基于斜螺线管型超导Gantry二极磁体设计

Design of a Superconducting Gantry Dipole Magnet Based on Tilted Solenoids

摘要:

为了解决当前Gantry治疗装置面临的难题—磁体重量庞大,运行成本昂贵,本文提出了一种新型的斜螺线管型线圈结构。目前,我们已经完成了一台2.5 T用于重离子Gantry的NbTi超导磁体样机设计,与质子Gantry相比,其有效缩减了磁体的尺寸和重量。该磁体由10层斜螺线管线圈组成,工作电流为1000A。线圈孔径为176mm,其中好场区达到孔径的2/3。由于线圈形状的特殊性,其端部结构无需优化,各高阶谐波量沿轴向积分为零。磁体采用传导冷却的方式,保证其在旋转的情况下安全稳定运行。本文从斜螺线管线圈的概念出发,详细介绍斜螺线管型超导二极磁体的磁场设计,借助于ANSYS有限元分析软件,仿真了超导磁体和冷屏的空间温度场,得到磁体低温系统的热分布,最后简要介绍磁体的加工情况。

Abstract:

To solve the problems of Gantry therapy device met—huge magnet weight, expensive operation, this paper proposes a new type of coil structure based on tilted solenoids. We have completed a 2.5 T NbTi superconducting magnet prototype design for heavy ion Gantry. The design can reduce the gantry’s size and weight and make it more comparable with gantries used for proton therapy. The magnet consists of ten layers of tilted solenoids with operating current of 1000 A. The coil clear bore is 176 mm and the good field region can be up to 2/3 of the aperture. Because of the magnet’s special shape, it doesn’t require optimization and the higher order harmonics naturally integrating to zero through the ends. To ensure magnet safe and stable operation in the case of rotation, it uses the conduction cooling form. From the concept of tilted solenoid coil,Sthe magnetic field design is reported in detail. Based on ANSYS thermal FEM software, we simulate the temperature profiles inside the magnet and the thermal shield and obtain the thermal distribution of magnet cryogenic system. Finally, we give a brief introduction about the magnet processing.