Year: 2023
Type: preprint
Abstract: Borexino could efficiently distinguish between alpha and beta radiation in its liquid scintillator by the characteristic time profile of their scintillation pulse. This alpha/beta discrimination, first demonstrated at the tonne scale in the Counting Test Facility prototype, was used throughout the lifetime of the experiment between 2007 and 2021. With this method, alpha events are identified and subtracted from the beta-like solar neutrino events. This is particularly important in liquid scintillator as alpha scintillation is quenched many-fold. In Borexino, the prominent Po-210 decay peak was a background in the energy range of electrons scattered from Be-7 solar neutrinos. Optimal alpha-beta discrimination was achieved with a "multi-layer perceptron neural network", which its higher ability to leverage the timing information of the scintillation photons detected by the photomultiplier tubes. An event-by-event, high efficiency, stable, and uniform pulse shape discrimination was essential in characterising the spatial distribution of background in the detector. This benefited most Borexino measurements, including solar neutrinos in the \pp chain and the first direct observation of the CNO cycle in the Sun. This paper presents the key milestones in alpha/beta discrimination in Borexino as a term of comparison for current and future large liquid scintillator detectors
Source: arXiv (Cornell University)
Authors: Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D'Angelo, D., Derbin, A., Di Giacintov, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G.d, Kumaran, Sindhujha, Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhová, Livia, Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, Luca, Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, Apeksha, Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., Zuzel, G., BOREXINO Collaboration
Institutions: Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Princeton University, Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso, Istituto Nazionale di Fisica Nucleare, Sezione di Genova, University of Genoa, Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Kurchatov Institute, Petersburg Nuclear Physics Institute, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Observatoire de Paris, Laboratoire AstroParticule et Cosmologie, Sorbonne Paris Cité, Institut National de Physique Nucléaire et de Physique des Particules, Institut de Recherche sur les Lois Fondamentales de l'Univers, Université Paris Diderot, Gran Sasso Science Institute, Johannes Gutenberg University Mainz, Jagiellonian University, Institute for Nuclear Research, Royal Holloway University of London, HUN-REN Institute for Nuclear Research, Forschungszentrum Jülich, RWTH Aachen University, National Research Nuclear University MEPhI, Technical University of Munich, University of Perugia, Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, University of Massachusetts Amherst, Joint Institute for Nuclear Research, GSI Helmholtz Centre for Heavy Ion Research, University of California, Irvine, Istituto Superiore per la Protezione e la Ricerca Ambientale, Institute of High Energy Physics, Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca, Max Planck Institute for Nuclear Physics, University of Milano-Bicocca, Virginia Tech, Technische Universität Dresden
Language: English
Topic: Neutrino Physics Research
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4387800698