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arXiv · 2310.07153

Simulating the secondary electron avalanche of MCP by Geant4

Huaxing Peng·Baojun Yan·Han Miao·Shulin Liu·Binting Zhang
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Abstract

Nowadays, Microchannel Plate (MCP), as a kind of electron multipliers based on the secondary electron emission, is widely used in many high-sensitive experiments, such as neutrino detection, which require the noise to be as low as possible, while the conventional straight-channel MCP will inevitably have ion feedback, resulting in the sequential after-pulses being the major source of noise. Normally, the problem can be effectively avoided by coupling two straight-channel MCPs in cascade and combining the channels into a `V` shape known as chevron MCPs, but this method is limited by the manufacturing techniques due to the unavoidable gap between the two pieces that will worsen the resolution and peak-to-valley ratio. However, the ion feedback can be inhibited significantly for MCPs with curved channels. Based on Geant4, we investigate how the geometrical parameters of curved-channel MCP influence the gain and get the optimum pore diameter for an MCP to reach the maximum gain with fixed thickness and applied voltage. Additionally, the track-by-track simulation reveals that the average acceleration distance of a secondary electron inside the curved-channel is approximately 20 um when the applied voltage, length-to-diameter ratio and pore diameter are 950 V, 50:1 and 20 um, respectively.

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Huaxing Peng, Baojun Yan, Han Miao, Shulin Liu, Binting Zhang. 2023-10-11. Simulating the secondary electron avalanche of MCP by Geant4. https://doi.org/10.1016/j.nima.2024.169163

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