FY2004 Measurments
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We are measuring the PMT Gain, P/V ratio, noize rate etc in a freezer box under extremely low temperature environment down to -40C. The left figure shows an example. This is the ADC spectrum. One can clealy seen the single photo-electron peak. The blue shaded region shows the case when we put a diffuser on the UV LED light sources while the black dots correponds to the case when the LED illuminates only the central region of a PMT. |