Characterization of AMIGA ADC signals with SiPMs

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

Otro; Notas internas para la Colaboración Pierre Auger; 2019

In this GAP note, laboratory measurements of four scintillator bars identical as those in AMIGA modules are analyzed to extract the main features of the muon detector ADC signals. Using a muon telescope as an external trigger, events of one and four injected muons were studied to characterize the signal timing and charge. The ADC signal starts with a ∼ 170 ns delay with respect to the binary signal within a 2% relative fluctuation. This feature, along with the binary channel, can be usedto separate signal from noise in the ADC channels to control the large fluctuations in the baseline charge introduced by SiPMs dark rate. As this might be needed to achieve the ADC calibration, the attenuation curve in amplitude and charge for one scintillator bar was measured to verify there is no signal loss in the ADC due to the cut in amplitude introduced in the binary channel. It was obtained that for a 2.5 photo-equivalent (PE) amplitude cut, a 4.9 PE charge cut is introduced. For typical muon signals of ∼ 20 PE, this cut does not imply any significant signal loss. Finally,data from module ID 108, at station ID 1764, was also analyzed to compare with laboratory result.