Cosmic Ray Detection
Experimental Report
Alisa Bredensteiner
Endeavour Institute
Santa Cruz Institute of Particle Physics
Quarknet
August 2010
Objective 1:
To establish the relative
accuracy of the newly
assembled CRMD (DAQ
#6416) through analysis of
a 5.4 x 1013 nanosecond
performance study.
Location of Muon Detection
36:59.909452 N, 122:03.625697 W
Methodology
Actual run time: 1.77 x 1012 nanoseconds (approx. 30 minutes)
Data Settings:
• 4 stacked scintillator paddles with a fixed separation
distance of about 3 cm
• a2-fold coincidence level at a 40 ns pre-trig rate with a
gate width of 100 ns
Voltage Settings:
Manually adjusted to allow for a 40 Hz singles rate
Objective 2:
To evaluate the
cosmic ray flux (фCR)
as a function of
time over a period
of 15 hours.
Flux
Events/area/ time
Average value:
8651 events/m2/min
Area of paddles: .075 m2
Calculated Average Flux:
фCR = 10.8 muons/s
Bin width = 60 seconds
Error Analysis
Absolute uncertainty
One standard deviation from the mean
√N = √8651 = 93
relative uncertainty = 1.08%
Maximum deviations
8053 deviates by 598 (6.9%)
9253 deviates by 602 (7.0%)
Discussion and Conclusions
The deviations of muon detection per minute
are greater than an expected random
sampling of data.
This deviation seems to confirm that there is not
a uniform bombardment of cosmic rays.
Further calibration of the voltage settings would
be beneficial