Background decomposition in the MINOS Near detector

The search for electron neutrino appearance in the MINOS Far detector relies strongly on our ability to determine the backgrounds, namely Neutral Current (NC), $\nu_\mu$ Charged Current (CC) and intrinsic beam $\nu_e$ CC events. MINOS makes use of its Near detector measurements to predict the Far detector spectrum thus reducing systematic uncertainties. This procedure must be done separately for each background component due to oscillations and beam line geometry considerations. In this talk we describe a method used by MINOS to accomplish this separation. The method compares data from different beam configurations to unravel the background components in the standard data. It further reduces systematic uncertainties by employing only ratios of simulated quantities.