Design and Testing of Metal Photocathode X-Ray Source Based on Microchannel Plate

This work developed a microchannel plate-based metal photocathode X-ray source (MCP-MPXS). The MCP-MPXS structure was optimized using the non-dominated sorting genetic algorithm (NSGA)-II algorithm. A prototype was then built based on the optimization results, and the current characteristics, X-ray pulse properties, and X-ray imaging performance of the MCP-MPXS were investigated using a dynamic vacuum system. The MCP-MPXS achieved a current gain exceeding $10^{{4}}$ and had not yet reached its performance limit. With an X-ray pulse modulation frequency (MF) exceeding 10 MHz, the MCP-MPXS outperformed current grid-controlled modulated and most photocathode X-ray sources (PXSs). Modulation rates of several tens of megahertz can be achieved by refining the LED drive circuit. Furthermore, the MCP-MPXS obtained the best focal spot with a focusing ring voltage of 2000 V, which was consistent with the simulation results and verified the effectiveness of the optimization algorithm. The optimal focal spot is $0.53\times 0.79$ mm with an imaging resolution of up to 3.9 lp/mm. The system is also capable of dynamic imaging with X-ray pulse widths as short as $50~\mu $ s. Results show that the developed MCP-MPXS solves the problem of insufficient output intensity of traditional MPXSs, realizes high-speed X-ray modulation, and is capable of high-resolution X-ray imaging. This X-ray source has broad application prospects in X-ray communication and high-speed X-ray imaging.