CMS week – December 8-12, 2003 1

TOB sensor qualityTOB sensor qualityTOB sensor qualityTOB sensor quality

Regina DeminaUniversity of Rochester

CMS week – December 8-12, 2003 2

OutlineOutlineOutlineOutline

• Stability of IV

• Leaky strips

CMS week – December 8-12, 2003 3

IV vs timeIV vs timeIV vs timeIV vs timeIdb vs Ifermi @ 400V - 2001

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I Production DB (microA)

I F

erm

i (m

icro

A)

Idb vs Ifermi @ 400V - 2002

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I Production DB (microA)

I F

erm

i (m

icro

A)

Idb vs Ifermi @ 400V - 2003

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I Production DB (microA)

I F

erm

i (m

icro

A)

Current at 400V FNAL remeasurement vs DB

3/61 failed on retest

0/65 failed on retest

17/250 failed on retest

CMS week – December 8-12, 2003 4

IVCV no vacuum effect so farIVCV no vacuum effect so farIVCV no vacuum effect so farIVCV no vacuum effect so far30210431830811

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Measurement 1

Measurement 2

No Vacuum

Sensor left on chuck for several hours between measurements 1 and 2.Just needed rest?

Istrip

-20

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measurement1

measurement2

CMS week – December 8-12, 2003 5

I leak and I stripI leak and I stripI leak and I stripI leak and I strip

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No vacuum 1 old

No vacuum 2 new

Vacuum old m1

No vacuum old m2

Vacuum new m1

vacuum new m2

T = 21.7 CH = 13%

Istrip

0.01

0.1

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measurement1

measurement2

CMS week – December 8-12, 2003 6

SummarySummarySummarySummary

• Some instability of I leak vs time is observed

• 2002 sensors seem to be the worst, fraction of originally passed sensors failing retests –6.8%

• 2003 sensors look better (but maybe not enough time)

• I leak increase seems to be related to leaky strip development