200kV闪光照相测试系统

200-kV flash X-ray radiographic test system

介绍了一种基于Marx发生器原理设计的200kV闪光照相测试系统,该系统具有延时功能,可按照实验要求,在预定时刻产生脉冲X射线进行闪光照相测试。设计了一台10级同轴结构的Marx发生器,采用了正负极充电,极间电容耦合为Z形回路的Marx发生器线路,利用开关与屏蔽外筒间的结构电容来锐化高压脉冲的输出,同时采用紧凑性、低电感设计获得窄脉冲的输出。在充电电压为25kV的情况下,75Ω的负载上获得了脉宽小于100ns、幅度大于200kV的高压脉冲,通过高压电缆驱动闪光X射线二极管,在距光源25cm处获得了剂量大于9×10-6 C/kg、脉冲宽度约为70ns的闪光X射线。

A 200-kV flash X-ray radiographic test system based on the principle of Marx generator is introduced. The system has a delay function that it can produce X rays at predetermined time in accordance with the experimental requirement. A 10-stage 200-kV Marx generator has been designed in coaxial structure, and low-jitter field-distortion switches, low-inductance solid-state resistors and ceramic capacitors are used in the pulse generator to shorten the risetime and pulse width of output pulses. The generator was demonstrated to deliver pulses of more than 200 kV onto a 75-Ω load with 100-ns pulse width. Being connected with an X-ray tube through a high-voltage cable, the pulse generator drove the X-ray tube to produce flash X-rays with a pulse width of 70 ns and a dose of 9×10-6 C/kg at the distance of 0.25 m from the laser source.