A low-ringing, high-bandwidth button beam position monitor for bunch-by-bunch diagnostics in advanced storage ring...

Modern electron storage rings that implement extreme operating modes require a high-accuracy bunch-by-bunch beam position monitor (BPM) system capable of diagnosing and controlling individual bunches while remaining compatible with bunch-selective feedback systems. Any signal ringing beyond a nanosecond in time is critical, as it can lead to the misinterpretation of beam position and current for subsequent bunches. This necessitates an improvement in the performance of BPM systems for bunch-selective operations. In this study, we present an empirical evaluation of the existing button BPMs in the BESSY II storage ring and propose a new button BPM design featuring advanced capabilities, such as optimized impedance matching within the button structure and enhanced signal processing techniques. Our beam experiments demonstrate a significant improvement in signal fidelity and precision, paving the way for more effective beam diagnostics and control in high-performance storage rings.