Difference between revisions of "Test Setup for SiPMs"

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m (Test Items and Instruments Needed)
m (Cross-Talk/After Pulsing)
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# Formalism to extract cross-talk is still needed to be derived, effect of pile up and after pulsing needed to be taken into account.
 
# Formalism to extract cross-talk is still needed to be derived, effect of pile up and after pulsing needed to be taken into account.
  
* ADC method (being tested, 30/80 done)
+
* ADC method '''(being tested, 30/80 done)'''
 
# Same method as '''pulse mode''' discussed in the PDE measurement
 
# Same method as '''pulse mode''' discussed in the PDE measurement
  

Revision as of 08:18, 18 March 2011

Test of First Article of Hamamatsu SiPMs at JLab

Time Line

  1. Mid Feb.2012: 10-20pcs partial shipment of first article units
  2. Mid Mar.2012: Delivery remainder first article units (60-70pcs)
  3. End Apr.2012: First article approval
  4. End Jul.2012: 1st delivery 500pcs
  5. End Aug.2012: 2nd delivery 500pcs
  6. End Sept.2012: 3rd delivery 120pcs

LabVIEW Programs and Data Directory

Directory

LabVIEW programs and acquired data are stored on sipm_pc.jlab.org in ARC building room 628.

  • Directory for LabVIEW programs: C:\SiPM_Test\LabVIEW
  • Directory for QDC data: C:\SiPM_Test\Data\QDC
  • Directory for instrument's manuals: C:\SiPM_Test\Manuals
  • Directory for instrument's drivers: C:\SiPM_Test\Drivers

LabView Programs

  • DAQ_Control.vi
    • DAQ Control.png
    • Performs multi-channel DAQ with V792 VME QDC module
    • Data saved in C:\SiPM_Test\Data\QDC and organized with directories named by the starting time
    • Each directory contains the following files:
      • Settings.txt: settings for the DAQ session
      • Raw_Data.txt: raw data file of individual events of active channels, two columns: channel number, ADC channel
      • Histo_xxx.txt: individual or stacked histograms of active channels, two columns: ADC channel (0-4095), count
      • Readings.txt: readings of voltage, current and temperature during DAQ, five columns: relative time (s), set voltage (V), output voltage (V), draw current (nA), temperature (C)
  • VI_Curve.vi
    • VI Curve.png
    • Performs V-I curve measurement of SiPMs
    • Data saved in C:\SiPM_Test\Data\VI_Curve and organized with directories named by the starting time
    • Each directory contains the following files:
      • Settings.txt: settings for the scan
      • Data.txt: readings of voltage, current and temperature during measurement, five columns: relative time (s), set voltage (V), output voltage (V), draw current (nA), temperature (C)

Analysis Code

  • replay.C
    • Sipm fit sample.png
    • Sipm uniformity sample.png

Test Results

Test Items and Instruments Needed

General Devices

Gain (being tested, 30/80 done)

  1. Measure ADC spectrum w. or w./o light source
  2. Measure distance between peaks, calculate the corresponding charge and then gain

Photo Detection Efficiency (PDE) (being tested, 30/80 done)

  • Continuous method (DC mode): overestimated due to cross-talk and after pulsing
  1. Measure draw current with calibrated light input
  2. Divide current by gain and photon flux to get "PDE"
  • Pulse mode
  1. Measure ADC spectrum triggered by calibrated pulse light source
  2. Fit the spectrum by the function derived here to extract detected number of photons and cross-talk/after pulsing
  3. Divide the detected number of photons by input to get PDE

Cross-Talk/After Pulsing

  • Cross-Talk and After Pulsing are sometimes mixed, in this context they are defined base on the timing:
  1. Cross-Talk means fast secondary signals which happen almost simultaneously with the primary signal which are likely due to the secondary photon generated by the primary signal leaked to adjacent pixels.
  2. After Pulsing means slow secondary signals which happen after the primary signal which are likely due to the delayed release of trapped electrons.
  • Threshold method
  1. Pure measurement with dark noise
  2. This method is mainly sensitive to Cross-Talk.
  3. Set threshold of counter at 0.5, 1.5 and 2.5 photon electrons, compare the rates at different rates to extract Cross-Talk.
  4. Formalism to extract cross-talk is still needed to be derived, effect of pile up and after pulsing needed to be taken into account.
  • ADC method (being tested, 30/80 done)
  1. Same method as pulse mode discussed in the PDE measurement
  • Flash method
  1. Use Oscilloscope or Flash ADC to record the time spectrum with very weak but instantaneous light input (laser for example),
  2. By comparing the shape of the time spectrum from the single photon events with all events to extract the after pulsing
  3. Such a method was discussed in SiPM radiation test

Test of First Article of Hamamatsu SiPMs at Regina

Time Line