MOP021 　高周波加速空胴　 8月8日 コンベンションホール 13:10 - 15:10

薄膜超伝導体の高周波臨界磁場評価のためのニオブ製マッシュルーム型空洞の設計研究

Design study of niobium mushroom-shaped cavity for evaluating RF critical magnetic field of thin-Film superconductor

○及川 大基，東口 武史（宇都宮大学），岩下 芳久，日野 正裕（京都大学），久保 毅幸，加藤 茂樹，佐伯 学行，早野 仁司（高エネ研）

○Hiroki Oikawa, Takeshi Higashiguchi (Utsunomiya University), Yoshihisa Iwashita, Masahiro Hino (Kyoto University), Takayuki Kubo, Shigeki Kato, Takayuki Saeki, Hitoshi Hayano (KEK)

According to the Technical Design Report (TDR) of International Linear Collider (ILC), the higher gradient of 45 MV/m is required in the second stage of ILC. One of such methods is coating multi-layer thin-film superconductor on the inner surface of RF superconducting cavity. The thin film improves the RF critical magnetic field on the inner surface of the cavity. To establish the RF performance of thin-film structure on a small coupon sample, we designed the RF mushroom-shaped cavity which could measure the RF critical magnetic field on a thin-film coupon sample set on the inner surface of the cavity. If the RF cavity is cooled down below the critical temperature of thin-film superconductor with supplying RF power, the heat dissipation might be measured on the coupon sample in the cavity. The shape of the cavity is necessary to produce a strong RF magnetic field parallel to the sample surface efficiently. The design, manufacturing and RF property of the Nb mushroom-shaped cavity are described in this presentation.