强激光与固体靶相互作用所致硬X射线的辐射安全初步研究

Preliminary Study on Hazard of Hard X-ray Radiation Produced in Interaction Between High Intensity Laser and Solid Target

激光技术的迅速发展使得国际国内涌现出一批强激光装置,而这些装置中强激光与固体靶相互作用所致硬X射线产生的辐射危害也逐渐被人们发现和重视。通过广泛的调研,对强激光与固体靶产生硬X射线的物理过程及其源项特点进行了分析和讨论,包括激光到电子的能量转换效率,热电子能谱和电子温度,以及热电子所产生硬X射线的能谱等,并且得到了激光强度在1014到1020 W/cm2之间的激光与靶相互作用后,产生的X射线剂量的初步评估结果。最后以斯坦福直线加速器中心(SLAC)的一个强激光装置为例,介绍了其辐射安全系统的初步设计。研究结果为强激光装置的辐射安全评估及其安全系统设计提供了相关参考。

With the rapid development of laser technology, a number of high intensity laser devices are emerging in China and other countries. At the same time, the hazard induced by the radiation produced in the interaction between high intensity laser and solid target has gradually been observed and attention has been paid to this hazard. In this paper, the physical process and character of the interaction between laser with high intensity and solid target were analyzed through extensive research. The parameters of the radiation sources were discussed, including the energy conversion efficiency of laser-electronic, thermal electron energy spectrum and electron temperature, the energy spectrum of hard X-ray produced by thermal electron, etc. Then the primary assessment of the resulting X-ray dose due to the interaction between the laser and the target with the laser intensity in 10^14 to 10^20 W/cm^2were obtained. Finally, as an example the preliminary design of the radiation safety system for a laser device at Stanford Linear Accelerator Center （SLAC） was described. The results of this study provide a reference for the radiation safety assessment and safety system design for strong laser devices.