PKU-SCAF 1.3GHz超导腔超流氦冷却循环设计及运行温度优化

Design of Super-Fluid Helium Cooling Cycle and Optimization of Operating Temperature of 1.3 GHz SRF Cavity Systems for PKU-SCAF

超导腔的BCS表面电阻是温度的指数函数,降低超导腔工作温度可以减少超导腔的射频功率损失,但同时制冷设备的效率也会急剧降低。本文以北京大学超导加速器实验装置(PKU-SCAF)1.3GHz的9壳型超导加速腔为例,对1.3GHz超导腔采用的压力为3.13kPa的饱和态超流氦冷却循环方案及运行温度进行了分析研究。从提高超流氦冷却系统的制冷系数、降低超导腔的动态损耗出发,通过对5种超流氦冷却循环方案以及超流氦冷却循环的效率和超导腔低温系统的能耗进行数值模拟和分析,得出了适合PKU-SCAF主超导腔的最佳工作温度为1.95K。

Due to the exponential dependence of the BCS surface resistance with temperature, reducing the operating temperature of SRF cavity will result in lower radio-frequency loss for the cavity, but the efficiency of the cryogenic plant reduces drastically too. In this paper, the saturated super-fluid helium cooling cycles and operation temperature for a 1.3GHz superconducting resonance frequency cavity system were analyzed in terms of improving the refrigeration efficiency of SRF cooling system and lowering the cavity dynamic loss. The optimized operation temperature for the 1.3GHz SRF cavity is around 1.95K. The suitable cooling cycle is proposed finally.