利用光核反应对激光等离子体中超热电子温度诊断的理论研究

超短超强激光与等离子体相互作用可以产生高能的超热电子, 利用光核反应的方法可以对这部分超热电子的温度进行诊断. 本文通过粒子输运程序(MCNP), 模拟了超热电子通过轫致辐射产生γ 光子, γ 光子再分别与⁶³Cu, ¹⁰⁷Ag, ¹²C等活化材料发生光核反应的物理模型, 并根据核素的活化截面数据, 计算了不同活化片的放射性活度, 得到了¹¹C/⁶²Cu, ¹¹C/¹⁰⁶Ag活度比与电子温度关系曲线, 采用理论模拟的方法实现了激光等离子体产生的超热电子的温度诊断. 关键词： 超热电子 轫致辐射光子 光核反应 MCNP程序

Temperature diagnostic using photonuclear reactions for hot electrons in laserplasma interactions

The temperature of hot electrons produced in ultra-short ultra-intense laser-plasma interactions could be measured by photonuclear diagnostic method. In this paper, the process of bremsstrahlung gamma photons generated by hot electrons interacting separately with ⁶³Cu, ¹⁰⁷Ag, and ¹²C, were simulated using the Monte Carlo N-particle transport code (MCNP). According to the different cross-sections, the activities of different samples were calculated. The activity ratios for ¹¹C/⁶²Cu and¹¹C/¹⁰⁶Ag were achieved at different electron temperatures. This method can realize the temperature diagnostic of hot electrons in laser-plasma interactions.