Design and end chamfer simulation of PEFP beam line curved dipole magnets

The design, fabrication and field measurement of 11 DC curved dipole magnets for the PEFP Beam Line have been completed. In this paper, a design method for a complex end chamfer using OPERA-3D is proposed. The conventional method for estimating chamfer shape is extended and applied to a curved dipole magnet by a coordinate transformation. Using the interface with CAD software, the complex end chamfer is modeled and fully determined by 3D simulation to meet the field uniformity requirement. The magnetic field measurement results are in good agreement with the simulation. The design considerations, field simulation results, end chamfer development process and measurement results are presented in detail.

用于质子治疗输运线的二极磁铁设计与优化

本文介绍了一套质子治疗输运线上的60°平行边二极磁铁的设计与优化过程。为了提高磁铁磁场质量,其横向场均匀度以及沿积分路径上的积分磁场均匀度均需要优化。根据70~250MeV的质子能量范围和1 500mm的偏转半径,二极磁铁的工作场强为0.80~1.62T。采用OPERA-2D/3D等软件进行设计与仿真计算,磁铁端部采用罗高斯基曲线进行切削以避免铁芯局部饱和,同时进行谐波削斜以减少积分场的四极、六极等高阶误差分量,保证积分场品质,最终在高、低场条件下,横向场相对误差≤±5×10^(-4),积分场相对误差≤±1×10^(-3),高阶谐波分量相对误差≤±5×10^(-4)。磁铁可以达到较高的中心磁场,满足结构紧凑的要求,适合应用于质子治疗的束线系统。