Performance drift over long periods of operation due to changes in machines settings or the environment has been a longstanding problem for particle accelerators. Algorithms which are capable of tuning machine settings while keeping the performance within a desired threshold can be used to compensate for such drifts. We have developed a modified version of the Multi-Generation Gaussian Process Optimizer (MG-GPO) which is capable of tuning accelerator settings during user operation. The modified algorithm uses Gaussian Process regression to predict the performance of potential trial settings and removes ones with a high probability of giving too poor of a performance before selection for evaluation on the machine. The modified MG-GPO has been tested on analytic functions and applied to the SPEAR3 kicker-bump matching problem as a proof of concept. It is expected that the modified MG-GPO will be applied to maintain optimal trajectory of the beam injected into the SPEAR3 storage ring.

Significant progress has been made in both hardware development and simulation capability to shorten the proton bunch width delivered to the Lujan Center at LANSCE via the Proton Storage Ring (PSR). We have successfully demonstrated operation of the PSR RF buncher at 5.6 MHz, doubled from the standard running condition, to accumulate the shorter beam pulse. A quick switch between two modes is under consideration. To extract the beam properly, a prototype kicker test stand has been established, and the measurement of the pulse width, rise time, and charging time will be demonstrated. On the simulation front, beam dynamics models have been refined using both ELEGANT and pyORBIT codes to optimize dual-pulse stacking scenarios. We have performed detailed studies of longitudinal phase space evolution, space charge mitigation, and bunch separation fidelity, which guide ongoing design efforts and beamline integration. These advancements will be the foundation for future development of shorter pulses for the Lujan Center.

To address the intrinsic dynamic aperture (DA) limitations of fourth-generation diffraction-limited synchrotron light source, we investigate a novel injection scheme utilizing multiple nonlinear kickers (NLKs) with optimized hardware design and phase advances in the storage ring (SR). Positioning the NLKs near the injection point reduces beam perturbation, while their on-axis zero field and gradient enable transparent injection—suppressing orbit and beam-shape oscillations during top-off operations. Particle-tracking simulations were performed using Accelerator Toolbox (AT), alongside the development of automated tools for converting magnetic field maps into AT-compatible kick maps, inserting NLKs at arbitrary lattice locations, conducting tracking, and optimizing NLK configurations. A key challenge is to shift the off-axis magnetic field peak closer to the beam orbit. Our novel NLK design achieves a peak within 5 mm of the axis—a significant improvement over the conventional greater than 7 mm range. Simulations accounting for realistic alignment and magnetic field errors indicate that a relaxed 5 mm DA and injection efficiency > 90% could be feasible for the NSLS-II upgrade lattice.

Positive-Ion Injector at ATLAS accelerator facility can accelerate heavy ions and has three key subsystems -- an electron cyclotron resonance (ECR) ion source, a 12-MHz multi-stage beam bunching system, and a 12-MV superconducting linac accelerator. The first stage of the bunching system is a multi-harmonic buncher that operates at 12.125 MHz and creates a bunch train with a period of 82.5 ns at ~70% bunching efficiency. The remaining unbunched beam must be removed to avoid the production of undesirable ‘satellite’ bunches, which can quench the superconducting solenoids downstream during operation. In this paper, we present the design of a resonant sine-wave RF-structure that effectively removes the bunch ‘tails’ using a vertically deflecting kick. We also discuss the effects of the RF-Kicker on the beam quality, which was estimated by TRACK3D simulations.

The Pseudo Single Bunch (PSB) operation mode is being developed at Stanford Synchrotron Radiation Lightsource (SSRL) to address growing interests from time-resolved experiments. To accommodate both regular user and timing user experiments simultaneously, a fast electron kicker will be installed in one of the long straight sections at SPEAR3. This kicker will provide a large spatial separation between the main bunch trains and the camshaft bunch. The resulting x-ray spatial separation from undulator beamlines will be highly dependent on the location of the PSB kicker to be installed. We present here considerations of the PSB kicker location with beamline simulations for both low and high repetition rate modes.