Temperature-Induced Aging Effect on Extruded Scintillators and Optical Fibers for the Pierre Auger Observatory Upgrade

Abstract

In the framework of the Pierre Auger Observatory upgrade, which foresees the installation of scintillator-based surface detectors placed above the water-Cherenkov tanks, we studied the light yield and the effect of temperature cycling for different extruded scintillators/optical fibers configurations. In this paper we will report on the light yield of extruded scintillators read out with wavelength shifting optical fibers, optically coupled to a PMT. We tested many different geometries, different fibers qualities and diameters and different scintillators providers. Then, for a selected number of configurations, we tested the effect of temperature variations on the detector response, in a climatic chamber. In order to reproduce the thermic excursion that will affect the detectors installed in the field in Argentina (between -5°C to +40°C), we studied the scintillator response in the temperature range from -20°C to +70°C. We performed as well many temperature cycles between -20°C to +50°C to study the temperature-induced degradation on the detectors due to mechanical stress