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Irradiation in KarlsruheIrradiation in Karlsruhe

• The Karlsruhe-Probestations

• Procedure of Irradiation

• Results

• Future annealing studies

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The ProbestationThe Probestation

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Cold measurementsCold measurements

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The SoftwareThe Software

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ProcedureProcedure• Measurements of sensors

– @ 20°C– @ rel. humidity < 30%– IV & CV– Ileak – Rpoly (2V) – CC (100Hz)

– Pinhole (10V) – Rint (0-0,5V) >10G

– Cint (1MHz)

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ProcedureProcedure

• Bias connections for irradiation (conductive rubber & bonds)

• Irradiation– 34 MeV-protons– Fluence

• Annealing – @ 60 °C & 80 min– Mistake: annealing of sensors in the envelopes

• Same measurements as before irradiation, but– @ -10°C & dew point << -10°C (39°C)

21

21 14

,14

, 108,0103cm

nbarreloutereqcm

nbarrelinnereq

MeVMeV

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Alpha @ -10°CAlpha @ -10°C

cmA

VI

C eq

C 1720 10420

??10

10

eq

C

VI

C 2010 20

10 C

C

II

C

From literature

cmA

CKK

CeTI

eTIC

KKBkeV

CTBkeV

C

CTBkeV

C

e 1820

2

293263

2010

102,12631

2931

24,1

2024,1

2200

1024,1

2100

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Leakage current before and Leakage current before and after irradiationafter irradiation

• Guardring connected (for defined Volume)• Increase of leakage current as expected• Breakdown voltage >1200V

irradII

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Depletion voltage before and Depletion voltage before and after irradiationafter irradiation

• Annealed @ 60°C and 80 min• But in the envelopes !

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Leakage current after IrradiationLeakage current after Irradiation

Low FluenceHigh Fluence

Increase of leakage current depends on fluence as aspected

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Rpoly after irradiationRpoly after irradiation

0V

1V

100V

No dependence on bias conditions !

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CC after IrradiationCC after Irradiation0V 100V

1V No dependence on bias conditions !

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Cint after irradiationCint after irradiation

1V

No increase of Cint seen

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IQC-rampsIQC-ramps

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Annealing curvesAnnealing curves

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Annealing @ 50°C ?Annealing @ 50°C ?• Problem of annealing studies @ 60 °C

• high stability of temperature needed• Effects of heating up and cooling down become important

• Problem of annealing studies @ 40 °C• long time constants

T[°C] -10 -7 0 10 20 40 60 80

a 306d 180d 53d 10d 55h 4h 19min 2min

b 1/134 1/78 1/23 1/5 1 16 174 1490

T[°C] -10 0 10 20 40 60 80 100

y 516y 61y 8y 475d 17d 1260min 92min 9min

b 1/396 1/47 1/6 1/1 29 544 7430 76650

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Time constants @ 50°CTime constants @ 50°C• Fit from values in the Moll-Thesis:

• Beneficial annealing: 65 min• Reverse annealing: 5162 min

Annealing steps: 15 min ?

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ConclusionsConclusions

• Measurements @ -10°C after irradiation

• Annealing without envelopes !

• No dependence of stripvalues from bias conditions

• Next irradiations without bias ?