Digital Hadron Calorimeter Cosmic Ray Test Stand

1
Digital Hadron CalorimeterCosmic Ray Test Stand
2
Status

• Multichannel system is working
• Good data on 12 channels but 2 channels very low
  gain
• Switched to unused channels over the weekend
  don't know results yet
• 1 other channel has fiber damaged
• Lightning caused computer to reset need to get
  UPS
• Changed software to save data every hour

3
Analysis Software

• Wrote my own software using Visual Basic to
  display data
• Can display by data by cell or by PMT channel
• Can switch between top layer and bottom layer of
  cells
• Show small histogram bin5
• Show large histogram bin1
• Primitive method of finding pedestal, pedestal
  cutoff, first peak cutoff
• Scatter plots of all data, data above pedestal
  cutoff, data above first peak cutoff

4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
Summary of Results

• Most show two peaks one of them is close to
  pedestal
• Is first peak single photoelectron, crosstalk, or
  noise?
• Not noise because I took samples with PMT covered
  by black paper and only get narrow pedestal
• Crosstalk can be
• optical crosstalk in cells
• electrical crosstalk in PMT
• Way to be sure if electrical crosstalk is to use
  LED to stimulate one channel and study the
  effects on nearby channels
• First curve goes away when PMT HV is reduced from
  1000V to 800V
• If first peak is single electron then light yield
  12 photoelectrons

9
Scatter Plots

• Also have scatter plots
• Can set the channel for the X-axis and then
  select top and bottom layers separately
• For example using Channel 4...

10
Ch4 vs
No pedestal
11
No pedestal and no first curve
12
No pedestal and no first curve
13
Next Steps

• Look at data from weekend with unused channels
• Stimulate PMT channel with PMT to determine
  electrical cross talk
• Enhance software
• Collect data with absorber