Laue lens development for hard X-rays (>60 keV)

Abstract

Abstract-Results of reflectivity measurements of mosaic crystal samples of Cu (111) are reported. These tests were performed in the context of a feasibility study of a hard X-ray focusing telescope for space astronomy with energy passband from 60 to 600 keV. The technique envisaged is that of using mosaic crystals in transmission configuration that diffract X-rays for Bragg diffraction (Laue lens). The Laue lens assumed has a spherical shape with focal length f . It is made of flat mosaic crystal tiles suitably positioned in the lens. The samples were grown and worked for this project at the Institute Laue-Langevin (ILL) in Grenoble (France), while the reflectivity tests were performed at the X-ray facility of the Physics Department of the University of Ferrara.

Laue Gamma-Ray Lenses for Space Astrophysics: Status and Prospects

“…From extended tests performed on Cu(111) supplied by ILL [32], it was found that the condition above is satisfied in single points [22], but not when the entire crystal cross section is irradiated (values even higher than 100 μm have been found [24]). In addition, in [24], it is found that t 0 is energy dependent, which is a surprising result that requires an interpretation (see discussion therein).…”

The Ferrara hard X-ray facility for testing/calibrating hard X-ray focusing telescopes

“…An PC-based interface running LabView provides a user-friendly environment for using this X-ray imager for locating the X-ray beam and other user applications. Details on the detector configuration can be found elsewhere ( [11], [5]). The CZT X-ray detector, Peltier-cooled to 250 K, is used to monitor the intensity and the spectrum of the pencil beam incident on the sample to be tested.…”

“…After the ground calibration of the JEM-X detectors, as mentioned before [4], the facility in the current configuration has been used for reflectivity measurements of crystal samples of Cu (111) in Laue configuration within the development project of a hard X-ray focusing optics [5]. The centroid energy of the monochromatized photons measured with the CZT detector is compared with the energy expected from the Bragg law (see Fig.…”

“…An example of reflectivity measurement of a mosaic crystal sample of Cu (111) expected to be used as reflecting material in a Laue lens [5] under development is shown in Fig. 8.…”

“…The Ferrara X-ray facility has already been used to, e.g., perform the ground calibration of the JEM-X (Joint European Monitor for X-rays) detectors on board the INTEGRAL satellite [4], reflectivity measurements of mosaic crystals (graphite [7], Cu (111) [5]) and non linearity tests of hard X-ray detectors ( [8]). Here we summarize the past configuration of the Ferrara X-ray facility and the current extention.…”