05/19/2011 n's detector threshold calibration source/(w/source)

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Revision as of 15:26, 3 June 2011 by Shaproma (talk | contribs)
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Below are my counts rate measurements as function of threshold voltage for n's detector. The source was CF252. The distance between source and n's PMT was about 50 cm. The counts rate was calculated as:

[math]\mbox{Rate} = \frac{N_{\mbox{source}} - N_{\mbox{w/source}}}{\mbox{Time}}[/math]


First I did my calibration for power supply voltage -1250 V:

Det1 calibraton source 1250V.png Det1 calibraton source 1250 log.png


Second I did my calibration for power supply voltage -1500 V:

Det1 calibraton source 1500V.png Det1 calibraton source 1500 log.png


And bellow I overlay both cases (-1250 V and -1500 V)

Det1 calibraton source 1250 1500.png Det1 calibraton source 1250 1500 log.png


Let's recalculate data using the formula:

[math]\mbox{Ratio} = \frac{R_s - R_{w/s}}{R_{w/s}}[/math]


There are no any plateaus, so what is the threshold should be?