Speaker
Description
The SPS-II storage ring requires high-precision beam position monitors (BPMs) for orbit control and fast feedback operation. The design employs a button-type BPM with a removable feedthrough flange, allowing independent fabrication, testing, and replacement without disassembling the main vacuum chamber. Following the first prototype, further improvements have been implemented in both mechanical design and signal performance. The main improvement focuses on mechanical tolerance control to ensure precise button positioning with respect to the chamber reference axis. A redesigned flange interface and alignment scheme were developed to reduce eccentricity and angular misalignment, improving geometric symmetry and measurement accuracy. Time domain reflectometry (TDR) measurements of the first prototype showed larger-than-expected reflections. CST Studio Suite was used to perform wake impedance, S-parameter and TDR simulation to intensively investigate impedance discontinuities along the button to connector transition. The feedthrough geometry was optimized to improve impedance matching. This paper presents the mechanical redesign, simulation analysis, and RF measurement results, confirming that the updated BPM design satisfies the SPS-II performance requirements.
| I have read and accept the Privacy Policy Statement | Yes |
|---|