Simulation of electron transport in a catoptric photomultiplier tube concept for large rectangular scintillator crystals

• Published in: Journal of instrumentation 2024-04, Vol.19 (4), p.P04025
• Main Authors: Beavers, J., Huddleston, K., Hines, N., McNeil, W.
• Format: Article
• Language: English
• Subjects: Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc); Electron multipliers (vacuum); Electron transport; Form factors; Photocathodes; Photoelectrons; Photomultiplier tubes; Photon detectors for UV, visible and IR photons (vacuum) (photomultipliers, HPDs, others); Power consumption; Scintillation counters; Transit time; Transportation planning; Vacuum-based detectors
• ISSN: 1748-0221; 1748-0221
• DOI: 10.1088/1748-0221/19/04/P04025

Spectroscopic scintillation detector form factors have been guided primarily by the design of commercially available photonic sensors. These devices, such as photomultiplier tubes, silicon photomultipliers, and hybrid photodetectors have underperformed in one or more areas such as size, power consumption, and resolution. A novel photomultiplier tube having a 50.8×152.4 mm 2   rectangular window, utilizing a reflection-mode photocathode, and a low-gain, miniaturized dynode set is considered here to improve photosensor packaging while enabling high-efficiency, low-resolution scintillation spectroscopy with large, planar scintillators. Using a phenomenological multiphysics simulation process informed by empirical data, photoelectron collection efficiency, single-photoelectron response, electron transit time, and transit time spread have been modeled over a range of operating potentials. At 750 V between the photocathode and anode, 72.5% of photoelectrons are collected at the first dynode, and the average gain is estimated to be 805. The most probable transit time is 14.9 ns, with a transit time spread of 2.7 ns full-width at half-maximum.