Speaker
Description
This detector R&D effort focuses on the development of long-life microchannel plate (MCP) photomultiplier tubes (PMTs) capable of high rate operations. MCP-PMTs typically use two compact lead glass plates with many small holes (pores) ~$10 \mu m$ under high voltage to provide electron multiplying functionality. The compact and segmented MCP-PMTs have the capacity to be photon detection devices of immense utility in high energy physics experiments and elsewhere due to their ability to detect one or more photons with excellent spatial and temporal resolution, and their ability to maintain a high level of performance when subjected to large magnetic fields. Their principal limitation has been a loss in efficiency of producing primary electrons (quantum efficiency) with usage, compromising their ability to operate in high rate environments. This QE degradation is typically attributed to positive ions damaging the photocathode. Attempts to increase the lifetime include ALD (atomic layer deposition) to suppress the emission of positive ions, active ion barriers to keep positive ions from reaching the photocathode, and use of alternative MCP’s that have less positive ion emission. Studies of the after-pulses created by the positive ions and their correlations with device lifetime for several different types of MCP-PMT are reported.
