Cosmogenic radio-nuclei are an important source of background for low-energy neutrino experiments. In Borexino, cosmogenic 11C decays outnumber solar pep and CNO neutrino events by about ten to one. In order to extract the flux of these two neutrino species, a highly efficient identification of this background is mandatory. We present here the details of the most consolidated strategy, used throughout Borexino solar neutrino measurements. It hinges upon finding the space-time correlations between 11C decays, the preceding parent muons and the accompanying neutrons. This article describes the working principles and evaluates the performance of this Three-Fold Coincidence (TFC) technique in its two current implementations: a hard-cut and a likelihood-based approach. Both show stable performances throughout Borexino Phases II (2012–2016) and III (2016–2020) data sets, with a 11C tagging efficiency of ∼ 90 % and ∼ 63–66 % of the exposure surviving the tagging. We present also a novel technique that targets specifically 11C produced in high-multiplicity during major spallation events. Such 11C appear as a burst of events, whose space-time correlation can be exploited. Burst identification can be combined with the TFC to obtain about the same tagging efficiency of ∼ 90 % but with a higher fraction of the exposure surviving, in the range of ∼ 66–68 %.

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., et al. (2021). Identification of the cosmogenic ¹¹C background in large volumes of liquid scintillators with Borexino. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 81(12) [10.1140/epjc/s10052-021-09799-x].

Identification of the cosmogenic ¹¹C background in large volumes of liquid scintillators with Borexino

Guffanti, D.;
2021

Abstract

Cosmogenic radio-nuclei are an important source of background for low-energy neutrino experiments. In Borexino, cosmogenic 11C decays outnumber solar pep and CNO neutrino events by about ten to one. In order to extract the flux of these two neutrino species, a highly efficient identification of this background is mandatory. We present here the details of the most consolidated strategy, used throughout Borexino solar neutrino measurements. It hinges upon finding the space-time correlations between 11C decays, the preceding parent muons and the accompanying neutrons. This article describes the working principles and evaluates the performance of this Three-Fold Coincidence (TFC) technique in its two current implementations: a hard-cut and a likelihood-based approach. Both show stable performances throughout Borexino Phases II (2012–2016) and III (2016–2020) data sets, with a 11C tagging efficiency of ∼ 90 % and ∼ 63–66 % of the exposure surviving the tagging. We present also a novel technique that targets specifically 11C produced in high-multiplicity during major spallation events. Such 11C appear as a burst of events, whose space-time correlation can be exploited. Burst identification can be combined with the TFC to obtain about the same tagging efficiency of ∼ 90 % but with a higher fraction of the exposure surviving, in the range of ∼ 66–68 %.
Articolo in rivista - Articolo scientifico
Scientifica
Neutrino detectors; Liquid scintillators; radioactive background;
English
Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., et al. (2021). Identification of the cosmogenic ¹¹C background in large volumes of liquid scintillators with Borexino. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 81(12) [10.1140/epjc/s10052-021-09799-x].
Agostini, M; Altenmüller, K; Appel, S; Atroshchenko, V; Bagdasarian, Z; Basilico, D; Bellini, G; Benziger, J; Biondi, R; Bravo, D; Caccianiga, B; Calaprice, F; Caminata, A; Cavalcante, P; Chepurnov, A; D’Angelo, D; Davini, S; Derbin, A; Di ZGiacintio, A; Di Marcello, V; Ding, X; Di Ludovico, A; Di Noto, L; Drachnev, I; Formozov, A; Franco, D; Galbiati, C; Ghiano, C; Giammarchi, M; Goretti, A; Göttel, A; Gromov, M; Guffanti, D; Ianni, A; Ianni, A; Jany, A; Jeschke, D; Kobychev, V; Korga, G; Kumaran, S; Laubenstein, M; Litvinovich, E; Lombardi, P; Lomskaya, I; Ludhova, L; Lukyanchenko, G; Lukyanchenko, L; Machulin, I; Martyn, J; Meroni, E; Meyer, M; Miramonti, L; Misiaszek, M; Muratova, V; Neumair, B; Nieslony, M; Nugmanov, R; Oberauer, L; Orekhov, V; Ortica, F; Pallavicini, M; Papp, L; Pelicci, L; Penek, Ö; Pietrofaccia, L; Pilipenko, N; Pocar, A; Porcelli, A; Raikov, G; Ranalli, M; Ranucci, G; Razeto, A; Re, A; Redchuk, M; Romani, A; Rossi, N; Schönert, S; Semenov, D; Settanta, G; Skorokhvatov, M; Singhal, A; Smirnov, O; Sotnikov, A; Suvorov, Y; Tartaglia, R; Testera, G; Thurn, J; Unzhakov, E; Vishneva, A; Vogelaar, R; von Feilitzsch, F; Wojcik, M; Wurm, M; Zavatarelli, S; Zuber, K; Zuzel, G
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10281/376616
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