THP53 　ポスター③　 8月31日 14号館1444教室 13:30-15:30

Snスパッタリングによる超伝導Nb3Sn膜形成の検討

Investigation of superconducting Nb3Sn film formation by Sn sputtering

○井藤 隼人（高エネルギー加速器研究機構）

○Hayato Ito (KEK)

Nb3Sn is a promising material for superconducting radio frequency cavities thanks to both high critical temperature and high critical magnetic field. However, Nb3Sn cavities have been limited to CW accelerating gradient < 22.5 MV/m. This report presents a new formation method of Nb3Sn film onto the cavities' inner surface to overcome this limitation. In the conventional process, SnCl2 and Sn are heated and evaporated in a vacuum furnace to perform Nb3Sn nucleation by SnCl2 vapor and Nb3Sn grain growth by Sn vapor. In this method, the nucleation density is limited by the SnCl2 vapor pressure resulting in the formation of the Nb3Sn layer with poor surface smoothness. This study aims to fundamentally solve the limitation caused by SnCl2 vapor pressure by depositing an Sn layer on the Nb substrate before the nucleation process. In this contribution, we present the detail of our Nb3Sn formation method to solve this problem and test results for the samples.