轻气炮加载下晶格响应的实时X射线衍射测量

Real-time X-ray diffractometry for lattice response measurement under gas-gun loading

开展了轻气炮加载条件下材料动力学微观响应测量的实验研究。基于脉冲宽度约25ns的商业化闪光X射线源,采用积分式记录设备,建立了轻气炮加载条件下的实时X射线衍射诊断系统。介绍了实时X射线衍射测量原理及系统,讨论了由于冲击过程持续时间短,且闪光源输出X射线脉冲时具有延时和抖动,X射线脉冲与冲击波到达样品被探测区域难以同步的问题。最后,提出了采用精细的多层靶结构设计和纳秒响应的压电探针实现探测X射线脉冲和冲击波精确同步的方法,并获得了轻气炮加载下LiF晶体峰值压缩状态的实时X射线衍射图像。实验结果显示:加载压力为2.33GPa时,LiF晶体的晶格形变量为1.73%。该实验技术为开展轻气炮加载下材料微观特性研究提供了一种有效技术途径。

The microscopic response measurement of material dynamics was researched experimentally under the loading conditions of gas gun loading.Based on a flash X ray source with the half width of25ns,a real time X ray diffraction diagnostic system was developed by using integral record devices.The measuring principle of X ray diffraction system was introduced.Due to the duration of shocked state in the probed region and the output timing jitter of the X ray source,the difficulty of system synchronization for X ray pulse and shock wave in arriving probe region was discussed.Finally,the method to realize the synchronization of the X ray pulse with the shock wave was achieved by utilizing a fine multilayered target and a piezoelectric pin with ns response time,and a real time X ray diffraction image of LiF in the peak compressed state was obtained under gas gun loading.Experimental results indicate that the lattice compression of LiF is1.73%when shocked pressure is2.33GPa.The experimental technique provides an effective means for research of the microscopic response under a gas gun loading experiment.