At Diamond, it was previously observed that the response of the beam changes with mode number when excited by the transverse multi-bunch feedback (TMBF). This study presents the results of various experimental campaigns carried out to investigate the behaviour of tune-sweep waveforms for a variety of stored beam conditions and TMBF settings. We demonstrate that it is unlikely that wakefields cause the mode dependence in the output TMBF waveforms. Investigations to explain what is causing the mode-dependent behaviour are ongoing.

In 2024, the Large Hadron Collider (LHC) delivered Pb-Pb ion collisions at a beam energy of 6.8 Z TeV with a stored beam energy of more than 20 MJ. In order to clean beam halo particles and avoid quenching the LHC superconducting magnets, the novel crystal collimation method employing 4 mm-long crystals was introduced for ion operation in the LHC Run 3. The LHC Beam Loss Monitoring (BLM) system triggers the beam dump in case the measured losses are above certain predetermined thresholds. Important adjustments were needed in order to optimize these thresholds in accordance with the peculiar loss pattern produced by crystal collimation. This contribution explains the newly observed beam loss patterns during Pb ion operation with crystal collimation in place, as well as the study that was carried out to update the BLM thresholds for Pb ion operation in the LHC Run 3.

In modern low-emittance electron storage rings, precise beam orbit control is crucial to ensure the beam passes through the magnetic center of each high-gradient multipole magnet, with an accuracy of 10 μm or even better. Accurate alignment of a BPM with the center of the neighboring magnet is imperative, a critical requirement for SPring-8-II. With a total of 340 BPMs, efficient beam commissioning of SPring-8-II necessitates a fast beam-based alignment (BBA) method. To assess the feasibility of this method, we conducted a fast BBA experiment at the current SPring-8 storage ring utilizing new BPM readout electronics based on MicroTCA.4, enabling a data acquisition rate at 10 kHz. We varied the strength of a quadrupole magnet adjacent to a BPM head connected to the new fast readout. We scanned the electron beam across the quadrupole center by adjusting a steering dipole magnet. The BPM offset from the quadrupole center was then determined by analyzing data from all BPMs connected to the fast readout. This contribution will detail the proposed fast BBA procedure for SPring-8-II and present the results obtained from the feasibility test at the existing SPring-8 storage ring.