Preliminary Research of Niobium Cavity Coating with Nb3Sn Film at IHEP

• Published in: Physica. C, Superconductivity Superconductivity, 2022-09, Vol.600, p.1354107, Article 1354107
• Main Authors: Dong, Chao, Lin, Zefeng, Sha, Peng, Liu, Baiqi, Ye, Lingxi, He, Xiangcong
• Format: Article
• Language: English
• Subjects: accelerating gradient; lower critical field; Nb3Sn; quality factor; SRF cavity
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2022.1354107

•Various cooling rates were tried during the vertical tests of Nb3Sn, which demonstrated very different results. It verified that slow and uniform cooldown resulted in high Q and low surface resistance of Nb3Sn coating cavities.•Several characterizations of the Nb3Sn coating were presented, which could be referenced by others. Nb3Sn has significant potential for superconducting radio-frequency (SRF) application in future particle accelerators, especially compact accelerators, which have attracted the attention of many scientific researchers. This paper reports the setup and process of Nb3Sn coating at the Institute of High Energy Physics (IHEP), and presents preliminary results of 1.3 GHz 1-cell cavities coated with Nb3Sn. The cavities had a matte, non-reflective gray visual appearance after coating. Various cooling rates were used in the vertical tests of Nb3Sn cavities, which resulted in different performances. The characteristics of witness samples at different locations inside the cavity revealed the uniform quality of the Nb3Sn coating. Experimental results indicated that a smooth surface was the key to the high-performance of Nb3Sn cavities.