In this contribution we report on the experimental generation of high energy (10 GeV), ultra-short (fs-duration), ultra-high current (∼ 0.1 MA), petawatt peak power electron beams in a particle accelerator. These extreme beams enable the exploration of a new frontier of high intensity beam-light and beam-matter interactions broadly relevant across fields ranging from laboratory astrophysics to strong field quantum electrodynamics and ultra-fast quantum chemistry. We generate such high peak current beams using the controlled shaping of the electron energy profile with an external, spectrally-modulated, ps-duration infrared (IR) laser pulse. This experimental demonstration opens the door to on-the-fly customization of extreme beam current profiles for desired experiments and is poised to benefit a broad swathe of cross-cutting applications of relativistic electron beams.

This talk will report on the status of commissioning of the Cathodes And Radio-frequency Interactions in Extremes (CARIE) C-band high gradient photoinjector test facility and other high-gradient C-band research activities at Los Alamos National Laboratory (LANL). The construction of CARIE began in October of 2022. CARIE is powered by a 50 MW 5.712 GHz Canon klystron and will house a high gradient copper RF photoinjector with a high quantum-efficiency cathode and produce an ultra-bright 250 pC electron beam accelerated to the energy of 7 MeV. The klystron was received, installed, and conditioned in 2024. The output of the klystron is connected to a circulator that was conditioned to operate for up to 12 MW of power. The WR187 waveguide line brings the power from the circulator into a concrete vault. The test RF injector is made of copper and does not have cathode plugs. It will be commissioned to validate operation of the CARIE facility in Spring of 2025. The second injector that will accommodate cathode plugs is in fabrication. The designs of the photoinjector and the beamline, and status of the high-power testing of the injector and other C-band components will be presented.

The Korea-4GSR is a next-generation diffraction-limited light source designed to provide beam brightness up to 100 times greater than existing facilities. Chromatic aberrations from strong focusing fields in quadrupoles are corrected using sextupoles and octupoles. However, these sextupoles and octupoles introduce nonlinear effects, causing electrons to follow nonlinear trajectories, ultimately reducing beam lifetime. Consequently, these nonlinear elements negatively impact both the dynamic aperture and local momentum aperture. The limitations on local momentum aperture are primarily due to transverse nonlinear dynamics. Recent studies have shown that minimizing one-turn resonance driving terms, reducing their fluctuations, or controlling amplitude-dependent tune shifts (ADTS) can enhance both dynamic aperture and local momentum aperture in various storage ring configurations, including DBA, MBA, and hybrid-MBA lattices. Therefore, we aim to optimize resonance driving terms using a Multi-Objective Genetic Algorithm (MOGA) to expand on- and off-momentum dynamic apertures and improve beam lifetime by increasing local momentum aperture for the Korea-4GSR.