Improving the energy uniformity for large liquid scintillator detectors

TL;DR

This paper presents a calibration method that significantly reduces energy non-uniformity in large liquid scintillator detectors, thereby enhancing their energy resolution for precise measurements.

Contribution

It introduces optimized calibration strategies and corrections for azimuthal asymmetry to improve energy uniformity in large liquid scintillator detectors.

Findings

Energy non-uniformity near boundary reduced from 0.64% to 0.38%.

Within fiducial volume, non-uniformity improved from 0.3% to 0.17%.

Enhanced energy resolution potential achieved.

Abstract

It is challenging to achieve high precision energy resolution for large liquid scintillator detectors. Energy non-uniformity is one of the main obstacles. To surmount it, a calibration-data driven method was developed previously to reconstruct event energy in the JUNO experiment. In this paper, we investigated the choice of calibration sources thoroughly, optimized the calibration positions and corrected the residual detector azimuthal asymmetry. All these efforts lead to a reduction of the energy non-uniformity near the detector boundary, from about 0.64% to 0.38%. And within the fiducial volume of the detector it is improved from 0.3% to 0.17%. As a result the energy resolution could be further improved.