Difference between revisions of "August 16, 2007 - Cosmic Telescope"

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Revision as of 17:44, 17 August 2007

Today we are continuing our plateauing of the scintillators. For this next test, we are replateauing the bottom scintillator but with its threshold at 225 mV instead of 275 like before while keeping the top scintillator at 275 mV. We are decreasing the threshold because we are still not seeing the count rate that we expect, which is about 8 coincidence counts per minute. Since the count rate in our past experiments is too low, it can be deduced that the threshold is too high and therefore we are not reading some of the cosmic rays that pass through.

Plateau of Bottom Scintillator
Time HV on top scint. HV on bottom scint. Singles Count (on top) Coinc. Counts Coinc. per minute
30 min 1300 1450 2831 111 3.7
30 min 1300 1400 2880 104 3.47
30 min 1300 1350 3000 101 3.37
30 min 1300 1300 3164 68 2.27
90 min 1300 1250 3121 77 2.57
30 min 1300 1200 3182 47 1.57
30 min 1300 1150 3100 16 0.533
30 min 1300 1100 3141 3 0.1

This next data set is from the replateau of the top scintillator with both scinitillators thresholds set at 225 mV.

Plateau of Top Scintillator
Time HV on top scint. HV on bottom scint. Singles Count (on top) Coinc. Counts Coinc. per minute
30 min 1300 1450
30 min 1300 1400
30 min 1300 1350 4088 87 2.9
30 min 1300 1300 4397 93 3.1
90 min 1300 1250 2120 75 2.5
30 min 1300 1200 1737 81 2.67
30 min 1300 1150 893 70 2.33
30 min 1300 1100 347 40 1.33