At the LHC, millions of top quark pairs will be produced each year and already during the first LHC runs, a large and clean sample of them can be selected. The properties of the top quark can be extracted with great precision and with one of the most complex event topologies predicted by the SM, it will play an essential role during the detector commissioning phase. Understanding the detector response in such events in this new energy regime early during LHC operation is essential when searching for predicted signals from new physics models.

PACS numbers: 14.65.Ha