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Asymmetrically grooved monolithic crystal monochromators for suppression of harmonics in synchrotron X‐radiation
Author(s) -
Hashizume H.
Publication year - 1983
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889883010729
Subject(s) - harmonics , monochromator , optics , synchrotron radiation , crystal (programming language) , diffraction , harmonic , beam (structure) , synchrotron , materials science , wavelength , silicon , radiation , physics , optoelectronics , acoustics , computer science , quantum mechanics , voltage , programming language
To suppress unwanted harmonics in crystal‐diffracted synchrotron X‐radiation, monolithic grooved‐crystal monochromators have been studied in theory and experiment. Simply by building non‐parallel groove walls in a perfect crystal, the overlap of dynamical diffraction ranges on the two crystals is canceled for higher harmonics, while a partial overlap is preserved for the fundamental, leading to a substantial improvement in fundamental‐to‐harmonics ratio in the diffracted beam. A grooved silicon 111 monochromator with wall angles of 0 and 7° delivers a beam of harmonic contamination better than 3.3% at fundamental wavelengths between 1.2 and 1.6 Å with a beam intensity exceeding 50% of that available from a standard channel‐cut crystal. Silicon 331 and 511 versions can achieve harmonic contaminations well below 0.1%. Asymmetrically grooved monochromators can work as stable wavelength scanners free from harmonics requiring no delicate control of angle.