Preparation of bent crystals as high-efficiency optical elements for hard x-ray astronomy

Buffagni, E.; Ferrari, C.; Rossi, Francesca; Marchini, L.; Zappettini, A.

doi:10.1117/12.893701

Cited by 11 publications

(17 citation statements)

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“…An extremely uniform and highly reproducible curvature is achieved even if the grooves cause damage and fragility of the crystals 12 . Instead, a self-standing curvature is obtained by imem/cnr Parma by means of a controlled mechanical damaging of one surface of the sample 13 . This lapping procedure introduces defects in a superficial layer of a few microns, providing a highly compressive strain responsible for the convexity appearing in the crystal.…”

Section: The Laue Project: An Overviewmentioning

confidence: 99%

Hard x-ray broad band Laue lenses (80-600 keV): building methods and performances

et al. 2015

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We present the status of the laue project devoted to develop a technology for building a 20 meter long focal length Laue lens for hard X-/soft gamma-ray astronomy (80-600 keV). The Laue lens is composed of bent crystals of Gallium Arsenide (GaAs, 220) and Germanium (Ge, 111), and, for the first time, the focusing property of bent crystals has been exploited for this field of applications. We show the preliminary results concerning the adhesive employed to fix the crystal tiles over the lens support, the positioning accuracy obtained and possible further improvements. The Laue lens petal that will be completed in a few months has a pass band of 80-300 keV and is a fraction of an entire Laue lens capable of focusing X-rays up to 600 keV, possibly extendable down to ∼20-30 keV with suitable low absorption crystal materials and focal length. The final goal is to develop a focusing optics that can improve the sensitivity over current telescopes in this energy band by 2 orders of magnitude.

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Section: The Laue Project: An Overviewmentioning

confidence: 99%

Hard x-ray broad band Laue lenses (80-600 keV): building methods and performances

et al. 2015

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“…The lens petal will be assembled with bent crystal tiles of Germanium (111) (LSS), and Gallium Arsenide (220) (IMEM). The curvature of the Ge (111) tiles are obtained by indentations 5,6 while the GaAs (220) tiles are bent by surface lapping 7,8 . For both the specimen an excellent cylindrical or spherical shape with the desired curvature radius can be obtained.…”

Section: Crystals Selectionmentioning

confidence: 99%

The LAUE project and its main results

et al. 2013

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We will describe the LAUE project, supported by the Italian Space Agency, whose aim is to demonstrate the capability to build a focusing optics in the hard X-/soft gamma-ray domain (80-600 keV). To show the lens feasibility, the assembling of a Laue lens petal prototype with 20 m focal length is ongoing. Indeed, a feasibility study, within the LAUE project, has demonstrated that a Laue lens made of petals is feasible. Our goal is a lens in the 80-600 keV energy band. In addition to a detailed description of the new LARIX facility, in which the lens is being assembled, we will report the results of the project obtained so far.

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“…The crystal curvature is obtained by a controlled surface damaging, which introduces defects in a superficial layer of few tens of nanometers in thickness undergoing a highly compressive strain. The controlled surface damaging were obtained by means of a mechanical lapping process on one of the two sides of the planar samples [9].…”

Section: Crystal Bendingmentioning

confidence: 99%

Bent crystal selection and assembling for the LAUE project

Liccardo¹,

Virgilli²,

Frontera³

et al. 2013

SPIE Proceedings

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For the first time, with the Laue project, bent crystals are being used for focusing photons in the 80-300 keV energy range. The advantage is their high reflectivity and better Point Spread Function with respect to the mosaic flat crystals. Simulations have already shown their excellent focusing capability which makes them the best candidates for a Laue lens whose sensitivity is also driven by the size of the focused spot. Selected crystals are Germanium (perfect, (111)) and Gallium Arsenide (mosaic, (220)) with 40 m curvature radius to get a spherical lens with 20 m long focal length. A lens petal is being built. We report the measurement technique by which we are able to estimate the exact curvature of each tile within a few percent of uncertainty and their diffraction efficiency. We also discuss some results.

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Preparation of bent crystals as high-efficiency optical elements for hard x-ray astronomy

Cited by 11 publications

References 0 publications

Hard x-ray broad band Laue lenses (80-600 keV): building methods and performances

Hard x-ray broad band Laue lenses (80-600 keV): building methods and performances

The LAUE project and its main results

Bent crystal selection and assembling for the LAUE project

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