Improved optical cavity quality of a waveguide free-electron laser with hole coupling by using a grating

2000 ◽  
Vol 39 (6) ◽  
pp. 1543 ◽  
Author(s):  
Yuanzhang Wang
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Optical Cavity

scholarly journals Specimen preparation for cryogenic coherent X-ray diffraction imaging of biological cells and cellular organelles by using the X-ray free-electron laser at SACLA

2016 ◽  
Vol 23 (4) ◽  
pp. 975-989 ◽  
Author(s):  
Amane Kobayashi ◽  
Yuki Sekiguchi ◽  
Tomotaka Oroguchi ◽  
Koji Okajima ◽  
Asahi Fukuda ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Internal Structures ◽  
Thin Membranes ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Cellular Organelles

Coherent X-ray diffraction imaging (CXDI) allows internal structures of biological cells and cellular organelles to be analyzed. CXDI experiments have been conducted at 66 K for frozen-hydrated biological specimens at the SPring-8 Angstrom Compact Free-Electron Laser facility (SACLA). In these cryogenic CXDI experiments using X-ray free-electron laser (XFEL) pulses, specimen particles dispersed on thin membranes of specimen disks are transferred into the vacuum chamber of a diffraction apparatus. Because focused single XFEL pulses destroy specimen particles at the atomic level, diffraction patterns are collected through raster scanning the specimen disks to provide fresh specimen particles in the irradiation area. The efficiency of diffraction data collection in cryogenic experiments depends on the quality of the prepared specimens. Here, detailed procedures for preparing frozen-hydrated biological specimens, particularly thin membranes and devices developed in our laboratory, are reported. In addition, the quality of the frozen-hydrated specimens are evaluated by analyzing the characteristics of the collected diffraction patterns. Based on the experimental results, the internal structures of the frozen-hydrated specimens and the future development for efficient diffraction data collection are discussed.

scholarly journals Multiple-Collision Free-Electron Laser Compton Backscattering for a High-Yield Gamma-Ray Source

2020 ◽  
Vol 10 (4) ◽  
pp. 1418
Author(s):  
Norihiro Sei ◽  
Hiroshi Ogawa ◽  
QiKa Jia
Keyword(s):  
Gamma Rays ◽  
Free Electron ◽  
Free Electron Laser ◽  
Gamma Ray ◽  
Optical Cavity ◽  
High Yield ◽  
Multiple Collision ◽  
Collision Point ◽  
Compton Backscattering ◽  
Multiple Collisions

We observed multiple-collision free-electron laser (FEL)-Compton backscattering in which a multi-bunch electron beam makes head-on collisions with multi-pulse FELs in an optical cavity, using an infrared FEL system in the storage ring NIJI-IV. It was demonstrated that the measured spectrum of the multiple-collision FEL-Compton backscattering gamma rays was the summation of the spectra of the gamma rays generated at each collision point. Moreover, it was demonstrated that the spatial distribution of the multiple-collision FEL-Compton backscattering gamma rays was the summation of those of the gamma rays generated at each collision point. Our experimental results proved quantitatively that the multiple collisions in the FEL-Compton backscattering process are effective in increasing the yield of the gamma rays. By applying the multiple-collision FEL-Compton backscattering to high-repetition FEL devices such as energy recovery linac FELs, an unprecedented high-yield gamma-ray source with quasi-monochromaticity and wavelength tunability will be realized.

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