First results from an aging test of a prototype RPC for the LHCb muon system

Recent results of an aging test performed at the CERN Gamma Irradiation Facility on a single-gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an accumulated charge of about 0.45 C/cm(2), corresponding to about 4 years of LHCb running at the highest background rate. The performance of the chamber has been studied, under several photon flux values, exploiting a muon beam. A degradation of the rate capability above 1 kHz/cm(2) is observed, which can be correlated to a sizeable increase of resistivity of the chamber plates. An increase of the chamber dark current is also observed. The chamber performance is found to fulfill the LHCb operation requirements