Dramatic improvement of superconducting accelerating cavity performance by introduction of laminated thin film structure

2017 Fiscal Year Final Research Report

• Project/Area Number: 26600142
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Quantum beam science
• Research Institution: Kyoto University
• Principal Investigator: Iwashita Yoshihisa 京都大学, 化学研究所, 准教授 (00144387)
• Co-Investigator(Kenkyū-buntansha): 佐伯 学行 大学共同利用機関法人高エネルギー加速器研究機構, 加速器研究施設, 准教授 (70282506) ; 久保 毅幸 大学共同利用機関法人高エネルギー加速器研究機構, 加速器研究施設, 助教 (30712666)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 超伝導 / 薄膜 / 高周波 / 積層薄膜 / 超伝導加速管 / 超伝導空胴

Outline of Final Research Achievements

The superconducting laminated thin film structure may dramatically improve the performance of superconducting acceleration cavities. In order to study the laminated thin film structure, characteristics of the superconducting thin film structure under cryogenic temperature were investigated. They were evaluated by measuring third harmonic distortions (THD) on induced voltages of an excitation coil of a magnetic field applied to the sample. We have developed the THD measurement system. In the sample of the system with NbN superconducting thin film coated on a high purity bulk niobium plate with a thin SiO2 insulation layer in between, we obtained the world's first measurement result withstanding the magnetic field exceeding the lower critical field of Nb. By this measurement, it becomes possible to formulate guidelines for future thin film fabrication, and it has become possible to accelerate further efforts to improve the performance of the superconducting acceleration cavity.

Free Research Field

ビーム物理