Study of RPC gas mixtures for the ARGO-YBJ experiment
  The ARGO-YBJ experiment consists of a RPC carpet to be operated at the Yangbajing laboratory (Tibet, P.R. China), 4300 m a.s.l., and devoted to the detection of showers initiated by photon primaries in the energy range 100 GeV - 20 TeV. The measurement technique, namely the timing on the shower front with a few tens of particles, requires RPC operation with 1 ns time resolution, low strip multiplicity, high efficiency and low single counting rate. We have tested RPCs with many gas mixtures, at sea level, in order to optimize these parameters. The results of this study are reported. 
B. Bartoli, R. Buonomo, E. Calloni, S. Catalanotti, B. D'Ettorre   Piazzoli, G. Di Sciascio, M. Iacovacci (INFN and Dipartim...