Measurement of the gamma background in Modane Underground Laboratory with SuperNEMO, and estimation of SuperNEMO's overall background levels

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A90263%2F24%3A00384506" target="_blank" >RIV/68407700:90263/24:00384506 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.5281/zenodo.13169405" target="_blank" >https://doi.org/10.5281/zenodo.13169405</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5281/zenodo.13169405" target="_blank" >10.5281/zenodo.13169405</a>

Result language

angličtina

Original language name

Measurement of the gamma background in Modane Underground Laboratory with SuperNEMO, and estimation of SuperNEMO's overall background levels

Original language description

Discovering neutrinoless double-beta decay (0vbb) would be a huge step in understanding the neutrino's nature. The SuperNEMO experiment is designed to search for 0vbb, using its Demonstrator Module in LSM, Modane, France, at a depth of 4800 m.w.e. Its tracker and segmented, scintillator-based calorimeter enable unambiguous particle identification, time-of-flight and individual energy measurements. SuperNEMO aims to achieve an ultra-low background level of < 10^-4 events/(keV.kg.yr) in the 0vbb ROI. We must therefore understand both internal (within the bb foil) and external sources of background. The main external background to the unshielded detector comes from photons produced by 208Tl, 214Bi and 40K decays in the LSM walls. These occasionally interact in the detector, mimicking bb events. Iron shielding, which will almost eliminate this background, will be installed by summer. This work takes advantage of data taken before shielding installation to measure this photon background. Using SuperNEMO's particle-identification abilities, we present a new measurement of this flux through multiple channels: by direct gamma detection; and independently via a measurement of bb-like events generated by gammas. Combining these measurements provides an overall estimate of the gamma flux at LSM. Additionally, we have simulated processes anticipated to contribute to the internal background, developing a first version of SuperNEMO's background model. The most significant contribution is expected to be due to contamination of the bb source foil, where isotopes of 208Tl, 214Bi, 234mPa and 40K can mimic bb events. Fully comprehending SuperNEMO's background, combined with its topological reconstruction capabilities, will allow us to search for the 0vbb mechanisms and test the possible deviations of the 2vbb spectrum from the Standard Model.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10304 - Nuclear physics

Project

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Continuities

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Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů