WEP121 　加速器技術／レーザー　 8月5日 小ホール 13:00 - 15:00

SuperKEKB入射器におけるRF電子銃用レーザーの高性能化

Improvements of the Laser System for RF-Gun at SuperKEKB Injector

○張 叡，周 翔宇，夏井 拓也，吉田 光宏，小川 雄二郎（高エ研）

○Rui Zhang, Xiangyu Zhou, Takuya Natsui, Mitsuhiro Yoshida, Yujiro Ogawa (KEK)

For realizing higher charge and low emittance electron and positron beams in SuperKEKB, we have been making improvements in laser system for RF-gun. The difficulty in controlling thermomechanical distortions has been one of the most important factors for preserving high laser conversion efficiency of infrared-to-ultraviolet and operating at higher repetition rate. We demonstrated that efficient removal of waste heat can be realized by adopting Yb:YAG thin disk and copper plate composite via gold-tin (Au-Sn) soldering. On the other hand, amplification under cryogenic environment is an excellent candidate for high repletion laser operation. Gain for seed laser at different wavelength under different pump power density are tested. Excellent thermal management and high charge beams have been achieved by improvements of these two aspects. These demonstrations indicate that effective and excellent thermal management can be realized for the laser system operating under 25 Hz with double bunch or 50 Hz to meet the requirements of SuperKEKB project.