等梯度加速结构瞬时束流负载效应的计算

Transient Beam Loading Problem in Constant Gradient Accelerator Structure

本文从能量守恒定律出发，对应于等梯度加速结构，推导出瞬时束流负载一般解的解析表达式．特别对应于热阴极微波枪做为注入器的情形，此时脉冲内电流随时间线性增加，首次给出这时的束负载效应的解析公式．对北京自由电子激光器的加速器系统，给出数值计算结果，可以看到由于脉内电流的增长导致脉内束能量下降的程度。

This paper starts with the general solution of the transient beam loading problem for a constant gradient travelling wave accelerator structure (SLAC type structure) by using the energy conversation law. In case where the electron beam in the accelerator comes from a thermionic microwave gun, the electron current increases with time, the beam loading problem is treated for the first time, and the analytic solution is used to analyse the linear accelerator of Beijing Free Electron Laser.