Editing ATLAS experiment (section)

===Muon Spectrometer===
The [[Muon]] [[Spectrometer]]<ref name=fact_sheets/><ref name=the_bible/><ref name="TPoveralldetector"/> is an extremely large tracking system, consisting of three parts: 
# A magnetic field provided by three toroidal magnets;  
# A set of 1200 chambers measuring with high spatial precision the tracks of the outgoing muons; 
# A set of triggering chambers with accurate time-resolution. 
The extent of this sub-detector starts at a radius of 4.25&nbsp;m close to the calorimeters out to the full radius of the detector (11&nbsp;m).  Its tremendous size is required to accurately measure the momentum of muons, which first go through all the other elements of the detector before reaching the muon spectrometer. It was designed to measure, standalone, the momentum of 100 GeV muons with 3% accuracy and of 1 TeV muons with 10% accuracy. It was vital to go to the lengths of putting together such a large piece of equipment because a number of interesting physical processes can only be observed if one or more muons are detected, and because the total energy of particles in an event could not be measured if the muons were ignored. It functions similarly to the Inner Detector, with muons curving so that their momentum can be measured, albeit with a different [[magnetic field]] configuration, lower spatial precision, and a much larger volume.  It also serves the function of simply identifying muons – very few particles of other types are expected to pass through the calorimeters and subsequently leave signals in the Muon Spectrometer.  It has roughly one million readout channels, and its layers of detectors have a total area of 12,000&nbsp;square meters.