Calibration of the AMIGA ADC channel with T1 background events

A. M. BOTTI, X. BERTOU, F. SANCHEZ, A. ALMELA, B. ANDRADA, A. ETCHEGOYEN, J. M. FIGUEIRA, A. FUSTER,; B. GARCIA, F. GESUALDI, N. GONZALEZ, M. R. HAMPEL, J. HULSMAN, A. LUCERO, D. MELO, S. MULLER, ; M. PERLIN, M. PLATINO, D. RAVIGNANI, M. RONCORONI, C. SARMIENTO-CANO, M. SCORNAVACCHE, G. SILLI, A. TABOADA, B. WUNDHEILER

Encuentro; Pierre Auger Internal GAP-Note 2019_046; 2019

In this GAP note, background events of the AMIGA underground muon detector are analyzed to obtain an online calibration of the ADC channels and to study the performance of the underground muon detector in the field. As proof of concept, we extracted T1 events from the module with Id. 101 of the station with Id. 93. Since most of these T1 events are empty, we use the binary channel to identify when a particle is injected in the muon detector and we use its timing information to integrate the charge in the ADC channel. We show that in these background events there is signal accumulation within the T1 trigger scope, and by subtracting the noise to these signals we can achieve a calibration histogram, from which the mean charge of a single-muon can be extracted. Furthermore, we compare this calibration result with the result obtained from the offline calibration with shower events, and both are proved to be compatible. Finally, we also demonstrate that the online calibrationis stable within the analyzed period of time (08-2018 to 02-2019) and robust under changes in the counting strategy implemented to identify injected particles.