2026-07-14 高輝度光科学研究センター,理化学研究所
図１ プロトタイプ機の内部（左）と、磁場測定試験の様子（右）
＜関連情報＞
- https://www.jasri.jp/development-search/press_prize/release/2026/260714.html
- https://journals.aps.org/prab/abstract/10.1103/vml2-pycy
次世代光源におけるビーム入射時の渦電流を抑制するために、縞模様の金属コーティングを施したセラミック真空チャンバー Ceramic vacuum chamber with a strip-patterned metallic coating to suppress eddy currents for beam injection in next-generation light sources
M. Tajima, K. Fukami, M. Masaki, T. Ohshima, M. Shoji, S. Takano,, K. Tamura, T. Taniuchi, and H. Tanaka
Physical Review Accelerators and Beams Published: 9 July, 2026
DOI: https://doi.org/10.1103/vml2-pycy
Abstract
Transparent top-up injection is important for maintaining photon beam stability and brightness in next-generation light sources. In traditional off-axis injection based on pulsed orbit bumps employing dipole kicker magnets, the injection transparency relies on the precise matching of magnetic fields to ensure a closed local orbit bump throughout the pulse duration. Similarly, alternative off-axis injection based on nonlinear kickers necessitates rigorous control of the magnetic field near the stored beam orbit. A key challenge common to both is mitigating the distortion of the pulsed kicker magnetic field caused by eddy currents in the metallic coating of the ceramic vacuum chamber, while simultaneously minimizing beam coupling impedance and heat load. This paper addresses this issue through the design of a ceramic vacuum chamber aimed at next-generation light sources, tailored to the requirements of the SPring-8 upgrade, SPring-8-II. We prototyped a ceramic vacuum chamber equipped with a strip-patterned titanium coating on its inner surface. Experimental characterization demonstrated that field deviations caused by eddy currents in the coating can be reduced to approximately 0.1% of the peak value throughout a pulse duration as short as 4 μs. These results satisfy the design requirements for beam injection in SPring-8-II.
