Commissioning of Japanese X-ray Free Electron Laser, SACLA and Achieved Laser Performance

Abstract

After 8 months of beam commissioning of SPring-8 Angstrom Compact free electron LAser, SACLA reached the primary target performance, i.e., a shortest laser wavelength of ～0.6 Angstrom and a laser pulse energy value of submJ at a wavelength of 1.2 Angstrom. This success was due to the following four factors; (1) performance estimation of each component of SACLA required for the target laser performance and its achievement, (2) elaboration of beam diagnostics and control systems enabling precise accelerator and undulator tuning, (3) a rational and strategic commissioning plan, (4) most adequate response to various accidental events during the beam commissioning period. This article, in order to light up the above four factors leading us to the success, starts with the features of SACLA and critical tolerance for the sub-system components, and then, explains our approach to achieve the target laser performance and how the beam commissioning of SACLA proceeded. At last, the article summarizes the present laser and operational status.