diamond sensor tests for the cms bcm
DESCRIPTION
Diamond Sensor Tests for the CMS BCM. Alexandr Ignatenko. FCAL collaboration meeting May 7, 2008. Overview. BRM system overview Standard set of measurements in Zeuthen Thickness Capacitance I-V characteristic Charge collection distance Results Usual behavior Abnormal cases - PowerPoint PPT PresentationTRANSCRIPT
Diamond Sensor Tests for the Diamond Sensor Tests for the CMS BCMCMS BCM
Alexandr IgnatenkoAlexandr Ignatenko
FCAL collaboration meetingMay 7, 2008
22May 7, 2008May 7, 2008 FCAL collaboration meetingFCAL collaboration meeting 22
OverviewOverview
BRM system overviewBRM system overviewStandard set of measurements in ZeuthenStandard set of measurements in Zeuthen
Thickness Thickness CapacitanceCapacitanceI-V characteristicI-V characteristicCharge collection distanceCharge collection distance
ResultsResultsUsual behaviorUsual behaviorAbnormal casesAbnormal cases
ConclusionConclusion
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The components:
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BCM1, 1.8m
BCM2+BSC2, 14.4m
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Thickness and capacitance measurements Thickness and capacitance measurements
Thickness: mechanically with 10 µm precisionValues 400-430 µm
A sensor assembled in the frame
Capacitance: with LCR meter HP 4263A10.7-12.1 pF
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I-V characteristicI-V characteristic
NN22 atmosphere 0-500-0 V 50V/30 sec steps atmosphere 0-500-0 V 50V/30 sec steps
Voltage source and picoamperemeter: Keithley 487 Voltage source and picoamperemeter: Keithley 487
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Charge collection efficiency = Qmeas/Qind
Charge collection distance CCD = × d
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Detection mechanism
traps
Charge collection distance (CCD)Charge collection distance (CCD)
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CCD setup
9999
~ CCD
CCD = (Mean-Ped)×calib×corr/Nexp
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Typical spectrum
CCD = (MPV-Ped)*calib/Nexp
10101010
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CCD setup
Source holder with collimator
Sensor box
Trigger box
Low voltage power supply
HV supply and picoampearmeter
ResultsNormal behaviorNormal behavior
P28
depumped
pumped
negative positiveMay 7, 2008May 7, 2008 1111FCAL collaboration meetingFCAL collaboration meeting
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CCD vs dose, pumping
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The current in the sensor circuit was The current in the sensor circuit was monitoredmonitored
CCD dependence on dose, irradiationCCD dependence on dose, irradiation @ 0.7 Gy/h@ 0.7 Gy/h
irradiation started
1313
1313
CCD dependence on time for the fully pumped sensors
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The current in the sensor circuit was The current in the sensor circuit was monitoredmonitored
After additional 60 mGy
200 V applied
400 V applied
Abnormal casesAbnormal cases
P18
Depumped state Pumped state
Currents up to hundreds of nA at high
bias voltagesMay 7, 2008May 7, 2008 1414FCAL collaboration meetingFCAL collaboration meeting
P 45
depumped
pumped
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Currents had changed in time even without irradiation
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ConclusionConclusion 25 samples have been investigated25 samples have been investigated
The characterization of each sample The characterization of each sample has been givenhas been given
6 sensors have shown unstable 6 sensors have shown unstable
currentscurrents
The parameters of the sensor were The parameters of the sensor were reproduciblereproducible