  Photon interactions at the LHC result in striking final states with much
lower hadronic activity in the central detectors than for pp interactions. In
addition, the elastic exchange of a photon leads to a proton scattered at
almost zero-degree angle. Tagging photon interactions relies on either the use
of large rapidity gaps or on the detection of the scattered proton using very
forward detectors. The studies related to such detectors are presented,
including their characterization, their acceptance and reconstruction
performance. Limitations due to the LHC beamline misalignment and possible
solutions are also given.
