Sep 13, 2007 CALICE Collaboration Meet ing Prague 1 Long term test of Long term test of LED pulsing LED pulsing Long LED system stability measurement Aging of part of optical system Future plans Jaroslav Zalesak, Jan Smolik Institute of Physics ASCR, Prague
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Sep 13, 2007CALICE Collaboration Meeting Prague 1 Long term test of LED pulsing Long LED system stability measurement Aging of part of optical system.
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Sep 13, 2007 CALICE Collaboration Meeting Prague
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Long term test of LED Long term test of LED pulsingpulsing
Long LED system stability measurement Aging of part of optical system Future plans
Jaroslav Zalesak, Jan Smolik Institute of Physics ASCR, Prague
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Setup: in-box viewSetup: in-box view
CMB - LED driver + PIN ampl + temp sensors
VME DAQcontrolled with PC
APD +electronics
black box
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Setup: CMB – LED + PINSetup: CMB – LED + PIN
UV LED PIN
CAN busV-calib +T-calib
signals
High LED light intensity
LED driver pulsing @ 1kHz
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Fiber +APD detectorFiber +APD detector
Scintillator tile w/ quarter circle groove- air gap to attenuate height of signal amplitude to APD
APD Ubias = 270Vvery low gain (~3)
↔ pin diode
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Measurement: temperatureMeasurement: temperature
• Long time period: 1 month → >2 billion pulses
• Large variations in temperature within 7 K• 3 sensors (2 @ CMB, 1 nearby APD) • same time history
• full correlated
Sep 13, 2007 CALICE Collaboration Meeting Prague
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ADP + PIN responseADP + PIN response
APD
PIN
• good correlation ADP-PIN response
• very similar time response• PIN more noisy due to low signal ampl
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Relative responseRelative response
• normalized at average over whole time scale• variation in response at level ± 10%
• visible time slope fall in PD responses• light intensity decrease in time
APD
PIN
Tempinverse
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Time stabilityTime stability
• PIN / APD – Temperature correlation• unexpected result -> time instability
• light intensity decrease in time – PIN & APD response decreasing
Sep 13, 2007 CALICE Collaboration Meeting Prague
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APD – PIN correctionAPD – PIN correction
• PIN correction (dividing responses) to APD signal as used in LED calibration procedure• almost flat result < 2% • difference from uniformity ↔ not same PIN / low gain APD temperature dependence• small jumps in time = (probably PIN) electronics instability
Sep 13, 2007 CALICE Collaboration Meeting Prague
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SummarySummary
Long time stability of LED-PIN-APD electronic-optical system was measured over one month Large temperature variation cause big variations in response of optical system -> PIN – low gain APD and/or temperature dependence PIN-APD system can correct on long time instability of whole system Probably visible aging effects of optical fibers
Sep 13, 2007 CALICE Collaboration Meeting Prague
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Future plansFuture plans
Test for two fibers with different lengths to study aging of fibers, avoiding possible aging of LED
Setup prepared for future (EUDET) CMB with new LED driver
Study of ‘party’ side-emitting fiber leading along many scintillator tiles with old/new LED driver