WEP054  加速構造  8月8日 大展示ホール 13:10 - 15:10
Development of Nb Mushroom-shaped cavity for evaluation of multi-layer thin-film superconductor
○及川 大基,東口 武史(宇都宮大学),早野 仁司,井上 均,江並 和宏(高エネ研)
○Hiroki Oikawa, Takeshi Higashiguchi (Utsunomiya University), Hitoshi Hayano, Hitoshi Inoue, Kazuhiro Enami (KEK)
The accelerating gradient of the Nb superconducting RF cavity is reaching the limit due to the intrinsic properties of the Nb material. To obtain more higher accelerating gradient, there has been proposed a method of increasing an RF critical magnetic field of the cavity inner surface by coating of multi-layer thin-film superconductor. In order to develop multi-layer thin-film, we are conducting thin-film process development on Nb sample. An RF cavity with a thin-film coated Nb sample is needed to evaluate an improvement of RF critical magnetic field. It is necessary to design a cavity to produce a strong RF magnetic field parallel to the surface of the thin-film sample. We designed a Nb mushroom-shaped cavity, which has a resonant frequency of 5.2 GHz. Before the Nb-based cavity, we observed the field distribution by use of an Al-based model cavity instead of Nb-based cavity. In this paper, we compare the observation of measured field distribution with the calculation, together with the design of Nb-based mushroom-shaped cavity under fabrication.