一种200kV的多功能脉冲辐射系统研制

Development of 200 kV multi-function pulsed radiation system

研制了一套峰值电压200 kV的多功能脉冲辐射系统,该系统具有产生脉冲电子束和脉冲X射线的功能,在两种运行状态中可以灵活切换.系统包括脉冲功率驱动源、真空二极管和实验腔体,其中,脉冲功率驱动源由Marx发生器、高储能的水介质传输线和脉冲压缩开关组成.系统负载等效阻抗2 W、负载电流半高宽30 ns,产生的脉冲电子束束流83 kA,产生的脉冲X射线平均能量67 keV,均匀性较好,辐射场中的电子份额不超过0.02%.为监测系统运行状态和输出指标,建立了包括运行参数和效应参数的全套测量系统,克服了强电磁场环境的干扰问题.研制了法拉第筒用于脉冲电子束的测量,既可以获得电子束的束流强度,也可以获得电子束总能量.脉冲X射线的测量系统包括能谱仪、剂量片、法拉第筒等,实现了能谱、剂量、均匀性、X射线中电子份额等多参数的同时测量.多功能脉冲辐射系统为脉冲功率技术、生物辐射效应、系统电磁脉冲效应等提供了一个多功能的实验平台.

A multi-functional pulsed radiation system with a peak voltage of 200 kV,an impedance of 2 W,and a full width at half maximum(FWHM)of 30 ns is developed.The system can be switched flexibly in two states of generating pulsed electron beam and pulsed X-ray by changing the cathode and anode.It consists of a pulse power driving source,a vacuum diode,and an experimental cavity.A Marx generator,a high energy storage water transmission line,and two pulse compression switches are utilized to generate a high voltage on diode.An effector can be placed in the experimental cavity which has the same vacuum as diode.An insulation structure of transmission line and a diode are optimized to guide in system design.The system can provide a multifunctional experimental platform for investigating pulse power technology,system-generated electromagnetic pulse,biological radiation effect,etc.The Marx generator generates a high-voltage pulse with hundreds of nanoseconds in FWHM and hundreds of kilovolts in peak value.The pulse is compressed by the main switch and pulse forming switch and then loaded to the diode.Electrons are emitted from diode cathode under the high-voltage pulse and accelerated in the gap.The electrons are extracted directly or converted into X-ray through the anode.Aluminized polyethylene is used as an anode when pulsed electron beam is generated,and tantalum film is used when pulsed X-ray is generated.Working state can be switched by changing the cathode and anode of diode.The result shows that a current of 83 kA pulsed electron beam and an average energy of 67 keV X-ray are generated.Pulsed X-ray has good uniformity and low electron proportion(0.02%).In order to monitor the operation state and output parameter of the system comprehensively,a complete measurement system is established.Three capacitive voltage dividers are set at the beginning of transmission line,the end of pulse forming line,and the end of output line,while a B-dot current monitor is set at the diode.A Faraday cup is developed to measure the current intensity and the total energy of pulsed electron beam.For energy spectrum,dose and electron proportion,the measurement system composed of pulsed X-ray including spectrometric system,dose system and Rogowski Coil is build.