S. Silvestri

The LAUE project and its main results

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.

Development status of the LAUE project

We present the status of LAUE, a project supported by the Italian Space Agency (ASI), and devoted to develop Laue lenses with long focal length (from 10–15 meters up to 100 meters), for hard X–/soft gamma–ray astronomy (80-600 keV). Thanks to their focusing capability, the design goal is to improve the sensitivity of the current instrumention in the above energy band by 2 orders of magnitude, down to a few times 10−8 photons/(cm2 s keV).

Development status of a Laue lens project for gamma-ray astronomy

We report the status of the HAXTEL project, devoted to perform a design study and the development of a Laue lens prototype. After a summary of the major results of the design study, the approach adopted to develop a Demonstration Model of a Laue lens is discussed, the set up described, and some results presented.

Development status of a Laue lens for high-energy x rays (>60 keV)

A Laue lens for focusing X-ray photons with energies above 60 keV for astrophysical applications is being developed. The lens is based on mosaic crystals of Cu (111) produced at the Institute Laue-Langevin. A feasibility study has allowed to establish lens geometry and crystal properties required. The test of the crystals has provided very satisfactory results. We are now developing a Demonstration Model (DM) of the lens in order to establish the best assembling technique of the crystals. We will discuss the status of the project and its prospects.

Focusing effect of bent GaAs crystals for γ-ray Laue lenses: Monte Carlo and experimental results

We report on results of observation of the focusing effect from the planes (220) of Gallium Arsenide (GaAs) crystals. We have compared the experimental results with the Monte Carlo simulations of the focusing capability of GaAs tiles performed with a dedicated ray-tracer. The GaAs tiles were bent using a lapping process developed at the cnr/imem - Parma (Italy) in the framework of the laue project, funded by ASI, dedicated to build a broad band Laue lens prototype for astrophysical applications in the hard X-/soft γ-ray energy range (80-600 keV). We present and discuss the results obtained from their characterization, mainly in terms of focusing capability. Bent crystals will significantly increase the signal to noise ratio of a telescope based on a Laue lens, consequently leading to an unprecedented enhancement of sensitivity with respect to the present non focusing instrumentation.

Gamma-ray lens development status for a European Gamma-Ray Imager

A breakthrough in the sensitivity level of the hard X-/gamma-ray telescopes, which today are based on detectors that view the sky through (or not) coded masks, is expected when focusing optics will be available also in this energy range. Focusing techniques are now in an advanced stage of development. To date the most efficient technique to focus hard X-rays with energies above 100 keV appears to be the Bragg diffraction from crystals in transmission configuration (Laue lenses). Crystals with mosaic structure appear to be the most suitable to build a Laue lens with a broad passband, even though other alternative structures are being investigated. The goal of our project is the development of a broad band focusing telescope based on gamma-ray lenses for the study of the continuum emission of celestial sources from 60 keV up to >600 keV. We will report details of our project, its development status and results of our assessment study of a lens configuration for the European Gamma Ray Imager (GRI) mission now under study for the ESA plan Cosmic Vision 2015-2025.

Feasibility study of a Laue lens for hard x rays for space astronomy

We report on the feasibility study of a Laue lens for hard X-rays (> 60 keV) based on mosaic crystals, for astrophysical applications. In particular we discuss the scientific motivations, its functioning principle, the procedure followed to select the suitable crystal materials, the criteria adopted to establish crystal dimensions and their distribution on the lens in order to obtain the best lens focusing capabilities, and the criteria for optimizing the lens effective area in a given passband. We also discuss the effects of misalignments of the crystal tiles due to unavoidable mechanical errors in assembling the lens. A software was developed to face all these topics and to evaluate the expected lens performance.

The ground support equipment for the LAUE project

The development of wide band Laue lens imaging technology is challenging, but has important potential applications in hard X- and γ-ray space instrumentation for the coming decades. The Italian Space Agency has funded a project dedicated to the development of a reliable technology to assemble a wide band Laue lens for use in space. The ground support equipment (GSE) for this project was fundamental to its eventual success... The GSE was implemented in a hard X-ray beam line built at the University of Ferrara and had the main purpose of controlling the assembly of crystals onto the Laue lens petal and to verify its final performance. The GSE incorporates the management and control of all the movements of the beam line mechanical subsystems and of the precision positioner (based on a Hexapod tool) of crystals on the petal, as well as the acquisition, storing and analysis of data obtained from the focal plane detectors (an HPGe spectrometer and an X-ray flat panel imager). The GSE is based on two PC’s connected through a local network: one, placed inside the beam line, to which all the movement subsystems and the detector I/O interface and on which all the management and acquisition S/W runs, the other in the control room allows the remote control and implements the offline analysis S/W of the data obtained from the detectors. Herein we report on the GSE structure with its interface with the beam line mechanical system, with the fine crystal positioner and with the focal plane detector. Furthermore we describe the SW developed for the handling of the mechanical movement subsystems and for the analysis of the detector data with the procedure adopted for the correct orientation of the crystals before their bonding on the lens petal support.

The Narrow Field telescope on board the ASTENA mission (Conference Presentation)

The ASTENA mission concept consists of a broad band Wide Field Monitor Imager and Spectrometer and a broad band Narrow Field Telescope. The latter is a Laue lens (∼3 m diameter, 20 m focal length) sensitive to the 50 – 600 keV energy pass-band made of Silicon and Germanium cylindrical bent crystals. Such crystals allow the radiation to be focused into a narrow point spread function never achieved so far. In the presented configuration the instrument field of view is ∼ 4 arcmin with angular resolution of ∼30 arcsec. The Laue lens is coupled with a high efficiency (>80% above 600 keV) focal plane position sensitive detector, with 3D spatial resolution of 300 μm in the (X,Y) plane, fine spectroscopic response (1% at 511 keV) and polarization sensitivity. In this paper we present an overview on the satellite configuration and we mainly focus on the Narrow Field Telescope design and performances estimated with Monte Carlo simulations.

The application software of the instrument control unit of Euclid-NISP: ready for qualification tests

In this paper we describe the application software (ASW) of the instrument control unit (ICU) of NISP, the Near-Infrared Spectro-Photometer of the Euclid mission. This software is based on a real-time operating system (RTEMS) and will interface with all the subunits of NISP, as well as the command and data management unit (CDMU) of the spacecraft for telecommand and housekeeping management.