51 research outputs found

    KM3NeT front-end and readout electronics system: hardware, firmware, and software

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    The KM3NeT research infrastructure being built at the bottom of the Mediterranean Sea will host water-Cherenkov telescopes for the detection of cosmic neutrinos. The neutrino telescopes will consist of large volume three-dimensional grids of optical modules to detect the Cherenkov light from charged particles produced by neutrino-induced interactions. Each optical module houses 31 3-inch photomultiplier tubes, instrumentation for calibration of the photomultiplier signal and positioning of the optical module and all associated electronics boards. By design, the total electrical power consumption of an optical module has been capped at seven watts. This paper presents an overview of the front-end and readout electronics system inside the optical module, which has been designed for a 1 ns synchronization between the clocks of all optical modules in the grid during a life time of at least 20 years.Peer Reviewe

    Multi-messenger Observations of a Binary Neutron Star Merger

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    International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∌1.7 s\sim 1.7\,{\rm{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of 40−8+8{40}_{-8}^{+8} Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26  M⊙\,{M}_{\odot }. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∌40 Mpc\sim 40\,{\rm{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∌10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∌9\sim 9 and ∌16\sim 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    The prototype detection unit of the KM3NeT detector: KM3NeT Collaboration

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    A prototype detection unit of the KM3NeT deep-sea neutrino telescope has been installed at 3500m depth 80 km offshore the Italian coast. KM3NeT in its final configuration will contain several hundreds of detection units. Each detection unit is a mechanical structure anchored to the sea floor, held vertical by a submerged buoy and supporting optical modules for the detection of Cherenkov light emitted by charged secondary particles emerging from neutrino interactions. This prototype string implements three optical modules with 31 photomultiplier tubes each. These optical modules were developed by the KM3NeT Collaboration to enhance the detection capability of neutrino interactions. The prototype detection unit was operated since its deployment in May 2014 until its decommissioning in July 2015. Reconstruction of the particle trajectories from the data requires a nanosecond accuracy in the time calibration. A procedure for relative time calibration of the photomultiplier tubes contained in each optical module is described. This procedure is based on the measured coincidences produced in the sea by the 40^{40}40K background light and can easily be expanded to a detector with several thousands of optical modules. The time offsets between the different optical modules are obtained using LED nanobeacons mounted inside them. A set of data corresponding to 600 h of livetime was analysed. The results show good agreement with Monte Carlo simulations of the expected optical background and the signal from atmospheric muons. An almost background-free sample of muons was selected by filtering the time correlated signals on all the three optical modules. The zenith angle of the selected muons was reconstructed with a precision of about 3∘^\circ ∘. © 2016, The Author(s)

    The high energy cosmic ray particle spectra measurements with the PAMELA calorimeter

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    Abstract Up until now there has been limited, contradictive data on the high energy range of the cosmic ray electron-positron, proton and helium spectra. Due to the limitations of the use of a magnetic spectrometer, over 8 years experimental data was processed using information from a sampling electro-magnetic calorimeter, a neutron detector and scintillator detectors. The use of these devices allowed us to successfully obtain the high energy cosmic ray particle spectra measurements. The results of this study clarify previous findings and greaten our understanding of the origin of cosmic rays

    Time dependence of the e-flux measured by PAMELA during the 2006 July-2009 December solar minimum

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    Precision measurements of the electron component of cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy not accessible from the study of cosmic-ray nuclear components due to their differing diffusion and energy-loss processes. However, when measured near Earth, the effects of propagation and modulation of Galactic cosmic rays in the heliosphere, particularly significant for energies up to at least 30 GeV, must be properly taken into account. In this paper the electron (e−) spectra measured by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics down to 70 MeV from 2006 July to 2009 December over six-month time intervals are presented. Fluxes are compared with a state-of-theart three-dimensional model of solar modulation that reproduces the observations remarkably wel

    PAMELA mission: heralding a new era in cosmic ray physics

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    After seven years of data taking in space, the experiment PAMELA is showing very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt

    PAMELA mission: heralding a new era in cosmic ray physics

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    After seven years of data taking in space, the experiment PAMELA is showing very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt

    Measurement of galactic cosmic-ray deuteron spectrum in the PAMELA experiment

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    62nonenoneKoldobskiy, S.A.; Formato, V.; Adriani, O.; Barbarino, G.C.; Bazilevskaya, G.A.; Bellotti, R.; Boezio, M.; Bogomolov, E.A.; Bonechi, L.; Bongi, M.; Bonvicini, V.; Borisov, S.V.; Bottai, S.; Bruno, A.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S.A.; Galper, A.M.; Danilchenko, I.A.; De Pascale, M.P.; De Santis, C.; De Simone, N.; Di Felice, V.; Jerse, G.; Zverev, V.G.; Zampa, G.; Zampa, N.; Karelin, A.V.; Cafagna, F.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; Kvashnin, A.N.; Koldashov, S.V.; Consiglio, L.; Krutkov, S.Y.; Leonov, A.A.; Marcelli, L.; Mayorov, A.G.; Malakhov, V.V.; Menn, W.; Mikhailov, V.V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Osteria, G.; Papini, P.; Pearce, M.; Picozza, P.; Pizzolotto, C.; Ricci, M.; Ricciarini, S.B.; Rossetto, L.; Runtso, M.F.; Simon, M.M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y.I.; Yurkin, Y.T.Koldobskiy, S. A.; Formato, V.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bonechi, L.; Bongi, M.; Bonvicini, V.; Borisov, S. V.; Bottai, S.; Bruno, A.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S. A.; Galper, A. M.; Danilchenko, I. A.; De Pascale, M. P.; De Santis, C.; De Simone, N.; Di Felice, V.; Jerse, G.; Zverev, V. G.; Zampa, G.; Zampa, N.; Karelin, A. V.; Cafagna, F.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; Kvashnin, A. N.; Koldashov, S. V.; Consiglio, L.; Krutkov, S. Y.; Leonov, A. A.; Marcelli, L.; Mayorov, A. G.; Malakhov, V. V.; Menn, W.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Osteria, G.; Papini, P.; Pearce, M.; Picozza, P.; Pizzolotto, C.; Ricci, M.; Ricciarini, S. B.; Rossetto, L.; Runtso, M. F.; Simon, M. M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Yurkin, Y. T