Performance of the missing transverse energy reconstruction in minimum bias events at $\sqrt{s}$ of 900~GeV and 2.36~TeV with the ATLAS detector

In December 2009, the ATLAS experiment collected more than half a million minimum bias events at center-of-mass energies of 900 GeV and 2.36 TeV. These events offer a good opportunity to test the performance of the missing transverse energy ($E_T^{miss}$) reconstruction with up to 100 GeV total transverse energy accumulated per event. Resolution and tails of the missing transverse energy distribution are in good agreement with the simulation. The stability of the reconstructed ETmiss over the course of the 15 days of data-taking has been studied, and the results are found to be stable to within $\pm$3%.