This thesis reports the studies for the a new beam pipe within the ATLAS experiment and of the high mass Drell-Yan (DY) differential cross-section measurement using 4.9 fb-1 of data recorded in 2011. A study using secondary hadronic interaction vertices in the 2010-2012 data indicates excellent stability. A simulation study for the design of a new beam pipe estimates the gain in radiation length when changing the material and shows no significant difference between three positions for a new vacuum flange. For the DY cross-section measurement, the electron identification efficiency is evaluated up to a transverse energy ET of 500 GeV. The results agree well with previous measurements below 50 GeV and Monte Carlo simulations above that. The DY differential cross-section is reported as a function of the electron-positron invariant mass, mee, for 116 - 1500 GeV within the fiducial volume. The results are largely consistent with the theoretical predictions.