Papers by Christophe Cara
Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave
Planetary and Space Science, 1991
... Observatoire de Paris-Meudon, 92195 Meudon, France VI MOROZ, AV DVACHKOV, AV GRYGORIEV, NG HA... more ... Observatoire de Paris-Meudon, 92195 Meudon, France VI MOROZ, AV DVACHKOV, AV GRYGORIEV, NG HAVINSON, IV KHATUNTSEV, AV K1SELEV, LV ... 91405 Orsay, France (Received 6 June 1990) Abstract The measurement of the CO; column density on Mars, from ...
The Athena+ mission concept is designed to implement the Hot and Energetic Universe science theme... more The Athena+ mission concept is designed to implement the Hot and Energetic Universe science theme submitted to the European Space Agency in response to the call for White Papers for the definition of the L2 and L3 missions of its science program. The Athena+ science payload consists of a large aperture high angular resolution X-ray optics and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), offering 2.5 eV spectral resolution, with ~5" pixels, over a field of view of 5 arc minutes in diameter. In this paper, we briefly describe the Athena+ mission concept and the X-IFU performance requirements. We then present the X-IFU detector and readout electronics principles, the current design of the focal plane assembly, the cooling chain and review the global architecture design. Finally, we describe ...
Planetary and Space Science, 1991
... More recently, microwave measurements led to the detection of CO and ' 'CO ( Kakar ... more ... More recently, microwave measurements led to the detection of CO and ' 'CO ( Kakar et al ... in order to increase the signal-to-noise ratio, and the spectra are divided by a reference spectrum (chosen near the summit of the volcano) to avoid the uncer-tainties of absolute calibration ...
Lunar and …, 1990
Proceedings of the 20th Lunar and Planetaiy Science Conference, pp. 461-471 Lunar and Planetary I... more Proceedings of the 20th Lunar and Planetaiy Science Conference, pp. 461-471 Lunar and Planetary Institute, Houston, 1990 ISM Observations of Mars and Phobos: First Results J.-P. Bibring1, M. Combes2, Y. Langevin1, C. Cara2, p* ~ T. Encrenaz2, S. Erard~, 0. Forni~, B. ...
IEEE Aerospace and Electronic Systems Magazine, 2000
In this paper, an extension to the SpaceWire standard [1] is presented which increases considerab... more In this paper, an extension to the SpaceWire standard [1] is presented which increases considerably its synchronization capability. Initially developed in the scope of Simbol-X [2], a CNES formation flying instrument where time-tagging of data science from three detectors is critical to perform on-board processing, the extension can be implemented in all equipments where the use of the performing SpaceWire standard is not possible due to its intrinsic synchronization limitation. This limitation gives a lack of precision ten times the data transmission period rate plus two periods of the receiver synchronization clock. With the additional feature this uncertainty is reduced to two periods of the receiver synchronization clock. The extension takes advantage of already existing capabilities of the SpaceWire standard with no impact on the data layer and very limited additional resource needs. The resulting performances measured on a prototype are presented still in the framework of the Simbol-X instrument using ACTEL space qualified FPGA as target.
Experimental Astronomy, 2012
A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dw... more A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood (d ≤ 15 pc) with uniform sensitivity down to Earth-mass planets within their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT -the Nearby Earth Astrometric Telescope.
Abstract:[en] A complete census of planetary systems around a volume-limited sample of solar-type... more Abstract:[en] A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood (d≤ 15 pc) with uniform sensitivity down to Earth-mass planets within their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT—the Nearby Earth Astrometric Telescope. NEAT is designed to carry out space-borne extremely-high-precision astrometric measurements at ...
The High Energy Detector (HED) is one of the three detection units on board the Simbol-X detector... more The High Energy Detector (HED) is one of the three detection units on board the Simbol-X detector spacecraft. It is placed below the Low Energy Detector so as to collect focused photons in the energy range from 8 to 80 keV. It consists of a mosaic of 64 independent cameras, divided in 8 sectors. Each elementary detection unit, called Caliste,
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V, 2010
The 6 K cooled primary mirror of the SPICA observatory, to be launched in 2018, allows a photomet... more The 6 K cooled primary mirror of the SPICA observatory, to be launched in 2018, allows a photometry gain in sensitivity in the far infrared of more than two orders of magnitude when compared with current instrumentation in space. All the proposed detector solutions will have to deploy radically different solutions from previous developments to cope with the extremely low background and very low power budgets available at all the temperature stages. We present the current design of very large "all Silicon" filled Bolometer Arrays cooled below 100 mK, and the solutions we develop for the BASIC (Bolometer Arrays for the All Silicon SAFARI Imaging Camera) focal planes of SAFARI. They will cover simultaneously three wavelength bands between 30 and 210 mum.
The Simbol-X focal plane is designed to detect photons focused by the mirror in the 0.5 to 100 ke... more The Simbol-X focal plane is designed to detect photons focused by the mirror in the 0.5 to 100 keV energy band. Composed of two detectors, it will measure the position, energy, and arrival time of each incoming X-ray. On top of it will be a collimator to shield all photons not coming from the mirror field of view. The whole system is surrounded by an active and passive shielding in order to ensure the required very low background.
Space Telescopes and Instrumentation I: Optical, Infrared, and Millimeter, 2006
Understanding the nature of Dark Matter and Dark Energy is one of the most pressing issues in cos... more Understanding the nature of Dark Matter and Dark Energy is one of the most pressing issues in cosmology and fundamental physics. The purpose of the DUNE (Dark UNiverse Explorer) mission is to study these two cosmological components with high precision, using a space-based weak lensing survey as its primary science driver. Weak lensing provides a measure of the distribution of dark matter in the universe and of the impact of dark energy on the growth of structures. DUNE will also include a complementary supernovae survey to measure the expansion history of the universe, thus giving independent additional constraints on dark energy. The baseline concept consists of a 1.2m telescope with a 0.5 square degree optical CCD camera. It is designed to be fast with reduced risks and costs, and to take advantage of the synergy between ground-based and space observations. Stringent requirements for weak lensing systematics were shown to be achievable with the baseline concept. This will allow DUNE to place strong constraints on cosmological parameters, including the equation of state parameter of the dark energy and its evolution from redshift 0 to 1. DUNE is the subject of an ongoing study led by the French Space Agency (CNES), and is being proposed for ESA's Cosmic Vision programme.
Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 2014
ABSTRACT We are developing the digital readout electronics (DRE) of the X-Ray Integral Field Unit... more ABSTRACT We are developing the digital readout electronics (DRE) of the X-Ray Integral Field Unit (X-IFU), one of the two Athena focal plane instruments. This subsystem is made of two main parts: the DRE-DEMUX and the DRE-EP. With a frequency domain multiplexing (FDM) the DRE-DEMUX makes the readout of the 3 840 Transition Edge Sensors (TES) in 96 channels of 40 pixels each. It provides the AC signals to voltage-bias the TES, it demodulates the detector&#39;s data which are readout by a SQUID and low noise amplifiers and it linearizes the detection chain to increase its dynamic range. The feedback is computed with a specific technique, so called baseband feedback (BBFB) which ensures that the loop is stable even with long propagation and processing delays (i.e. a few μs) and with high frequency AC-bias (up to 5 MHz). This processing is partly analogue (anti aliasing and reconstruction filters) but mostly digital. The digital firmware is simultaneously applied to all the pixels in digital integrated circuits. After the demultiplexing the interface between the DRE-DEMUX and the DRE-EP has to cope with a data rate of 61.44 Gbps to transmit the data of the individual pixels. Then, the DRE-EP detects the events and computes their energy and grade according to their spectral quality: low resolution, medium resolution and high resolution (i.e. if two consecutive events are too close the estimate of the energy is less accurate). This processing is done in LEON based processor boards. At its output the DRE-EP provides the control unit of the instrument with a list including for each event its time of arrival, its energy, its location on the focal plane and its grade.
Proceedings of SPIE - The International Society for Optical Engineering, 2012
Euclid-VIS is a large format visible imager for the ESA Euclid space mission in their Cosmic Visi... more Euclid-VIS is a large format visible imager for the ESA Euclid space mission in their Cosmic Vision program, scheduled for launch in 2019. Together with the near infrared imaging within the NISP instrument it forms the basis of the weak lensing measurements of Euclid. VIS will image in a single r+i+z band from 550-900 nm over a field of view of ~0.5 deg 2 . By combining 4 exposures with a total of 2240 sec, VIS will reach to V=24.5 (10σ) for sources with extent ~0.3 arcsec. The image sampling is 0.1 arcsec. VIS will provide deep imaging with a tightly controlled and stable point spread function (PSF) over a wide survey area of 15000 deg 2 to measure the cosmic shear from nearly 1.5 billion galaxies to high levels of accuracy, from which the cosmological parameters will be measured. In addition, VIS will also provide a legacy imaging dataset with an unprecedented combination of spatial resolution, depth and area covering most of the extra-Galactic sky. Here we will present the results of the study carried out by the Euclid Consortium during the Euclid Definition phase.
Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 2010
The NIP is a near infrared imaging photometer that is currently under investigation for the Eucli... more The NIP is a near infrared imaging photometer that is currently under investigation for the Euclid space mission in context of ESA&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s 2015 Cosmic Vision program. Together with the visible camera (VIS) it will form the basis of the weak lensing measurements for Euclid. The NIP channel will perform photometric imaging in 3 near infrared bands (Y, J, H) covering
Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 2010
Euclid is an ESA Cosmic Vision wide-field space mission concept dedicated to the high-precision s... more Euclid is an ESA Cosmic Vision wide-field space mission concept dedicated to the high-precision study of Dark Energy and Dark Matter. The mission relies on two primary cosmological probes: Weak gravitational Lensing (WL) and Baryon Acoustic Oscillations (BAO). The first probe requires the measurement of the shape and photometric redshifts of distant galaxies. The second probe is based on the
Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 2010
ABSTRACT The Euclid Imaging Channels Instrument of the Euclid mission is designed to study the we... more ABSTRACT The Euclid Imaging Channels Instrument of the Euclid mission is designed to study the weak gravitational lensing cosmological probe. The combined Visible and Near Infrared imaging channels will be controlled by a common data handling unit (PDHU), implementing onboard the instrument digital interfaces to the satellite. The PDHU main functionalities include the scientific data acquisition and compression, the instrument commanding and control and the instrument health monitoring. Given the high data rate and the compression needs, an innovative architecture, based on the use of several computing and interface modules, considered as building blocks of a modular design will be presented.
Optics for High-Brightness Synchrotron Radiation Beamlines II, 1996
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Papers by Christophe Cara