Microchannel plates (MCPs) are widely used in the fields of electron, ion, and X-ray detection and serve as indispensable image intensifiers in many large-scale scientific experiments. A three-dimensional MCP structure with an aspect ratio of 40 was modeled in CST Particle Studio. Using the time-domain finite-difference method, the secondary electron multiplication process in the microchannels was simulated under constant voltage bias and Gaussian pulse excitation, yielding time-dependent distribution curves of particle counts at various locations. When a voltage bias of -700 V was applied, the multiplication of secondary electrons within the channels exhibited an approximately Gaussian distribution over time; at the MCP output surface, however, the distribution of electron numbers over time was characterized by a fast rising edge (63 ps) and a slow falling edge (150 ps). Using the normalized first-order moment of the output surface distribution data, the average transit time of the MCP was calculated to be 270 ps; the standard deviation of the transit time distribution was taken as the transit time dispersion, which was 132 ps. After removing background noise from the raw data, the results were 240 ps and 53 ps, respectively.

Ultrafast Diagnostics；,Microchannel Plates,Transit Time and Its Dispersion