Fabrication and performance testing of a metal photocathode pulsed X-ray tube prototype based on microchannel plate

Abstract

In this study, we report the fabrication and characterization of a prototype metal photocathode pulsed X-ray tube (MPPXT) integrated with a microchannel plate (MCP) structure. Key structural parameters of the X-ray tube were optimized using CST Particle Studio and the Non-dominated Sorting Genetic Algorithm II (NSGA-II), which we applied to guide the fabrication of the prototype. Au photocathodes with various deposition times were characterized, with a deposition time of 150 s yielding a maximum photocurrent of 20.45 nA. When the optimal Au photocathode was integrated into the prototype, the electron multiplication characteristics of both single- and dual-MCP configurations in an X-ray tube were systematically characterized for the first time. The single-MCP configuration at 1000 V achieved a tube current of 35 μA, with a current gain of ∼1.76 × 10³. The dual-MCP configuration at 1800 V further improved the multiplication efficiency, producing a tube current of 223 μA with a gain of ∼1.17 × 10⁴. Imaging experiments showed a minimum focal spot size of 0.27 × 0.47 mm, which was consistent with simulations. Moreover, the MPPXT achieved stable pulse modulation at 2 MHz. Thus, the proposed MPPXT exhibited enhanced output intensity and offered the advantage of convenient high-speed modulation. These results demonstrate that the proposed method is promising for applications in high-speed imaging, X-ray communication, and scintillator time-response measurements.