Diffraction and rapidity gap measurements with the ATLAS detector

These proceedings report of two measurements performed with the ATLAS detector. These measurements use the notion of 'rapidity gaps', although the definition of gap and the probed physics are quite different. The paper [1] presents the rapidity gap cross sections measured with the ATLAS detector using early 2010 pp collisions data. Gap translates the absence of particle produced in a rapidity region. Diffractive events are recorded using the Minimum Bias Trigger Scintillators mounted in front of the end-cap calorimeters. The paper [2] presents the measurement of dijet production with a jet veto on additional central jet activity in pp collisions recorded by ATLAS in 2010. Rapidity gaps are defined by the absence of jet in the rapidity interval bounded by the dijet system, of transverse momentum above 20 GeV. There is therefore some QCD activity in these rapidity gaps. Dijet events are collected using calorimeters jets trigger.