负极性杆箍缩二极管物理特性研究

项目名称： 负极性杆箍缩二极管物理特性研究

项目编号： No.11505142

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 孙江

作者单位： 西北核技术研究院

项目金额： 22万元

中文摘要： 强流箍缩二极管是闪光X射线照相装置的关键部件与核心技术，一直以来都是各个国家研究的重点和难点。负极性杆箍缩二极管（NPRPD）在高电压（4MV以上）条件下仍然能够在前向产生小焦斑、高剂量的脉冲X射线，是高电压闪光照相装置研制的重要技术途径之一。NPRPD阴阳极等离子体产生早，运动复杂，特别是电子束、等离子体和强电磁场三者的相互作用给其物理特性的研究带来较大困难。本项目拟采用理论分析、数值模拟和实验研究相结合的方法，研究NPRPD的动力学行为和辐射特性，诊断不同二极管结构下等离子体的产生时间、区域、运动过程，分析高电压下等离子体引起阻抗崩溃的物理机制，通过优化二极管结构，延缓等离子体的产生、约束等离子体的运动范围，避免阻抗崩溃的同时减少阳极材料对X射线的吸收，在保证小焦斑的前提下，提高前向X射线的辐射剂量。

中文关键词： 负极性杆箍缩二极管；电子束；等离子体；脉冲X射线

英文摘要： Intensity-current-pinched diode as one of the most important element of flash X-ray radiography devices, has always been the key and difficult point for researchers in ralated field all over the word. Negative-polarity rod-pinch diode (NPEPD) can still radiate small-spot and high-dose pulsed X-ray in condition of high voltage (>4MV) . This diode is one of the important way to develop the high voltage flash X-ray radiography devices. Plasma emerges earlier and drifts complicated in NPRPD. It is hard to figure out physical characteristic of NPRPD because of interaction of electron beam, plasma and high power pulsed electromagnetic field. This project synthesizes ways of theoretical analysis, numerical simulation and experiments to research the dynamic and radiation characteristic of NPRPD. According to the diagnostic results of plasma generation time, area and motion process, the reason of impedance collapse happened in the final period of pulse will be given out. In order to avoid empedance collapse and reduce self-absorbtion of X-ray by anode electrode, diode stucture should be optimize to delay plasma produced time and comfine plamsa drifting area. By this way, we’d better to keep small spot size and promote higher dose X-ray in front of device.

英文关键词： negative-polarity rod-pinch diode;electron beam;plasma;pulsed X-ray;impedance collapse