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Title: Finite-element modelling of multilayer X-ray optics

Abstract

Multilayer optical elements for hard X-rays are an attractive alternative to crystals whenever high photon flux and moderate energy resolution are required. Prediction of the temperature, strain and stress distribution in the multilayer optics is essential in designing the cooling scheme and optimizing geometrical parameters for multilayer optics. The finite-element analysis (FEA) model of the multilayer optics is a well established tool for doing so. Multilayers used in X-ray optics typically consist of hundreds of periods of two types of materials. The thickness of one period is a few nanometers. Most multilayers are coated on silicon substrates of typical size 60 mm × 60 mm × 100–300 mm. The high aspect ratio between the size of the optics and the thickness of the multilayer (10 7) can lead to a huge number of elements for the finite-element model. For instance, meshing by the size of the layers will require more than 10 16elements, which is an impossible task for present-day computers. Conversely, meshing by the size of the substrate will produce a too high element shape ratio (element geometry width/height > 10 6), which causes low solution accuracy; and the number of elements is still very large (10 6). Inmore » this work, by use of ANSYS layer-functioned elements, a thermal-structural FEA model has been implemented for multilayer X-ray optics. The possible number of layers that can be computed by presently available computers is increased considerably.« less

Authors:
;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1360944
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Synchrotron Radiation (Online); Journal Volume: 24; Journal Issue: 3
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Cheng, Xianchao, and Zhang, Lin. Finite-element modelling of multilayer X-ray optics. United States: N. p., 2017. Web. doi:10.1107/S1600577517004738.
Cheng, Xianchao, & Zhang, Lin. Finite-element modelling of multilayer X-ray optics. United States. doi:10.1107/S1600577517004738.
Cheng, Xianchao, and Zhang, Lin. Tue . "Finite-element modelling of multilayer X-ray optics". United States. doi:10.1107/S1600577517004738.
@article{osti_1360944,
title = {Finite-element modelling of multilayer X-ray optics},
author = {Cheng, Xianchao and Zhang, Lin},
abstractNote = {Multilayer optical elements for hard X-rays are an attractive alternative to crystals whenever high photon flux and moderate energy resolution are required. Prediction of the temperature, strain and stress distribution in the multilayer optics is essential in designing the cooling scheme and optimizing geometrical parameters for multilayer optics. The finite-element analysis (FEA) model of the multilayer optics is a well established tool for doing so. Multilayers used in X-ray optics typically consist of hundreds of periods of two types of materials. The thickness of one period is a few nanometers. Most multilayers are coated on silicon substrates of typical size 60 mm × 60 mm × 100–300 mm. The high aspect ratio between the size of the optics and the thickness of the multilayer (107) can lead to a huge number of elements for the finite-element model. For instance, meshing by the size of the layers will require more than 1016elements, which is an impossible task for present-day computers. Conversely, meshing by the size of the substrate will produce a too high element shape ratio (element geometry width/height > 106), which causes low solution accuracy; and the number of elements is still very large (106). In this work, by use of ANSYS layer-functioned elements, a thermal-structural FEA model has been implemented for multilayer X-ray optics. The possible number of layers that can be computed by presently available computers is increased considerably.},
doi = {10.1107/S1600577517004738},
journal = {Journal of Synchrotron Radiation (Online)},
number = 3,
volume = 24,
place = {United States},
year = {Tue Apr 11 00:00:00 EDT 2017},
month = {Tue Apr 11 00:00:00 EDT 2017}
}