Record Details

Title:
Specification of X-ray Mirrors in Terms of System Performance: new Twist to an old Plot
Affiliation(s):
EuXFEL staff
Author group:
X-Ray Optics
Topic:
Abstract:
In the early 1990s, Church and Takacs pointed out that the specification of surface figure and finish of x-ray mirrors must be based on their performance in the beamline optical system. We demonstrate the limitations of specification, characterization, and performance evaluation based on conventional statistical approaches, including root-mean-square roughness and residual slope variation, evaluated over spatial frequency bandwidths that are system specific, and a more refined description of the surface morphology based on the power spectral density distribution. We show that these limitations are fatal, especially in the case of highly collimated coherent x-ray beams, like beams from x-ray free electron lasers (XFELs). The limitations arise due to the deterministic character of the surface profile data for a definite mirror, while the specific correlation properties of the surface are essential for the performance of the entire x-ray optical system. As a possible way to overcome the problem, we treat a method, suggested by Yashchuk and Yashchuk in 2012, based on an autoregressive moving average modeling of the slope measurements with a limited number of parameters. The effectiveness of the approach is demonstrated with an example specific to the x-ray optical systems under design at the European XFEL.
Imprint:
Bellingham, Wash., SPIE, 2015
Journal Information:
Opt. Eng., 54, 2, 025108 (2015)
ISSN:
0036-1860
0091-3286
1560-2303
Related external records:
DOI: 10.1117/1.OE.54.2.025108
WOS: WOS:000350481900026
Language(s):
English


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 Record created 2016-10-11, last modified 2019-01-30

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