A 256 channel photon counting module using a square microchannel plate PMT in a tight packing envelop achieving

Abstract

Photek have developed a square microchannel plate (MCP) photomultiplier tube (PMT) using 6 μm pore MCPs to achieve superior timing, compared to the previous generation which used 15 μm pores. The native anode pattern is 64 × 64, but for this module the pattern is ganged to a 16 × 16 design using an epoxy bonded PCB giving an anode size of 3.3 × 3.3 mm in a 53 × 53 mm active area. The electronic front-end is the TOFPET2d ASIC from Petsys Electronics, a combined amplifier/discriminator/TDC with 30 ps time bins and capable of 480 kHz per channel count rate, with sufficient dynamic range to allow for the gain variation inherent in large area MCP-PMTs. The outer envelope of the combined PMT and electronic front-end package allows for close packing on 4 sides with outer dimensions of 60 × 62 mm giving a 76% fill factor. We present results showing the combined performance of the PMT and TOFPET2d ASIC and the uniformity of single photon timing accuracy.