Difference between revisions of "05/19/2011 n's detector threshold calibration source/(w/source)"

Revision as of 21:16, 19 May 2011

By Dr. Dale suggestions to make threshold adjusting of n's detectors according to as function of threshold I did the following test.

Set up like that:

The voltages, thresholds and widths are:

@@ Line 2: / Line 2: @@
-Because is something wrong I decided to measure the counts rate as function of threshold energy. Maybe my threshold was incorrect.
+By Dr. Dale suggestions to make threshold adjusting of n's detectors according to <math>(/mbox{RATE_{source}} - <math>/mbox{RATE_{source}})</math> as function of threshold I did the following test.
-Below are my results for n's detector with HAMAMATSU PMT (-1500 V):
+Set up like that:
-[[File:Det1 callibration.png | 1000 px]]
+[[File:Detector1.png | 400px]]
+The voltages, thresholds and widths  are:
-So it looks like my previous threshold value (-500 mV) was not good. '''Let's set it up the -200 mV.''' And let's see does the n's detector sensitive to the source. The same set up and distances as before.
 {| border="1" cellspacing="0" style="text-align: center; width: 800px; height: 100px;"
 ! scope="col" width="50" |
-! scope="col" width="50" | counts/sec (5 min test), no source
+! scope="col" width="50" | PMT voltage, V
-! scope="col" width="50" | counts/sec (5 min test), with source on the top of PS1
+! scope="col" width="50" | threshold, mV
+! scope="col" width="50" | discr. width, ns
+|-
+!PS1
+| -1000|| -100|| 50
+|-
+!PS1
+| -1000|| -100|| 50
 |-
 !n's
-|19.89<math>\pm</math>0.26   (total 5966 cnts) || 58.84<math>\pm</math>0.29   (total 17652 cnts)
+| -1500|| varying||  10
 |}
-So now we see the source. The ratio are:
- <math>\frac{Rate_{source}}{Rate_{w/source}} = \frac{58.84}{19.89} = 2.96 </math>