부산대학교 도서관

Nb[sub.3]Sn-coating experiments on samples and single-cell cavities were conducted at Peking University (PKU) to understand the Nb[sub.3]Sn growth process using the vapor diffusion method. The evaporation of tin and tin chloride used in the vapor diffusion process was simulated and experimentally analyzed. The results show that the nucleation process is generally uniform, and the atomic ratios of Nb/O and Sn/O were found to be 1:2 within the 10 nm surface of the nucleated samples. Three tin sources were distributed along the cavity axis to obtain a uniform grain size on the cavity surface, and a surface tin content of 25~26% was achieved. The tin segregation effect was found in long-time coatings or coatings with insufficient tin, resulting in a low Sn% and bad cavity performance. By overcoming the tin segregation problem, a Nb[sub.3]Sn cavity with a 750 nm grain size was produced by 1200 °C coating for 80 min and 1150 °C annealing for 60 min. The acceleration gradient reached 17.3 MV/m without quenching and an obvious Q-slope at 4.2 K. The relationship between coating recipes and vertical test results is discussed and conclusive advice is provided in this paper.
Author(s): Gai Wang [1]; Shengwen Quan (corresponding author) [1,*]; Lin Lin [1]; Manqian Ren [1]; Jiankui Hao [1]; Fang Wang [1]; Fei Jiao [1]; Feng Zhu [1]; Senlin Huang [1]; [...]