Muon and Cosmogenic Neutron Detection in Borexino

Abstract

Borexino, a liquid scintillator detector at LNGS, is designed for the detection of neutrinos and antineutrinos from the Sun, supernovae, nuclear reactors, and the Earth. The feeble nature of these signals requires a strong suppression of backgrounds below a few MeV. Very low intrinsic radiogenic contamination of all detector components needs to be accompanied by the efficient identification of muons and of muon-induced backgrounds. Muons produce unstable nuclei by spallation processes along their trajectory through the detector whose decays can mimic the expected signals; for isotopes with half-lives longer than a few seconds, the dead time induced by a muon-related veto becomes unacceptably long, unless its application can be restricted to a sub-volume along the muon track. Consequently, not only the identification of muons with very high efficiency but also a precise reconstruction of their tracks is of primary importance for the physics program of the experiment. The Borexino inner detector is surrounded by an outer water-Cherenkov detector that plays a fundamental role in accomplishing this task. The detector design principles and their implementation are described. The strategies adopted to identify muons are reviewed and their efficiency is evaluated. The overall muon veto efficiency is found to be 99.992% or better. Ad-hoc track reconstruction algorithms developed are presented. Their performance is tested against muon events of known direction such as those from the CNGS neutrino beam, test tracks available from a dedicated External Muon Tracker and cosmic muons whose angular distribution reflects the local overburden profile. The achieved angular resolution is 3-5 deg and the lateral resolution is 35-50 cm, depending on the impact parameter of the crossing muon. The methods implemented to efficiently tag cosmogenic neutrons are also presented.

42 pages. 32 figures on 37 files. Uses JINST.cls. 1 auxiliary file (defines.tex) with TEX macros. submitted to Journal of Instrumentation

References in corpus (5)

• Observation of a first ${\nu }_{\tau }$ candidate in the OPERA experiment in the CNGS beam
• Study of solar and other unknown anti-neutrino fluxes with Borexino at LNGS
• The detection of neutrino interactions in the emulsion/lead target of the OPERA experiment
• Pulse-Shape discrimination with the Counting Test Facility
• Probing the Earth's interior with the LENA detector

Cited by in corpus (37)

• Final results of Borexino Phase-I on low energy solar neutrino spectroscopy
• First evidence of pep solar neutrinos by direct detection in Borexino
• Experimental evidence of neutrinos produced in the CNO fusion cycle in the Sun
• Results from the first use of low radioactivity argon in a dark matter search
• Simultaneous Precision Spectroscopy of $pp$, ${}^7$Be, and $pep$ Solar Neutrinos with Borexino Phase-II
• Measurement of geo-neutrinos from 1353 days of Borexino
• Cosmogenic Backgrounds in Borexino at 3800 m water-equivalent depth
• Absence of day-night asymmetry of 862 keV Be-7 solar neutrino rate in Borexino and MSW oscillation parameters
• Comprehensive geoneutrino analysis with Borexino
• Borexino calibrations: Hardware, Methods, and Results
• Cosmic-muon flux and annual modulation in Borexino at 3800 m water-equivalent depth
• Search for Solar Axions Produced in $p(d,{}^3\mathrm{He})\mathrm{A}$ Reaction with Borexino Detector
• Improved measurement of ${}^8$B solar neutrinos with 1.5 kt y of Borexino exposure
• A test of electric charge conservation with Borexino
• Muon-induced background in the EDELWEISS dark matter search
• Modulations of the Cosmic Muon Signal in Ten Years of Borexino Data
• New limits on heavy sterile neutrino mixing in ${}^8\mathrm{B}$-decay obtained with the Borexino detector
• Measurement of CNGS muon neutrino speed with Borexino
• The Monte Carlo simulation of the Borexino detector
• Seasonal Modulation of the ${}^7$Be Solar Neutrino Rate in Borexino
• Geo-neutrinos
• A search for low-energy neutrinos correlated with gravitational wave events GW150914, GW151226 and GW170104 with the Borexino detector
• Muon-induced neutrons do not explain the DAMA data
• The Performance of the Muon Veto of the GERDA Experiment
• Solar Neutrino Spectroscopy
• Borexino results on neutrinos from the Sun and Earth
• Measuring Muon-Induced Neutrons with Liquid Scintillation Detector at Soudan Mine
• A search for low-energy neutrino and antineutrino signals correlated with gamma-ray bursts with Borexino
• Fast Neutron Detection with a Segmented Spectrometer
• The Electronics and Data Acquisition System for the DarkSide-50 Veto Detectors
• Signatures of muonic activation in the Majorana Demonstrator
• Neutron Tagging Can Greatly Reduce Spallation Backgrounds in Super-Kamiokande
• Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun
• Identification of the cosmogenic ${}^{11}$C background in large volumes of liquid scintillators with Borexino
• New Spallation Background Rejection Techniques to Greatly Improve the Solar Neutrino Sensitivity of JUNO
• Performance of a SiPM-based, plastic scintillator muon veto prototype for CUPID
• Low Energy Neutrino Measurements