Calibration of a large water-Cherenkov detector at the Sierra Negra site of LAGO

Abstract The Latin American Giant Observatory (LAGO) is an international network of water-Cherenkov detectors (WCD) set in different sites across Latin America. On top of the Sierra Negra volcano in Mexico at an altitude of 4530 m, LAGO has completed its first out of three instrumented detector. It consists of a cylindrical water tank with a diameter of 7.3 m and a height of 1 m and a total detection area of 40 m 2 that is sectioned in four equal slices. In this work we present the full calibration procedure of this detector and the initial measurements of stability in rate. We also derive the effective area to gamma-ray bursts for the complete array using the LAGO simulation chain, based on CORSIKA and GEANT4.