Performance studies of microchannel plate PMTs

In the P ¯ ANDA experiment at FAIR, Cherenkov detectors using the DIRC principle are foreseen for particle identification. Micro-channel plate (MCP) photomultipliers (PMT) have been proven to be promising photo sensor candidates for this task. They provide a high gain for single photon detection, an excellent time resolution and a high resistivity against magnetic fields. The drawbacks on these devices are their rate capability and lifetime. Various types of MCP-PMTs were studied. s paper the focus will be on the performance of the R10754-00-L4 from Hamamatsu and two Photonis devices, the XP85112 and XP85012. For these three devices a single photon time resolution of better than 40 ps ( σ ) was measured. Concerning the photon rate capability, the Photonis XP85112 was stable up to about 2 MHz / cm 2 and the Hamamatsu up to 7 MHz / cm 2 . Also time resolution and gain were investigated in magnetic fields up to 2 T. After these studies were done, lifetime measurements of the two Photonis devices were started. The peak quantum efficiency (QE) was determined to 24%. With an average collected charge of 1 – 5 mC / cm 2 per day, a total integrated charge of 305 mC / cm 2 (XP85112) and 135 mC / cm 2 (XP85012) were put on these devices. The gain and QE were determined in irregular intervals of 1–3 days.