Optimization and testing of microfocus pulsed X-ray source

Abstract

Pulsed X-ray sources have applications in laser additive manufacturing monitoring, high-speed X-ray imaging, distributed pulsed X-ray systems, X-ray elastic imaging, and X-ray communication. In this paper, we propose a hot-cathode pulsed micro-focus X-ray source (PMFX) with multiple focusing electrodes. The source has been optimized using the CST-MATLAB joint simulation method, with the objective of achieving small focal spot, high tube current, low cut-off voltage, and excellent modulation performance. Simulation results show that the focal spot of the PMFX can be reduced to 45 μm × 25 μm and 6 μm × 20 μm at cut-off voltages of −11 V and −23 V, respectively, with corresponding relative tube currents of 35% and 48%. The current, pulse performance, and focal spot size of the structure with two focusing electrodes were tested in a dynamic vacuum system. The minimum effective focal spot was measured to be 285 μm × 53 μm at 25 kV, with an anode current of 98 μA, consistent with the trend observed in the simulation results. Additionally, an X-ray pulse frequency of 840 kHz was achieved.