基于超导磁场环境真空测量电离规磁屏蔽结构仿真研究

Simulation on the Magnetic Shielding Structure of Ionization Gauge in a Superconducting Magnetic Field

聚变装置超导磁场环境下真空测量电离规因灯丝变形、带电粒子轨迹变化等物理机制导致真空测量精度不高,不能满足工程精确测量的需求。基于磁屏蔽的理论,构建了半封闭式和开放式的两种多层磁屏蔽结构模型,利用Maxwell有限元软件,仿真研究了结构材料层不同厚度和不同磁场方向等条件下磁屏蔽效能的变化规律。结果表明,屏蔽效能随铁层材料径向厚度的增加而增大,铁层材料端部厚度对其影响较小;超导材料层厚度对屏蔽效能影响较小;磁场方向角在0°~90°范围内,屏蔽效能先减后增,并在90°(屏蔽结构轴向与磁场方向平行)时达到最大值。为电离规在复杂磁场应用条件下的屏蔽结构工程设计提供了依据。

In the superconducting magnetic field of a fusion device, the uncertainty of vacuum measurement increases because the ionization gauge cannot meet the needs of accurate measurement due to physical mechanisms such as filament deformation and changes in the trajectory of charged particles.Based on the basic principles of magnetic shielding, two semi-closed and open-type multilayer shielding structures were designed, and the simulation was carried out using Maxwell finite element software.The shielding effectiveness was obtained in different material layer thicknesses, different field directions, and other conditions.The results show that the shielding effectiveness increases with the increase of the radial thickness of the iron layer material.It is also found that the thickness of the superconducting material layer and the end thickness of the iron layer material have little effect on it.In the range of 0°-90°,the shielding effectiveness firstly decreases and then increases.The shielding effectiveness reaches the maximum value at 90°.This work provides a reference for the engineering design of the shielding structure of the ionization gauge under complex magnetic field application conditions.