Study of the Properties of Additional Jets in Top Pair Events with the ATLAS Detector

After the successful rediscovery of the top-quarks at the LHC whose properties have already been described satisfactorily by Monte Carlo simulations, precision measure- ments are now the next step. The aim of this thesis is to study the properties of the additional jets to the top pair final state and to compare the predictions from Monte Carlo simulations with real data. Various sensitive kinematical distributions of these jets have been studied using a kinematical fit for the final event selection. The influence of different top reconstruction algorithms on the variables have been studied and the systematical uncertainties derived.