飞秒和皮秒激光器标定X射线条纹相机性能研究

Performance of X-ray streak cameras calibration by femtosecond and picosecond laser

为激光惯性约束聚变(ICF)诊断,研制了一台大动态范围X射线皮秒条纹相机系统。分别使用130fs和8ps的紫外激光器搭建了X射线条纹相机的动态测试系统,标定了条纹相机的性能。两组标定条件下,实验结果显示,X射线条纹相机极限时间分辨率为5.0ps,动态范围分别为513.7∶1和2 237.1∶1。理论分析了实验结果的差异由于光电子的空间电荷效应导致,其中包括时间弥散和技术时间分辨率中的空间展宽。在飞秒和皮秒激光激励条件下,飞秒电子脉冲的发射电流密度是皮秒电子脉冲的61.5倍,飞秒电子脉冲的空间电荷效应导致的条纹相机时间弥散和空间展宽更大,对条纹相机极限性能作用程度更大。本文研究结果对分析X射线条纹相机中时间和空间信息的物理机制具有重要作用,对优化设计条纹相机系统,激光测试和标定条纹相机性能具有指导意义。

A large-dynamic-range X-ray picosecond streak camera system is devel oped for diagnosis of laser inertial confinement fusion.The 130fs and 8ps UV lasers are used to build X-r ay streak camera dynamic test systems,and the performance of the streak camera is tested.W ith two sets of calibration conditions,the experimental results show that the limiting temporal resolution of the X-ray s treak camera is 5.0ps and the dynamic range is 513.7∶1and 2237.1∶1respectively.The diff erence in experimental results is due to the space charge effect of photoelectrons,including time disp ersion and spatial broadening in the technical temporal resolution.In the femtosecond and picosecond laser excitatio n conditions,the femtosecond electron pulse emission current density is 61.5times of that of picosecond case the streak camera time dispersion and spatial broadening caused by space charge effe ct of femtosecond electron pulse are larger,and the extent limited streak camera performance is more serious.T he results of this study are important to analyze the temporal and spatial information mechanisms of X-ray s treak camera,and have guiding significance for optimizing the design of streak camera systems and laser experi ment and calibration of streak cameras.