2025-09-30 理化学研究所
Web要約 の発言：
新型のcos 2θ型BPMにより非接触かつリアルタイムなビーム広がりのモニタリングを実現
＜関連情報＞
- https://www.riken.jp/press/2025/20250930_1/index.html
- https://journals.aps.org/prab/abstract/10.1103/8ct7-x1xf
超伝導線形加速器における低ベータ重イオンビームのビーム位置モニターを用いた非破壊ビームエンベロープ測定 Nondestructive beam envelope measurements using beam position monitors for low-beta heavy ion beams in a superconducting linear accelerator
Takahiro Nishi, Tamaki Watanabe, Taihei Adachi, Ryo Koyama, Naruhiko Sakamoto, Kazunari Yamada, and Osamu Kamigaito
Physical Review Accelerator and Beams Published: 29 September, 2025
DOI: https://doi.org/10.1103/8ct7-x1xf
Abstract
In a superconducting linear accelerators (linacs), accurately monitoring beam dynamics is essential for minimizing beam losses and ensuring stable operations. However, destructive diagnostics must be avoided in superconducting sections to prevent the occurrence of particulates and outgassing, rendering direct measurements of the beam envelope particularly challenging. This study presents a nondestructive method that uses beam position monitors (BPMs) to estimate the transverse beam envelope based on measurements of the quadrupole moment of the beam distribution. Although this concept was originally proposed in the 1980s, its application, especially to hadron beams, has been limited because of low signal sensitivity and the accuracy constraints associated with conventional BPM geometries. To overcome these challenges, we employed cos2-type BPMs, which offer improved sensitivity to quadrupole components and are well suited for low- heavy ion beams. This method was applied to the heavy ion beams in the superconducting RIKEN linac (SRILAC), for which data from eight BPMs were combined with transfer matrix calculations and supplemental wire scanner data. The resulting beam envelope estimates exhibited good agreement with conventional quadrupole scan results, demonstrating the feasibility of this technique for routine, nondestructive beam monitoring in superconducting accelerator sections.
