Calibration Strategy of the JUNO-TAO Experiment

TL;DR

This paper details the calibration methods and results for the JUNO-TAO neutrino detector, achieving high precision in energy response and stability essential for accurate antineutrino measurements.

Contribution

It introduces a comprehensive calibration strategy using multiple systems to control energy non-linearity and non-uniformity within tight tolerances.

Findings

Non-linear energy response controlled within 0.6%

Residual non-uniformity less than 0.2%

Energy bias and resolution degradation within 0.3% and 0.05%

Abstract

The Taishan Antineutrino Observatory (JUNO-TAO, or TAO) is a satellite detector for the Jiangmen Underground Neutrino Observatory (JUNO). Located near the Taishan reactor, TAO independently measures the reactor's antineutrino energy spectrum with unprecedented energy resolution. To achieve this goal, energy response must be well calibrated. Using the Automated Calibration Unit (ACU) and the Cable Loop System (CLS) of TAO, multiple radioactive sources are deployed to various positions in the detector to perform a precise calibration of energy response. The non-linear energy response can be controlled within 0.6% with different energy points of these radioactive sources. It can be further improved by using $^{12}\rm B$ decay signals produced by cosmic muons. Through the energy non-uniformity calibration, residual non-uniformity is less than 0.2%. The energy resolution degradation and energy bias caused by the residual non-uniformity can be controlled within 0.05% and 0.3%, respectively. In addition, the stability of other detector parameters, such as the gain of each silicon photo-multiplier, can be monitored with a special ultraviolet LED calibration system.