Neutrinos Angra experiment: commissioning and first operational measurements

The Neutrinos Angra Experiment has completed a major step by finishing the commissioning of the detector and the data acquisition system at the experimental site located in the Angra dos Reis nuclear power plant. The experiment, consisting of a water-based detector and associated electronics, was designed with the goal of detecting the electron antineutrinos produced by the nuclear reactor. The detection is possible due to the Inverse Beta Decay, where the final products in the water are photons in the UV-to-visible range of the spectrum. The assembled detector comprises three active volumes filled with water: (i) a cubic detector (Target) for electron antineutrinos, covered by 32 8-inch photomultiplier tubes (PMTs), (ii) a lateral layer surrounding the Target (Lateral veto) equipped with 4 PMTs and (iii) a third volume covering the top of both (Top veto), also equipped with 4 PMTs. In the present document the main features of the detector assembly as well as the integration of the readout electronics on-site are reported. Finally, some operational characteristics are shown based on analysis of the first measurements performed with the fully working detector.