激光驱动中子源由于中子通量高、短脉冲等特点受到广泛关注。通过辐射流体动力学、粒子动力学和蒙特卡罗三种数值模拟程序的组合使用,对超短强激光与铜靶作用产生光核中子进行了全物理过程模拟。首先使用辐射流体动力学程序获得激光预脉冲产生的预等离子体密度分布,然后将预等离子体输入粒子动力学程序获得超短强激光主脉冲产生的超热电子信息,最后将超热电子输入蒙特卡罗程序得到光核中子。模拟获得了光核中子的产额、能谱和角分布信息,发现采用强度1022 W/cm2激光、直径和厚度均为4 cm的Cu圆柱靶,可以获得产额为1.2×108/J的光核中子。

Laser-driven neutron sources have potential applications in many fields of science and technology due to ultrahigh neutron flux and ultrashort pulse duration. We simulated the generation of photonuclear neutrons in the full-physical process by use of several numerical simulation codes. At first, we used 1D radiation hydrodynamics code to simulate the process of ultraintense laser prepulse interacting with Cu target, acquiring the preplasma electrons density profile. Then we got hot electrons information by 3D PIC code to simulate ultraintense laser main pulse interacting with the preplasma. At last we acquired the yield, spectrum and angular spectrum of photonuclear neutrons when the hot electrons impinging with Cu target simulated by Monte Carlo code. The simulation results show that the photonuclear neutrons yield up to 1.2×108/J can be obtained using ultraintense laser with intensity 1022 W/cm2 interacting with Cu cylinder target whose thickness and diameter are 4 cm.