A micro channel-cut crystal X-ray monochromator for a self-seeded hard X-ray free-electron laser
説明
<jats:p>A channel-cut Si(111) crystal with a channel width of 90 µm was developed for achieving reflection self-seeding in hard X-ray free-electron lasers (XFELs). With the crystal a monochromatic seed pulse is produced from a broadband XFEL pulse generated in the first undulator section with an optical delay of 119 fs at 10 keV. The small optical delay allows a temporal overlap between the seed optical pulse and the electron bunch by using a small magnetic chicane for the electron beam placed between two undulator sections. Peak reflectivity reached 67%, which is reasonable compared with the theoretical value of 81%. By using this monochromator, a monochromatic seed pulse without broadband background in the spectrum was obtained at SACLA with a conversion efficiency from a broadband XFEL pulse of 2 × 10<jats:sup>−2</jats:sup>, which is ∼10 times higher than the theoretical efficiency of transmission self-seeding using a thin diamond (400) monochromator.</jats:p>
収録刊行物
-
- Journal of Synchrotron Radiation
-
Journal of Synchrotron Radiation 26 (5), 1496-1502, 2019-08-27
International Union of Crystallography (IUCr)
