I2: Geoparticles


A measurement campaign on the Apollonia archaeological site in Greece is underway!
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  • Elementary particles can nowadays be used as probes of their sources or of the matter they have traversed.

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


    Earth.jpg1) muons from the decay of radioactive elements in the crust and mantle, called atmospheric muons, 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 atmospheric muons’ 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 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 leads 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  improved the knowledge of atmospheric muons backgrounds and thus the precision on current and future measurements. In addition, the APC group is involved in the Borexino experiment, which has reinforced the evidence for atmospheric muons and provides a more precise measurement in the near future. Participating in this data analysis is useful to gain experience on the topic.

    3) The results of current atmospheric muons experiments are dominated by the thick continental crust. However, the importance of atmospheric muons 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 atmospheric muons 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 atmospheric muons 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.


    After establishing techniques to use elementary particles to explore the Earth and its structure, WP I2 is focusing on a novel application to archaeology. Cosmic muons that traversed a structure can provide information on its internal structure in a non-destructive way. The feasibility of using this method to explore the interior of Macedonian tumuli has been assessed with simulation studies. A measurement campaign on the Apollonia archaeological site in Greece is foreseen.


    WP leader Alessandra TONAZZO APC PR, Université Paris-Diderot
    WP co-leader Fernando LOPES IPGP IR, IPGP
    WP member Theodore AVGITAS APC PhD   student, LabEx UnivEarthS
    WP member Davide FRANCO APC CR, CNRS
    WP member Héctor GOMEZ-MALUENDA APC PostDoc, LabEx UnivEarthS
    WP member Stavros KATSANEVAS APC PR, Univ. Paris-Diderot
    WP member Antoine KOUCHNER APC PR, Univ. Paris-Diderot



    The feasibility of using cosmic muon attenuation measurements (muon tomography ) to explore the internal structure of volcanoes was established and developed under several aspects, from instrumentation to data analysis. This led to several publications. Data from the Double Chooz experiment allowed detailed studies on models and simulations of cosmic muons, useful as input for muon tomography. This topic was finalised in 2017 and led to a publication.

    Analysis of data from the Borexino experiment to measure atmospheric muons, i.e. neutrinos produced from radiogenic activity inside the crust and mantle, which carry unique information on the Earth’s composition and origin. The activity was led by Romain Roncin during his thesis and led to two publications of the Borexino Collaboration. A paper was also published by IPGP WP members on geo-neutrino models and comparison with data. The analysis of data from the Double Chooz neutrino experiment has allowed an evaluation of the potential of future detectors to measure the directionality of neutrinos, which may be relevant for future atmospheric muons measurements. This was also part of Romain Roncin’s thesis.

    Instrumental development for future atmospheric muons detectors has been carried out on two aspects: a grouped photomultiplier readout electronics card, useful for future large-scale detectors, and techniques to reject background based on the timing properties of the signal.


    The focus of the most recent developments of WP I2 has been on the novel application of muon tomography to archaeology. In cooperation with the Laboratory of Exploration Geophysics of the university of Thessaloniki (Greece) and with other laboratories in France, an interdisciplinary project was started to study the feasibility of this technique to explore archaeological structures and, if possible, perform first set of measurements as proof of concept. Thanks to our sensitivity studies we have obtained an exploitation permission to install a muon detector near a tumulus in Apollonia, in northern Greece. This tumulus has been already explored by other techniques like electrical resistivity tomography, revealing two internal structures. For this reason, this tumulus represents an ideal scenario to perform the first experimental measurements to proof the capabilities of the muon tomography.

    The installation of a muon detector at the Apollonia site in Greece has been postponed to 2018. It will provide the first dedicated data for this specific application of the muon tomography technique, allowing for validation of our simulation studies and for better estimates of the sensitivity for future measurements.


    • Gómez,C. Goy, Y. Karyotakis, S. Katsanevas, J. Marteau, A. Tonazzo, D. Gibert, K. Jourde, M. Rosas-Carbajal,

    Forward scattering effects on muon imaging,

    e-Print: arXiv:1709.05106 [physics.ins-det], submitted to JINST


    • Double ChoozCollaboration,

    Cosmic-muon characterization and annual modulation measurement with Double Chooz detectors,

    JCAP 1702 (2017) no.02, 017


    • Albert et al, ANTARES Collaboration,

    An algorithm for the reconstruction of high-energy neutrino-induced particle showers and its application to the ANTARES neutrino telescope,
    Eur. Phys. J. C 77 (2017) 419


    • KM3NeT Collaboration: S. Adrián-Martínez et al.,

    KM3NeT 2.0 – Letter of Intent for ARCA and ORCA.

    J. Phys. G: Nucl. Part. Phys. 43 (2016) 084001 (published after the 2016 SC)


    • 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]