Cosmic Ray Test Stand with Scintillating Cells for Digital Hadron Calorimeter

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Cosmic Ray Test Stand with Scintillating Cells
for Digital Hadron Calorimeter
As of 9am 05/28/2003
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Status

• Determined single electron peak - two checks to
  justify calling it a single photoelectron peak
• as I reduce light average drops but distance from
  pedestal remains same
• comparison of Oscilloscpe captures
• Also determined that the cause of bad channels in
  previous data sets was due to QDC

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Used 3 layers of paper to attenuate signal and
changed voltage Peak remains at same position as
voltage is decreased
8.25V
9.75V
7.00V
9.00V
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Comparison of Oscilloscpe captures
Sample with gate with 2 layers of filter paper
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Sample with gate with 3 layers of filter paper
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Summary

• These two checks lead me to think that this IS a
  single photo-electron peak
• Set pulse generator to 22.3ns pulse width, 9.75V
  and 3 layers of white paper as attenuator between
  LED and PMT photocathode
• For Channel 6 Pedestal76, S.P.E.Peak 100, MIP
  peak439
• Therefore we have a light yield of 15 P.E.
• Also, using upper 16 channels of QDC I can get
  collect data from all 14 cells (the lower 16
  channels only had 13 working channels)

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Light yields for 14 channels based on ESTIMATES
of single electron and MIP peaks.
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Next Steps

• Collect pedestal only data for PMT connected to
  upper 16 channels
• Get better determination of single electron and
  MIP peaks (using PAW after subtracting pedestal)
• Refine calculation of Light Yield
• Subtract variations in channels to get properties
  of cells
• Would like to collect one more long weekend of
  data with absorber