The high-precision detector of the JUNO-TAO experiment

Abstract

The Taishan Antineutrino Observatory (TAO) is a proposed ton scale liquid scintillator (LS) detector designed to precisely measure the reactor neutrino energy spectrum with the highest possible energy resolution. This will provide a reference spectrum for Jiangmen Underground Neutrino Observatory (JUNO) and a benchmark to verify the nuclear database. As a satellite experiment of JUNO, TAO will be installed near the reactor core at a distance of $\sim$30 m. The detector uses 2.8 $m^3$ of Gd-doped liquid scintillator ($\sim$1 ton fiducial volume, Gd-LS) contained in a spherical acrylic vessel. To maximize the photon collection efficiency in the detector, a 10 $m^2$ SiPM array is proposed to fully cover the acrylic vessel and collect as many scintillation photon as possible. The photon detection efficiency of SiPMs should be larger than 50%, in order to achieve the desired energy resolution (1.5%/$\sqrt{E}$, photon statistical resolution). Additionally, the SiPMs will be operated at low temperature (−50 °C or lower) to reduce dark noise. Meanwhile, a shield and muon veto system will be located outside of the neutrino detector to control the environmental background. An overview of the JUNO-TAO experiment and its current progress are discussed.