Investigation and development of microchannel plate phototubes

The development of photomultiplier tubes (PMTs) with microchannel plates (MCPs) in Novosibirsk began 10 years ago. PMT based on MCP is compact, has a high time resolution and can work in a strong magnetic field. Eighty such PMTs have been working in ASHIPH counters of the KEDR detector since 2003. Now we are focusing on the MCP PMT lifetime improvement. It was shown that the photocathode lifetime cannot be expressed unambiguously in units of the collected anode charge. Two new models of PMTs were developed: PMT with the photocathode protective layer and PMT with three MCPs. The comparison of the photocathode aging of both new and one old models has been done.