高能闪光X射线二极管设计与模拟

 为了研制出便携式的具有较高性能的高能闪光X射线系统，需要发展新型紧凑型的高能闪光X射线二极管，要求其体积小，能工作在较高电压下。简要介绍了冷阴极X射线二极管的结构和工作原理；阐述了二极管绝缘结构设计原则，设计了一种新型的紧凑型轴向绝缘结构的X射线二极管；在高压端和地电极之间采用绝缘环和金属均压环交替叠加进行轴向绝缘，有利于减小二次电子发射几率，降低绝缘体表面爬电几率，缩短轴向绝缘距离。二极管工作电压为1 MV，轴向绝缘距离约260 mm，结合ANSYS数值模拟软件进行了静电场数值计算。二极管轴向绝缘区最大工作场强为95 kV/cm，各阳极三相点最大场强为26 kV/cm。计算结果表明：二极管的工作场强低于真空闪络场强；所有三相点的工作场强均满足绝缘要求。

Design and simulation of high energy flash X-ray tube

Developing a compact flash X-ray tube with high operating voltage is necessary to high energy pulsed X-radiography. The operating principle of the field-emission cold-cathode X-ray tube is described in this paper. A novel compact flash X-ray tube with vacuum insulator stack, the voltage of the tube of 1 MV and exposure of 4.128×10-4 C/kg per pulse, is designed. The stack is composed of ten insulators and nine grading rings in alternating sequence. The length of the stack is 260 mm. Static simulation results show that the highest operating field strength of the tube is 94.8 kV/cm, which is lower than the empirical 120 kV/cm; the highest operating field strength of all the triple piont is 26 kV/cm, also lower than the empirical 30 kV/cm. The cubage of the tube is small and high vacuum will