Characterization of AMIGA binary signals with SiPMs

A. M. BOTTI, F. SANCHEZ, A. FUSTER, M. R. HAMPEL, A. ALMELA, B. ANDRADA,A. CANCIO, A. ETCHEGOYEN, L. FERREYRO, J. M. FIGUEIRA, B. GARCIA,N. GONZALEZ, E. HOLT, J. HULSMAN, M. JOSEBACHUILI, A. LUCERO, D. MELO;; S. MULLER, M. PERLIN, M. PLATINO, D. RAVIGNANI, M. RONCORONI,C. SARMIENTO-CANO, D. SCHMIDT, G. SILLI, A. TABOADA, B. WUNDHEILER

Encuentro; Pierre Auger Internal GAP Note N° 2018-049; 2018

In this GAP note, lab measurements of 4 scintillator bars identical as those in AMIGA modules are analyzed to asses the main characteristics of the binary signals of the detector. Using a muon telescope as external trigger, both muons and background signals were studied at two different discriminator thresholds (2.5 SPEs and 3.5 SPEs) to quantify the signal over noise ratio in different scenarios (both as raw data and after reconstruction strategies). The main source of noise at 2.5 SPEs is produced by SiPMs dark rate. At 3.5 SPEs, the main source of noise arrives from the bars and cannot be separated from muon signals. In both scenarios, an inhibition window of 12 digital samples will contain more than 99% of the muon signals. A counting efficiency of (98.5±0.3)% or (98.7±0.5)% setting a discrimination threshold of 2.5 or 3.5 SPEs in 10 m2 modules can be achieved by choosing a proper strategy. Finally, data from module ID 108, at station ID 1764, was also analyzed to compare with results obtained in the lab. The pros and cons of each strategy are discussed.