超导腔垂直测量系统中的磁屏蔽

简要介绍空间磁场对纯铌超导加速腔性能的影响,以及在超导腔垂直测量时对空间磁场进行有效屏蔽的方法.由于多数磁性材料对应力和温度变化非常敏感,而且国内缺乏在低温下相关磁屏蔽材料性能的数据,为此对8种国产铁磁和软磁材料在低温下的初始磁导率进行了测量,并给出了相应的测试结果.最后介绍了作者研制的1.3GHz超导腔垂直测量低温恒温器内置式磁屏蔽装置及其性能.

Magnetic Shield for the Vertical Test System of Superconducting Cavity

In this paper the influence of the space magnetic field on the performance of a superconducting niobium bulk cavity is introduced briefly. And an effective magnetic shielding method for superconducting cavity vertical test is presented. The initial permeabilities of eight different kinds of Fe-Si and Fe-Ni materials at liquid helium or liquid nitrogen temperature has been measured to compare with those at room temperature. The measurement data are given also. Based on it a double layers cylinder magnetic shield has been developed for the cryostat of 1.3GHz superconducting cavity.