References of "Rochus, Pierre"
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See detailHu, Luojia , Estimation of a censored dynamic panel data model,Econometrica. Journal of the Econometric Society
Rochus, Pierre ULg

in Mathematical Reviews [=MR] (2002), 70(6), 2499--2517

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See detailDesign of the Heliospheric Imager for the STEREO mission
Defise, Jean-Marc ULg; Halain, Jean-Philippe ULg; Mazy, Emmanuel ULg et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2001, December 01)

The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO spacecrafts to be launched in 2005. The two HI instruments will provide stereographic image pairs of solar ... [more ▼]

The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO spacecrafts to be launched in 2005. The two HI instruments will provide stereographic image pairs of solar coronal plasma and address the observational problem of very faint coronal mass ejections (CME) over a wide field of view (~90 degree(s)) ranging from 13 to 330 R[SUB]0[/SUB]. The key element of the instrument design is to reject the solar disk light, with straylight attenuation of the order of 10[SUP]-13[/SUP] to 10[SUP]-15[/SUP] in the camera systems. This attenuation is accomplished by a specific design of straylight baffling system, and two separate observing cameras with complimentary FOV's cover the wide FOV. A multi-vane diffractive system has been theoretically optimized to achieve the lower requirement (10[SUP]-13[/SUP] for HI-1) and is combined with a secondary baffling system to reach the 10[SUP]-15[/SUP] rejection performance in the second camera system (HI-2). This paper presents the design concept of the HI optics and baffles, and the preparation of verification tests that will demonstrate the instrument straylight performances. The baffle design has been optimized according to accommodation constrains on the spacecraft, and the optics were studied to provide adequate light gathering power and image quality. Straylight has been studied in the complete configuration, including the lens barrels and the focal plane assemblies. A specific testing facility is currently being studied to characterize the effective straylight rejection of the HI baffling. An overview of the developments for those tests is presented. [less ▲]

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See detailStraylight tests for the Heliospheric imagers of STEREO
Defise, Jean-Marc ULg; Halain, Jean-Philippe ULg; Mazy, Emmanuel ULg et al

in ESA-SP (2001), 467

The design of the Heliospheric Imager (HI) of the NASA Solar TErrestrial Relations Observatory (STEREO) is based on an optical baffle system. It will reject the solar disk light with attenuation of the ... [more ▼]

The design of the Heliospheric Imager (HI) of the NASA Solar TErrestrial Relations Observatory (STEREO) is based on an optical baffle system. It will reject the solar disk light with attenuation of the order of 10-13 and 10-15, and let two separate camera systems (HI-1 and HI-2) measure the extremely faint solar coronal mass ejections. A multi-vane diffractive system has been optimized to achieve the lower requirement (10-13 for HI-1) and is combined with a secondary baffling system to reach the 10-15 rejection performance in the second camera system (HI-2). The theoretical performances of the baffling systems will be experimentally verified during the instrument development phase. A specific straylight test facility is being studied at CSL and preliminary tests have been conducted to prepare the HI instrument testing. The test set-up requirements and design considerations are discussed in this paper. The very high rejection performance requires to perform those tests under vacuum to avoid ambient air perturbations. Several light trapping systems have been developed for this application. A first breadboard has been built and is currently under testing. Preliminary results of those tests are presented. [less ▲]

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See detailStellar calibration of the WIC and SI imagers and the GEO photometers on IMAGE/FUV
Gladstone, G. R.; Mende, S. B.; Frey, H. U. et al

Poster (2000, December)

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See detailFar ultraviolet imaging from the IMAGE spacecraft. 1. System design
Mende, S. B.; Heetderks, H.; Frey, H. U. et al

in Space Science Reviews (2000), 91

Direct imaging of the magnetosphere by the IMAGE spacecraft will be supplemented by observation of the global aurora, the footprint of magnetospheric regions. To assure the simultaneity of these ... [more ▼]

Direct imaging of the magnetosphere by the IMAGE spacecraft will be supplemented by observation of the global aurora, the footprint of magnetospheric regions. To assure the simultaneity of these observations and the measurement of the magnetospheric background neutral gas density, the IMAGE satellite instrument complement includes three Far Ultraviolet (FUV) instruments. In the wavelength region 120-190 nm, a downward-viewing auroral imager is only minimally contaminated by sunlight, scattered from clouds and ground, and radiance of the aurora observed in a nadir viewing geometry can be observed in the presence of the high-latitude dayglow. The Wideband Imaging Camera (WIC) will provide broad band ultraviolet images of the aurora for maximum spatial and temporal resolution by imaging the LBH N_2 bands of the aurora. The Spectrographic Imager (SI), a monochromatic imager, will image different types of aurora, filtered by wavelength. By measuring the Doppler-shifted Ly-alpha, the proton-induced component of the aurora will be imaged separately. Finally, the GEO instrument will observe the distribution of the geocoronal emission, which is a measure of the neutral background density source for charge exchange in the magnetosphere. The FUV instrument complement looks radially outward from the rotating IMAGE satellite and, therefore, it spends only a short time observing the aurora and the Earth during each spin. Detailed descriptions of the WIC, SI, GEO, and their individual performance validations are discussed in companion papers. This paper summarizes the system requirements and system design approach taken to satisfy the science requirements. One primary requirement is to maximize photon collection efficiency and use efficiently the short time available for exposures. The FUV auroral imagers WIC and SI both have wide fields of view and take data continuously as the auroral region proceeds through the field of view. To minimize data volume, multiple images are taken and electronically co-added by suitably shifting each image to compensate for the spacecraft rotation. In order to minimize resolution loss, the images have to be distortion-corrected in real time for both WIC and SI prior to co-adding. The distortion correction is accomplished using high speed look up tables that are pre-generated by least square fitting to polynomial functions by the on-orbit processor. The instruments were calibrated individually while on stationery platforms, mostly in vacuum chambers as described in the companion papers. Extensive ground-based testing was performed with visible and near UV simulators mounted on a rotating platform to estimate their on-orbit performance. The predicted instrument system performance is summarized and some of the preliminary data formats are shown. [less ▲]

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See detailFar ultraviolet imaging from the IMAGE spacecraft. 3. Spectral imaging of Lyman-alpha and OI 135.6 nm
Mende, S. B.; Heetderks, H.; Frey, H. U. et al

in Space Science Reviews (2000), 91

Two FUV Spectral imaging instruments, the Spectrographic Imager (SI) and the Geocorona Photometer (GEO) provide IMAGE with simultaneous global maps of the hydrogen (121.8 nm) and oxygen 135.6 nm ... [more ▼]

Two FUV Spectral imaging instruments, the Spectrographic Imager (SI) and the Geocorona Photometer (GEO) provide IMAGE with simultaneous global maps of the hydrogen (121.8 nm) and oxygen 135.6 nm components of the terrestrial aurora and with observations of the three dimensional distribution of neutral hydrogen in the magnetosphere (121.6 nm). The SI is a novel instrument type, in which spectral separation and imaging functions are independent of each other. In this instrument, two-dimensional images are produced on two detectors, and the images are spectrally filtered by a spectrograph part of the instrument. One of the two detectors images the Doppler-shifted Lyman-alpha while rejecting the geocoronal `cold' Ly-alpha, and another detector images the OI 135.6 nm emission. The spectrograph is an all-reflective Wadsworth configuration in which a grill arrangement is used to block most of the cold, un-Doppler-shifted geocoronal emission at 121.567 nm. The SI calibration established that the upper limit of transmission at cold geocoronal Ly-alpha is less than 2%. The measured light collecting efficiency was 0.01 and 0.008 cm^2 at 121.8 and at 135.6 nm, respectively. This is consistent with the size of the input aperture, the optical transmission, and the photocathode efficiency. The expected sensitivity is 1.8x10^-2 and 1.3x10^-2 counts per Rayleigh per pixel for each 5 s viewing exposure per satellite revolution (120 s). The measured spatial resolution is better than the 128x128 pixel matrix over the 15 degx15 deg field of view in both wavelength channels. The SI detectors are photon counting devices using the cross delay line principle. In each detector a triple stack microchannel plate (MCP) amplifies the photo-electronic charge which is then deposited on a specially configured anode array. The position of the photon event is measured by digitizing the time delay between the pulses detected at each end of the anode structures. This scheme is intrinsically faster than systems that use charge division and it has a further advantage that it saturates more gradually at high count rates. The geocoronal Ly-alpha is measured by a three-channel photometer system (GEO) which is a separate instrument. Each photometer has a built in MgF_2 lens to restrict the field of view to one degree and a ceramic electron multiplier with a KBr photocathode. One of the tubes is pointing radially outward perpendicular to the axis of satellite rotation. The optic of the other two subtend 60 deg with the rotation axis. These instruments take data continuously at 3 samples per second and rely on the combination of satellite rotation and orbital motion to scan the hydrogen cloud surrounding the earth. The detective efficiencies (effective quantum efficiency including windows) of the three tubes at Ly-alpha are between 6 and 10%. [less ▲]

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See detailMR1750785,Radiation in enclosures, Mbiock, Aristide and Weber, Roman
Rochus, Pierre ULg

in Mathematical Reviews [=MR] (2000)

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See detailPSF modeling of the XMM flight mirror modules
Stockman, Yvan ULg; Houbrechts, Yvette ULg; Nazé, Yaël ULg et al

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

In the frame of XMM testing, all the mirror modules have been illuminated by a vertical EUV collimated beam a the Centre Spatial de Liege. A mirror module consists in 58 co- focal and co-axial Wolter I ... [more ▼]

In the frame of XMM testing, all the mirror modules have been illuminated by a vertical EUV collimated beam a the Centre Spatial de Liege. A mirror module consists in 58 co- focal and co-axial Wolter I mirrors. Up to now the images obtained at CSL have been used to assess the Mirror Module optical performances in a flight representative configuration, and also to verify the impact of the thermal environmental and vibration test on the optical performance. Due to the highly complex design of the Mirror Modules, simulating XMM images in details is very difficult. The Point Spread Function of some of the mirror modules presents slight asymmetry. In the facility design study, it has been demonstrated that the diffraction impact at 58.4 nm is negligible with respect to the half energy width mirror module specification. Presently all the mirror modules are better than 165 arcsec. This paper presents first the diffraction contribution on the image. In a second step a point spread function is built by using the metrological mirror shell data. EUV images are then analyzed to evaluate the impact of the mirror interface structure integration process on the PSF. An analytical model of the measured EUV pSF is developed. The modelization technique is applied to simulate in-orbit image. Finally the different modelizations are evaluated and compared. [less ▲]

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See detailOptical calibration of the FUV spectrographic imager for the IMAGE mission
Habraken, Serge ULg; Houbrechts, Yvette ULg; Renotte, Etienne ULg et al

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

The FUV Spectrographic Imager for IMAGE is simultaneously imaging auroras at 1218 and 1358 angstrom. It is designed to efficiently reject the Lyman-(alpha) emission line at 1215.7 angstrom. This paper ... [more ▼]

The FUV Spectrographic Imager for IMAGE is simultaneously imaging auroras at 1218 and 1358 angstrom. It is designed to efficiently reject the Lyman-(alpha) emission line at 1215.7 angstrom. This paper describes the optical calibration. The content is: 1) field of view calibration: detector pixels location with respect to the reference optical cube; distortion matrix used to computer the TDI. b) Radiometric calibration: detector response and linearity; instrument throughput according to its clear aperture and mirror reflection lost; response vs. wavelength and band-rejection certification. [less ▲]

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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 ▲]

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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)

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See detailMR1741782,Kabanikhin, S. I. and Lorenzi, A.Identification problems of wave phenomena
Rochus, Pierre ULg

in Mathematical Reviews [=MR] (1999)

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