Neural Network Based Approach to Recognition of Meteor Tracks in the Mini-EUSO Telescope Data

Mini-EUSO is a wide-angle fluorescence telescope that registers ultraviolet (UV) radiation in the nocturnal atmosphere of Earth from the International Space Station. Meteors are among multiple phenomena that manifest themselves not only in the visible range but also in the UV. We present two simple artificial neural networks that allow for recognizing meteor signals in the Mini-EUSO data with high accuracy in terms of a binary classification problem. We expect that similar architectures can be effectively used for signal recognition in other fluorescence telescopes, regardless of the nature of the signal. Due to their simplicity, the networks can be implemented in onboard electronics of future orbital or balloon experiments.Comment: 15 page

Experimental study of distorted beams coupling in a single mode waveguide

International audienceSpatial filters, such as single mode waveguides (SMW), are widely used to remove the aberrated part of a beam. This paper addresses the coupling between a distorted optical beam and a single mode waveguide. The goal is to experimentally confirm the theoretical analytic laws given by Ruilier and Cassaing (2001 J. Opt. Soc. Am. A 18 143-9), which are recalled. A good agreement is found for the coupling efficiency, and the theoretical prediction of an additional filter-induced piston is clearly demonstrated. The amplitude of this piston must be considered when designing an interferometer with SMW-filtered arms

Aspect de la France, actuellement, et depuis dix mois, dans un péril qui s'accroît de plus en plus, jusqu'à l'an VIII, par les sourds attentats directoriaux, sans que les Corps législatifs se déterminent d'obéir aux adresses rigoureuses des départemens pour le salut public ; par l'auteur de L'art de régner et autres

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HVPS system for ∗ – EUSO detectors

International audienceIn the JEM-EUSO focal instrument four multianode photomultipliers (Elementary Cell unit) are powered by one high voltage generator. The HV control system for Photo Detection Module consists of 9 high voltage generators. HV generators are Cockcroft-Walton voltage multipliers with protection system and with 3 level very fast switches for HV at cathodes. Protection systems were made to protect HVPS itself against possible excess of power consumption, but might be as well used as a protection of PMTs in case of unexpected enlighting. Externally controlled switches can reduce 100 times or 10000 times the PMT collection efficiency to enlarge the PMT dynamics up to factor 10 6 . The HV control unit provides galvanic insulation of HV system, andallows for input voltage in a range 15-35 V. Control unit provides interface for external voltage setting, control of switches, and emits information about the statuses of 9 HV generators

Absolute calibration of the JEM-EUSO photodetection modules

International audienceThe JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) collaboration constructs a series of balloon and orbital telescopes to detect fluorescent UV emission from the Earth atmosphere, with the primary aim to study ultra-high-energy cosmic rays (UHECRs) from space.The detectors have wide field-of-view (more than 20 degrees FOV), high temporal resolution (1-2.5 µs) and high sensitivity provided by a large aperture. Currently, one of these detectors is operating onboard the International Space Station (Mini-EUSO). The next one is planned to be launched in the spring of 2023 (EUSO-SPB2) and another one is in preparation stage (K-EUSO). These projects use the same photo-detection modules (PDMs) composed of 36 multi-anode photomultiplier tubes (MAPMTs), each with 64 pixels, for a total of 2304 pixels. Mini-EUSO uses one PDM, EUSO-SPB2 uses three and the future full-scale missions will use several tens of PDMs.In the process of preparing and testing of PDMs, a new technique was developed to characterize their performance and provide absolute calibration of the MAPMTs used in the different JEM-EUSO missions. The method provides the efficiency of each pixel (including the sub-pixel structures), as well as the actual area occupied by the different pixels on the photocathode of the MAPMT.The method and its application to EUSO-SPB2 PDMs at different high voltages and in different modes of operation are presented

Synchrotron Microbeam Diffraction Studies on the Alignment within 3D-Printed Smectic-A Liquid Crystal Elastomer Filaments during Extrusion

3D printing of novel and smart materials has received considerable attention due to its applications within biological and medical fields, mostly as they can be used to print complex architectures and particular designs. However, the internal structure during 3D printing can be problematic to resolve. We present here how time-resolved synchrotron microbeam Small-Angle X-ray Diffraction (μ-SAXD) allows us to elucidate the local orientational structure of a liquid crystal elastomer-based printed scaffold. Most reported 3D-printed liquid crystal elastomers are mainly nematic; here, we present a Smectic-A 3D-printed liquid crystal elastomer that has previously been reported to promote cell proliferation and alignment. The data obtained on the 3D-printed filaments will provide insights into the internal structure of the liquid crystal elastomer for the future fabrication of liquid crystal elastomers as responsive and anisotropic 3D cell scaffolds

Performance of the EUSO-Balloon UV Camera

International audienceJEM-EUSO [1] is intended to be a space-borne fruorescence te lescope onboard of JEM/EF (Japanese Experimental Modeul/Exposure Facility) on the International Space Station (ISS). The main goal of the JEM-EUSO project is to detect the Extensive A ir Showers (EAS) produced by the Extreme Energy Cosmic Rays (EECRs) with energies above 1 0 19 eV from the extragalactic objects. As a pathfinder, the JEM-EUSO collaboration is curr ently developing a balloon-borne fluorescence telescope experiment, called EUSO-Balloon, f unded by CNES, the French space agency. It will perform end-to-end tests of the JEM-EUSO sub systems and instrumental concept, and measure the UV background for space-based EECR detector s. It involves several French in- stitutes (LAL, APC and IRAP) as well as several key institute s of the JEM-EUSO collaboration. The EUSO-Balloon instrument consists of an UV telescope and an infrared camera. The UV telescope will be operated at an altitude of 40 km to observe t he background and possibly signal photons in the fluorescence UV range (290-430 nm), which are e mitted along shower tracks gen- erated by ultra high energy cosmic rays with energies above 1 0 18 eV interacting with the earth’s atmosphere. The balloon experiment will be equipped with el ectronics and acquisition systems, as close as possible to the ones designed for the UV telescope of main JEM-EUSO instrument. The past years have been devoted to the design, the fabricati on and the tests of the prototype boards of the PDM, of the digital processor, and the flight mod els of optics, electronics and the IR camera for EUSO-Balloon. Here we focus on the PDM, the core element of the JEM-EUSO foca l surface. We first describe all key items of the PDM, from the photodetectors to the FPGA b oard, the first stage of the data processing (DP). We then report on the tests carried out on th e integration to assess their func- tionality and their suitability for a balloon mission

Volatile and intermediate volatility organic compounds in suburban Paris: variability, origin and importance for SOA formation

International audienceMeasurements of gaseous and particulate organic carbon were performed during the MEGAPOLI experiments, in July 2009 and January–February 2010, at the SIRTA observatory in suburban Paris. Measurements comprise primary and secondary volatile organic compounds (VOCs), of both anthropogenic and biogenic origins, including C 12 –C 16 n-alkanes of intermediate volatility (IVOCs), suspected to be efficient precursors of secondary organic aerosol (SOA). The time series of gaseous carbon are generally consistent with times series of particulate organic carbon at regional scale, and are clearly affected by meteorology and air mass origin. Concentration levels of anthropogenic VOCs in urban and suburban Paris were surprisingly low (2–963 ppt) compared to other megacities worldwide and to rural continental sites. Urban enhancement ratios of anthropogenic VOC pairs agree well between the urban and suburban Paris sites, showing the regional extent of anthropogenic sources of similar composition. Contrary to other primary anthropogenic VOCs (aromatics and alkanes), IVOCs showed lower concentrations in winter (< 5 ppt) compared to summer (13– 27 ppt), which cannot be explained by the gas-particle partitioning theory. Higher concentrations of most oxygenated VOCs in winter (18–5984 ppt) suggest their dominant primary anthropogenic origin. The respective role of primary anthropogenic gaseous compounds in regional SOA formation was investigated by estimating the SOA mass concentration expected from the anthropogenic VOCs and IVOCs (I / VOCs) measured at SIRTA. From an integrated approach based on emission ratios and SOA yields, 38 % of the SOA measured at SIRTA is explained by the measured concentrations of I / VOCs, with a 2 % contribution by C 12 –C 16 n-alkane IVOCs. From the results of an alternative time-resolved approach, the average IVOC contribution to SOA formation is estimated to be 7 %, which is half of the average contribution of the traditional aromatic compounds (15 %). Both approaches, which are based on in situ observations Published by Copernicus Publications on behalf of the European Geosciences Union. 10440 W. Ait-Helal et al.: Volatile and intermediate volatility organic compounds in suburban Paris of particular I / VOCs, emphasize the importance of the intermediate volatility compounds in the SOA formation, and support previous results from chamber experiments and mod-eling studies. They also support the need to make systematic the IVOCs' speciated measurement during field campaigns

Questions d’éthique

Comme tout chercheur, l’ethnomusicologue se doit de respecter certains principes déontologiques en différentes phases de son activité, notamment la collecte, l’archivage, l’analyse, la communication et la publication. Comment la recherche a-t-elle évolué pour s’adapter aux conditions de terrains souvent marqués par les migrations, les conflits ou les tensions économiques et religieuses ? L’éthique du métier s’applique aussi aux droits des individus et des communautés produisant les musiques étudiées par les ethnomusicologues. Comment les instances internationales régulant le « patrimoine immatériel », sa « sauvegarde » ou encore la « propriété intellectuelle » (UNESCO, OMPI…) influent-t-elles sur la production des documents de recherche ? Comment ces différents facteurs contribuent-ils à redéfinir la relation enquêteur/enquêté ? Telles sont les questions auxquelles les ethnomusicologues sont constamment confrontés dans leur pratique, et sur lesquelles ce volume propose quelques pistes de réflexio

EUSO-Balloon: Observation and Measurement of Tracks from a Laser in a Helicopter

International audienceEUSO-Balloon is a prototype detector of the Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO). EUSO-Balloon was flown successfully as a balloon payload from the Timmins Stratospheric Balloon Launch Facility in Ontario, Canada on 2014 August 24-25 at an altitude of 38 km. To simulate the optical signatures of UV fluorescence photons emitted from cosmic ray air showers generated in the atmosphere, a pulsed UV laser and two UV flashers (LED and Xe) were used. These sources were fired in the instrument field of view for about 2 hours from a helicopter that circled at an altitude of 3 km under the balloon. UV signals were effectively detected, including 270 laser track events. We describe the helicopter laser system and the geometric reconstruction of the laser events that were generated by this system. We report here on the reconstruction of the laser events starting from the information contained in the observed tracks. We note that this work represents the first observation and measurement of aircraft based laser tracks by an optical fluorescence detector flown at near space altitudes