178 research outputs found
Expected performance of a Laue lens based on bent crystals
In the context of the LAUE project devoted to build a long focal length
focusing optics for soft gamma-ray astronomy (70/100 keV to 600 keV), we
present results of simulation of a Laue lens, based on bent crystals in
different assembling configurations (quasi-mosaic and reflection-like
geometries). The main aim is to significantly overcome the sensitivity limits
of the current generation of gamma-ray telescopes and improve the imaging
capability.Comment: 7 pages, 7 figures, presented at the Space Telescopes and
Instrumentation Symposium 2012: Ultraviolet to Gamma Ray Conference.
Published in Proceedings of the SPIE, Volume 8443, id. 844331-844331-7 (2012
Crystals for X/gamma-ray space telescopes
We will review the status of the Laue lens development of space astrophysics and the importance of the curved crystals for optimizing the lens performance
Bent crystal selection and assembling for the LAUE project
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.Comment: 9 pages, 15 figures, SPIE conference vol. 8861 (2013
Results of the simulations of the petal/lens as part of the LAUE project
In the context of the LAUE project for focusing hard X-/gamma rays, a petal
of the complete lens is being assembled at the LARIX facility in the Department
of Physics and Earth Science of the University of Ferrara. The lens petal
structure is composed of bent Germanium and Gallium Arsenide crystals in
transmission geometry. We present the expectations derived from a mathematical
model of the lens petal. The extension of the model for the complete LAUE
project in the 90 -- 600 keV energy range will be discussed as well. A
quantitative analysis of the results of these simulations is also presented.Comment: 12 pages, 26 figures, SPIE optics + Photonics conference 2013, Vol:
886
Expected performances of a Laue lens made with bent crystals
In the context of the LAUE project devoted to build a Laue lens prototype for
focusing celestial hard X-/soft gamma-rays, a Laue lens made of bent crystal
tiles, with 20 m focal length, is simulated. The focusing energy passband is
assumed to be 90--600 keV. The distortion of the image produced by the lens on
the focal plane, due to effects of crystal tile misalignment and radial
distortion of the crystal curvature, is investigated. The corresponding
effective area of the lens, its point spread function and sensitivity are
calculated and compared with those exhibited by a nominal Laue lens with no
misalignment and/or distortion. Such analysis is crucial to estimate the
optical properties of a real lens, in which the investigated shortcomings could
be present.Comment: 20 pages, 14 figure
Hard x-ray broad band Laue lenses (80 - 600 keV): building methods and performances
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
Estudo do efeito do bombardeamento iônico na evolução do recozimento de Nióbio
Orientador: Sílvio Francisco BrunattoDissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçao em Engenharia - PIPE. Defesa: Curitiba, 2006Inclui bibliografiaÁrea de concentraçao: Engenharia e ciências de materiai
The LAUE project for broadband gamma-ray focusing lenses
We present the LAUE project devoted to develop an advanced technology for
building a high focal length Laue lens for soft gamma--ray astronomy (80-600
keV). The final goal is to develop a focusing optics that can improve the
current sensitivity in the above energy band by 2 orders of magnitude.Comment: 7 pages, 6 figures, presented at the SPIE conference on "Optics for
EUV, X-ray, and Gamma-ray Astronomy". To be published in the Proceedings of
SPIE, vol.8147, 201
Monitoring of the conservation state of the internal wall surfaces of Room with Golden Vault in the Domus Aurea
This project describes the monitoring campaign, performed in situ with the collaboration of Konica Minolta Sensing Europe, in order to verify the actual conservation state of the internal wall surfaces of the Room with Golden Vault in the Domus Aurea in Rome. Particularly, the main aim of this work was to evaluate the problems caused by aggressive environmental conditions (combination of low air temperature and high relative humidity).
During this survey, characterized by the integrated use of two and three-dimensional techniques, the environmental conditions were carefully monitored.
Reference sample regions of the vault were acquired by means of the 3D laser scanner Konica Minolta Vivid 9i (optical triangulation-based) that allows capturing morphological details of the stucco decorations with a good resolution. Moreover, each detailed scan was supplied with related high resolution images taken by a digital reflex camera Olympus E-510 rigidly connected to the scanner. In Cultural Heritage monitoring applications it is important to integrate the data acquired with different instruments and techniques. Therefore, by this methodological approach, it has been possible to integrate both two and three dimensional data by the projection of the acquired images on the corresponding digital model. In order to complete the cognitive framework of the vault, systematic measures of spectrophotometry by means of the portable spectrophotometer Minolta 2600d were also carried out. The digital data, collected and elaborated by this monitoring campaign, allowed to create a database of morphological information, high resolution digital images, colorimetric values and reflectance curves that may be used in the future as reference data to periodically monitor the conservation state of the surfaces
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