05/16/2011 coincidence test

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	$7513\pm$	60 min	$\pm$
PS2	$9036\pm$	60 min	$\pm$
PS1+PS2	$251\pm$	60 min	$(\pm)\cdot 10^{-2}$

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]