05/12/2011 random coincidence cosmic test

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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 1.

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 (30 cm away)	[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 random coincidence cosmic ray test 2.

But now the distance between PS1 and PS2 is about 5 cm. And let's look on the coincidence signal between PS1 and PS2:

	total counts	time	counts/min	counts/sec
PS1	[math]9101\pm[/math]	60 min	[math]\pm[/math]	[math]\pm[/math]
PS1	[math]11394\pm[/math]	60 min	[math]\pm[/math]	[math]\pm[/math]
PS1+PS2 (5 cm away)	[math]8\pm[/math]	60 min	[math]\pm[/math]	[math]\pm[/math]

And below my scope pictures of no so rear event as before:

So what we are measured?

○ purely random events from different reaction?. But why does rate depend from distance? Statistical fluctuation?

○ some of them are from air shower originated from one particle. Now if detectors located closer to each other the rate should be higher because the detectors are closer to initial reaction.

, Sadiq did something at that time with gamma source. Maybe that effect somehow my measurements.