Description
JUNO aims at simultaneously probing the two main frequencies of three-flavor neutrino oscillations, as well as their interference related to the mass ordering, at a distance of ~53 km from two powerful nuclear reactor complexes in China. The present information on the reactor spectra is not meeting the requirements of an experiment like JUNO, with a design resolution of 3 % at 1 MeV. Unknown fine structures in the reactor spectrum might cause severe uncertainties, which could even make the interpretation of JUNO’s reactor neutrino data impossible. TAO is aiming for a measurement of the reactor neutrino spectrum at very low distances (< 30 m) to the core with a groundbreaking resolution better than 2 % at 1 MeV. Furthermore, TAO will make a major contribution in the investigation of the so-called reactor anomaly. Present calculations of the reactor neutrino spectrum indicate a deficit of approx. 3 % in the measured reactor fluxes. Currently, these anomalies can be interpreted as indications for the existence of right-handed sterile neutrinos. Beyond that, the reactor neutrino spectra recorded by Double Chooz, Reno and Daya Bay show an excess in the neutrino flux from 5 MeV to 6 MeV of unknown origin. This can be considered as one of the most-puzzling questions in the physics of reactor neutrinos today. The TAO experiment will realize the unprecedented neutrino detection rate of about 2000 per day, which is approximately 30 times the rate in the JUNO main detector. In order to achieve its goals, TAO is relying on cutting-edge technology, both in photosensor and liquid scintillator (LS) development which is expected to have an impact on future neutrino and Dark Matter detectors. The experiment will realize an optical coverage of the 2.6 tons of Gd-loaded LS close to 95 % with novel silicon photomultipliers (SiPMs), with a photon detection efficiency (PDE) above 50 %. To efficiently reduce the dark count of these light sensors, the entire detector will be cooled down to -50 °C. The combination of SiPMs with cold LS will lead to an increase in the photo electron yield by a factor of 4.5 compared to the JUNO central detector. In this talk, the design of the TAO detector with special focus on calorimetry with this novel high-resolution liquid scintillation detector technology will be discussed. In addition, an overview of the progress currently being made in the R&D for both SiPM and LS technology in the frame of the TAO project will be presented.
