A Precise Method to Determine the Energy Scale and Resolution using Gamma Calibration Sources in a Liquid Scintillator Detector

TL;DR

This paper introduces a precise method for calibrating the energy scale and resolution of liquid scintillator detectors using gamma sources, accounting for energy losses and improving accuracy through Monte Carlo simulations.

Contribution

A novel method that accurately determines gamma energy centroid and width in liquid scintillator detectors by modeling energy losses with Monte Carlo simulations.

Findings

Achieves 0.03% precision in centroid determination.

Achieves 0.50% precision in width measurement.

Validates the method with Daya Bay detector data.

Abstract

Gamma sources are routinely used to calibrate the energy scale and resolution of liquid scintillator detectors. However, non-scintillating material surrounding the source introduces energy losses, which may bias the determination of the centroid and width of the full absorption peak. In this paper, we present a general method to determine the true gamma centroid and width to a relative precision of 0.03\% and 0.50\%, respectively, using energy losses predicted by the Monte Carlo simulation. In particular, the accuracy of the assumed source geometry is readily obtained from the fit. The method performs well with experimental data in the Daya Bay detector.