Characterization of AMIGA binary signals with SiPMs

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

Otro; Nota interna de la Colaboracion Auger; 2018

In this GAP note, lab measurements of 4 scintillator bars identical as those inAMIGA modules are analyzed to asses the main characteristics of the binary signals ofthe detector. Using a muon telescope as external trigger, both muons and background25signals 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 andafter reconstruction strategies). The main source of noise at 2.5 SPEs is producedby SiPMs dark rate. At 3.5 SPEs, the main source of noise arrives from the barsand cannot be separated from muon signals. In both scenarios, an inhibition window30of 12 digital samples will contain more than 99% of the muon signals. A countingefficiency of (98.5±0.3)% or (98.7±0.5)% setting a discrimination threshold of 2.5or 3.5 SPEs in 10 m2modules can be achieved by choosing a proper strategy. Finally,data from module ID 108, at station ID 1764, was also analyzed to compare withresults obtained in the lab. The pros and cons of each strategy are discussed.