Journal Article

PUBDB-2015-01502

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Specification of X-ray Mirrors in Terms of System Performance: new Twist to an old Plot

Yashchuk, V. V. (Corresponding Author) ; Samoylova, L.>Extern*XFEL* ; Kozhevnikov, I. V.

2015
SPIE Bellingham, Wash.

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Please use a persistent id in citations: doi:10.1117/1.OE.54.2.025108

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.

Note: OA

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Contributing Institute(s):

1. European XFEL (Eur.XFEL)

Research Program(s):

1. 6G13 - XFEL (POF3-622) (POF3-622)

Experiment(s):

1. Measurement at external facility

Appears in the scientific report 2015

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Database coverage:
; ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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