Editing ATLAS experiment (section)

===Forward detectors===
{{further|ATLAS Forward Proton Project}}
The ATLAS detector is complemented by a set of four sub-detectors in the forward region to measure particles at very small angles.<ref>[http://atlas-project-lumi-fphys.web.cern.ch/ The ATLAS Forward Detector project]</ref> 
# LUCID (LUminosity Cherenkov Integrating Detector) <br> is the first of these detectors designed to measure luminosity, and located in the ATLAS cavern at 17 m from the interaction point between the two muon endcaps;  
# ZDC (Zero Degree Calorimeter) <br> is designed to measure neutral particles on-axis to the beam, and located at 140 m from the IP in the LHC tunnel where the two beams are split back into separate beam pipes; 
# AFP (Atlas Forward Proton) <br> is designed to tag diffractive events, and located at 204 m and 217 m; 
# ALFA (Absolute Luminosity For ATLAS) <br> is designed to measure elastic proton scattering located at 240 m just before the bending magnets of the LHC arc.