  Diffractive events at hadron colliders are typically characterised by a
region of the detector without particles, known as a rapidity gap. In order to
observe diffractive events in this way, we consider the pseudorapidity
acceptance in the forward region of the ATLAS and CMS detectors at the Large
Hadron Collider (LHC) and discuss the methods to select soft diffractive
dissociation for pp collisions at sqrt(s) = 7 TeV. We showed that in the
limited detector rapidity acceptance, it is possible to select diffractive
dissociated events by requiring a rapidity gap in the event, however, it is not
possible to distinguish single diffractive dissociated events from double
diffractive dissociated events with a low diffractive mass.
