在圆周对称的磁场作用下,环形电子束以一定角度轰击在圆柱面的相对论返波管振荡器（RBWO）收集极上并将能量沉积其中,采用蒙特卡罗程序FLUKA,建立了电子的能量沉积分布计算模型,研究了电子能量沉积分布规律；建立了背散射电子的运动模型,模拟了磁场作用下背散射电子的运动轨迹；研究了圆周对称径向磁场的近似方法。研究结果表明：随着磁场强度的增大,最大能量沉积密度增大,背散射电子在更靠近电子束入射区域的位置再次入射并沉积能量,且可能形成一个新的能量沉积峰值。在磁场强度较大时,采用单向的径向磁场即可较好地计算圆周对称径向磁场下背散射电子的能量沉积分布。

In the circular symmetrical magnetic field, the annular electron beam impacts on the cylindrical relativistic backward-wave oscillator (RBWO), in which the energy of the electrons are deposited. The model of the electron energy deposition is built with Monte Carlo code FLUKA, and the distribution of the electron energy deposition is studied. The motion model for the backscattering electron is built and the electron trajectory in magnetic field is simulated. The method for approximating the circular symmetrical magnetic field is developed. Several conclusions are made as follows: with the magnetic field enhanced, the maximal energy deposition density becomes larger, and the position of the backscattering electron is nearer to the incident electrons region and a new energy deposition peak may occur. When the magnetic field is strong enough, the unidirectional magnetic field could be applied to the calculation of the energy deposition distribution under circular symmetrical magnetic field.