JASRI/SPring-8, Hyogo-ken
JAEA/Kansai, Kyoto
SOLEIL, Gif-sur-Yvette
RIKEN/SPring-8, Hyogo
The University of Tokyo, Tokyo
Keio University, Kanagawa-ken
RIKEN, Saitama
NTT Corp., Kanagawa-ken
KEK, Tsukuba
A seeded FEL is the most promised way to generate fully coherent radiation in a short-wavelength region. After the improvement of the laser and HHG system at the SCSS test accelerator, we have succeeded the amplification of the seed, for the first time, in the plateau region. The wavelength of the seed is 61.5 nm, which is the 13th harmonic of a Ti:Sa laser, and clear intensity increase and spectral narrowing by the FEL was observed. Although there still remains room for optimization of the transverse matching and synchronization of the seed, this result leads to realization of a fully coherent light source to users in VUV and soft x-ray regions.
JASRI/SPring-8, Hyogo-ken
RIKEN/SPring-8, Hyogo
An interlock sensor is indispensable to protect the undulator magnets against radiation damage. The beam halo monitor using diamond detectors, which are operated in photoconductive mode, has been developed for the X-ray free electron laser facility at SPring-8 (XFEL/SPring-8). Pulse-by-pulse measurements are adopted to suppress the background noise efficiently, and to improve the detective sensitivity. The feasibility tests of this monitor have been demonstrated at the SPring-8 compact SASE source (SCSS) test accelerator for SPring-8 XFEL. As the next step, we are trying to improve the high-frequency properties: (a) dimension of diamond detectors was newly designed to optimize the beam halo monitor for SPring-8 XFEL, (b) the microstripline structure is applied in the vacuum chamber to improve the high-frequency property, (c) RF fingers are also applied to suppress the effect of the wake field from intense electron beam. Details of these devices and experimental results are presented.