1.3GHz单cell高梯度低损耗超导腔设计研究

计划中的国际直线对撞机(简称 ILC), 已确定采用低温超导技术. 研究表明, ILC的整体造价与超导腔的加速梯度密切相关, 因此新型高梯度超导腔的研制, 已成为目前ILC的热门课题. 目前超导腔加速梯度的提高受限于超导体射频临界磁场(H_c^rf), 希望通过腔形的优化设计, 来减小超导腔表面峰值磁场与加速梯度的比值(H_p/E_acc), 进而提高超导腔的加速梯度, 以满足ILC的要求. 目前, 具有代表性的高梯度超导腔新腔形有两种, 即低损耗超导腔(LLSCC)和重入式超导腔(RESCC). LLSCC相对于RESCC而言, 具有较低的H_p/E_acc, 因此在理论上LLSCC更易于达到较高的梯度. 作者对1.3GHz单cell高梯度低损耗超导腔的腔形进行了详细的研究, 给出了相应低损耗超导腔腔形, 并对这一设计结果进行了分析比较.

Design Study on 1.3GHz Mono-cell High Gradient Low Loss Superconducting Cavity

Superconducting (SC) RF technology is an excellent choice for International Linear Collider (ILC), and the whole cost of ILC is closely related to the gradient of SC cavity. However, the gradient of Nb SC cavity is limited by SRF critical magnetic field at present. So it is very necessary to optimize the cavity shape to decrease the ratio of surface peak magnetic field and accelerating gradient (Hp/Eacc). A serial of new cavity shapes have been proposed including Low Loss shape and Re-Entrant shape etc. Low Loss shape has lower Hp/Eacc than Re-Entrant shape, so theoretically Low Loss shape can reach higher gradient. In this paper, an optimal design is illustrated. Then a Low Loss SC Cavity shape and its calculation results are presented, and finally these results are compared with TESLA 800 cavity and Re-Entrant Cavity.