TUP054 　レーザー　 8月9日 コンベンションホール 13:10 - 15:10

SuperKEKB入射器におけるRF電子銃用レーザー安定性と出力エネルギーの高性能化

Improvements of Stable and High Output Energy 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)

In order to achieve high charge and low emittance electron beam as well as positron beam in SuperKEKB, we have been making improvements in thin disk laser part for RF-gun. By use of gold tin soldering, Yb:YAG thin disk and copper plate composite is available to realize efficient removal of waste heat. More than 3 nC electron charge has been generated successfully under 5 Hz laser operation. For final aim 50 Hz laser operation, further improvements should be taken for controlling thermomechanical distortions in thin disk laser part. Heat sink with high quality has been adopted and investigated in place of the former copper plate. By soldering the Yb:YAG thin disk on the heat sink directly, more excellent thermal management can be achieved as to reduce thermal lens effect. Besides, residual stress introduced by soldering becomes weaker than that of former design. In addition, laser operation at low temperature has been investigated by use of the new soldering composite. The design with high gain which is realized by a small size vacuum chamber possesses flexibility for pump arrangement and seed laser injection.