ATLAS RPC detector as Luminosity monitor

ATLAS RPC Detector Control System has been mainly used to monitor and safely operate the RPC detector during 2010 and 2011 LHC run. The large number (~3500) of gap currents, individually monitored with nA accuracy, allowed us to study the detector behavior with a growing Luminosity and beam currents. A clear linear correlation between the average gap current and the luminosity has been observed over more than four decades. In this presentation will be shown how this method has a good potential for improving the accuracy and the stability of the standard luminosity measurements on a long time basis.