SFEL高亮度注入器的设计和粒子动力学特性

Design and beam dynamics of SFEL high brightness injector

使用国际通用程序ＥＴＰ．ＰＡＲＭＥＬＡ和自编程序ＰＬＳ－ＩＭ－６０等对高亮度注入器作了详细的优化设计和粒子动力学数值模拟。注入器出口的电子束品质的主要参数为：能量３．５ＭｅＶ。能散２％（６２％电子），微脉冲束团相宽－４ｐｓ（６２％电子）。在第一根加速管出口的电子束品质的主要参数为：能量３３ＭｅＶ，能散０．３％（６２％电子），微脉冲峰值电流－８０Ａ，束团相宽３ｐｓ（６２％电子），束归一化发射度２０－３０ｍｍ·ｍｒａｄ（６２％电子）。

The SFEL high brightness injector consists of a ns- grid gun driven at 476MHz, a 476MHz subharmonic buncher and a 2856MHz travellingt wave buncher(TWB) with high field gradient. Electron beam leaving the injector is then injected into a constant gradient travelling-wave accelerating section(Accl, SLAC type). By using programs ETP, PARMELA, PLS- IM-60 etc., beam dynamics simulation was performed from the gun to. the end of Accl in order to find the optimized gun electrode geometry, sutbharmonic buncher gap voltage, bunching drift distance, TWB injecting phase, TWB structure parameters and axial magnetic field profile for predicting beam quality requested.