摘要
在相对论激光强度下,对p偏振30fs激光与固体Cu靶相互作用中产生的Kα射线进行了实验研究.采用刀边成像技术和单光子计数X射线CCD相结合的探测装置,在单发激光脉冲打靶时同时得到X射线源的尺寸、能谱以及Kα光子的转换效率等多种信息.实验结果与Reich等人的理论计算结果有明显的差异,Kα光子的能量转换效率在激光功率密度为1·6×1018W/cm2的条件下达到最大值7·08×10-6/sr.根据这一结果并结合蒙特卡罗程序,推断出在这一聚焦光强下激光能量转换为前向超热电子的效率约为10%.
The characteristics of Ka X-ray sources generated by p-polarized femtosecond laser-solid interactions are experimentally studied in the relativistic regime. By use of knife-edge image technique and a single-photon-counting X-ray CCD camera, we obtaine the source size, the spectrum and the conversion efficiency of the Kα X-ray sources. The experimental results show that the conversion efficiency of Kα photons reaches an optimum value of 7.08 × 10^-6/sr at the laser intensity of 1.6 × 10^18 W/cm^2, which is different from the Reich' s simulation results (Reich et al., 2000 Phys. Rev. Lett. 84 4846). We find that about 10% of laser energy is converted into the forward hot electrons at the laser intensity of 1.6 × 10^18W/cm^2 .
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第1期353-358,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10474134
10374115
60321003
10510490
10334110)
国家高技术惯性约束聚变主题基金
日本Kakenhi主题资助的课题~~