Determination of the 14C Concentration in a Liquid Scintillator for a Neutrino Detector

Abstract

A setup has been developed for studying ultralow ¹⁴C concentrations in liquid scintillator samples for a large neutrino detector. The setup is located at the low-background underground laboratory of the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) at a depth of 4900 m of water equivalent. The ¹⁴C concentrations in a liquid scintillator based on linear alkyl benzene, the background counting rates, and the spectra of particle energies deposited in the technological scintillator sample have been measured. The ratio ¹⁴C/¹²C = (1.41 ± 0.12) × 10^–16 has been obtained. A model of the γ-ray background has been developed, with which it is possible to extract the energy spectrum of 14C and reduce the systematic uncertainty of measurements.