三膜片单透镜中束流传输的模拟计算

摘要

强流脉冲束流在三膜片单透镜中的传输时,束流的空间电荷效应显著,需要考虑空间电荷效应对束流传输的影响.三膜片单透镜中强流脉冲束流的传输是一个相当复杂的问题,因为不同类型的粒子束分布产生不同的空间电荷场,而在束流运动过程中,空间电荷场也在不断地变化,而且粒子运动的轨迹与空间电荷势又是相互依赖的,因此需要求得一个自恰的解.采用矩阵法分析非强流脉冲束流 与强流脉冲束流在三膜片单透镜中的传输矩阵,采用迭代方法计算强流脉冲束流的空间电荷效应对束流传输的影响,并编写了束流在三膜片单透镜等元件中传输的计算程序.用该程序与其它程序进行了模拟计算,并对模拟结果进行了比较分析.%When the intense pulsed beam is transported in three - diaphragm einzel lenses, it is necessary to consider the influence of space - charge effect on the intense pulsed beam, because the space - charge effect of intense pulsed beam is obvious. Intense beams transport in the three - diaphragm einzel lenses is a very complicated problem, because the particle trajectories depend on the electric potentials excited by the particle beams, and the electric potentials of the beams depend on the particle trajectories and the particle distributions in the phase spaces. So, it is necessary to solve the problem by iterations to get self ?consistent solutions. We use the transport matrix method to analyze the transportation in three - diaphragm einzel lenses of non - intense pulsed beam and intense pulsed beam respectively, and write a computer code for the pulsed beam transporting in three - diaphragm einzel lenses. The code can give the self - consistent solution by using iteration calculation method. The calculations were made by using the code and other codes, and the simulation results were compared and analyzed.