Calibration of the underground muon detector of the Pierre Auger Observatory

GARCIA, B. ( 400+ AUTORES DE LA COL. INTERNACIONAL PIERRE AUGER)

JOURNAL OF INSTRUMENTATION

IOP PUBLISHING LTD

Lugar: Londres; Año: 2021 vol. 16 p. 1 - 24

1748-0221

To obtain direct measurements of the muon content of extensive airshowers with energy above 10**16.5 eV,the Pierre Auger Observatory is currently being equipped with anunderground muon detector (UMD),consisting of 219 10 m**2 -modules, each segmented into 64scintillators coupled to siliconphotomultipliers (SiPMs). Direct access to the shower muon contentallows for the study of both ofthe composition of primary cosmic rays and of high-energy hadronicinteractions in the forwarddirection. As the muon density can vary between tens of muons per m 2close to the ntersection of theshower axis with the ground to much less than one per m**2 when faraway, the necessary broaddynamic range is achieved by the simultaneous implementation of twoacquisition modes in theread-out electronics: the binary mode, tuned to count single  muons,and the ADC mode, suited tomeasure a high number of them. In this work, we present theend-to-end calibration of the muon detectormodules: first, the SiPMs are calibrated by means of the binarychannel, and then, the ADCchannel is calibrated using atmospheric muons, detected in parallelto the shower data acquisition.The laboratory and field measurements performed to develop theimplementation of the fullcalibration chain of both binary and ADC channels are presented anddiscussed. The calibrationprocedure is reliable to work with the high amount of channels in theUMD.p { margin-bottom: 0.1in; line-height: 115%; background: transparent }