Astronomie neutrino

L’astronomie neutrino (parfois astronomique neutrinique) est la branche de l'astronomie qui observe les objets célestes à l'aide de détecteurs de neutrinos, des leptons neutres de faible masse décrits par la théorie électrofaible. Étant donné leur très faible interaction avec la matière, les neutrinos ont la capacité de traverser des distances cosmologiques sans dévier de leur trajectoire initiale, faisant d'eux d'excellents messagers astronomiques permettant de retracer directement l'origine de leur lieu de production. L'observation de neutrinos cosmiques permet de mieux étudier le fonctionnement des phénomènes les plus énergétiques et les plus éloignés de l'Univers. Toutefois, la difficulté de détecter ces particules limite à ce jour la capacité de détection d'objets célestes émettant des neutrinos. Avant 2022, seules trois associations de neutrinos à des objets célestes ont pu être établies: le Soleil, la supernova 1987A, ainsi que la galaxie active TXS0506+056. Histoire

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Measurement of sound speed vs. depth in South Pole ice for neutrino astronomy

Xiaoxia Bai

We have measured the speed of both pressure waves and shear waves as a function of depth between 80 and 500 m depth in South Pole ice with better than 1% precision. The measurements were made using the South Pole Acoustic Test Setup (SPATS), an array of transmitters and sensors deployed in the ice at the South Pole in order to measure the acoustic properties relevant to acoustic detection of astrophysical neutrinos. The transmitters and sensors use piezoceramics operating at similar to 5-25 kHz. Between 200 m and 500 m depth, the measured profile is consistent with zero variation of the sound speed with depth, resulting in zero refraction, for both pressure and shear waves. We also performed a complementary study featuring an explosive signal propagating vertically from 50 to 2250 m depth, from which we determined a value for the pressure wave speed consistent with that determined for shallower depths, higher frequencies, and horizontal propagation with the SPATS sensors. The sound speed profile presented here can be used to achieve good acoustic source position and emission time reconstruction in general, and neutrino direction and energy reconstruction in particular. The reconstructed quantities could also help separate neutrino signals from background. (C) 2010 Elsevier B.V. All rights reserved.

2010

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Calibration and characterization of the IceCube photomultiplier tube

Xiaoxia Bai

Over 5000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-in. diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance to IceCube event reconstruction and simulation efforts. (C) 2010 Elsevier B.V. All rights reserved.

2010

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Neutrino signal from γ-ray-loud binaries powered by high energy protons

Mathieu Ribordy

We present a hadronic model of activity for galactic γ-ray-loud binaries, in which the multi-TeV neutrino flux from the source can be much higher and/or harder than the detected TeV γ-ray flux. This is related to the fact that most neutrinos are produced in proton-proton interactions close to the bright massive star, in a region optically thick for the TeV γ rays. Considering the specific example of LS I+61°303, we derive upper bounds for neutrino fluxes from various proton injection spectra compatible with the observed multiwavelength spectrum. At this upper level of neutrino emission, we demonstrate that ICECUBE will not only detect this source at 5σ C.L. after one year of operation, but, after three years of exposure, will also collect a sample marginally sufficient to constrain the spectral characteristics of the neutrino signal, directly related to the underlying source acceleration mechanisms. © 2009 The American Physical Society.

2009

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PHYS-439: Introduction to astroparticle physics

We present the role of particle physics in cosmology and in the description of astrophysical phenomena. We also present the methods and technologies for the observation of cosmic particles.

PHYS-400: Selected topics in nuclear and particle physics

This course presents the physical principles and the recent research developments on three topics of particle and nuclear physics: the physics of neutrinos, dark matter, and plasmas of quarks and gluons. An emphasis is given on experimental aspects in these three research fields.

PHYS-415: Particle physics I

Presentation of particle properties, their symmetries and interactions. Introduction to quantum electrodynamics and to the Feynman rules.

Neutrino

Le neutrino est une particule élémentaire du modèle standard de la physique des particules. Les neutrinos sont des fermions de , plus précisément des leptons. Ils sont électriquement neutres. Il en

Observatoire de neutrinos

thumb|Intérieur de , un détecteur de neutrinos lancé en 2002. Un observatoire de neutrinos est un dispositif permettant de détecter les neutrinos. En raison de la très faible interaction des neutrinos

IceCube

LObservatoire de neutrinos IceCube, ou simplement IceCube, « cube de glace », est un observatoire de neutrinos construit au pôle Sud. Ses milliers de capteurs sont situés sous la glace antarctique,