Performance des jets et mesure de la section efficace de production de paires t tbar dans le canal tout hadronique auprès du détecteur ATLAS.

In this report, we summarise our research program within the ATLAS collaboration between 2005-2012. We summarise our contribution to the integration of two of the Inner Detector sub-detectors, the SCT and the TRT. We describe also our contribution to the optimisation and tuning of the jet reconstruction in the harsh ATLAS environment. We compare the performances of these different algorithms. Finally, with the data collected at a centre of mass energy of 7 TeV, we extract the top-anti-top production cross section in the challenging all-hadronic decay channel.