The CMS is named for its compact magnet, called a solenoid because of its coiled shape, and for one of the particles it specializes in detecting, the muon. When protons collide inside the CMS, the magnet at its heart (metal collar, below) deflects the resulting subatomic particles so that their paths intersect with many layers of detectors.
Layers of silicon tiles inside the inner tracker barrel (below), which nests inside the magnet, pinpoint the location of charged particles and measure their momentum.
The protruding barrel of the piece below also fits inside the magnet’s hollow. The rings of gold-colored boxes are muon chambers that will detect the particles.
Credit: Cern (silicon); Maximilien Brice, Claudia Marcelloni (magnet); Patrice Loiez (barrel)