Work

Background characterization of the CONUS+ experimental location

Year: 2025

Type: article

Abstract: CONUS is an experiment aiming at detecting coherent elastic neutrino-nucleus scattering (CE $$\nu $$ ν NS) of reactor antineutrinos on germanium nuclei in the fully coherent regime, continuing the CONUS physics program conducted at the Brokdorf nuclear power plant (KBR), Germany. The CONUS experiment is installed in the Leibstadt nuclear power plant (KKL), Switzerland, at a distance of 20.7 m from the 3.6 GW reactor core, where the antineutrino flux is $$1.5\cdot 10^{13}$$ 1.5 · 10 13 s $$^{-1}$$ - 1 cm $$^{-2}$$ - 2 . The CE $$\nu $$ ν NS signature will be measured with four point-contact high-purity low energy threshold germanium (HPGe) detectors. A good understanding of the background is crucial, especially events correlated with the reactor thermal power are troublesome, as they can mimic the predicted CE $$\nu $$ ν NS interactions. A large background characterization campaign was conducted during reactor on and off times to find the best location for the CONUS setup. On-site measurements revealed a correlated, highly thermalized neutron field with a maximum fluence rate of $$(2.3\pm 0.1)\cdot 10^{4}$$ ( 2.3 ± 0.1 ) · 10 4 neutrons d $$^{-1}$$ - 1 cm $$^{-2}$$ - 2 during reactor operation. The $$\gamma $$ γ -ray background was studied with a HPGe detector without shield, paying special attention to the thermal power correlated $$^{16}$$ 16 N decay and other neutron capture $$\gamma $$ γ -lines. The muon flux was examined using a liquid scintillator detector measuring (107 ± 3) muons s $$^{-1}$$ - 1 m $$^{-2}$$ - 2

Source: The European Physical Journal C

DOI: 10.1140/epjc/s10052-025-14160-7