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- This workshop was organized with the help
of:
- This workshop was organized with the help
of:
LIST of ABSTRACTS
| Scientific requirements and
prospects |
Gamma-ray Optics |
| Focal plane
instrumentation |
Ground facilities and
Flight systems |
Session 4 : Ground facilities and Flight systems for focusing telescopesAlvarez Jose Manuel
Future gamma-ray beam line at the synchrotron ALBA: a powerful tool to calibrate gamma lenses
A proposal for a future gamma-ray beam line at the spanish synchrotron ALBA, to be built near Barcelona, was presented. The gamma-rays are produced by Compton backscattering of laser light from the ring electrons. In this proposal we have shown that such gamma-ray beam would be very well suited to measure the performance of instruments for gamma-ray astronomy. The expected intensity of the beam, its high collimation and polarization would provide an unique opportunity to test instruments in the gamma-ray domain, such as the prototype of an innovative LAUE gamma-ray lens for nuclear astrophysics.
Barrière Nicolas
MAX, a Laue diffraction lens for nuclear astrophysics
The next generation of instrumentation for the domain of nuclear astrophysics will have to achieve a factor of 10-100 improvement in sensitivity over present technologies. With the focusing gamma-raytelescope MAX we take up this challenge : combining unprecedented sensitivity with high spectral and angular resolution, and the capability of measuring the polarization of the incident photons.MAX consists of a Laue diffraction lens containing more than 7800 germanium and copper crystal tiles disposed on 24 concentric rings. It simultaneously focuses in two energy pass bands, each one centered on main scientific objectives of the mission: the 800 - 900 keV band is dedicated to the study of nuclear gamma ray lines from type Ia supernovae (e.g. 56Co decay line at 847 keV) while the 450 - 530 keV band concentrates on electron-positron annihilation (511 keV emission) from the Galactic Center. MAX will make use of satellite formation flight to achieve a 86 m focal length, with the lens being carried by one satellite and the detector by the other. MAX has already successfully undergone a pre-phase A study with the French Space Agency CNES.After a summary of the principal scientific objectives of MAX, the characteristics of the instrument are reviewed, and sensitivity estimates for various crystal and detector options are compared. Finally, the status of the MAX R&D is presented, in particular the techniques for crystal mounting and orientation, and the development of new diffracting materials such as composites crystals.
Borde Jacques
Small-sat Platforms and Formation Flying: an opportunity for the gamma ray telescope MAX
This paper presents the results of a study performed by EADS Astrium in support to the Centre d'Etude Spatiale des Rayonnements (CESR, Toulouse, France) for the preliminary definition of the MAX space segment, based on a small-sat platform in the 200 kg range.
MAX is a new concept of gamma ray telescope with as prime objective the study of type Ia supernovae by measuring intensities, shifts and shapes of their nuclear gamma-ray lines. When finally understood and calibrated, these profoundly radioactive events will be crucial in measuring the size, shape, and age of the Universe.
The concept of MAX is radically different from the traditional gamma ray telescopes: gamma rays are focussed from the large collecting area of a crystal diffraction lens on a very small detector volume. Thus, the implementation of the MAX space mission consists in flying a lens-detector duo satellites in an active Formation Flying geometry. The lens satellite is kept inertial and pointing to the gamma ray source with an accuracy of 15 arcsec, while the detector satellite is controlled in position and attitude with respect to the lens at a constant distance of 86 m, within an accuracy of 1 cm in lateral and 10 cm in longitudinal.
This paper discusses the various complex technical challenges of the MAX mission: GNC (Guidance Navigation Control) algorithms for the deployment, initialisation and control of the lens-detector geometry, accurate pointing of the lens to the gamma ray sources, definition and accommodation of the optical metrology, mechanical and thermal accommodation of the 8200-crystal lens, fine attitude/position actuators sizing, FDIR (Failure Detection Isolation and Recovery) and collision avoidance algorithms.
This paper depicts a baseline mission derived from these analyses and provides a preliminary definition of the space segment, with an emphasis on the command / control architecture of the formation, including the distributed on-board data management, the formation-to-ground interface and the inter-satellites communication. The paper then describes the GNC, metrology and propulsion systems required to fulfill the requirements of the MAX mission with margins.
Beyond its scientific interest for nuclear astrophysics, MAX is a good opportunity for demonstrating Formation Flying concepts and technologies in space.Clédassou Rodolphe
SIMBOL-X a hard-X ray Formation Flying
SIMBOL-X is a part of a more general CNES (PASO*) study entitled "Formation Flying for Astrophysics" (AMPS : ASPICS, MAX, PEGASE & SIMBOL-X) . The main objective is to demonstrate the feasibility of this new hard-X ray formation flying mission . Description of the space segment corresponding to this scientific mission.
Delpech Michel
MAX & SIMBOL-X Guidance Navigation and Control
Description and comparison of this 2 missions from the point of view of "The formation flying Guidance Navigation and Control".
Duchon Paul
MAX Formation Flying for nuclear astrophysics
MAX is a part of a more general CNES study entitled "Formation Flying for Astrophysics" (AMPS : ASPICS, MAX, PEGASE & SIMBOL-X). The main objective is to demonstrate the feasibility of this Nuclear Astrophysics mission with an important innovation ("Laue Lens" + FF). Description of the space segment corresponding to this scientific mission.
Hinglais Emmanuel
Distributed space segment architectures for high energy astrophysic: Similarities and specificities
Pilot studies have been carried out in CNES for X and Gamma energy band missions. These missions are based on distributed space segment architecture utilizing formation flying technics. Some similarities are identified which could be re used for other missions of the same type. On the other hand, these kinds of missions allow to embark new type of instruments as large specific lens or mirror for instance. Their stability is a challenge which is specific to each mission.
Huet Bertrand
Recent Advances and Low cost concept for the Gamma-Ray Lens Project MAX
A first outline of the MAX project (gamma-ray lens for nuclear astrophysics) has been elaborated by Alcatel Alenia Space in the frame of Formation Flying missions for the French national programs of CNES . This preliminary concept had demonstrated that such ambitious configurations enabling low signal/noise ratio as well as high angular and energy resolution were feasible and offered promising perspectives for future instrumentation.
Recent developments and achievements in Formation Flying mission components have brought confirmation that the expected performances would be achieved with reasonable developments .Following a brief overview of the MAX concept from Alcatel Alenia Space, this paper will describe the major recent steps that give confidence in the MAX project feasibility and will highlight the key areas, at satellite and instrument levels, that would deserve short term efforts to secure the MAX programme.Loffredo Gianluca
A hard X-ray facility for testing/calibrating hard X-ray focusing telescopes
We will report on the equipment and performance of the X-ray facility of the University of Ferrara. Initially developed to test the PDS (Phoswich Detection System) instrument aboard the BeppoSAX satellite and to perform reflectivity measurements of mosaic crystal samples of HOPG (Highly Oriented Pyrolytic Graphite), with time the facility has been improved and its applications extended. Now these applications include test and calibration of hard X-ray (10 keV) detectors, reflectivity measurements of hard X-ray mirrors, reflectivity tests of crystals and X-ray transparency measurements. The facility is being further improved in order to determine the optical axis mosaic crystals in Laue configuration within a project devoted to develop a hard X--ray focusing optics.
Pareschi Giovanni
Calibration of hard X-ray (15 50 keV) optics at the MPE test facility PANTER
The Max-Planck-Institut fr extraterrestrische Physik (MPE) in Garching, Germany, operates the large X-ray beam line facility PANTER for testing astronomical systems. At PANTER a number of telescopes like EXOSAT, ROSAT, SAX, JETX, ABRIXAS, XMM and SWIFT operating in the soft energy range (0.02 15 keV) have been successfully calibrated. In the present paper we report on an important upgrade recently implemented that enables the calibration of hard X-ray optics (from 15 up to 50 keV). Currently hard X-ray optics based on single and multilayer coating are being developed for several future X-ray missions. The hard X-ray calibrations at PANTER are carried out by a high energy source based on an electron gun and several anodes, able to cover the energy range from 4.5 up to 50 keV. It provides fluxes up to 10^4 counts/sec/cm^2 at the instrument chamber with a stability better than 1 %. As detector a pn-CCD camera operating between 0.2 and 50 keV and a collecting area of 36 cm^2 is used. Taking into account the high energy resolution of the CCD (145 eV at 6 keV), a very easy way to operate the facility in hard X-ray is in energy-dispersive mode (i.e. with a broad-band beam).
A double crystal monochromator is also available providing energies up to 20 keV. In this paper we present a number of results obtained by using PANTER for hard X-ray calibrations, performed on prototype multilayer optics developed by the INAF-Osservatorio Astronomico di Brera (OAB), Milano, Italy, in collaboration with the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, MA, USA. The extension to energies even larger than 50 keV, and the discussion of the problematic and possible solutions for the calibration of very long focal length optics (like e.g. for the Simbol-X mission) will be also discussed.Ubertini Pietro
The INTEGRAL - HESS connection: a new class of cosmic high energy accelerators from keV to TeV
The recent completion and operation of the High Energy Stereoscopic System (Aharonian et al., 2005), an array of ground based imaging Cherenkov telescopes, have provided a survey with unprecedented sensitivity of the inner part of the Galaxy and revealed a new population very high energy gamma-rays sources emitting at E>100 GeV. At least two of them were reported to have no known radio or X-ray counterpart and hypothesised to be representative of a new class of dark nucleonic cosmic sources. In fact, very high energy gamma-rays with energies E > 10 exp 11 eV are the best proof of non-thermal processes in the universe and provide a direct in-site view of matter-radiation interaction at energies by far greater than producible ground accelerators. At lower energy INTEGRAL has regularly observed the entire galactic plane during the first 1000 day in orbit providing a survey in the 20-100 keV range resulted in a soft gamma-ray sky populated with more than 200 sources, most of them being galactic binaries, either BHC or NS (Bird et al., 2005). Very recently, the INTEGRAL new source IGR J18135-1751 has been identified as the soft gamma-ray counterpart of HESS1813-178 (Ubertini et al., 2005) and AXJ1838.0-0655 as the X/gamma-ray counterpart of HESS J1837-069 (Malizia et al., 2005). Detection of non thermal radio, X and gamma-ray emission from these TeV sources is very important to discriminate between various emitting scenarios and, in turn, to fully understand their nature. The implications of these new findings in the high energy Galactic population will be addressed.
Peter Von Ballmoos
CLAIRE : First Light for a Gamma-Ray Lens
The objective of the R&D project CLAIRE was to prove the principle of a Laue lens for nuclear astrophysics. After tests with a ground-based prototype, and measuring diffraction efficiencies of individual Ge crystals on a synchrotron light source, the next logical step towards a space borne crystal lens telescope was to demonstrate the principle for astrophysical observations.On June 14 2001, the gamma-ray lens telescope CLAIRE was flown on a stratospheric balloon by the French Space Agency CNES; the astrophysical target was a "standard candle", the Crab nebula. The lens was composed of Ge-Si mosaic crystals, focusing gamma-ray photons from its 511 cm2 area onto a small solid state detector, with only ~ 18 cm3 equivalent volume for background noise. CLAIRE's first light consisted of ~33 diffracted 170 keV photons from the Crab. The performance of the gamma-ray lens during the balloon flight has been confirmed by ground data obtained on a 205 m optical bench, set up on a small airfield near Figueras in northern Catalonia.
Update : September 2005
Questions and comments : Peter von Ballmoos