LCLS-II has been in user operations since 2023 and has ramped the beam rate up to 33 kHz to date. The LCLS-II photoinjector has demonstrated a low-emittance (half-micron) beam operating at a high rate. During the injector operation, we have also encountered several challenges, such as e-beam splitting and large dark current from the gun. The split e-beam compromises FEL lasing, while the large...
It has been shown that a transverse deflecting cavity (TDC)-based de-chirper can be made by altering the drift sections in a TDC-based chirper to form negative drifts. While five appropriately configured quadrupole magnets can implement such negative drifts, this approach is limited by spatial and experimental constraints. In this study, we investigate an alternative configuration that uses...
The performance of electron injector linear accelerators (linacs) critically influences the beam brightness and stability in 4th generation light sources. In this study, we employ a multi-objective Bayesian optimization (MOBO) framework to optimize the injector linac design, targeting the simultaneous minimization of transverse emittances and energy spread at the linac exit. This...
