横向运动对驻波加速管电子反轰的影响

驻波加速管的电子反轰除和各种纵向运动因素有关外,还和横向运动因素有关。本文分析了横向运动因素对电子反轰的影响,指出由于横向运动,最终作反向运动的电子只有一部分能反轰到电子枪阴极表面,本文给出了计算反轰束流包络、反轰率、反轰电流及反轰功率的方法。

INFLUENCES OF THE TRANSVERSE MOTION OF THE ELECTRON BACK BOMBARDMENT IN THE STANDINGWAVE LINEAR ACCELERATORS

The electron back bombardment in the SW linacs with higher accelerating gradient is a undesirable phenomenon which will cause overheat of the electron gun cathode and destruction of the electron optics. The influences of the longitudinal motion on the electron back bombardment in SW linacs have been analysed by the same authors1]. In this paper, the influ ences of the transverse motion on the electron back bamardment in SW linacs have been analysed by solving the beam envelope equations under backward motion. It is indicated that owing to the transverse motion under the backward motion, only part of the backward electrons can strike right on the cathode surface, the other part will strike on the inner walls of the cavity and beam hole. The definitions with their calculating methods of the back bombardment parameters such as back bombardment ratio, back bombardment current, back bombardment power are presented.