Rings of iron for the CMS detector

27 October 1999

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The Compact Muon Solenoid (CMS) is one of the two general purpose detectors being built for the Large Hadron Collider (LHC), at CERN, the European Laboratory for Particle Physics, Geneva. The detector will be centred around a large superconducting solenoid, which will create a strong magnetic field of 4 teslas. (The strong field ensures a compact design for the detector while retaining precise measurements of the momentum of particles.). The magnet will have a stored energy of 27,000 million joules, a bore of 6 m and a length of 12.5 m, and an iron yoke surrounding the solenoid will contain the magnetic field. Here we see the first of five rings of iron that will form the barrel part of the yoke (which will also have two end-cap sections). This twelve-sided ring is about 15.8 m high, weighs nearly 1200 tonnes and consists of 1668 different parts. It has been manufactured in Germany, and having been dismantled, is now being transported by convoy to CERN.

Credit: CERN Photo / CMS