超短超强激光与固体靶相互作用, 可以产生大量的Kα特征谱线发射。这种Kα线光源在背光照相、医学成像和超快诊断等方面具有显著优势。为了寻求获得Kα线高产额的方法, 利用ITS蒙卡模拟程序, 对超短超强激光产生的超热电子在固体靶中产生的Kα线发射进行了模拟。系统研究了Kα线发射强度随出射角度、靶厚度和超热电子温度等参数的变化情况。研究发现在恒定的激光功率密度或超热电子温度下, 存在最佳的靶厚度, 使得Kα线光子产额最大, 并用模拟结果对已有实验数据进行了解释。

In the interaction of a high-intensity laser pulse with a solid target, most of the absorbed laser energy is converted into hot electrons. These electrons transport in solid targets, and in the same time can ionize the K-shell electrons, and produce Kα radiation, which can serve as a backlit source to diagnose dense matters by radiography. To achieve high Kα yield, simulations were done with the ITS code to study the Kα radiation. The effects of hot electron temperature, target thickness, and emission angle on the Kα radiation were investigated. It is found that, for fixed laser power density or hot electron temperature, there is an optimal target thickness, at which the yield of Kα photons reaches the maximum. The simulated results explained the experimental results.