Initial Tests of DHC Tower

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Initial Tests of DHC Tower
Kurt Francis, Donna Kubik - Northern Illinois
University
Update - 09/03/2003
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Current Status

• DHC Tower is operating with 4 layers of cells
• Trigger is based on 3 way coincidence of two
  external PMT/scintillator paddles and Dynode 12
  of one PMT
• Tower is collecting cosmic rays at low rate

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Summary

• Low rate of about 1.2 events/minute (compared to
  2 events/minute with test stand) - due to the
  paddles having a greater separation then with
  earlier setup 1.25m compared to .45m
• Using dynode 12 from one of the multichannel PMTs
  is a good way to generate additional trigger
  signal
• We needed to adjust the delay from the dynode 12
  signal because the data pulse was not being
  integrated inside trigger/gate
• Three of the cells/ channels do not seem to work
  - still need to debug
• MIP peak close to pedestal - low amount of light
  due to lower HV setting of PMT (900V) and smaller
  fibers
• Pedestal is 86 of events -gt data14 of events
  or about 1/7 - which is expected since there are
  7 cells -gt good efficiency

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Next Steps

• Keep improving ROOT based analysis software
• Debug non-working channels
• Collect more statistics
• Find the single photoelectron peak for the 2 PMTs
  we are currently using so we can determine the
  Light Yield
• Do more careful tests to determine efficiency
• Attempt to track particle through four layers