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Proceedings Paper • Open Access

Structure in defocused beams of x-ray mirrors: causes and possible solutions

Paper Abstract

Grazing incidence mirrors are now a standard optic for focusing X-ray beams. Both bimorph and mechanically bendable mirrors are widely used at Diamond Light Source because they permit a wide choice of focal lengths. They can also be deliberately set out of focus to enlarge the X-ray beam, and indeed many beamline teams now wish to generate uniform beam spots of variable size. However, progress has been slowed by the appearance of fine structure in these defocused beams. Measurements showing the relationship between the medium-frequency polishing error and this structure over a variety of beam sizes will be presented. A theoretical model for the simulations of defocused beams from general mirrors will then be developed. Not only the figure error and its first derivative the slope error, but also the second derivative, the curvature error, must be considered. In conclusion, possible ways to reduce the defocused beam structure by varying the actuators' configuration and settings will be discussed.

Paper Details

Date Published: 5 September 2014
PDF: 13 pages
Proc. SPIE 9208, Adaptive X-Ray Optics III, 92080G (5 September 2014); doi: 10.1117/12.2061941
Show Author Affiliations
John P. Sutter, Diamond Light Source Ltd. (United Kingdom)
Simon G. Alcock, Diamond Light Source Ltd. (United Kingdom)
Fiona Rust, Univ. of Bath (United Kingdom)
Hongchang Wang, Diamond Light Source Ltd (United Kingdom)
Kawal Sawhney, Diamond Light Source Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 9208:
Adaptive X-Ray Optics III
Stephen L. O'Dell; Ali M. Khounsary, Editor(s)

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