  The Resistive Plate Chambers (RPCs) are employed in the CMS experiment at the
LHC as dedicated trigger system both in the barrel and in the endcap. This note
presents results of the radiation background measurements performed with the
2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given
to the measurements of the background distribution inside the RPCs. The
expected background rates during the future running of the LHC are estimated
both from extrapolated measurements and from simulation.
