Study on the relationship between MCP spatial resolution and electron output angle and energy, and its synergistic optimization with gain

Microchannel plates (MCPs) are extensively applied as position-sensitive photodetectors, with spatial resolution representing a key performance metric. Increasing the immersion depth of the output electrode is a conventional approach to improving MCP spatial resolution, but it inevitably leads to significant gain degradation. In this study, the Finite Integration technique, Monte Carlo method, and Furman secondary electron emission model are employed to investigate the relationship between electron emission angle, energy, and spatial resolution. Results indicate that a smaller emission angle relative to the MCP output surface normal yields higher spatial resolution. Moreover, output electrons whose energy is concentrated in the lower range correspond to a higher proportion originating from the end-spoiling region, thus degrading spatial resolution. To balance the trade-off between spatial resolution and gain, an Al 2 O 3 -NiCr MCP is proposed, featuring a nickel-chromium output electrode while coating the remaining areas with Al 2 O 3 , a material exhibiting high secondary electron yield. Simulation results show that the Al 2 O 3 -NiCr MCP with an output electrode depth equal to three times the channel aperture achieves speckle FWHM values of 31.4 µm (X-direction) and 30.9 µm (Y-direction), matching the performance of a conventional Glass-NiCr MCP with the same output electrode depth, while delivering 2.5 times higher gain.