The final assembly of the large chambers which are used to detect muons.They are mounted in the gaps of the iron yoke and are made up of a large array of plastic tubes with a signal wire mounted down the centre of each tube. The presence of muons is usually a crucial signature for identifying particular reactions. Muons are recognised by means of their unique ability to penetrate large quantities of iron almost without deflection whereas most other particles are absorbed. To recognize muons travelling in the forward direction, an additional toroid of magnetised iron has been added.
