Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Detection chain and electronic readout of the QUBIC instrument

The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10⁻¹⁶ W/√Hz

Detection chain and electronic readout of the QUBIC instrument

The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10⁻¹⁶ W/√Hz

Multiple Scenario Generation of Subsurface Models:Consistent Integration of Information from Geophysical and Geological Data throuh Combination of Probabilistic Inverse Problem Theory and Geostatistics

Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming \u3c4 neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in 3c 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an E\u3bd-2 spectrum in the energy range 1.0 7 1017 eV -2.5 7 1019 eV is E2 dN\u3bd/dE\u3bd < 4.4 7 10-9 GeV cm-2 s-1 sr-1, placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays

Elaboration of lead-free Na0.5Bi0.5TiO3–BaTiO3 (NBT-BT) thick films by aerosol deposition method (ADM)

International audienceThick and dense ceramic films of lead-free 0.94 Na 0.5 Bi 0.5 TiO 3 – 0.06 BaTiO 3 (NBT-BT) composition were elaborated by aerosol deposition method (ADM) at room temperature. A powder of suitable grain size was elaborated by solid state reaction. Using this powder, two samples were elaborated by ADM respectively on glass and metallic substrates, in order to check for microstructure and electrical properties. This process allowed obtaining a thick film (3.2 µm) with dense microstructure. Measurement of electrical properties revealed a lossy dielectric behavior indicating interfacial phenomena at the electrode – film interface. The measurement of the ferroelectric hysteresis cycle does not show any characteristics of a ferroelectric behavior, but corresponds well to the one of a lossy non-linear dielectric. The absence of ferroelectricity is probably due to the low grain size of the obtained thick film (130 nm). Further experiments are in progress in order to try to obtain ferroelectric properties

Mise en oeuvre de la méthode de dépôt par aérosol pour la réalisation de revêtements aux propriétés originales

International audienceLa fabrication de matériaux céramiques en couches nécessite typiquement une première étape de mise en forme du film puis une seconde étape de traitement thermique afin de lui conférer les propriétés souhaitées. L'application d'un frittage interdit un certain nombre d'applications de matériaux céramiques dont la température de frittage est incompatible avec celles de matériaux de nature différente (métaux, plastiques, verres). En outre, parmi les nombreux procédés de dépôts céramiques, très peu permettent d'obtenir des objets aux détails très fins, en des temps courts et avec des coûts de fabrication suffisamment bas. Depuis quelques années le procédé de dépôt par aérosol froid 1 suscite un intérêt croissant en raison des nombreux avantages qu'il procure. En revanche ce procédé performant pour les métaux est encore peu adapté aux céramiques. Ainsi, le procédé ADM 2 trouve toute sa place dans l'éventail des procédés de dépôts céramique et s'est fortement développé depuis une dizaine d'années. Le principe est de générer un aérosol sec d'une poudre micronique puis de l'accélérer à travers une buse de projection pour fragmenter les particules solides sur un substrat. Lors de la fragmentation, l'énergie cinétique est transformée en énergie de cohésion, permettant la densification du matériau sans qu'aucun frittage ne soit requis. De plus, les couches obtenues sont nanostructurées. Le CTTC conduit un projet de développement d'une machine à pilotage numérique, capable de réaliser des objets sans intervention d'un opérateur, à l'aide d'un fichier CAO desdits objets (brevet n°FR1160790). Ce projet, nommé INPACT, pour Inorganic Nanostructured Parts by Aerosol Cold Technology, est réalisé en collaboration avec le laboratoire Science des Procédés Céramiques et de Traitements de Surface (Limoges) et l'entreprise CERADROP, fabricant de machine d'impression jet d'encre (Limoges). L'intervention vise à présenter cette nouvelle technologie de dépôts sans frittage, au travers de quelques exemples de réalisations de couches céramiques aux propriétés originales

Dense and highly textured coatings obtained by aerosol deposition method from Ti3SiC2 powder: Comparison to a dense material sintered by Spark Plasma Sintering

International audienceA commercial Ti3SiC2 MAX-phase powder of micron size was impacted onto glass substrates by aerosol deposition method (ADM) to get dense and adhesive films without sintering and with thicknesses up to 16μm. The overall grain organization follows a wavelike texture with some significant grain deformation. Individual grains appear elongated and c-oriented. Grain boundaries are made of amorphous phase with small Ti3SiC2 crystallites of a size lower than 10nm embedded. This structure is similar to that observed at the interface with the substrate where grain fragmentation is more pronounced. Inside grains, Ti3SiC2 typical nano-lamellar structure is clearly seen, as well as some crystal deformations quantified around 2.5%. XRD analyses are in accordance to TEM results and the mean crystallite size calculated evolves with the thickness. It is equal to a few nanometers close to the substrate up to an average of 40-50nm for thicker films