05/13/2011 coincidence test

Go Back

Set up like that:

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.

1. The distance between PS and n's PMT is about 80 cm

	counts	time	counts/sec
PS1	[math]\displaystyle{ 2823\pm53.1 }[/math]	20 min	[math]\displaystyle{ 2.35\pm0.04 }[/math]
PS2	[math]\displaystyle{ 3091\pm55.6 }[/math]	20 min	[math]\displaystyle{ 2.58\pm0.05 }[/math]
PS1+PS2	[math]\displaystyle{ 93\pm9.6 }[/math]	20 min	[math]\displaystyle{ (7.7\pm0.8)\cdot 10^{-2} }[/math]

2. The distance between PS and n's PMT is about 50 cm

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

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

1. The distance between PS and n's PMT is about 80 cm

	counts	time	counts/sec
PS1	[math]\displaystyle{ 3229\pm56.8 }[/math]	20 min	[math]\displaystyle{ 2.69\pm0.05 }[/math]
PS2	[math]\displaystyle{ 3192\pm56.5 }[/math]	20 min	[math]\displaystyle{ 2.66\pm0.05 }[/math]
PS1+PS2+n's	[math]\displaystyle{ 59\pm7.7 }[/math]	20 min	[math]\displaystyle{ (4.9\pm0.6)\cdot 10^{-2} }[/math]

2. The distance between PS and n's PMT is about 50 cm

	counts	time	counts/sec
PS1	[math]\displaystyle{ 7700\pm87.7 }[/math]	60 min	[math]\displaystyle{ 2.14\pm0.02 }[/math]
PS2	[math]\displaystyle{ 9060\pm95.2 }[/math]	60 min	[math]\displaystyle{ 2.52\pm0.03 }[/math]
PS1+PS2+n's	[math]\displaystyle{ 214\pm14.6 }[/math]	60 min	[math]\displaystyle{ (5.9\pm0.4)\cdot 10^{-2} }[/math]

The scope pictures of coincidence events looks like:

PS1+PS2 event looks like:	PS1+PS2+n event looks like: