003':14 '0.08':27 '0.1':68 '0.3':21 '10mhz':6 '3e-10':19 'ambient':77 'anywher':62 'assum':1 'better':81 'bought':38 'chang':85 'coeffici':61 'compens':99 'depend':48 'durat':88 'error':23 'even':80 'expect':58 'extrem':10 'hz':15 'idk':32 'impress':46 'issu':109 'know':72 'much':75 'nomin':18 'ocxo':40 'often':102 'oscil':53,83,100 'plot':31,91 'ppb':22,28,69 'ppm':66 'rather':45 'refer':7,12 'see':107 'sever':65 'stabil':47 'tcxo':39 'temperatur':60,78,84,98 'temperature-compens':97 'type':51 'vari':25 'whatev':41 'work':95"
      +ranking: 0
      +commentCount: 0
      +upVotes: 0
      +downVotes: 0
      +visibility: "visible             "
      +apId: "https://lemmy.world/comment/587266"
      +editedAt: null
      +createdAt: DateTimeImmutable @1687911492 {#1620
        date: 2023-06-28 02:18:12.0 +02:00
      }
      +"title": 4720
    }
  ]
  -id: 469
  -titleTs: "'crystal':5 'damag':3"
  -bodyTs: "'12':39,49 '5':57 'advertis':12 'alix':9 'also':20 'appar':37 'bought':2 'cheap':5 'come':44 'constant':15 'crystal':6,17 'damag':81 'didn':21 'fluctuat':65 'found':29 'frequenc':67 'howev':41,60 'know':23,72 'need':38 'normal':76 'ok':55 'one':35 'oscil':7,54 'photo':31 'random':4 'refer':18 'seem':52,62 'similar':34 'smoke':42 'start':43 'temperatur':16 'though':59 'took':27 'tri':48 'v':40,50,58 'voltag':25 'whether':78"
  +cross: false
  +upVotes: 0
  +downVotes: 0
  +ranking: 1687924184
  +visibility: "visible             "
  +apId: "https://discuss.tchncs.de/post/341517"
  +editedAt: null
  +createdAt: DateTimeImmutable @1687902184 {#2143
    date: 2023-06-27 23:43:04.0 +02:00
  }
  +__isInitialized__: true
   …2
}
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryVoter"
 ACCESS DENIED 
"App\Security\Voter\MagazineVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageThreadVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MessageVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\NotificationVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\OAuth2UserConsentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\PostVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\UserVoter"
 ACCESS ABSTAIN
Show voter details
5 DENIED ROLE_USER 
null
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
 ACCESS ABSTAIN 
"Symfony\Component\Security\Core\Authorization\Voter\RoleHierarchyVoter"
 ACCESS DENIED 
"App\Security\Voter\EntryCommentVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\EntryVoter"
 ACCESS ABSTAIN 
"App\Security\Voter\MagazineVoter"
 ACCESS ABSTAIN 
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Show voter details
6 DENIED moderate 
App\Entity\EntryComment {#1613
  +user: App\Entity\User {#260 …}
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    +user: Proxies\__CG__\App\Entity\User {#2333 …}
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    +image: Proxies\__CG__\App\Entity\Image {#2043 …}
    +domain: Proxies\__CG__\App\Entity\Domain {#2139 …}
    +slug: "Did-I-damage-my-crystal"
    +title: "Did I damage my crystal?"
    +url: "https://discuss.tchncs.de/pictrs/image/cf713e59-9c8f-43c3-a378-afc038e56ab2.png"
    +body: """
      I bought a random cheap crystal oscillator off AliX. It was advertised as a “constant temperature crystal reference”.\n
      \n
      I also didn’t know what voltage it took. I found a photo of a similar one which apparently needed 12 V. However, smoke started coming out when I tried 12 V.\n
      \n
      It seems to oscillate OK on 5 V though. However, it seems to be fluctuating in frequency, and I don’t know if this is normal, or whether I have damaged it.
      """
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      date: 2023-06-27 23:43:04.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: null
  +root: null
  +body: "Assuming that this is a 10MHz reference, at the extreme your reference is 0.003Hz off from nominal (3e-10, or 0.3ppb error). It varies by 0.08ppb in the plot. IDK what it is that you bought (TCXO, OCXO, whatever), but that's rather impressive stability. Depending on what type of oscillator it is you can expect a temperature coefficient anywhere in the several ppm to 0.1ppb. Do you know by how much the ambient temperature (or even better, the oscillator temperature) changed over the duration of the plot? I don't work with temperature-compensated oscillators very often, but I don't see an issue here."
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}
 
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Show voter details
7 DENIED edit 
App\Entity\EntryComment {#1613
  +user: App\Entity\User {#260 …}
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    +domain: Proxies\__CG__\App\Entity\Domain {#2139 …}
    +slug: "Did-I-damage-my-crystal"
    +title: "Did I damage my crystal?"
    +url: "https://discuss.tchncs.de/pictrs/image/cf713e59-9c8f-43c3-a378-afc038e56ab2.png"
    +body: """
      I bought a random cheap crystal oscillator off AliX. It was advertised as a “constant temperature crystal reference”.\n
      \n
      I also didn’t know what voltage it took. I found a photo of a similar one which apparently needed 12 V. However, smoke started coming out when I tried 12 V.\n
      \n
      It seems to oscillate OK on 5 V though. However, it seems to be fluctuating in frequency, and I don’t know if this is normal, or whether I have damaged it.
      """
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    +cross: false
    +upVotes: 0
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    +createdAt: DateTimeImmutable @1687902184 {#2143
      date: 2023-06-27 23:43:04.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: null
  +root: null
  +body: "Assuming that this is a 10MHz reference, at the extreme your reference is 0.003Hz off from nominal (3e-10, or 0.3ppb error). It varies by 0.08ppb in the plot. IDK what it is that you bought (TCXO, OCXO, whatever), but that's rather impressive stability. Depending on what type of oscillator it is you can expect a temperature coefficient anywhere in the several ppm to 0.1ppb. Do you know by how much the ambient temperature (or even better, the oscillator temperature) changed over the duration of the plot? I don't work with temperature-compensated oscillators very often, but I don't see an issue here."
  +lang: "en"
  +isAdult: false
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    date: 2023-06-28 10:20:30.0 +02:00
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  +ranking: 0
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  +apId: "https://lemmy.world/comment/587266"
  +editedAt: null
  +createdAt: DateTimeImmutable @1687911492 {#1620
    date: 2023-06-28 02:18:12.0 +02:00
  }
  +"title": 4720
}
 
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Show voter details
8 DENIED moderate 
App\Entity\EntryComment {#1613
  +user: App\Entity\User {#260 …}
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    +user: Proxies\__CG__\App\Entity\User {#2333 …}
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    +domain: Proxies\__CG__\App\Entity\Domain {#2139 …}
    +slug: "Did-I-damage-my-crystal"
    +title: "Did I damage my crystal?"
    +url: "https://discuss.tchncs.de/pictrs/image/cf713e59-9c8f-43c3-a378-afc038e56ab2.png"
    +body: """
      I bought a random cheap crystal oscillator off AliX. It was advertised as a “constant temperature crystal reference”.\n
      \n
      I also didn’t know what voltage it took. I found a photo of a similar one which apparently needed 12 V. However, smoke started coming out when I tried 12 V.\n
      \n
      It seems to oscillate OK on 5 V though. However, it seems to be fluctuating in frequency, and I don’t know if this is normal, or whether I have damaged it.
      """
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      date: 2023-06-27 23:43:04.0 +02:00
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     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: null
  +root: null
  +body: "Assuming that this is a 10MHz reference, at the extreme your reference is 0.003Hz off from nominal (3e-10, or 0.3ppb error). It varies by 0.08ppb in the plot. IDK what it is that you bought (TCXO, OCXO, whatever), but that's rather impressive stability. Depending on what type of oscillator it is you can expect a temperature coefficient anywhere in the several ppm to 0.1ppb. Do you know by how much the ambient temperature (or even better, the oscillator temperature) changed over the duration of the plot? I don't work with temperature-compensated oscillators very often, but I don't see an issue here."
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    date: 2023-06-28 10:20:30.0 +02:00
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  -id: 4720
  -bodyTs: "'0.003':14 '0.08':27 '0.1':68 '0.3':21 '10mhz':6 '3e-10':19 'ambient':77 'anywher':62 'assum':1 'better':81 'bought':38 'chang':85 'coeffici':61 'compens':99 'depend':48 'durat':88 'error':23 'even':80 'expect':58 'extrem':10 'hz':15 'idk':32 'impress':46 'issu':109 'know':72 'much':75 'nomin':18 'ocxo':40 'often':102 'oscil':53,83,100 'plot':31,91 'ppb':22,28,69 'ppm':66 'rather':45 'refer':7,12 'see':107 'sever':65 'stabil':47 'tcxo':39 'temperatur':60,78,84,98 'temperature-compens':97 'type':51 'vari':25 'whatev':41 'work':95"
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  +editedAt: null
  +createdAt: DateTimeImmutable @1687911492 {#1620
    date: 2023-06-28 02:18:12.0 +02:00
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  +"title": 4720
}
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
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 ACCESS DENIED 
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Show voter details
9 DENIED ROLE_USER 
null
 
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 ACCESS ABSTAIN 
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 ACCESS ABSTAIN
Show voter details
10 DENIED moderate 
Proxies\__CG__\App\Entity\Entry {#1549
  +user: Proxies\__CG__\App\Entity\User {#2082 …}
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
  +slug: "MOSFET-as-Radiation-Detector"
  +title: "MOSFET as Radiation Detector"
  +url: null
  +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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    date: 2023-07-12 20:23:14.0 +02:00
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    5 => App\Entity\EntryComment {#1665
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: null
      +root: null
      +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        "@Lazyhotodogu@discuss.tchncs.de"
      ]
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      -id: 1118
      -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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      +editedAt: null
      +createdAt: DateTimeImmutable @1687177876 {#1612
        date: 2023-06-19 14:31:16.0 +02:00
      }
      +"title": 1118
    }
    4 => App\Entity\EntryComment {#1795
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
      +root: App\Entity\EntryComment {#1665}
      +body: """
        Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
        \n
        - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
        - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
        - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
        - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
        """
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      +isAdult: false
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        date: 2023-06-27 18:55:34.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
      ]
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      -id: 8525
      -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
      +ranking: 0
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      +editedAt: null
      +createdAt: DateTimeImmutable @1687884934 {#1692
        date: 2023-06-27 18:55:34.0 +02:00
      }
      +"title": 8525
    }
    3 => App\Entity\EntryComment {#1726
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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      +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
      +root: App\Entity\EntryComment {#1665}
      +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
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      +createdAt: DateTimeImmutable @1688845425 {#1728
        date: 2023-07-08 21:43:45.0 +02:00
      }
      +"title": 9161
    }
    2 => App\Entity\EntryComment {#1611
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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      +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
      +root: App\Entity\EntryComment {#1665}
      +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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        date: 2023-07-08 21:47:13.0 +02:00
      }
      +"title": 9162
    }
    1 => App\Entity\EntryComment {#2363
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
      +root: App\Entity\EntryComment {#1665}
      +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -id: 13679
      -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
      +ranking: 0
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      +apId: "https://lemmy.world/comment/1177817"
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        date: 2023-07-12 20:23:14.0 +02:00
      }
      +"title": 13679
    }
    0 => App\Entity\EntryComment {#2458
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
      +root: App\Entity\EntryComment {#1665}
      +body: """
        You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
        \n
        For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
        """
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        date: 2023-07-10 15:01:48.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -id: 9375
      -bodyTs: "'250ua':49 '2v':45 '4v':47 '5v':67 'accept':114 'across':23 'affect':94,107 'calcul':99 'chang':90 'close':62 'current':96,105 'error/innacuracy':112 'ever':12 'fine':71 'haven':10 'high':57 'increas':6 'irfp250n':35 'know':28 'lm334':15 'math':86 'method':81 'minimum':21 'much':101 'need':4,19 'probabl':3 'read':109 'resistor':80 'setup':74 'somewher':43 'still':32 'suitabl':77 'threshold':42,52 'tri':65 'use':13,33,66 'variabl':103 'vds':92 'voltag':8,22 'won':53 'would':64"
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  ]
  -id: 135
  -titleTs: "'detector':4 'mosfet':1 'radiat':3"
  -bodyTs: "'/gate':82 '2.0':86 '250':99 '3.5':212 '4':186 '4.0':88 'add':164 'alreadi':168 'also':69,161,214 'altern':13 'arduino':219 'ask':48 'btw':58 'channel':65 'check':228 'condit':93,115 'current':47 'datasheet':72 'detector':15 'determin':41 'dose':44 'drain':135,198 'drop':206 'explain':18 'extern':29 'feel':149 'first':112 'free':150 'gate':144,176 'got':210 'hello':1 'help':50 'id':98 'increas':35 'irfp250npbf':68 'irradi':26 'like':162 'm':46 'make':4 'manufactur':76 'max':87 'mean':103 'measur':54,106,117,127,195,221 'min':85 'model':67 'mosfet':10,24,66 'multimet':226 'n':64 'n-channel':63 'need':110 'node':122 'provid':73 'radiat':14,30,43 'respect':178 'satisfi':113 'say':78 'share':152 'sourc':31,138,147,181,200 'still':141 'suppli':171,188 'termin':139,148,182 'th':81,130 'thesi':6 'thought':154 'threshold':34,57,83,120 'tri':169,193 'use':9,39,61,125,184,217 'v':89,187,213 'vds':96,197 've':209 'vgs':80,97,108,129 'voltag':33,56,84,119,173,189,201,205,223 'work':21 'would':160"
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    date: 2023-06-19 07:37:26.0 +02:00
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11 DENIED edit 
Proxies\__CG__\App\Entity\Entry {#1549
  +user: Proxies\__CG__\App\Entity\User {#2082 …}
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
  +slug: "MOSFET-as-Radiation-Detector"
  +title: "MOSFET as Radiation Detector"
  +url: null
  +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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    date: 2023-07-12 20:23:14.0 +02:00
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  +ip: null
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  +comments: Doctrine\ORM\PersistentCollection {#2057 …}
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  +children: [
    5 => App\Entity\EntryComment {#1665
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: null
      +root: null
      +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        "@Lazyhotodogu@discuss.tchncs.de"
      ]
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      -id: 1118
      -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
      +ranking: 0
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      +apId: "https://lemmy.world/comment/348462"
      +editedAt: null
      +createdAt: DateTimeImmutable @1687177876 {#1612
        date: 2023-06-19 14:31:16.0 +02:00
      }
      +"title": 1118
    }
    4 => App\Entity\EntryComment {#1795
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
      +root: App\Entity\EntryComment {#1665}
      +body: """
        Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
        \n
        - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
        - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
        - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
        - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
        """
      +lang: "en"
      +isAdult: false
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        date: 2023-06-27 18:55:34.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
      ]
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      -id: 8525
      -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
      +ranking: 0
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      +createdAt: DateTimeImmutable @1687884934 {#1692
        date: 2023-06-27 18:55:34.0 +02:00
      }
      +"title": 8525
    }
    3 => App\Entity\EntryComment {#1726
      +user: App\Entity\User {#260 …}
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      +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
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        date: 2023-07-08 21:43:45.0 +02:00
      }
      +"title": 9161
    }
    2 => App\Entity\EntryComment {#1611
      +user: App\Entity\User {#260 …}
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      +root: App\Entity\EntryComment {#1665}
      +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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        date: 2023-07-08 21:47:13.0 +02:00
      }
      +"title": 9162
    }
    1 => App\Entity\EntryComment {#2363
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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      +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
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      +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
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      -id: 13679
      -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
      +ranking: 0
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        date: 2023-07-12 20:23:14.0 +02:00
      }
      +"title": 13679
    }
    0 => App\Entity\EntryComment {#2458
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
      +root: App\Entity\EntryComment {#1665}
      +body: """
        You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
        \n
        For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
        """
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -id: 9375
      -bodyTs: "'250ua':49 '2v':45 '4v':47 '5v':67 'accept':114 'across':23 'affect':94,107 'calcul':99 'chang':90 'close':62 'current':96,105 'error/innacuracy':112 'ever':12 'fine':71 'haven':10 'high':57 'increas':6 'irfp250n':35 'know':28 'lm334':15 'math':86 'method':81 'minimum':21 'much':101 'need':4,19 'probabl':3 'read':109 'resistor':80 'setup':74 'somewher':43 'still':32 'suitabl':77 'threshold':42,52 'tri':65 'use':13,33,66 'variabl':103 'vds':92 'voltag':8,22 'won':53 'would':64"
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  ]
  -id: 135
  -titleTs: "'detector':4 'mosfet':1 'radiat':3"
  -bodyTs: "'/gate':82 '2.0':86 '250':99 '3.5':212 '4':186 '4.0':88 'add':164 'alreadi':168 'also':69,161,214 'altern':13 'arduino':219 'ask':48 'btw':58 'channel':65 'check':228 'condit':93,115 'current':47 'datasheet':72 'detector':15 'determin':41 'dose':44 'drain':135,198 'drop':206 'explain':18 'extern':29 'feel':149 'first':112 'free':150 'gate':144,176 'got':210 'hello':1 'help':50 'id':98 'increas':35 'irfp250npbf':68 'irradi':26 'like':162 'm':46 'make':4 'manufactur':76 'max':87 'mean':103 'measur':54,106,117,127,195,221 'min':85 'model':67 'mosfet':10,24,66 'multimet':226 'n':64 'n-channel':63 'need':110 'node':122 'provid':73 'radiat':14,30,43 'respect':178 'satisfi':113 'say':78 'share':152 'sourc':31,138,147,181,200 'still':141 'suppli':171,188 'termin':139,148,182 'th':81,130 'thesi':6 'thought':154 'threshold':34,57,83,120 'tri':169,193 'use':9,39,61,125,184,217 'v':89,187,213 'vds':96,197 've':209 'vgs':80,97,108,129 'voltag':33,56,84,119,173,189,201,205,223 'work':21 'would':160"
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   …2
}
 
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12 DENIED moderate 
Proxies\__CG__\App\Entity\Entry {#1549
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  +slug: "MOSFET-as-Radiation-Detector"
  +title: "MOSFET as Radiation Detector"
  +url: null
  +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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    date: 2023-07-12 20:23:14.0 +02:00
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  +ip: null
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  +comments: Doctrine\ORM\PersistentCollection {#2057 …}
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  +children: [
    5 => App\Entity\EntryComment {#1665
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: null
      +root: null
      +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        "@Lazyhotodogu@discuss.tchncs.de"
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      +ranking: 0
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      +editedAt: null
      +createdAt: DateTimeImmutable @1687177876 {#1612
        date: 2023-06-19 14:31:16.0 +02:00
      }
      +"title": 1118
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    4 => App\Entity\EntryComment {#1795
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
      +root: App\Entity\EntryComment {#1665}
      +body: """
        Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
        \n
        - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
        - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
        - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
        - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
        """
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      +isAdult: false
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        date: 2023-06-27 18:55:34.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
      ]
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      -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
      +ranking: 0
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      +apId: "https://lemmy.world/comment/578647"
      +editedAt: null
      +createdAt: DateTimeImmutable @1687884934 {#1692
        date: 2023-06-27 18:55:34.0 +02:00
      }
      +"title": 8525
    }
    3 => App\Entity\EntryComment {#1726
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
      +root: App\Entity\EntryComment {#1665}
      +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
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        date: 2023-07-08 21:43:45.0 +02:00
      }
      +"title": 9161
    }
    2 => App\Entity\EntryComment {#1611
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
      +root: App\Entity\EntryComment {#1665}
      +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
      +lang: "en"
      +isAdult: false
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        date: 2023-07-08 21:47:13.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -id: 9162
      -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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      +editedAt: null
      +createdAt: DateTimeImmutable @1688845633 {#1598
        date: 2023-07-08 21:47:13.0 +02:00
      }
      +"title": 9162
    }
    1 => App\Entity\EntryComment {#2363
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
      +root: App\Entity\EntryComment {#1665}
      +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
      +lang: "en"
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        date: 2023-07-12 20:23:14.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -id: 13679
      -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
      +ranking: 0
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      +apId: "https://lemmy.world/comment/1177817"
      +editedAt: null
      +createdAt: DateTimeImmutable @1689186194 {#2371
        date: 2023-07-12 20:23:14.0 +02:00
      }
      +"title": 13679
    }
    0 => App\Entity\EntryComment {#2458
      +user: App\Entity\User {#260 …}
      +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
      +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
      +image: null
      +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
      +root: App\Entity\EntryComment {#1665}
      +body: """
        You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
        \n
        For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
        """
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        date: 2023-07-10 15:01:48.0 +02:00
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        "@Lazyhotodogu@discuss.tchncs.de"
        "@blarbasaurus@lemmy.world"
        "@Lazyhotodogu@lemmy.world"
      ]
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      -id: 9375
      -bodyTs: "'250ua':49 '2v':45 '4v':47 '5v':67 'accept':114 'across':23 'affect':94,107 'calcul':99 'chang':90 'close':62 'current':96,105 'error/innacuracy':112 'ever':12 'fine':71 'haven':10 'high':57 'increas':6 'irfp250n':35 'know':28 'lm334':15 'math':86 'method':81 'minimum':21 'much':101 'need':4,19 'probabl':3 'read':109 'resistor':80 'setup':74 'somewher':43 'still':32 'suitabl':77 'threshold':42,52 'tri':65 'use':13,33,66 'variabl':103 'vds':92 'voltag':8,22 'won':53 'would':64"
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      +apId: "https://lemmy.world/comment/1074286"
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        date: 2023-07-10 15:01:48.0 +02:00
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      +"title": 9375
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  ]
  -id: 135
  -titleTs: "'detector':4 'mosfet':1 'radiat':3"
  -bodyTs: "'/gate':82 '2.0':86 '250':99 '3.5':212 '4':186 '4.0':88 'add':164 'alreadi':168 'also':69,161,214 'altern':13 'arduino':219 'ask':48 'btw':58 'channel':65 'check':228 'condit':93,115 'current':47 'datasheet':72 'detector':15 'determin':41 'dose':44 'drain':135,198 'drop':206 'explain':18 'extern':29 'feel':149 'first':112 'free':150 'gate':144,176 'got':210 'hello':1 'help':50 'id':98 'increas':35 'irfp250npbf':68 'irradi':26 'like':162 'm':46 'make':4 'manufactur':76 'max':87 'mean':103 'measur':54,106,117,127,195,221 'min':85 'model':67 'mosfet':10,24,66 'multimet':226 'n':64 'n-channel':63 'need':110 'node':122 'provid':73 'radiat':14,30,43 'respect':178 'satisfi':113 'say':78 'share':152 'sourc':31,138,147,181,200 'still':141 'suppli':171,188 'termin':139,148,182 'th':81,130 'thesi':6 'thought':154 'threshold':34,57,83,120 'tri':169,193 'use':9,39,61,125,184,217 'v':89,187,213 'vds':96,197 've':209 'vgs':80,97,108,129 'voltag':33,56,84,119,173,189,201,205,223 'work':21 'would':160"
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    date: 2023-06-19 07:37:26.0 +02:00
  }
  +__isInitialized__: true
   …2
}
 
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14 DENIED moderate 
App\Entity\EntryComment {#1665
  +user: App\Entity\User {#260 …}
  +entry: Proxies\__CG__\App\Entity\Entry {#1549
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    +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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    +comments: Doctrine\ORM\PersistentCollection {#2057 …}
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    +children: [
      5 => App\Entity\EntryComment {#1665}
      4 => App\Entity\EntryComment {#1795
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          date: 2023-06-27 18:55:34.0 +02:00
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
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        -id: 8525
        -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
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          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
      }
      3 => App\Entity\EntryComment {#1726
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
        +lang: "en"
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          date: 2023-07-08 21:47:13.0 +02:00
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
        +ranking: 0
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        +visibility: "visible             "
        +apId: "https://lemmy.world/comment/995819"
        +editedAt: null
        +createdAt: DateTimeImmutable @1688845633 {#1598
          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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          date: 2023-07-12 20:23:14.0 +02:00
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      0 => App\Entity\EntryComment {#2458
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        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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    ]
    -id: 135
    -titleTs: "'detector':4 'mosfet':1 'radiat':3"
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: null
  +root: null
  +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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}
 
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15 DENIED edit 
App\Entity\EntryComment {#1665
  +user: App\Entity\User {#260 …}
  +entry: Proxies\__CG__\App\Entity\Entry {#1549
    +user: Proxies\__CG__\App\Entity\User {#2082 …}
    +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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    +comments: Doctrine\ORM\PersistentCollection {#2057 …}
    +votes: Doctrine\ORM\PersistentCollection {#2047 …}
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    +badges: Doctrine\ORM\PersistentCollection {#2127 …}
    +children: [
      5 => App\Entity\EntryComment {#1665}
      4 => App\Entity\EntryComment {#1795
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          date: 2023-06-27 18:55:34.0 +02:00
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        +mentions: [
          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
        ]
        +children: Doctrine\ORM\PersistentCollection {#1718 …}
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        -id: 8525
        -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
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          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
      }
      3 => App\Entity\EntryComment {#1726
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          date: 2023-07-08 21:47:13.0 +02:00
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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        +apId: "https://lemmy.world/comment/995819"
        +editedAt: null
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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          date: 2023-07-12 20:23:14.0 +02:00
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      0 => App\Entity\EntryComment {#2458
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        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
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    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: null
  +root: null
  +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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16 DENIED moderate 
App\Entity\EntryComment {#1665
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  +entry: Proxies\__CG__\App\Entity\Entry {#1549
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      5 => App\Entity\EntryComment {#1665}
      4 => App\Entity\EntryComment {#1795
        +user: App\Entity\User {#260 …}
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        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
        ]
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        -id: 8525
        -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
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          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
      }
      3 => App\Entity\EntryComment {#1726
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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      0 => App\Entity\EntryComment {#2458
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        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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    -id: 135
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     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: null
  +root: null
  +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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18 DENIED moderate 
App\Entity\EntryComment {#1795
  +user: App\Entity\User {#260 …}
  +entry: Proxies\__CG__\App\Entity\Entry {#1549
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    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
      }
      4 => App\Entity\EntryComment {#1795}
      3 => App\Entity\EntryComment {#1726
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
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        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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      0 => App\Entity\EntryComment {#2458
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        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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    -id: 135
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     …2
  }
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  +body: """
    Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
    \n
    - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
    - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
    - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
    - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
    """
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19 DENIED edit 
App\Entity\EntryComment {#1795
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    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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    +lastActive: DateTime @1689186194 {#1410
      date: 2023-07-12 20:23:14.0 +02:00
    }
    +ip: null
    +adaAmount: 0
    +tags: null
    +mentions: null
    +comments: Doctrine\ORM\PersistentCollection {#2057 …}
    +votes: Doctrine\ORM\PersistentCollection {#2047 …}
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    +children: [
      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          "@Lazyhotodogu@discuss.tchncs.de"
        ]
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        -id: 1118
        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
      }
      4 => App\Entity\EntryComment {#1795}
      3 => App\Entity\EntryComment {#1726
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
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        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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      0 => App\Entity\EntryComment {#2458
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        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
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    -id: 135
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     …2
  }
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  +body: """
    Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
    \n
    - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
    - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
    - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
    - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
    """
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20 DENIED moderate 
App\Entity\EntryComment {#1795
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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    +ip: null
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    +children: [
      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -id: 1118
        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
        +ranking: 0
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        +downVotes: 0
        +visibility: "visible             "
        +apId: "https://lemmy.world/comment/348462"
        +editedAt: null
        +createdAt: DateTimeImmutable @1687177876 {#1612
          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
      }
      4 => App\Entity\EntryComment {#1795}
      3 => App\Entity\EntryComment {#1726
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        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
        +lang: "en"
        +isAdult: false
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        +createdAt: DateTimeImmutable @1688845425 {#1728
          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
        +lang: "en"
        +isAdult: false
        +favouriteCount: 0
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          date: 2023-07-08 21:47:13.0 +02:00
        }
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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        +apId: "https://lemmy.world/comment/995819"
        +editedAt: null
        +createdAt: DateTimeImmutable @1688845633 {#1598
          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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      }
      0 => App\Entity\EntryComment {#2458
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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    ]
    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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  +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
  +root: App\Entity\EntryComment {#1665}
  +body: """
    Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
    \n
    - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
    - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
    - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
    - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
    """
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    "@blarbasaurus@lemmy.world"
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}
 
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App\Entity\EntryComment {#1726
  +user: App\Entity\User {#260 …}
  +entry: Proxies\__CG__\App\Entity\Entry {#1549
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    +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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    +ip: null
    +adaAmount: 0
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    +children: [
      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          "@Lazyhotodogu@discuss.tchncs.de"
        ]
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          date: 2023-06-19 14:31:16.0 +02:00
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      4 => App\Entity\EntryComment {#1795
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@blarbasaurus@lemmy.world"
        ]
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          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
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      3 => App\Entity\EntryComment {#1726}
      2 => App\Entity\EntryComment {#1611
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 13679
        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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          date: 2023-07-12 20:23:14.0 +02:00
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      0 => App\Entity\EntryComment {#2458
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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    ]
    -id: 135
    -titleTs: "'detector':4 'mosfet':1 'radiat':3"
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      date: 2023-06-19 07:37:26.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
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  +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
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}
 
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23 DENIED edit 
App\Entity\EntryComment {#1726
  +user: App\Entity\User {#260 …}
  +entry: Proxies\__CG__\App\Entity\Entry {#1549
    +user: Proxies\__CG__\App\Entity\User {#2082 …}
    +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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    +commentCount: 15
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    +lastActive: DateTime @1689186194 {#1410
      date: 2023-07-12 20:23:14.0 +02:00
    }
    +ip: null
    +adaAmount: 0
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    +comments: Doctrine\ORM\PersistentCollection {#2057 …}
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    +children: [
      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          "@Lazyhotodogu@discuss.tchncs.de"
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
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      4 => App\Entity\EntryComment {#1795
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@blarbasaurus@lemmy.world"
        ]
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          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
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      3 => App\Entity\EntryComment {#1726}
      2 => App\Entity\EntryComment {#1611
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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        -id: 13679
        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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          date: 2023-07-12 20:23:14.0 +02:00
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      0 => App\Entity\EntryComment {#2458
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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    ]
    -id: 135
    -titleTs: "'detector':4 'mosfet':1 'radiat':3"
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      date: 2023-06-19 07:37:26.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
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  +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
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    date: 2023-07-08 21:43:45.0 +02:00
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}
 
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24 DENIED moderate 
App\Entity\EntryComment {#1726
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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    +ip: null
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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        +editedAt: null
        +createdAt: DateTimeImmutable @1687177876 {#1612
          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
      }
      4 => App\Entity\EntryComment {#1795
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        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
        ]
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        +createdAt: DateTimeImmutable @1687884934 {#1692
          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
      }
      3 => App\Entity\EntryComment {#1726}
      2 => App\Entity\EntryComment {#1611
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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        -id: 13679
        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
        +ranking: 0
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          date: 2023-07-12 20:23:14.0 +02:00
        }
        +"title": 13679
      }
      0 => App\Entity\EntryComment {#2458
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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          date: 2023-07-10 15:01:48.0 +02:00
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    ]
    -id: 135
    -titleTs: "'detector':4 'mosfet':1 'radiat':3"
    -bodyTs: "'/gate':82 '2.0':86 '250':99 '3.5':212 '4':186 '4.0':88 'add':164 'alreadi':168 'also':69,161,214 'altern':13 'arduino':219 'ask':48 'btw':58 'channel':65 'check':228 'condit':93,115 'current':47 'datasheet':72 'detector':15 'determin':41 'dose':44 'drain':135,198 'drop':206 'explain':18 'extern':29 'feel':149 'first':112 'free':150 'gate':144,176 'got':210 'hello':1 'help':50 'id':98 'increas':35 'irfp250npbf':68 'irradi':26 'like':162 'm':46 'make':4 'manufactur':76 'max':87 'mean':103 'measur':54,106,117,127,195,221 'min':85 'model':67 'mosfet':10,24,66 'multimet':226 'n':64 'n-channel':63 'need':110 'node':122 'provid':73 'radiat':14,30,43 'respect':178 'satisfi':113 'say':78 'share':152 'sourc':31,138,147,181,200 'still':141 'suppli':171,188 'termin':139,148,182 'th':81,130 'thesi':6 'thought':154 'threshold':34,57,83,120 'tri':169,193 'use':9,39,61,125,184,217 'v':89,187,213 'vds':96,197 've':209 'vgs':80,97,108,129 'voltag':33,56,84,119,173,189,201,205,223 'work':21 'would':160"
    +cross: false
    +upVotes: 0
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      date: 2023-06-19 07:37:26.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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  +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
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  +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
  ]
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    date: 2023-07-08 21:43:45.0 +02:00
  }
  +"title": 9161
}
 
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26 DENIED moderate 
App\Entity\EntryComment {#1611
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  +entry: Proxies\__CG__\App\Entity\Entry {#1549
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    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          "@Lazyhotodogu@discuss.tchncs.de"
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        -id: 1118
        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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        +editedAt: null
        +createdAt: DateTimeImmutable @1687177876 {#1612
          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
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      4 => App\Entity\EntryComment {#1795
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        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
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        +createdAt: DateTimeImmutable @1687884934 {#1692
          date: 2023-06-27 18:55:34.0 +02:00
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        +"title": 8525
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          "@blarbasaurus@lemmy.world"
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          date: 2023-07-08 21:43:45.0 +02:00
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        +"title": 9161
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      2 => App\Entity\EntryComment {#1611}
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
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          date: 2023-07-12 20:23:14.0 +02:00
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        +"title": 13679
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      0 => App\Entity\EntryComment {#2458
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
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    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
    }
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     …2
  }
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  +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
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}
 
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27 DENIED edit 
App\Entity\EntryComment {#1611
  +user: App\Entity\User {#260 …}
  +entry: Proxies\__CG__\App\Entity\Entry {#1549
    +user: Proxies\__CG__\App\Entity\User {#2082 …}
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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        +editedAt: null
        +createdAt: DateTimeImmutable @1687177876 {#1612
          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
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      4 => App\Entity\EntryComment {#1795
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@blarbasaurus@lemmy.world"
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          date: 2023-06-27 18:55:34.0 +02:00
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        +"title": 8525
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          date: 2023-07-08 21:43:45.0 +02:00
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        +"title": 9161
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      2 => App\Entity\EntryComment {#1611}
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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          date: 2023-07-12 20:23:14.0 +02:00
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      0 => App\Entity\EntryComment {#2458
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        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
  }
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  +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
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}
 
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28 DENIED moderate 
App\Entity\EntryComment {#1611
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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        +editedAt: null
        +createdAt: DateTimeImmutable @1687177876 {#1612
          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
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      4 => App\Entity\EntryComment {#1795
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        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@blarbasaurus@lemmy.world"
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        +createdAt: DateTimeImmutable @1687884934 {#1692
          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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          "@blarbasaurus@lemmy.world"
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          date: 2023-07-08 21:43:45.0 +02:00
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        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611}
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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        -bodyTs: "'/lit/ds/symlink/lm334.pdf?ts=1689139734':49 '/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':52 '100':145 '1000':148 'across':87,114 'appli':140 'becom':163 'behaviour':111 'chang':102,118,123,158 'circuit':24,56 'complet':42 'constant':73 'current':70,78,121 'datasheet':46 'dictat':80 'doesn':27 'dose':105 'error':127,137,166 'exampl':55 'figur':37 'first':34 'generat':126 'high':143 'increas':106 'isn':71 'keep':65 'least':10 'lm334z':20,23 'make':39 'method':64 'mind':67 'minim':135 'minimum':16 'minus':94 'need':3 'plus':14 'problem':35 'provid':5 'read':43,130 'refer':60 'resistor':63,83,116,154 'round':165 'suppli':92 'sure':40 'therefor':119 'threshold':12,96,100,161 'typic':110 'volt':151 'voltag':7,13,17,75,86,93,97,101,113,144 'way':133 'work':29 'would':162 'www.ti.com':48,51 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734':47 'www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253a%252f%252fwww.google.com%252f),':50"
        +ranking: 0
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          date: 2023-07-12 20:23:14.0 +02:00
        }
        +"title": 13679
      }
      0 => App\Entity\EntryComment {#2458
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
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    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
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  +root: App\Entity\EntryComment {#1665}
  +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
  ]
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}
 
"Scheb\TwoFactorBundle\Security\Authorization\Voter\TwoFactorInProgressVoter"
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30 DENIED moderate 
App\Entity\EntryComment {#2363
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  +entry: Proxies\__CG__\App\Entity\Entry {#1549
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    +image: null
    +domain: Proxies\__CG__\App\Entity\Domain {#2050 …}
    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: null
        +root: null
        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          "@Lazyhotodogu@discuss.tchncs.de"
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          date: 2023-06-19 14:31:16.0 +02:00
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      4 => App\Entity\EntryComment {#1795
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        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          date: 2023-06-27 18:55:34.0 +02:00
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
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      1 => App\Entity\EntryComment {#2363}
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        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
  }
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  +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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31 DENIED edit 
App\Entity\EntryComment {#2363
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          date: 2023-06-19 14:31:16.0 +02:00
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      4 => App\Entity\EntryComment {#1795
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        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          date: 2023-06-27 18:55:34.0 +02:00
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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      1 => App\Entity\EntryComment {#2363}
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        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
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  +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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    "@blarbasaurus@lemmy.world"
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32 DENIED moderate 
App\Entity\EntryComment {#2363
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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          date: 2023-06-19 14:31:16.0 +02:00
        }
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      4 => App\Entity\EntryComment {#1795
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        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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      }
      2 => App\Entity\EntryComment {#1611
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
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      1 => App\Entity\EntryComment {#2363}
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
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        +body: """
          You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
          \n
          For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
          """
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          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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      date: 2023-06-19 07:37:26.0 +02:00
    }
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     …2
  }
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  +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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    "@blarbasaurus@lemmy.world"
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}
 
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34 DENIED moderate 
App\Entity\EntryComment {#2458
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
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        +image: null
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        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          date: 2023-06-19 14:31:16.0 +02:00
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      4 => App\Entity\EntryComment {#1795
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        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          date: 2023-06-27 18:55:34.0 +02:00
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        +"title": 9161
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      2 => App\Entity\EntryComment {#1611
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
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      1 => App\Entity\EntryComment {#2363
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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  +body: """
    You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
    \n
    For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
    """
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
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35 DENIED edit 
App\Entity\EntryComment {#2458
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
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      4 => App\Entity\EntryComment {#1795
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        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
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          "@blarbasaurus@lemmy.world"
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          date: 2023-06-27 18:55:34.0 +02:00
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        +"title": 8525
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      3 => App\Entity\EntryComment {#1726
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        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
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        +"title": 9161
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      2 => App\Entity\EntryComment {#1611
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        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
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          "@blarbasaurus@lemmy.world"
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      1 => App\Entity\EntryComment {#2363
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        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
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          "@blarbasaurus@lemmy.world"
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    -id: 135
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      date: 2023-06-19 07:37:26.0 +02:00
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     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
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  +body: """
    You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
    \n
    For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
    """
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    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
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36 DENIED moderate 
App\Entity\EntryComment {#2458
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    +slug: "MOSFET-as-Radiation-Detector"
    +title: "MOSFET as Radiation Detector"
    +url: null
    +body: "Hello, we are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the mosfet is irradiated with an external radiation source; its voltage threshold increases, which will be used to determine the radiation dose. I'm currently asking for help on how we measure the voltage threshold. BTW, we are using an n-channel MOSFET (model: IRFP250NPbF). Also in the datasheet provided by the manufacturer, it says here VGS(th)/Gate Threshold Voltage Min: 2.0 ––– Max: 4.0 V. There is a condition here with VDS = VGS, ID = 250 A. Does this mean that to measure the VGS, we need to first satisfy the conditions? To measure the voltage threshold, what node will we use to measure the VGS (th)? Is it at the drain to the source terminal or still at the gate to the source terminal? Feel free to share your thoughts, if you have any. I would also like to add that we have already tried to supply a voltage at the gate with respect to the source terminal. We use a 4 V supply voltage, and when we tried to measure the VDS (drain to source voltage), there was a voltage drop, so we've got a 3.5 V. Also, we are using an Arduino to measure its voltage and a multimeter for checking."
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      date: 2023-07-12 20:23:14.0 +02:00
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      5 => App\Entity\EntryComment {#1665
        +user: App\Entity\User {#260 …}
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        +body: "Using MOSFETs as TID sensors is common enough. A term that you can use for more research is RADFET. The best way to measure threshold voltage is to sweep the gate voltage. In my experience however, if you intend to measure this in a non-lab environment (say, in a satellite), I would recommend that you instead connect the gate to the drain, force a small constant current (maybe 10uA) from the drain to source, and measure Vds (which is equal to Vgs in this configuration). This won't give you the threshold voltage per se, but this will produce a voltage that changes as dose accumulates, is a far easier metric to measure, and is as equally valid as measuring the threshold voltage to determine TID. You can't really predict the shift in threshold voltage according to TID unless your MOSFETs are all from the same batch (manufacturing defects and tolerances), and you need to calibrate them in order to obtain a calibration curve (this is done by simply going to irradiate several (the more the better, I suggest at least 10 for statistical significance). Alternatively, you can buy pre-calibrated ones from companies who make MOSFETs for this intended purpose like Varadis. If you really want to measure the threshold voltage, you could read MIL-STD-750, which outlines how to measure the threshold voltage."
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        -bodyTs: "'10':185 '10ua':71 '750':223 'accord':139 'accumul':108 'altern':189 'batch':150 'best':21 'better':180 'buy':192 'calibr':159,166,195 'chang':105 'common':7 'compani':198 'configur':87 'connect':59 'constant':68 'could':218 'current':69 'curv':167 'defect':152 'determin':127 'done':170 'dose':107 'drain':64,74 'easier':112 'enough':8 'environ':48 'equal':82,119 'experi':35 'far':111 'forc':65 'gate':31,61 'give':91 'go':173 'howev':36 'instead':58 'intend':39,204 'irradi':175 'lab':47 'least':184 'like':206 'make':200 'manufactur':151 'mayb':70 'measur':24,41,78,115,122,213,228 'metric':113 'mil':221 'mil-std':220 'mosfet':2,144,201 'need':157 'non':46 'non-lab':45 'obtain':164 'one':196 'order':162 'outlin':225 'per':96 'pre':194 'pre-calibr':193 'predict':133 'produc':101 'purpos':205 'radfet':19 'read':219 'realli':132,210 'recommend':55 'research':17 'satellit':52 'say':49 'se':97 'sensor':5 'sever':176 'shift':135 'signific':188 'simpli':172 'small':67 'sourc':76 'statist':187 'std':222 'suggest':182 'sweep':29 'term':10 'threshold':25,94,124,137,215,230 'tid':4,128,141 'toler':154 'unless':142 'use':1,14 'valid':120 'varadi':207 'vds':79 'vgs':84 'voltag':26,32,95,103,125,138,216,231 'want':211 'way':22 'won':89 'would':54"
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        +editedAt: null
        +createdAt: DateTimeImmutable @1687177876 {#1612
          date: 2023-06-19 14:31:16.0 +02:00
        }
        +"title": 1118
      }
      4 => App\Entity\EntryComment {#1795
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1720 …}
        +root: App\Entity\EntryComment {#1665}
        +body: """
          Ultimately, yes you will need to bias the gate. If you put the MOSFET in the diode connection mode, the gate will automatically be biased when you force a constant Ids current. While I have never worked with this MOSFET nor with Cs137, I don’t see why it wouldn’t be sensitive. A few notes:\n
          \n
          - This MOSFET is in a TO-247 package, so make sure that you have the front of the MOSFET pointed towards the Cs137 source during irradiation, otherwise the leadframe will likely act as an attenuator, reducing the sensitivity.\n
          - This MOSFET is a HEXFET, which normally aren’t designed for continuous high DC power dissipation (they are meant for switching). So keeping the dissipated power in the FET would be best.\n
          - I’m not sure if there is a difference in general sensitivity between HEXFETs and other MOSFET types like VDMOS or traditional monolithic planar MOSFETs.\n
          - I’m not sure if you already planned this, put generally it is recommended for the MOSFET to have all pins grounded during irradiation. Biasing of the MOSFET can affect its sensitivity (depends on every MOSFET), so having all pins grounded keeps them in a constant state during irradiation (and lets all accumulated charge get shunted to ground, preventing ESD damage).
          """
        +lang: "en"
        +isAdult: false
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          date: 2023-06-27 18:55:34.0 +02:00
        }
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
        ]
        +children: Doctrine\ORM\PersistentCollection {#1718 …}
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        -bodyTs: "'-247':63 'accumul':204 'act':88 'affect':181 'alreadi':158 'aren':102 'attenu':91 'automat':23 'best':126 'bias':7,25,176 'charg':205 'connect':18 'constant':30,197 'continu':106 'cs137':43,79 'current':32 'damag':212 'dc':108 'depend':184 'design':104 'differ':135 'diod':17 'dissip':110,119 'esd':211 'everi':186 'fet':123 'forc':28 'front':72 'gate':9,21 'general':137,162 'get':206 'ground':173,192,209 'hexfet':99,140 'high':107 'id':31 'irradi':82,175,200 'keep':117,193 'leadfram':85 'let':202 'like':87,145 'm':128,153 'make':66 'meant':113 'mode':19 'monolith':149 'mosfet':14,40,58,75,96,143,151,168,179,187 'need':5 'never':36 'normal':101 'note':56 'otherwis':83 'packag':64 'pin':172,191 'plan':159 'planar':150 'point':76 'power':109,120 'prevent':210 'put':12,161 'recommend':165 'reduc':92 'see':47 'sensit':53,94,138,183 'shunt':207 'sourc':80 'state':198 'sure':67,130,155 'switch':115 'toward':77 'tradit':148 'type':144 'ultim':1 'vdmos':146 'work':37 'would':124 'wouldn':50 'yes':2"
        +ranking: 0
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        +visibility: "visible             "
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        +editedAt: null
        +createdAt: DateTimeImmutable @1687884934 {#1692
          date: 2023-06-27 18:55:34.0 +02:00
        }
        +"title": 8525
      }
      3 => App\Entity\EntryComment {#1726
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1721 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "I’m not entirely sure, but I suspect that the die is mounted to the leadframe on the flat side of the package. In this case you should point the flat side towards the source."
        +lang: "en"
        +isAdult: false
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
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        -id: 9161
        -bodyTs: "'case':26 'die':11 'entir':4 'flat':19,31 'leadfram':16 'm':2 'mount':13 'packag':23 'point':29 'side':20,32 'sourc':35 'sure':5 'suspect':8 'toward':33"
        +ranking: 0
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        +visibility: "visible             "
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        +editedAt: null
        +createdAt: DateTimeImmutable @1688845425 {#1728
          date: 2023-07-08 21:43:45.0 +02:00
        }
        +"title": 9161
      }
      2 => App\Entity\EntryComment {#1611
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#1714 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "The wiring is simple enough, see image. Since the gate is connected to the drain, you can measure either Vds or Vgs. They are equal in this configuration so it doesn’t matter. ![](https://lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)"
        +lang: "en"
        +isAdult: false
        +favouriteCount: 0
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          date: 2023-07-08 21:47:13.0 +02:00
        }
        +ip: null
        +tags: null
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          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
        +children: Doctrine\ORM\PersistentCollection {#1716 …}
        +nested: Doctrine\ORM\PersistentCollection {#1739 …}
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        -id: 9162
        -bodyTs: "'/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':36 'configur':28 'connect':12 'doesn':31 'drain':15 'either':19 'enough':5 'equal':25 'gate':10 'imag':7 'lemmy.world':35 'lemmy.world/pictrs/image/31bfe6ff-540e-4281-8ae8-ab7d6683d796.png)':34 'matter':33 'measur':18 'see':6 'simpl':4 'sinc':8 'vds':20 'vgs':22 'wire':2"
        +ranking: 0
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        +visibility: "visible             "
        +apId: "https://lemmy.world/comment/995819"
        +editedAt: null
        +createdAt: DateTimeImmutable @1688845633 {#1598
          date: 2023-07-08 21:47:13.0 +02:00
        }
        +"title": 9162
      }
      1 => App\Entity\EntryComment {#2363
        +user: App\Entity\User {#260 …}
        +entry: Proxies\__CG__\App\Entity\Entry {#1549 …2}
        +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
        +image: null
        +parent: Proxies\__CG__\App\Entity\EntryComment {#2370 …}
        +root: App\Entity\EntryComment {#1665}
        +body: "You will need to provide a voltage of at least the threshold voltage PLUS the minimum voltage of the LM334Z. If the LM334Z circuit by itself doesn’t work, that will be the first problem to figure out. Make sure you completely read through the datasheet [www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734…](https://www.ti.com/lit/ds/symlink/lm334.pdf?ts=1689139734046&ref_url=https%253A%252F%252Fwww.google.com%252F), there are example circuits in it for reference. For the resistor method, keep in mind that the current isn’t constant; the voltage is. Your current is dictated by your resistor and the voltage across it, which is the supply voltage minus the threshold voltage. If your threshold voltage changes as the dose increases (which is the typical behaviour), the voltage across the resistor will change, therefore your current will change, which will generate error in your reading. The only way to minimize this error is to apply a very high voltage (100’s to 1000’s of volts) to the resistor, such that a change in the threshold would become a rounding error."
        +lang: "en"
        +isAdult: false
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          date: 2023-07-12 20:23:14.0 +02:00
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        +ip: null
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        +mentions: [
          "@Lazyhotodogu@discuss.tchncs.de"
          "@blarbasaurus@lemmy.world"
          "@Lazyhotodogu@lemmy.world"
        ]
        +children: Doctrine\ORM\PersistentCollection {#2377 …}
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        -id: 13679
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        +ranking: 0
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        +apId: "https://lemmy.world/comment/1177817"
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          date: 2023-07-12 20:23:14.0 +02:00
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        +"title": 13679
      }
      0 => App\Entity\EntryComment {#2458}
    ]
    -id: 135
    -titleTs: "'detector':4 'mosfet':1 'radiat':3"
    -bodyTs: "'/gate':82 '2.0':86 '250':99 '3.5':212 '4':186 '4.0':88 'add':164 'alreadi':168 'also':69,161,214 'altern':13 'arduino':219 'ask':48 'btw':58 'channel':65 'check':228 'condit':93,115 'current':47 'datasheet':72 'detector':15 'determin':41 'dose':44 'drain':135,198 'drop':206 'explain':18 'extern':29 'feel':149 'first':112 'free':150 'gate':144,176 'got':210 'hello':1 'help':50 'id':98 'increas':35 'irfp250npbf':68 'irradi':26 'like':162 'm':46 'make':4 'manufactur':76 'max':87 'mean':103 'measur':54,106,117,127,195,221 'min':85 'model':67 'mosfet':10,24,66 'multimet':226 'n':64 'n-channel':63 'need':110 'node':122 'provid':73 'radiat':14,30,43 'respect':178 'satisfi':113 'say':78 'share':152 'sourc':31,138,147,181,200 'still':141 'suppli':171,188 'termin':139,148,182 'th':81,130 'thesi':6 'thought':154 'threshold':34,57,83,120 'tri':169,193 'use':9,39,61,125,184,217 'v':89,187,213 'vds':96,197 've':209 'vgs':80,97,108,129 'voltag':33,56,84,119,173,189,201,205,223 'work':21 'would':160"
    +cross: false
    +upVotes: 0
    +downVotes: 0
    +ranking: 1687237046
    +visibility: "visible             "
    +apId: "https://discuss.tchncs.de/post/156149"
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    +createdAt: DateTimeImmutable @1687153046 {#2336
      date: 2023-06-19 07:37:26.0 +02:00
    }
    +__isInitialized__: true
     …2
  }
  +magazine: Proxies\__CG__\App\Entity\Magazine {#1559 …}
  +image: null
  +parent: Proxies\__CG__\App\Entity\EntryComment {#2461 …}
  +root: App\Entity\EntryComment {#1665}
  +body: """
    You will probably need to increase your voltage. I haven’t ever used the LM334, but it will need a minimum voltage across it. I don’t know if you are still using the IRFP250N, but if so it has a threshold somewhere between 2V and 4V for 250uA, so the threshold won’t be as high but it should be close. I would try using 5V if it’s fine with your setup.\n
    \n
    For the suitability of the resistor method, you should do the math on how a change in Vds will affect the current, and then calculate how much this variability in current will affect your readings. If this error/innacuracy is acceptable, then why not.
    """
  +lang: "en"
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    date: 2023-07-10 15:01:48.0 +02:00
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    "@Lazyhotodogu@discuss.tchncs.de"
    "@blarbasaurus@lemmy.world"
    "@Lazyhotodogu@lemmy.world"
  ]
  +children: Doctrine\ORM\PersistentCollection {#2456 …}
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}
 
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