Separating double-beta decay events from solar neutrino interactions in a kiloton-scale liquid scintillator detector by fast timing

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• 作者：Andrey Elagin^a ; ^{elagin@hep.uchicago.edu} ; Henry J. Frisch^a ; Brian Naranjo^b ; Jonathan Ouellet^c ; Lindley Winslow^c ; Taritree Wongjirad^c
• 关键词：Double beta decay ; Fast timing ; Liquid scintillator ; Spherical harmonics
• 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 出版年：2017
• 出版时间：21 March 2017
• 年：2017
• 卷：849
• 期：Complete
• 页码：102-111
• 全文大小：1464 K
• 卷排序：849

文摘

We present a technique for separating nuclear double beta decay (ββββ-decay) events from background neutrino interactions due to 8B decays in the sun. This background becomes dominant in a kiloton-scale liquid-scintillator detector deep underground and is usually considered as irreducible due to an overlap in deposited energy with the signal. However, electrons from 0νββνββ-decay often exceed the Cherenkov threshold in liquid scintillator, producing photons that are prompt and correlated in direction with the initial electron direction. The use of large-area fast photodetectors allows some separation of these prompt photons from delayed isotropic scintillation light and, thus, the possibility of reconstructing the event topology. Using a simulation of a 6.5 m radius liquid scintillator detector with 100 ps resolution photodetectors, we show that a spherical harmonics analysis of early-arrival light can discriminate between 0νββνββ-decay signal and 8B solar neutrino background events on a statistical basis. Good separation will require the development of a slow scintillator with a 5 ns risetime.