电子回旋自共振加速器输出能量的影响因素及优化

Influence Factor and Optimization of Output Energy of Electron Cyclotron Auto-resonance Accelerator

回旋自共振加速器(CARA)加速效率高,在低能、大功率电子束领域具有非常好的应用前景。由于加速腔浸没在螺线管磁场中,电子束在轴向静态磁场的约束下螺旋前进,与加速腔中的TE11模微波场保持同步而被横向持续加速。但加速器的输出能量并不随加速过程递增,而是与电子束的注入能量、轴向静态磁场、加速腔波导长度及微波场强度等多个相互约束的参数相关。本文从理论上分析了相关参数对输出能量的影响,利用三维电磁场仿真软件CST及粒子跟踪程序分别研究了相关参数对输出电子束状态的约束关系,并对这些参数进行联合优化,使得电子输出能量达到设计值。

Cyclotron auto-resonance accelerator(CARA)has very high acceleration efficiency,and has a very good application prospect in the field of low energy and high power electron beam.Since the accelerating cavity of a CARA is immersed in the solenoid magnetic fields,the electron beam spirals forward under the constraint of the axial static magnetic field and keeps synchronization with the TE11 mode microwave field in the accelerating cavity and is continuously accelerated transversely.The output energy of electron beam does not increase with acceleration monotonously but is determined by the reciprocal parameters,such as the electron beam injection energy,axial static magnetic field,accelerating cavity waveguide length and the amplitude of microwave electromagnetic field.In this paper,the effects of these reciprocal parameters on the output energy of the electron beam were analyzed theoretically.Numerical calculations based on the electromagnetic simulation code CST and the particle tracking code were done to study the constraint relationship of the reciprocal parameters.The designed output energy is achieved after optimization of the reciprocal parameters.