射频超导谐振腔中的电磁场研究

由高纯铌制成的射频超导谐振腔在高场时会出现Q值下降现象，这是高场下超导腔表面局部磁场增强所致. 为研究高场下超导腔表面的电磁场特性，用单cell超导腔设计了腔表面峰值磁场的研究实验. 通过对单cell超导腔表面峰值磁场的测量，可以确定超导腔焊缝及iris附近表面是否存在缺陷，以便进一步进行腔的处理来改进腔的性能.

Researches on the Electromagnetic Field in RF Superconducting Cavities

Q-drop phenomenon usually occurs in RF superconducting cavities made from high pure niobium at high field level. This is caused by the enhancement of local magnetic field at the surface of the niobium cavities. To study the electromagnetic performances of the superconducting cavities at high field, a series of experiments are designed with single cell niobium cavity. By the measurements of the peak surface magnetic field of the cavity, the defects in the cavity can be located with special method. Effective treatments can be used to improve the properties of the superconducting cavities.