强流二极管阳极电子束时域能量沉积特性模拟

Simulation of intense electron beam time-dependent energy deposition on anode target of high-current diode

以强流脉冲电子束为研究对象,提出了一种基于离散时间、限定靶面位置,通过测量靶面不同时刻入射角分布,利用蒙卡程序计算得到电子束的能量(r,z)二维分布沉积值的方法。给出了典型弱箍缩平板二极管(电压峰值700kV、阻抗7Ω)阳极靶面不同位置时域的能量沉积值,分析了(0,0°),(25 mm,135°),(36mm,270°)三个位置纵切剖面的能量沉积特性,结果表明:在各个时间段内电子束入射能量确定的情况下,能量沉积特性与入射角呈现相关性,仿真结果与实验结果符合较好,偏差均小于10%;距阳极靶心25mm以外的靶面位置,受束流箍缩影响,入射角分布变化较大;当入射角较小时(小于40°),强流电子束能量沉积峰值深度约0.2mm;当入射角超过40°时,能量沉积峰值深度减小到0.1mm左右;而阳极靶心位置附近,受束流箍缩影响较小,这些位置的能量沉积特性更接近于小角度入射角情形。

This paper presents a new method to obtain the time-dependent electron beam energy deposition at different anode target position.First,the electron beam energy should be discrete according to diode working time,so that the electron beam in each time period is considered to have one single energy value.Then the energy deposition profile at this position can be calculated accurately by Monte Carlo method while only the incidence angle here is available.The time-dependent energy deposition characteristics in r(radial)and z(depth)directions of a weak-pinched diode working at 600 kV and 7Ωare analyzed.The results show that the energy deposition characteristics are related to the incidence angle in the case of the energy of the electron beam is confirmed in each time period.The experimental results are in good agreement with the simulation results,the deviations are less than 10%.The energy deposition at each position of the target surface is different due to the influence of the incident energy and the incidence angle.The energy deposition profile at a designated position is also time-dependent.Under the influence of the beam pinching,the incidence angle changes greatly with time at the position more than 25 mm away from the center of the target surface.When the incidence angle is less than 40°,the peak depth of the high current electron beam energy deposition is about 0.2 mm.When the incidence angle exceeds 40°,the energy deposition peak depth is reduced to about 0.1 mm.At the positions near the center of the target surface,the influence of the beam pinching is weakened.The energy deposition characteristics of these locations are closer to the case of the deposition with small incidence angles(<40°).