Simulating performance of microchannel plate photomultipliers in magnetic fields

Photon counting detectors are utilised for applications in medical imaging, nuclear and particle physics where a strong magnetic field may be present, requiring a detector that can operate in these circumstances. We illustrate how a PMT can be simulated using a model generated using Computer Simulation Technology (CST) Studio Suite software. The model consists of a photocathode, an MCP structure including electrodes, resistive and secondary electron emitting dynode surfaces, and a readout anode, with appropriate potentials applied to the components of the model. Magnetic fields can be applied to the model with different directions and amplitudes. Using this simulation it is possible to produce the gain and timing characteristics of the PMT. We present simulation results from the modelled PMT, demonstrating electron multiplication performance and timing performance as a function of external magnetic field strength and direction.