Discriminating cosmic muons and radioactivity using a liquid scintillation fiber detector

TL;DR

This paper presents a new liquid scintillation fiber detector optimized for discriminating cosmic muons from environmental radioactivity, achieving over 98% muon detection efficiency and validated through simulations and prototype tests.

Contribution

It introduces a novel detector design using wavelength-shifting fibers and liquid scintillator, with optimized reflectivity and validated performance for background rejection in underground experiments.

Findings

Muon detection efficiency >98%

Average of 58 photo-electrons collected per muon

Good agreement between simulation and experimental data

Abstract

In the case of underground experiments for neutrino physics or rare event searches, the background caused by cosmic muons contributes significantly and therefore must be identified and rejected. We proposed and optimized a new detector using liquid scintillator with wavelenghth-shifting fibers which can be employed as a veto detector for cosmic muons background rejection. From the prototype study, it has been found that the detector has good performances and is capable of discriminating between muons induced signals and environmental radiation background. Its muons detection efficiency is greater than 98$\%$, and on average, 58 photo-electrons (p.e.) are collected when a muon passes through the detector. To optimize the design and enhance the collection of light, the reflectivity of the coating materials has been studied in detail. A Monte Carlo simulation of the detector has been developed and compared to the performed measurements showing a good agreement between data and simulation results.