05/12/2011

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The powers are:

PS1 and PS2:  -1000 V (the old 2-channel TENNELEC TC952)
n's: -1100 V (the new 2-channel C.A.E.N N471)

The thresholds are:

PS1 and PS2:  -80 mV
n's: -200 mV

The discriminator widths are:

PS1: -20 ns
PS2: -10 ns
n's: -20 ns

Let's do the random coincidence cosmic ray test. PS1 and PS2 is about 30 cm away from each other. And let's look on the coincidence signal between PS1 and PS2:

	total counts	time	counts/min	counts/sec
PS1	[math]10247\pm101.2[/math]	70 min	[math]146.4\pm1.44[/math]	[math]2.44\pm0.02[/math]
PS1	[math]12969\pm113.9[/math]	70 min	[math]185.3\pm1.63[/math]	[math]3.09\pm0.03[/math]
PS1+PS2	[math]3\pm1.7[/math]	70 min	[math]0.043\pm0.024[/math]	[math]0.0007\pm0.0004[/math]

And below my scope pictures of this rear event:

Let's do the 2n correlation test with CF252 source. The voltages and thresholds are the same. First the set up is like:

PS1 and PS2 are parallel to each other and are faced to the source.

the CF252 source in the middle

the distance between PS1(PS2) and source is 6 cm

The total number of events (2n fission events + random coincident) are:

	total counts	time	counts/min	counts/sec
PS1	[math]255977\pm505.9[/math]	10 min	[math]25597.7\pm50.6[/math]	[math]426.63\pm0.84[/math]
PS1	[math]421917\pm649.5[/math]	10 min	[math]42191.7\pm64.9[/math]	[math]703.19\pm1.08[/math]
PS1+PS2	[math]1224\pm34.9[/math]	10 min	[math]122.4\pm3.5[/math]	[math]2.04\pm0.06[/math]

Second the set up is like:

PS1 and PS2 are perpendicular to each other and are faced to the source.

the CF252 source in the middle

the distance between PS1(PS2) and source is 6 cm

The total number of events (2n fission events + random coincident) are:

	total counts	time	counts/min	counts/sec
PS1	[math]250116\pm500.1[/math]	10 min	[math]25011.6\pm50.0[/math]	[math]416.86\pm0.83[/math]
PS1	[math]414774\pm644.0[/math]	10 min	[math]64.4\pm64.9[/math]	[math]691.29\pm1.07[/math]
PS1+PS2	[math]1359\pm36.9[/math]	10 min	[math]135.9\pm3.7[/math]	[math]2.26\pm0.06[/math]