The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR, browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters. Finally we briefly discuss on the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, and touch on communication and outreach activities, the consortium organisation, and finally on the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental Astronomy with minor editin

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory. Athena is a versatile observatory designed to address the Hot and Energetic Universe science theme, as selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), X-IFU aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over a hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR (i.e. in the course of its preliminary definition phase, so-called B1), browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters, such as the instrument efficiency, spectral resolution, energy scale knowledge, count rate capability, non X-ray background and target of opportunity efficiency. Finally, we briefly discuss the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, touch on communication and outreach activities, the consortium organisation and the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with ESA member state contributions from Belgium, Czech Republic, Finland, Germany, Poland, Spain, Switzerland, with additional contributions from the United States and Japan.The French contribution to X-IFU is funded by CNES, CNRS and CEA. This work has been also supported by ASI (Italian Space Agency) through the Contract 2019-27-HH.0, and by the ESA (European Space Agency) Core Technology Program (CTP) Contract No. 4000114932/15/NL/BW and the AREMBES - ESA CTP No.4000116655/16/NL/BW. This publication is part of grant RTI2018-096686-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This publication is part of grant RTI2018-096686-B-C21 and PID2020-115325GB-C31 funded by MCIN/AEI/10.13039/501100011033

Description and performance of track and primary-vertex reconstruction with the CMS tracker

A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For tbar t events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of pT > 0.9GeV is 94% for pseudorapidities of |η| < 0.9 and 85% for 0.9 < |η| < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of pT = 100GeV emitted at |η| < 1.4, the resolutions are approximately 2.8% in pT, and respectively, 10μm and 30μm in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10–12μm in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung

Alignment of the CMS tracker with LHC and cosmic ray data

© CERN 2014 for the benefit of the CMS collaboration, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation and DOI.The central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous determination of up to 200 000 alignment parameters with tracks, the measurement of individual sensor curvature parameters, the control of systematic misalignment effects, and the implementation of the whole procedure in a multi-processor environment for high execution speed. Overall, the achieved statistical accuracy on the module alignment is found to be significantly better than 10μm

Euclid Near Infrared Spectrometer and Photometer instrument concept and first test results obtained for different breadboards models at the end of phase C

The Euclid mission objective is to understand why the expansion of the Universe is accelerating through by mapping the geometry of the dark Universe by investigating the distance-redshift relationship and tracing the evolution of cosmic structures. The Euclid project is part of ESA's Cosmic Vision program with its launch planned for 2020 (ref [1]). The NISP (Near Infrared Spectrometer and Photometer) is one of the two Euclid instruments and is operating in the near-IR spectral region (900- 2000nm) as a photometer and spectrometer. The instrument is composed of: - a cold (135K) optomechanical subsystem consisting of a Silicon carbide structure, an optical assembly (corrector and camera lens), a filter wheel mechanism, a grism wheel mechanism, a calibration unit and a thermal control system - a detection subsystem based on a mosaic of 16 HAWAII2RG cooled to 95K with their front-end readout electronic cooled to 140K, integrated on a mechanical focal plane structure made with molybdenum and aluminum. The detection subsystem is mounted on the optomechanical subsystem structure - a warm electronic subsystem (280K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the spacecraft via a 1553 bus for command and control and via Spacewire links for science data This presentation describes the architecture of the instrument at the end of the phase C (Detailed Design Review), the expected performance, the technological key challenges and preliminary test results obtained for different NISP subsystem breadboards and for the NISP Structural and Thermal model (STM)

Prédiction du mouvement 2D d'une plaque épaisse fissurée et caractérisation de la fissure par inversion de la réponse à une sollicitation périodique

Université de la Méditerranée - Aix-Marseille IIL'étude présentée a pour but général la modélisation du Contrôle Non Destructif par ultrasons d'une plaque homogène isotrope. Le contrôle ultrasonore permet non seulement de déceler la présence d'un défaut mais aussi, en principe du moins, d'en déterminer les caractéristiques tant physiques que géométriques, et d'en évaluer la nocivité, compte tenu des conditions d'utilisation futures de la pièce. La production des ultrasons se fait au moyen d'un transducteur piézo-électriques: les oscillations électriques sont traduites en vibrations mécaniques qui génèrent des ondes élastiques. Dans le cas de plaques homogènes isotropes a géométrie bidimensionnelle, deux systèmes d'ondes indépendants (SH) et (P-SV) existent dès lors que cette même plaque est excitée par une source linéique générant l'un de ces deux systèmes d'ondes. Le champ de déplacement est dû à cette source impulsionnelle harmonique correspond à la fonction de Green en élastodynamique en l'absence de défaut. Afin d'étudier la détectabilité d'une fissure horizontale dans une plaque (i.e. résoudre le problème direct), une Méthode de Décomposition de Domaine en modes (SH) (respectivemet en mode (P-SV)) est mise en oeuvre analytiquement et numériquement. La plaque se décompose alors en deux guides d'ondes semi-infinis où une représentation est utilisée pour décrire le champ de déplacement, et un domaine borné contenant la fissure où le champ est représenté de manière discrète par Eléments Finis. L'application des conditions de continuité sur les déplacements et les contraintes sur les frontières fictives entre chacun des trois sous-domaines permet de relier les modes et les EF. Il en résulte un système linéaire dont la résolution donne le champ de déplacement dans toute la plaque. Après avoir validé la MMD en modes (SH) à l'aide de deux solutions connues, des résultats portant sur l'analyse du champ en présence d'une fissure sont présentés dans le domaine fréquentiel. La résolution du problème inverse, i.e. la localisation et le dimensionnement de la fissure, revient à minimiser une fonction coût en utilisant l'algorithme itératif de Levenberger-Marquardt. La fonction coût correspond à la différence au sens des moindres carrés entre les coefficients de réflexion calculés à partir des "mesures" sur un segment de la face supérieure de la plaque et ceux calculés par une MMD modale. Le champ "mesuré" utilisé pour l'inversion a été obtenu au moyen de la MDD en ajoutant un bruit gaussien ou en "sous-maillant". Les résultats obtenus montrent que l'erreur sur les paramètres de localisation et de dimensionnement de la fissure est inférieure a une demi-longueur d'onde

AT-SEA EXPERIMENTAL EVALUATION OF THE INFLUENCE OF ENVIRONMENTAL FLUCTUATIONS ON THE ACOUSTIC COHERENCE RADIUS

International audienceSound propagation in a fluctuating medium can be impacted by local space and time variation of the celerity. In the ocean, this environmental variability is mainly due to internal waves, tides or gyres and is well studied by oceanographers. More specifically, major research tackles the issue of characterizing the impact of these internal waves on a measured signal propagated throughout the perturbed medium. One important quantity defined in this literature is the ''coherence radius'': a metric that evaluates the distance between two sensors on which the received signals can be considered as correlated. It can be related to the level of spatial fluctuations under a high frequency approximation. Hence, integrated as prior knowledge on the propagating medium, the coherence radius can be very useful to determine the degree of corruption of a measured signal for typical inverse problems in underwater acoustics, such as tomography and source localization. In this work, we present different results from the analysis of the ALMA 2017 measurement campaign. ALMA (for Acoustic Laboratory for Marine Applications) is an autonomous acoustic observatory designed by DGA Naval Systems in 2012 and deployed in 2017 in the Saint-Florent Gulf, in the Western Mediterranean Sea. We specifically aim at assessing the intensity of environmental and acoustic fluctuations on sound waves propagated from a known source to a set of vertical line arrays and at comparing it to the theoretical predictions. Results suggest a strong relationship between the coherence radius and temperature fluctuations as well as other phenomena such as tides or water-mixing areas. Given hypotheses made about the influence of fluctuations on the radius of coherence, we further discuss future experimental settings to validate or discard these hypotheses

L’approche microbiote : stratégies pour prédire et prévenir les infections à Salmonella chez le poulet

National audienceSalmonellosis is one of the most important zoonosis worldwide resulting in a significant loss to agrifood industry as well as a substantial burden on the healthcare system. Depending of the hosts and the serotypes, Salmonella induce a wide spectrum of diseases among which typhoid fevers, asymptomatic infections and gastroenteritis. Poultry, which are the main source of human contamination, are mainly asymptomatic carriers. This asymptomatic Salmonella carrier state is thus a major issue for the European authority of food safety (EFSA) and the European center of prevention and control of the diseases (ECDC). Numerous strategies have been developed to fight Salmonella infections leading to a decrease or at least a stabilisation of the human cases. To go further, novel approaches must be developed in particular in response to the increase and spread of antimicrobial resistance. This article describes the current and future strategies used to fight Salmonella infection especially those related to the chicken gut microbiota. We finally address the new avenues opened by studies on host-microbiota-pathogen relationships.La salmonellose est l’une des zoonoses dont le fardeau économique et sanitaire est le plus élevé dans le monde. En fonction de l’hôte et du sérotype, Salmonella peut induire un large spectre de maladies qui vont des fièvres typhoïdes aux infections asymptomatiques en passant par les gastroentérites. Les volailles, qui sont majoritairement porteuses asymptomatiques, sont les principales sources de contamination de l’homme et l’un des enjeux majeurs pour l’autorité européenne de sécurité des aliments (EFSA) et le centre européen de prévention et de contrôle des maladies (ECDC). De nombreuses stratégies de lutte au niveau de l’élevage ont été mises en place pour combattre les infections à Salmonella, ce qui a permis de réduire ou au moins stabiliser le nombre d’infections humaines. Pour aller plus loin, de nouvelles stratégies doivent être mises en place, en particulier face à la diminution de l’utilisation des antibiotiques en élevage. Cet article décrit les différentes stratégies de lutte, actuelles et à venir, et en particulier celles liées aux travaux sur le microbiote intestinal du poulet. Il aborde également les conséquences que peuvent avoir les recherches sur les interactions microbiote-hôte-pathogèn

3D metrology with a laser tracker inside a vacuum chamber for NISP test campaign

International audienceIn the frame of the test of NISP instrument for ESA Euclid mission, the question was raised to perform a metrology measurement of different components during the thermal vacuum test of NISP instrument. NISP will be tested at Laboratoire d'Astrophysique de Marseille (LAM) in ERIOS chamber under vacuum and thermal conditions in order to qualify the instrument in its operating environment and to perform the final acceptance test before delivery to the payload. One of the main objectives of the test campaign will be the measurement of the focus position of NISP image plane with respect to the EUCLID object plane. To simulate the EUCLID object plane, a telescope simulator with a very well know focal distance will be installed in front of NISP into ERIOS chamber. We need to measure at cold and vacuum the position of reflectors installed on NISP instrument and the telescope simulator. From these measurements, we will provide at operational temperature the measurement of references frames set on the telescope simulator and NISP, the knowledge of the coordinates of the object point source provided by the telescope simulator and the measurement of the angle between the telescope simulator optical axis and NISP optical axis. In this context, we have developed a metrology method based on the use of a laser tracker to measure the position of the reflectors inside ERIOS. The laser tracker is installed outside the vacuum chamber and measure through a curved window reflectors put inside the chamber either at ambient pressure or vacuum pressure. Several tests campaigns have been done at LAM to demonstrate the measurement performance with this configuration. Using a well know reflectors configuration, we show that it is possible to correct the laser tracker measurement from the window disturbances and from the vacuum impact. A corrective term is applied to the data and allows retrieving the real coordinates of the reflectors with a bias lower than 30µm, which is lower than the laser tracker measurement uncertainties estimated at 60µm. No additional error term of the laser tracker measurement is observed when using the laser tracker with the curved window and in vacuum, comparing with a classical use of the laser tracker. With these test campaign, we have been able to demonstrate the possibility to use a laser tracker to measure in real time during a vacuum thermal test the position of different mechanical parts into a vacuum chamber with an accuracy better than 60µm