References of "Plesseria, Jean-Yves"
     in
Bookmark and Share    
Full Text
See detailThe JWST MIRI Double-Prism, Design and Science Drivers
Fisher, Sebastian; Rossi, Laurence ULg; Renotte, Etienne ULg et al

in Proceedings of SPIE (2008, July 12), 7010

We present how it is achieved to mount a double prism in the filter wheel of MIRIM - the imager of JWST’s Mid Infrared Instrument. In order to cope with the extreme conditions of the prisms’ surroundings ... [more ▼]

We present how it is achieved to mount a double prism in the filter wheel of MIRIM - the imager of JWST’s Mid Infrared Instrument. In order to cope with the extreme conditions of the prisms’ surroundings, the low resolution double prism assembly (LRSDPA) design makes high demands on manufacturing accuracy. The design and the manufacturing of the mechanical parts are presented here, while ’Manufacturing and verification of ZnS and Ge prisms for the JWST MIRI imager’ are described in a second paper [1]. We also give insights on the astronomical possibilities of a sensitive MIR spectrometer. Low resolution prism spectroscopy in the wavelength range from 5-10 microns will allow to spectroscopically determine redshifts of objects close to/at the re-ionization phase of the universe. [less ▲]

Detailed reference viewed: 12 (1 ULg)
Full Text
See detailManufacturing and verification of ZnS and Ge prisms for the JWST MIRI imager
Rossi, Laurence ULg; Renotte, Etienne ULg; Plesseria, Jean-Yves ULg et al

in Proceedings of SPIE (2008, June 23), 7018

The JWST Mid-Infrared Instrument (MIRI) is designed to meet the JWST science requirements for mid-IR capabilities and includes an Imager MIRIM provided by CEA (France). A double-prism assembly (DPA ... [more ▼]

The JWST Mid-Infrared Instrument (MIRI) is designed to meet the JWST science requirements for mid-IR capabilities and includes an Imager MIRIM provided by CEA (France). A double-prism assembly (DPA) allows MIRIM to perform low-resolution spectroscopy. The MIRIM DPA shall meet a number of challenging requirements in terms of optical and mechanical constraints, especially severe optical tolerances, limited envelope and very high vibration loads. <br />The University of Cologne (Germany) and the Centre Spatial de Liege (Belgium) are responsible for design, manufacturing, integration, and testing of the prism assembly. A companion paper (Fischer et al. 2008) is presenting the science drivers and mechanical design of the DPA, while this paper is focusing on optical manufacturing and overall verification processes. <br />The first part of this paper describes the manufacturing of Zinc-sulphide and Germanium prisms and techniques to ensure an accurate positioning of the prisms in their holder. (1) The delicate manufacturing of Ge and ZnS materials and (2) the severe specifications on the bearing and optical surfaces flatness and the tolerance on the prism optical angles make this process innovating. The specifications verification is carried out using mechanical and optical measurements; the implemented techniques are described in this paper. <br />The second part concerns the qualification program of the double-prism assembly, including the prisms, the holder and the prisms anti-reflective coatings qualification. Both predictions and actual test results are shown. [less ▲]

Detailed reference viewed: 26 (6 ULg)
Full Text
Peer Reviewed
See detailFresnel rhombs as achromatic phase shifters for infrared nulling interferometry
Mawet, D.; Hanot, Charles ULg; Lenaers, C. et al

in Optics Express (2007), 15

We propose a new family of achromatic phase shifters for infrared nulling interferometry. These key optical components can be seen as optimized Fresnel rhombs, using the total internal reflection ... [more ▼]

We propose a new family of achromatic phase shifters for infrared nulling interferometry. These key optical components can be seen as optimized Fresnel rhombs, using the total internal reflection phenomenon, modulated or not. The total internal reflection indeed comes with a phase shift between the polarization components of the incident light. We propose a solution to implement this vectorial phase shift between interferometer arms to provide the destructive interference process needed to disentangle highly contrasted objects from one another. We also show that, modulating the index transition at the total internal reflection interface allows compensating for the intrinsic material dispersion in order to make the subsequent phase shift achromatic over especially broad bands. The modulation can be induced by a thin film of a well-chosen material or a subwavelength grating whose structural parameters are thoroughly optimized. We present results from theoretical simulations! together with preliminary fabrication outcomes and measurements for a prototype in Zinc Selenide. [less ▲]

Detailed reference viewed: 44 (9 ULg)
Full Text
See detailFresnel rhombs as achromatic phase shifters for infrared nulling interferometry: first experimental results
Hanot, Charles ULg; Mawet, D.; Loicq, Jerôme ULg et al

in Coulter, Daniel R (Ed.) "Techniques and Instrumentation for Detection of Exoplanets III" Proceedings of the SPIE, Volume 6693, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2007, September 01)

One of the most critical units of nulling interferometers is the Achromatic Phase Shifter. The concept we propose here is based on optimized Fresnel rhombs, using the total internal reflection phenomenon ... [more ▼]

One of the most critical units of nulling interferometers is the Achromatic Phase Shifter. The concept we propose here is based on optimized Fresnel rhombs, using the total internal reflection phenomenon, modulated or not. The total internal reflection induces a phase shift between the polarization components of the incident light. We present the principles, the current status of the prototype manufacturing and testing operations, as well as preliminary experiments on a ZnSe Fresnel rhomb in the visible that have led to a first error source assessment study. Thanks to these first experimental results using a simple polarimeter arrangement, we have identified the bulk scattering as being the main error source. Fortunately, we have experimentally verified that the scattering can be mitigated using spatial filters and does not decrease the phase shifting capabilities of the ZnSe Fresnel rhomb. [less ▲]

Detailed reference viewed: 56 (7 ULg)
Full Text
Peer Reviewed
See detailNew applications of rapid prototyping and rapid manufacturing (RP/RM) technologies for space instrumentation
Rochus, Pierre ULg; Plesseria, Jean-Yves ULg; van Elsen, M. et al

in Acta Astronautica (2007), 61

In the frame of a research project, CRIF, KUL and CSL have investigated the possibility to use rapid prototyping and rapid manufacturing (RP/RM) techniques during space instrument development. Rapid ... [more ▼]

In the frame of a research project, CRIF, KUL and CSL have investigated the possibility to use rapid prototyping and rapid manufacturing (RP/RM) techniques during space instrument development. Rapid prototyping and rapid manufacturing terms gather several techniques with the common baseline that parts are built layer by layer, starting from a CAD model. These techniques imply powder, paste or liquid and are applicable to polymers, ceramics and metals. In a first step, the major advantages of these techniques have been presented to Belgian industries implied in the space sector and, as a result of the discussions, development goals for the project have been identified. Several types of use have also been pointed, from demonstration mock-up to real space hardware. In parallel to technical developments, several case studies and tests have been performed. The case studies have shown that the rapid manufacturing allows complex geometries to be created. A drastic decrease of the number of separate parts and bolted junctions ease the predictability of the mechanical and thermal behaviour and limit the risk of imperfect junction. As a result of the project, a guidelines document has been issued to give as much information as possible on how to perform a space instrument design using the advantages of RP/RM techniques. [less ▲]

Detailed reference viewed: 67 (19 ULg)
Full Text
See detailA solid-state phase conjugate mirror for space Lidar systems
Brignon, Arnaud; Richard, Sébastien; Georges, Marc ULg et al

Conference (2007, June)

Detailed reference viewed: 20 (3 ULg)
See detailThe Belgian Contribution
Noels-Grötsch, Arlette ULg; Aerts, Conny; Plesseria, Jean-Yves ULg et al

in Fridlund, M.; Baglin, A.; Lochard, J. (Eds.) et al Proceedings of "The CoRoT Mission Pre-Launch Status - Stellar Seismology and Planet Finding" (2006)

Not Available

Detailed reference viewed: 7 (4 ULg)
Full Text
See detailOptical and mechanical design of a straylight rejection baffle for CoRoT
Plesseria, Jean-Yves ULg; Mazy, Emmanuel ULg; Defise, Jean-Marc ULg et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2003, November 01)

The COROT mission is part of the program "Petites Missions" of CNES (French space agency). It implies international cooperation between France, Belgium, Germany, Austria, Spain and the European Space ... [more ▼]

The COROT mission is part of the program "Petites Missions" of CNES (French space agency). It implies international cooperation between France, Belgium, Germany, Austria, Spain and the European Space Agency (ESA). COROT aims to perform astroseismology measurements and to detect exoplanets. Long duration observations of stars will be used to detect periodic variations with an afocal telescope followed by a dioptric objective and 4 CCDs. Due to the orbit of the spacecraft (low altitude polar orbit) and even if the observation are performed in a direction perpendicular to orbit plane, the measurements can be disturbed by the straylight reflected on the earth (albedo) that can generate periodic perturbation. CSL is in charge of the design and procurement, with the help of Belgian industries, of a baffle and its protective cover that will be mounted on top of the afocal entrance telescope. The requirements are very stringent from the optical point of view as well as from the mechanical point of view. The rejection of the baffle must be of the order of 10[SUP]13[/SUP] for field angles above 20 degrees while the allocated mass is 19 kilograms. [less ▲]

Detailed reference viewed: 61 (2 ULg)
Full Text
Peer Reviewed
See detailOMC: An Optical Monitoring Camera for INTEGRAL - Instrument description and performance
Mas-Hesse, J. M.; Gimenez, A.; Culhane, J. L. et al

in Astronomy and Astrophysics (2003), 411(1), 261-268

The Optical Monitoring Camera (OMC) will observe the optical emission from the prime targets of the gammaray instruments onboard the ESA mission INTEGRAL, with the support of the JEM-X monitor in the X ... [more ▼]

The Optical Monitoring Camera (OMC) will observe the optical emission from the prime targets of the gammaray instruments onboard the ESA mission INTEGRAL, with the support of the JEM-X monitor in the X-ray domain. This capability will provide invaluable diagnostic information on the nature and the physics of the sources over a broad wavelength range. Its main scientific objectives are: ( 1) to monitor the optical emission from the sources observed by the gamma- and X-ray instruments, measuring the time and intensity structure of the optical emission for comparison with variability at high energies, and ( 2) to provide the brightness and position of the optical counterpart of any gamma- or X-ray transient taking place within its field of view. The OMC is based on a refractive optics with an aperture of 50 mm focused onto a large format CCD (1024 x 2048 pixels) working in frame transfer mode (1024 x 1024 pixels imaging area). With a field of view of 5degrees x 5degrees it will be able to monitor sources down to magnitude V = 18. Typical observations will perform a sequence of different integration times, allowing for photometric uncertainties below 0.1 mag for objects with V less than or equal to 16. [less ▲]

Detailed reference viewed: 81 (8 ULg)
See detailThe Herschel-PACS Grating Drive and its controller
Renotte, Etienne ULg; Callut, Eric ULg; Guiot, Marc ULg et al

(2003)

The Photodetector Array Camera and Spectrometer (PACS), on board the Herschel Space Observatory, is designed for imaging and spectroscopy in the wavelength region between 60 and 210 gm. This paper reports ... [more ▼]

The Photodetector Array Camera and Spectrometer (PACS), on board the Herschel Space Observatory, is designed for imaging and spectroscopy in the wavelength region between 60 and 210 gm. This paper reports the design of the grating cryogenic mechanism of the PACS spectrometer and its remote controller (DEC/MEC) located on the outside of the Herschel cryostat. The PACS grating shall be capable of accurate positioning (4 arcsec) within a large angular stroke (40 arcdeg) in cryogenic environment (4.2 K). Technologies of actuators, position sensors, pivots, dry lubricants, servo-control and cryogenic test set-up are presented. At the other end of the Herschel 10-meter high-impedance cryogenic harness, the DEC/MEC consists of DSP processor-based electronics that control and synchronise the cold focal plane mechanisms and infrared detector arrays. The DEC/MEC operates an on board software running under a real-time operating system. Technologies involved in the control electronics are discussed and correlated to validation tests conducted with actual hardwares. [less ▲]

Detailed reference viewed: 96 (18 ULg)
See detailA Test Cryostat for Herschel-PACS Mechanism
Renotte, Etienne ULg; Barzin, Pascal ULg; Guiot, Marc ULg et al

in SCHÜRMANN B. (Ed.) ESA-SP-467 (2001, September)

The PACS Grating Assembly consists of a flat ruled grating of 320x80 mm²; its positioning mechanism; and launch-locking system. The Grating Assembly is part of the PACS Focal Plane Unit (FPU) and is ... [more ▼]

The PACS Grating Assembly consists of a flat ruled grating of 320x80 mm²; its positioning mechanism; and launch-locking system. The Grating Assembly is part of the PACS Focal Plane Unit (FPU) and is operated at liquid helium temperature (4K). It is remote-controlled from the Detector & Mechanism Controller (DEC/MEC), which is located on the Herschel Service Module. The grating shall be capable of accurate positioning (4 arcsec) within a large angular throw (40 arcdeg) and restricted dissipation to the 4K heat sink (< 5 mW). The development of the Grating mechanism controller has urged the need for a cryogenic simulator of the Grating Assembly with regard to the large change in value of mechanical and electrical characteristics between room temperature and liquid helium temperature. The simulator consists of a functional prototype of the Grating Assembly and a dedicated helium cryostat with appropriate interfaces. The test cryostat is a homemade facility (CSL) designed to cool down the prototype (and subsequent models) to liquid helium temperature. The test set-up also provides relevant instrumentation such as cryogenic temperature read-out, electrical feedthroughs toward the payload and optical viewport. [less ▲]

Detailed reference viewed: 37 (7 ULg)
Full Text
Peer Reviewed
See detailAcceptance tests of the INTEGRAL Optical Monitoring Camera subsystems
Mazy, Emmanuel ULg; Plesseria, Jean-Yves ULg; Renotte, Etienne ULg et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (1999, October 01)

The Optical Monitoring Camera (OMC) is a part of the scientific payload being developed for the ESA INTEGRAL mission, scheduled to be launched in 2001. The OMC is a imager that will monitor star ... [more ▼]

The Optical Monitoring Camera (OMC) is a part of the scientific payload being developed for the ESA INTEGRAL mission, scheduled to be launched in 2001. The OMC is a imager that will monitor star variations in the V-band in a 5 X 5 degree(s) field of view. This paper describes the acceptance tests for 3 sub-systems of OMC: the optical system, the baffle and the cover system. [less ▲]

Detailed reference viewed: 41 (2 ULg)
Full Text
Peer Reviewed
See detailSM98-146/413 Effective Modal Parameters to Evaluate Structural Stresses
Rochus, Pierre ULg; Defise, Jean-Marc ULg; Plesseria, Jean-Yves ULg et al

in Spacecraft Structures, Materials and Mechanical Testing (1999)

Detailed reference viewed: 27 (9 ULg)