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 nanosecond performance study.

Location of Muon Detection 36: N, 122: W

Methodology Actual run time: 1.77 x 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 (ф CR ) as a function of time over a period of 15 hours.

Flux Events/area/ time Average value: 8651 events/m 2 /min Area of paddles:.075 m 2 Calculated Average Flux: ф CR = 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