A cosmic rays based method to detect and correct PMT gain variations for the ν-Angra veto system

The Neutrinos Angra (ν-Angra) Experiment aims to construct an antineutrinos detection device capable of monitoring the Angra dos Reis nuclear reactor activity. The proposed system considers a detector operating on the surface, which makes it exposed to a high rate of background noise, mainly due to cosmic rays. Therefore, the veto system has a fundamental role in the experiment viability. This paper proposes an innovative methodology to monitor the gain variation of the photomultiplier tubes in the veto system, during operation, based on cosmic rays muons.