Fast neutron background characterization of the future Ricochet experiment at the ILL research nuclear reactor

Abstract

The future Ricochet experiment aims at searching for new physics in the electroweak sector by providing a high precision measurement of the Coherent Elastic Neutrino-Nucleus Scattering (CENNS) process down to the sub-100 eV nuclear recoil energy range. The experiment will deploy a kg-scale low-energy-threshold detector array combining Ge and Zn target crystals 8.8 meters away from the 58 MW research nuclear reactor core of the Institut Laue Langevin (ILL) in Grenoble, France. Currently, the Ricochet collaboration is characterizing the backgrounds at its future experimental site in order to optimize the experiment's shielding design. The most threatening background component, which cannot be actively rejected by particle identification, consists of keV-scale neutron-induced nuclear recoils. These initial fast neutrons are generated by the reactor core and surrounding experiments (reactogenics), and by the cosmic rays producing primary neutrons and muon-induced neutrons in the surrounding materials. In this paper, we present the Ricochet neutron background characterization using ${}^3$He proportional counters which exhibit a high sensitivity to thermal, epithermal and fast neutrons. We compare these measurements to the Ricochet Geant4 simulations to validate our reactogenic and cosmogenic neutron background estimations. Eventually, we present our estimated neutron background for the future Ricochet experiment and the resulting CENNS detection significance.

14 pages, 14 figures, 1 table

References in corpus (7)

• Observation of Coherent Elastic Neutrino-Nucleus Scattering
• Searching for low-mass dark matter particles with a massive Ge bolometer operated above-ground
• Constraints on elastic neutrino nucleus scattering in the fully coherent regime from the CONUS experiment
• Measurement of Coherent Elastic Neutrino-Nucleus Scattering from reactor antineutrinos
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• Coherent Elastic Neutrino-Nucleus Scattering at the European Spallation Source
• DIAPHANE: Muon tomography applied to volcanoes, civil engineering, archaelogy

Cited by in corpus (4)

• Final CONUS results on coherent elastic neutrino-nucleus scattering at the Brokdorf reactor
• Results from a Prototype TES Detector for the Ricochet Experiment
• On the impact of the Migdal effect in reactor CE$\nu$NS experiments
• Particle background characterization and prediction for the NUCLEUS reactor CE$\nu$NS experiment