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تسجيل مستخدم جديدAn accurate measurement of PMT TTS based on the photoelectron spectrum
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The water Cherenkov detector array (WCDA) for the large high altitude air shower observatory(LHAASO) will employ more than 3600 hemisphere 8 inch photomultiplier tubes (PMT). The good time performance of PMT, especially the transit time spread (TTS), is required for WCDA. TTS is usually defined as the TTS of single photoelectron, and usually determined by using single photoelectron counting technique. A method using the photoelectron spectrum is researched for the measurement of TTS. The method is appropriate for multi-photoelectrons and makes it possible to measure the TTS of different photoelectrons at the same time. The TTS of different photoelectrons is measured for Hamamatsu R5912 with the divider circuit designed in specifically. The TTS of single photoelectron is determined to 3.3 ns and satisfies the requirement of WCDA.
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Results are presented from radioactivity screening of two models of photomultiplier tubes designed for use in current and future liquid xenon experiments. The Hamamatsu 5.6 cm diameter R8778 PMT, used in the LUX dark matter experiment, has yielded a
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