一种用于Z箍缩实验的软X射线成像系统

Soft x-ray imaging system used for Z-pinch experiments

基于塑料闪烁体转换和光学条纹相机的方法建立了一套用于Z箍缩实验中的软X射线条纹图像诊断系统,解决了以往实验中使用的X射线条纹相机易被电磁环境干扰以及相机电极部件易被实验产生的高速粒子损伤的问题.诊断系统的光谱响应范围主要集中在0.2-10 keV,系统的空间分辨率经过理论评估小于120μm,通过标定闪烁体对X射线的时间响应特性给出了系统的时间分辨率约为1 ns.诊断系统拍摄到了铝丝阵内爆等离子体的一维空间和时间分辨的X射线条纹图像,给出了等离子体的内爆一致性和辐射均匀性等特征信息.

As an important imaging diagnostic manner in Z-pinch experiments,an X-ray streak camera can record a continuous time evolution of X-ray emission and has a better temporal resolution of about several picoseconds.Unfortunately,during experiment the transient strong electromagnetic noise produced by the device interferes with sensitive electronic components of the X-ray streak camera,making it unworkable frequently.In addition,the camera’s position is close to the load chamber so that the photocathode and metallic grid of the camera may suffer the risk of being broken by high speed charged particles and exploding debris.In order to solve this problem,a novel soft X-ray streak imaging system based on the conversion of fast scintillator and an optical streak camera is designed.In the streak camera system,the plastic scintillator foil and fiber bundles are used to convert X-ray image into optical image and transmit it into an optical streak camera which is placed in a shielding cabinet far from the target chamber.The camera system proves efficient in avoiding the damage caused by high speed particles and suppressing the electromagnetic interference.The scope of response spectrum of the camera system is given by theoretical calculation and roughly from 0.2 to 10 keV.The spatial resolution of the camera system is designed to be less than 120 microns and the temporal resolution of the camera system is calibrated to be about 1 ns in X-pinch experiments.The camera system is used in aluminum wire-array experiments to capture the time-resolved and 1D space-resolved images of imploding plasmas.The spatiotemporal distribution information about the X-ray emission is presented.On the other hand,because of the transmission of the filter in sub-kilo-electron-volt emission,the spectral response of the camera system in the sub-kilo-electron-volt photon energy range decreases obviously,which affects the physical analysis of the image.In addition,because of the slow response time of the scintillator to Xrays,the temporal resolution of the camera system decreases obviously and is about1 ns.How to solve these problems will be carried out in the future work.