Open AccessDesign of a variable‐included‐angle Monk–Gillieson monochromator with varied‐line‐spacing gratings
Author(s) -
Amemiya Kenta,
Ohta Toshiaki
Publication year - 2004
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049503023598
Subject(s) - monochromator , beamline , undulator , optics , grating , thermal emittance , photon energy , ray tracing (physics) , physics , line (geometry) , materials science , photon , beam (structure) , geometry , mathematics , wavelength
A novel design concept is presented for a variable‐included‐angle Monk–Gillieson mounting monochromator with a varied‐line‐spacing (VLS) plane grating, in which the grating is illuminated by converging X‐rays. The energy resolution for a beamline with a typical undulator source is estimated by means of the ray‐tracing method. It is shown that the source‐size or slope‐error limited resolution is achieved in a wide energy range by properly changing the included angle. Moreover, relatively high resolution is maintained even if one scans the photon energy with a fixed included angle, which is a great advantage over the previous VLS grating monochromator with diverging illumination on the grating. A design example for a bending‐magnet beamline is also presented, indicating that the new design concept is valid even for high‐emittance sources.