Heat bump on a monochromator crystal measured with X‐ray grating interferometry. (8th February 2013)

• Record Type: Journal Article
• Authors: Rutishauser, Simon; Rack, Alexander; Weitkamp, Timm; Kayser, Yves; David, Christian; Macrander, Albert T.
• Is Part Of: Journal of synchrotron radiation. Volume 20:Part 2(2013)
• Page Start: 300
• Page End: 305
• Publication Date: 2013-02-08
• Subjects: Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S0909049513001817
• Languages: English
• ISSNs: 0909-0495

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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 <italic>in situ</italic> 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.</p> </abstract>