Ultrahigh accelerating gradient and quality factor of CEPC 650 MHz superconducting radio-frequency cavity  

作　　者：Peng Sha Wei-Min Pan Song Jin Ji-Yuan Zhai Zheng-Hui Mi Bai-Qi Liu Chao Dong Fei-Si He Rui Ge Liang-Rui Sun Shi-Ao Zheng Ling-Xi Ye 

机构地区：[1]Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China [2]Key Laboratory of Particle Acceleration Physics and Technology,Chinese Academy of Sciences,Beijing 100049,China [3]Center for Superconducting RF and Cryogenics,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China [4]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Nuclear Science and Techniques》2022年第10期33-40,共8页核技术（英文）

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB25000000);the National Natural Science Foundation of China(No.12075270);the Platform of Advanced Photon Source Technology R&D。

摘　　要：Two 650 MHz single-cell superconducting radio-frequency(SRF)cavities used for the Circular Electron Positron Collider(CEPC)were studied to achieve a high accelerating gradient(E_(acc))and high intrinsic quality factor(Q_(0)).The 650 MHz single-cell cavities were subjected to a combination of buffered chemical polishing(BCP)and electropolishing(EP),and their E_(acc) exceeded40 MV/m.Such a high E_(acc) may result from the cold EP with more uniform removal.BCP is easy,cheap,and rough,whereas EP is complicated,expensive,and precise Therefore,the combination of BCP and EP investigated in this study is suitable for surface treatments of mass SRF cavities.Medium temperature(mid-T)furnace baking was also conducted,which demonstrated an ultrahigh Q_(0) of 8×10^(10) at 22 MV/m for both cavities,and an extremely low BCS resistance(R_(BCS))of~1.0 nΩwas achieved a2.0 K.

关 键 词：SRF cavity Accelerating gradient Quality factor ELECTROPOLISHING Vertical test 

分 类 号：TL50[核科学技术—核技术及应用] O572.214[理学—粒子物理与原子核物理]