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K α 1 – K α 2 characteristic of a parabolic graded multilayer
Author(s) -
Toraya H.,
Hibino H.
Publication year - 2000
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/s0021889800010396
Subject(s) - diffraction , wavelength , intensity (physics) , beam (structure) , resolution (logic) , optics , crystal (programming language) , spectral line , physics , materials science , artificial intelligence , computer science , astronomy , programming language
Line shapes of the K α 1 – K α 2 doublet beam reflected from a parabolic graded multilayer (PGM) were analysed by ray tracing and rocking‐curve measurements using an Si(400) flat single crystal. The integrated intensity and the intensity ratio of K α 2 to K α 1 of the reflected beam vary with the angle of incidence at the PGM. The rates of these variations are considered to increase with increasing spectral resolution of the PGM. The K α 1 and K α 2 beams are reflected from the PGM in slightly different directions. Therefore, the angular separation between the K α 1 and K α 2 peaks of the observed diffraction profile of a sample becomes smaller than that calculated from the two wavelengths for K α 1 and K α 2 when the PGM and the sample are arranged in the (+−) setting, and vice versa when they are in the (++) setting. The magnitude of the shift of the angular separation is close to the experimental uncertainty in the determination of the peak positions when the PGM consists of W/Si bilayers, whereas it is estimated to be three times as large when a PGM of high spectral resolution is used.