Speaker
Description
SuperKEKB is an electron-positron collider aiming for high luminosity. However, its stable operation is challenged by Sudden Beam Loss (SBL), where beam instability occurs within tens of microseconds, leading to significant beam loss and triggering a beam abort. To better understand and mitigate SBL, we developed a new Bunch Oscillation Recorder (BOR) using AMD/Xilinx RFSoC. The BOR records bunch-by-bunch beam position and charge before a beam abort. In the 2024 operation, two BORs were deployed in the main ring, enabling detailed observation of SBL. Analysis of the BOR data revealed that during SBL, not only do bunch positions oscillate, but their sizes also increase. Furthermore, SBL is strongly correlated with "pressure burst", where the local vacuum pressure in the beam chamber rises abnormally at specific locations. Our results suggest that at these locations, the beam may receive kicks, triggering instability. Inspections of these locations revealed dust and vacuum seal contamination in the chamber, suggesting that interactions between the beam and these foreign materials could be a potential cause of SBL.
