I2: Geoparticles

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  • Elementary particles can nowadays be used as probes of their sources or of the matter they have traversed.

    We propose to investigate the use of particles as probes of the Earth’s interior in two ways:

    Earth.jpgVolcano.jpg

    1) neutrinos from the decay of radioactive elements in the crust and mantle, called geoneutrinos, to gather information on the composition and distribution of the radioactive elements whose decay provides a large fraction of the Earth’s thermal power.

    2) geophysical tomography with muon telescopes, to map the internal density structure of volcanoes, unstable cliffs, and geological layers located over mines, nuclear waste storages, and CO2 reservoirs.

    The main difficulty in geo-neutrino detection lies in their weak flux with respect to other antineutrinos, mainly those issued from power reactors (which are, on the other hand, the signal for reactor neutrino experiments such as Double Chooz in the Ardennes region, in which the APC group has a leading role). Conversely, muons represent one of the most dangerous backgrounds for neutrino experiments located underground.

    The research program we propose is along the following lines:

    1) The modelling of muon propagation through the rock is critical to extract the relevant information from the muon telescope data. Detailed simulations have been carried out by the APC group to predict the background to the Double Chooz experiment, and independently by the IPGP group to predict the signal in muon telescopes. A synergy of the two teams will lead to the development of the most accurate methods for the inverse tomography problem.

    2) An accurate modelling of reactor anti-neutrino spectra can be obtained from the analysis of the data that will come from the Double Chooz experiment (2011-2016). This will improve the knowledge of geo-neutrino backgrounds and thus the precision on current and future measurements. In addition, the APC group is involved in the Borexino experiment, which has recently reinforced the evidence for geo-neutrinos and will provide a more precise measurement in the near future. Participating in this data analysis will be useful to gain experience on the topic.

    3) The results of current geo-neutrino experiments are dominated by the thick continental crust. However, the importance of geo-neutrinos lies in the possibility to probe the geochemistry of the mantle. We propose two approaches, to be studied jointly by IPGP and APC: either detect geo-neutrinos at specific locations, or precisely subtract the contribution from the crust. The option of a movable detector could be interesting in this regard.

    4) Future detectors for geo-neutrinos demand R&D on specific items. We propose to construct a test bench to address some key topics. In parallel with the R&D on future large detectors, a selection of the most promising sites for geosciences, i.e. where to deploy these detectors, has to be performed.

  • APC:

    Luca Agostino (PhD student)

    Anatael Cabrera (Physicist)

    Jaime Dawson (Physicist)

    Davide Franco (Physicist)

    Didier Kryn (Physicist)

    Michel Obolensky (Physicist

    Thomas Patzak (Professor)

    Alessandra Tonazzo (Professor, co-PI)

    Daniel Vignaud (Researcher)

     

    IPGP:

    Dominique Gibert (Physicist, co-PI)

    Claude Jaupart (Professor)

    Kevin Jourde (PhD student)

    Nolwenn Lesparre (Post-doc)

    Jacques Sibilla (Engineer)

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    Muon telescopes for volcano tomography Photo0051.jpg Previously built telescopes are being improved. The time resolution of the electronics of the Guadeloupe telescope has been improved from 10ns to 1ns. This improves the capability to flag particles, in particular it is now possible to determine the flight direction and thus to remove a large fraction of the background. The Guadeloupe telescope has also received a rotating base allowing for easier orientation of the instrument.
    The MEMPHYNO R&D test bench Memphyno_foto.jpg A tomography of the building has been performed with the muon hodoscope.

    The first data with the electronics card for a 16 PMT matrix has been taken,

    For details, see the presentation and e-Print: arXiv:1306.6865 [physics.ins-det]

    The BOREXINO neutrino experiment BorexinoPMTs.jpg The new geo-neutrino analysis has been published.

    e-Print: arXiv:1303.2571 [hep-ex]

    he DOUBLE CHOOZ reactor neutrino experiment DoubleChoozDetector14102009.jpg Measurement of anti-neutrino directionality : thesis in progress (R.Roncin)

    Precise prediction of the reactor spectrum for the oscillation analysis: http://arxiv.org/abs/1207.6632

    http://arxiv.org/abs/1301.2948

    Detailed simulation of underground muon flux with the MUSIC code: http://arxiv.org/abs/1210.3748

    • L. Agostino et al.,

    Future large-scale water-Cherenkov detector

    Published in Phys. Rev. ST Accel. Beams 16, 061001 (2013)
    e-Print: arXiv:1306.6865 [physics.ins-det]
    • S. Perasso et al.,

    Measurement of ortho-positronium propoerties in liquid scintillators

    Published in Phys. Rev. C88 (2013) 065502
    e-Print: arXiv:1306.6001 [physics.ins-det]

     

    • Borexino Collaboration,

    Measurement of geo-neutrinos from 1353 days of Borexino

    Published in Phys.Lett. B722 (2013) 295-300
    e-Print: arXiv:1303.2571 [hep-ex]

     

    • D. Franco et al.,

    Mass hierarchy discrimination with atmospheric neutrinos in large volume ice/water Cherenkov detectors

    Published in JHEP 1304 (2013) 008
    e-Print: arXiv:1301.4332 [hep-ex]
    • Double Chooz Collaboration,

    First measurement of θ13 from delayed neutron capture on hydrogen in the Double Chooz experiment,

    Published in Phys.Lett. B723 (2013) 66-70
    e-Print: >arXiv:1301.2948 [hep-ex]
    • Double Chooz Collaboration,

    Direct Measurement of Backgrounds using Reactor-Off Data in Double Chooz,

    Published in Phys.Rev. D87 (2013) 011102
    e-Print: arXiv:1210.3748 [hep-ex]

     

    • Double Chooz Collaboration,

    Reactor electron antineutrino disappearance in the Double Chooz experiment,

    Published in Phys.Rev. D86 (2012) 052008
    e-Print: arXiv:1207.6632 [hep-ex]

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