05/16/2011 coincidence test

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Set up like that:


the distance between PS and n's PMT is abot 50 cm

The voltages, thresholds and widths are as below. Note: I increased my thresholds for PS1 and PS2 from 80 mV up to 100 mV according to my previous calibration threshold line.

PMT voltage, V threshold, mV discr. width, ns
PS1 -1000 -100 50
PS1 -1000 -100 50
n's -1500 -200 10

First let's do the PS1+PS2 coincidence test

counts time counts/sec
PS1 [math]7513\pm86.5[/math] 60 min [math]2.09\pm0.02[/math]
PS2 [math]9036\pm95.1[/math] 60 min [math]2.51\pm0.03[/math]
PS1+PS2 [math]251\pm15.8[/math] 60 min [math](6.9\pm0.4)\cdot 10^{-2}[/math]

Second do the PS1+PS2+n's coincidence test

The ratio of (PS+PS2) rate to (PS+PS2+n's) rate is

[math]\frac{7.7}{4.9} = 1.6[/math]