引导磁场对收集极中电子能量沉积的影响

理论分析了引导磁场对收集极材料中电子运动的约束作用,推导了引导磁场作用下二次电子的逃逸条件,利用蒙特卡罗方法计算了引导磁场作用下电子束在收集极中的能量沉积规律。研究结果表明:引导磁场对电子在材料内部的运动约束作用很弱,对二次电子有强约束作用;大部分二次电子经拉莫回旋再次轰击在收集极上被收集,逃逸的二次电子沿引导磁场方向进入束波作用区;增大电子的入射角度时,束流密度的降低和二次电子的再次入射降低了收集极中电子的最大沉积能量密度,提高了收集极的耐电子轰击能力。

Influence of guiding magnetic field on energy deposition of electrons in collector

In relativistic backward-wave oscillator(RBWO), electrons bomb on the collector surface under the guiding of magnetic field at some incident angle after the beam-wave interaction. Restriction from guiding magnetic field to electrons was analyzed theoretically, and condition for backscattering electrons escaping from the collector surface was derived. Using Monte Carlo method, energy deposition of electrons was calculated. It was found that restriction from guiding magnetic field to electrons moving inside materials was quite weak, but was extremely strong out of materials. Most of the backscattering electrons strike again on the collector surface due to Larmor precession. Electrons escaping enter into beam-wave interaction area, reducing the efficiency of energy transformation and output of microwave. When enlarging the incident angle of spent electrons, reduction of beam current density and re-bombardment of backscattering electrons result in the drop of the maximum energy deposition density and improvement of bombard-resistance of collectors.