Impacts of The Radiation Environment At L2 On Bolometers Onboard The Herschel Space Observatory

We present the effects of cosmic rays on the detectors onboard the Herschel satellite. We describe in particular the glitches observed on the two types of cryogenic far- infrared bolometer inside the two instruments PACS and SPIRE. The glitch rates are also reported since the launch together with the SREM radiation monitors aboard Herschel and Planck spacecrafts. Both have been injected around the Lagrangian point L2 on May 2009. This allows probing the radiation environment around this orbit. The impacts on the observation are finally summarized.Comment: 8 pages, 13 figures, 2 images, Author Keywords: Bolometers, Infrared detectors, cryogenics, radiation effects, submillimeter wave technology IEEE Terms: Bolometers, Detectors, Instruments, Picture archiving and communication systems, Protons, Silicon, Space vehicles; Radiation and Its Effects on Components and Systems (RADECS), 2011 12th European Conference. Conference location: Sevilla. Date of Conference: 19-23 Sept. 2011. Session H: Radiation Environment: Space, Atmospheric and Terrestrial (PH2

CAGIRE: a wide-field NIR imager for the COLIBRI 1.3 meter robotic telescope

The use of high energy transients such as Gamma Ray Bursts (GRBs) as probes of the distant universe relies on the close collaboration between space and ground facilities. In this context, the Sino-French mission SVOM has been designed to combine a space and a ground segment and to make the most of their synergy. On the ground, the 1.3 meter robotic telescope COLIBRI, jointly developed by France and Mexico, will quickly point the sources detected by the space hard X-ray imager ECLAIRs, in order to detect and localise their visible/NIR counterpart and alert large telescopes in minutes. COLIBRI is equipped with two visible cameras, called DDRAGO-blue and DDRAGO-red, and an infrared camera, called CAGIRE, designed for the study of high redshift GRBs candidates. Being a low-noise NIR camera mounted at the focus of an alt-azimutal robotic telescope imposes specific requirements on CAGIRE. We describe here the main characteristics of the camera: its optical, mechanical and electronics architecture, the ALFA detector, and the operation of the camera on the telescope. The instrument description is completed by three sections presenting the calibration strategy, an image simulator incorporating known detector effects, and the automatic reduction software for the ramps acquired by the detector. This paper aims at providing an overview of the instrument before its installation on the telescope.Comment: Accepted by Experimental Astronom

AIRS: the Infrared Spectroscopic Instrument of ESA M4 ARIEL mission

The AIRS spectrometer will be used for Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, which will allow to measure atmospheric signals from the planet at levels of 10-100 part per million (ppm) relative to the star. This will require exquisite control of the full photon to digital codes acquisition chain bias along the long duration observation sequence. The prism-based spectrometer has been specifically designed to use anamorphosis of the prisms for circularizing the PSF of the elliptical primary mirror pupil in order to ensure optimal sampling and SNR. Because of the large dynamics of the stars the detector for the long waveband in the 7.80 µm range will need to be state-of-the-art and to be operated at 40-K. <P /

Localized Surface Plasmon Resonance of Metallic Nanoparticles--Optical Property Characterization for Rational Applications

在光的激发下金属纳米结构中的自由电子能够发生群体性的振荡，进而产生表面等离激元（SPP）。发生等离激元共振时，金属纳米结构会将光束缚在表面，并在表面产生极强的电场增强。表面等离激元有两种类型：一类具有传播的特点，其表面等离激元能够在表面传播，称之为propagatingSPP；另一类不具有传播性，共振局域在一个很小的金属结构中，称之为localizedSPP，即局域表面等离激元共振（LSPR）。金属纳米颗粒就具有很强的表面等离激元共振的（LSPR）性质，使其对光产生增强的吸收和增强的散射，并表现出相关的热、光电场增强和热电子等效应。近年，随着纳米科技的发展，金属纳米粒子的LSPR效应已经成为一...The collective oscillation of free electrons in metal nanostructures excited with light is called surface plasmon polaritons (SPP). The light will be confined to a small area on the surface under the resonance condition (SPR), thus a giant enhancement in the electric field will be produced. There are two kinds of surface plasmon polaritons (SPP): one is propagating plasmon polaritons (PSPP), which...学位：理学博士院系专业：化学化工学院_物理化学(含化学物理)学号：2052010015366

Le spectrographe UV prime equipe d'un CCD : ses performances

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Influence of the CdZnTe substrate thickness on the response of HgCdTe detectors under irradiation: modeling of the substrate luminescence

International audienceThe most extensively used infrared (IR) detectors in astrophysics are based on mercury cadmium telluride (MCT) technology: the MCT light-sensitive layer is grown on a cadmium zinc telluride (CZT) substrate. When launched on a satellite, these detectors are subjected to ionizing radiation from cosmic rays or solar flares (mainly protons) which degrade the detector performance. Indeed, an elevation of the detector background was noted under irradiation, which is believed to be associated with the luminescence of the CZT substrate. Complete removal of the substrate eliminates the problem, but it is a challenging step in the fabrication process. A deeper understanding of the response of IR detectors under irradiation, when the substrate is fully removed, will enable the optimization of substrate design for high-performance space-based scientific imaging. Here, the first results of proton irradiation modeling in MCT detectors, including energy deposition in the CZT substrate, are presented. The estimation of image pollution relies on GEANT4 (GEometry ANd Tracking 4) Monte Carlo simulations as well as analytical and numerical calculations of carrier transport inside the detector structure. In particular, recombination processes in the CZT substrate are taken into account to model the luminescence effect induced by proton irradiation. According to this model, considering published material properties, the diffusion of the carriers generated inside the CZT substrate toward the MCT layer is the main source of pollution. As the substrate thickness increases, more pixels are impacted by a proton impact on the IR. Consequently, depending on the targeted application, either partial or complete removal may be chosen

Caractérisation absolue de la fonction de transfert optique d'un objectif cryogénique infrarouge de grande ouverture

International audienceThe field of infrared detectors is experiencing a strong movement towards smaller pixel pitches, and it is now common to see pitches close to the wavelength. This raises major problems in measuring their characteristics, especially their transfer function. The latter can be measured by optical pattern projection methods using a low F/# objective, such as the spot scan method. However, in order to obtain the quantitative transfer function measurement of detectors, the objective spatial response should be measured and deconvoluted precisely, since the size of the focused optical spot is close to the pixel pitch. Therefore, the purpose of this paper is to propose a protocol that performs an absolute measurement of a high-quality infrared objective. The main idea of the article is to link the measurement standard to a fundamental theory, the Huygens-Fresnel principle, using a particular wavefront sensor as a secondary measurement standard. This has various metrological advantages, that allow the uncertainties of the optical transfer function measurement to be controlled and evaluated. The protocol and the propagation of errors described in the article are both used to demonstrate the value of this approach.Le domaine des détecteurs infrarouges connaît une tendance vers des pas pixels plus petits, et il est désormais courant de voir des pas proches de la longueur d'onde. Ceci pose des problèmes importants pour la mesure de leurs caractéristiques, notamment de leur fonction de transfert. Cette dernière peut être mesurée par des méthodes de projection de motifs optiques utilisant un objectif à faible F/#, comme la méthode du spot scan, mais cela suppose que la réponse spatiale de l'objectif soit mesurée et déconvoluée avec précision, étant donné que la taille de la tache optique focalisée est proche du pas du pixel. L'objectif de cet article est donc de proposer un protocole permettant d'effectuer une mesure absolue d'un objectif infrarouge de haute qualité. L'idée principale de l'article est de relier l'étalon de mesure à une théorie fondamentale, à savoir le principe de Huygens-Fresnel, en utilisant un trou de diffraction couplé à un capteur de front d'onde permettant de restituer les erreurs de mesures

Status of the development of 2k2 IR FPAs for astronomy and space in Europe

International audienceWe report on the development of short wave infrared (SWIR) imaging arrays for astronomy and space observation in Europe. LETI and Sofradir demonstrated 640x480 SWIR HgCdTe (MCT) arrays geared at low flux, low dark noise operation. Currently, we are developing 2048x2048 arrays mated to a newly developed ROIC. In parallel, the European Space Agency and the European Commission are funding the development and industrialization of 4 '' CdZnTe substrates and HgCdTe epitaxy. These large wafers are needed to achieve the necessary economies of scale and address the need for even larger arrays. HgCdTe SWIR detector performance at LETI/Sofradir is known from previous programs and will be discussed here. However, we will only be able to summarize the features and specifications of the new 2048x2048 detectors which are still at a prototype stage

ROIC glow reduction in very low flux short wave infra-red focal plane arrays for astronomy

International audienc