Sacla 軟 x 線自由電子レーザービームラインのビーム特性 beam characteristics of the soft x-ray free-electron laser beamline of sacla

At the x-ray free-electron laser (FEL) facility, SACLA, a spontaneous beamline-1 (BL1) has been upgraded to a soft x-ray FEL beamline. A dedicated electron-beam accelerator, which is a refinement of the SCSS test accelerator, was installed beside the hard XFEL beamlines in the SACLA undulator hall. In the 2016 summer shutdown period, the electron beam energy was upgraded from 500 MeV to 800 MeV by adding two C-band rf units. The maximum K-value of the undulator magnet is 2.1. The available wavelengths of the FEL lights were extended to the range from 8 to 60 nm with the pulse energies between several to one hundred microjoules at a pulse repetition rate of 60 Hz. In this paper, we report an overview of the upgraded SACLA-BL1 and characteristics of the electron beam and the FEL light beam.