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Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment

The efficiency of a Laue lens for X- and γ-ray focusing in the energy range 60–600 keV is closely linked to the diffraction efficiency of the single crystals composing the lens. A powerful focusing system is crucial for applications like medical imaging and X-ray astronomy where wide beams must be f...

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Autores principales: Bonnini, Elisa, Buffagni, Elisa, Zappettini, Andrea, Doyle, Stephen, Ferrari, Claudio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4453971/
https://www.ncbi.nlm.nih.gov/pubmed/26089758
http://dx.doi.org/10.1107/S1600576715006809
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author Bonnini, Elisa
Buffagni, Elisa
Zappettini, Andrea
Doyle, Stephen
Ferrari, Claudio
author_facet Bonnini, Elisa
Buffagni, Elisa
Zappettini, Andrea
Doyle, Stephen
Ferrari, Claudio
author_sort Bonnini, Elisa
collection PubMed
description The efficiency of a Laue lens for X- and γ-ray focusing in the energy range 60–600 keV is closely linked to the diffraction efficiency of the single crystals composing the lens. A powerful focusing system is crucial for applications like medical imaging and X-ray astronomy where wide beams must be focused. Mosaic crystals with a high density, such as Cu or Au, and bent crystals with curved diffracting planes (CDPs) are considered for the realization of a focusing system for γ-rays, owing to their high diffraction efficiency in a predetermined angular range. In this work, a comparison of the efficiency of CDP crystals and Cu and Au mosaic crystals was performed on the basis of the theory of X-ray diffraction. Si, GaAs and Ge CDP crystals with optimized thicknesses and moderate radii of curvature of several tens of metres demonstrate comparable or superior performance with respect to the higher atomic number mosaic crystals generally used. In order to increase the efficiency of the lens further, a stack of several CDP crystals is proposed as an optical element. CDP crystals were obtained by a surface-damage method, and a stack of two surface-damaged bent Si crystals was prepared and tested. Rocking curves of the stack were performed with synchrotron radiation at 19 keV to check the lattice alignment: they exhibited only one diffraction peak.
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spelling pubmed-44539712015-06-18 Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment Bonnini, Elisa Buffagni, Elisa Zappettini, Andrea Doyle, Stephen Ferrari, Claudio J Appl Crystallogr Research Papers The efficiency of a Laue lens for X- and γ-ray focusing in the energy range 60–600 keV is closely linked to the diffraction efficiency of the single crystals composing the lens. A powerful focusing system is crucial for applications like medical imaging and X-ray astronomy where wide beams must be focused. Mosaic crystals with a high density, such as Cu or Au, and bent crystals with curved diffracting planes (CDPs) are considered for the realization of a focusing system for γ-rays, owing to their high diffraction efficiency in a predetermined angular range. In this work, a comparison of the efficiency of CDP crystals and Cu and Au mosaic crystals was performed on the basis of the theory of X-ray diffraction. Si, GaAs and Ge CDP crystals with optimized thicknesses and moderate radii of curvature of several tens of metres demonstrate comparable or superior performance with respect to the higher atomic number mosaic crystals generally used. In order to increase the efficiency of the lens further, a stack of several CDP crystals is proposed as an optical element. CDP crystals were obtained by a surface-damage method, and a stack of two surface-damaged bent Si crystals was prepared and tested. Rocking curves of the stack were performed with synchrotron radiation at 19 keV to check the lattice alignment: they exhibited only one diffraction peak. International Union of Crystallography 2015-04-25 /pmc/articles/PMC4453971/ /pubmed/26089758 http://dx.doi.org/10.1107/S1600576715006809 Text en © Elisa Bonnini et al. 2015 http://creativecommons.org/licenses/by/2.0/uk/ This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
spellingShingle Research Papers
Bonnini, Elisa
Buffagni, Elisa
Zappettini, Andrea
Doyle, Stephen
Ferrari, Claudio
Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment
title Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment
title_full Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment
title_fullStr Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment
title_full_unstemmed Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment
title_short Surface-treated self-standing curved crystals as high-efficiency elements for X- and γ-ray optics: theory and experiment
title_sort surface-treated self-standing curved crystals as high-efficiency elements for x- and γ-ray optics: theory and experiment
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4453971/
https://www.ncbi.nlm.nih.gov/pubmed/26089758
http://dx.doi.org/10.1107/S1600576715006809
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