Selection of neutral current antineutrino events at the MINOS Near Detector to search for sterile neutrinos

The MINOS experiment measures neutrino oscillation phenomena using two detectors separated by 734 km and a neutrino beam produced by the Fermilab Main Injector. MINOS has previously searched for active to sterile neutrino mixing $(\nu_{\mu} \rightarrow \nu_{s})$ using muon neutrinos and has set limit on this process. We are now conducting a search for the muon anti-neutrino to sterile neutrino transition using the NuMI beam optimized for $\overline{\nu}_{\mu}$ production.Since the rates of neutral current interactions on both detectors are unchanged by standard oscillations , any depletion of the Far Detector neutral current event rate can be a signature of active to sterile neutrino transition. The precise measurement of the anti-neutrino neutral current rate at the Near Detector is important for this study. In this talk I will discuss how MINOS identifies neutral current events and rejects charged current events, and the technique of reducing the number of poorly reconstructed events at the lower energy range.