Open AccessHeat bump on a monochromator crystal measured with X‐ray grating interferometry
Author(s) -
Rutishauser Simon,
Rack Alexander,
Weitkamp Timm,
Kayser Yves,
David Christian,
Macrander Albert T.
Publication year - 2013
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/s0909049513001817
Subject(s) - monochromator , optics , interferometry , wavefront , grating , synchrotron radiation , materials science , crystal (programming language) , deformation (meteorology) , x ray optics , wavelength , physics , photon energy , photon , x ray , computer science , composite material , programming language
Deformation of the first crystal of an X‐ray monochromator under the heat load of a high‐power beam, commonly referred to as `heat bump', is a challenge frequently faced at synchrotron beamlines. Here, quantitative measurements of the deformations of an externally water‐cooled silicon (111) double‐crystal monochromator tuned to a photon energy of 17.6 keV are reported. These measurements were made using two‐dimensional hard X‐ray grating interferometry, a technique that enables in situ at‐wavelength wavefront investigations with high angular sensitivity. The observed crystal deformations were of the order of 100 nm in the meridional and 5 nm in the sagittal direction, which lead to wavefront slope errors of up to 4 µrad in the meridional and a few hundred nanoradians in the sagittal direction.