Implementation, calibration and operation of a Water Cherenkov Detector at Escuela Politécnica Nacional

Abstract

This paper describes the installation, calibration and operation of a Water Cherenkov Detector (WCD) at Escuela Politécnica Nacional in Quito-Ecuador at 2810 m.a.s.l. and latitude 0 • 13'47" S. The project was developed as part of the Latin American Giant Observatory (LAGO) Collaboration. The instrumentation consists of a polyethylene tank, a 5" PMT (EMI 9530A) and the electronic acquisition system from the LAGO-México project. Data analysis estimates the average time of a pulse to be 154.83±22.1 ns for an input voltage set at 1550±20 V and a threshold of 22 mV. In addition, there are two baseline tendencies, one at −49.06 mV and another one at −41.16 mV. Moreover, the value of the deposited charge associated to a vertical relativistic muon passing through the detector, the so-called Vertical Equivalent Muon (VEM), was determined from (1) the experiment and from (2) the use of an in-house code developed by the LAGO Collaboration, called 'LagoSim'. The VEM value obtained (1) from the experiment is 3350±1160 pC and (2) from the simulation is 3800±250 pC. Therefore, the PMT's ability to register the charge is 88% of the expected value, which is interpreted as a consequence of the lifetime quality of the PMT. Finally, muon angular incidence and interaction with materials such as concrete, iron and water are studied to explain the deficit in the charge histogram around 1000 pC. * Speaker.