Long-term stable UV laser system with millijoule-class picosecond pulses and beam shaping for photocathode RF gun applications

Abstract For the SuperKEKB electron–positron collider project, electron beams are generated by an electron gun and accelerated to 7 GeV using the Linac linear accelerator. To generate these beams, a laser source is employed, producing millijoule-level picosecond ultraviolet pulses. This laser system has demonstrated exceptional performance in the Linac system over several years. To minimize the emittance of the electron beams, the laser pulse must be cylindrically reshaped in three dimensions using an adaptive optics system. A hybrid fiber–Nd:YAG solid-state laser system is developed, which achieves excellent beam quality and stability while maintaining scalability.