The compact muon solenoid (CMS) hadron calorimeter

The Hadron Calorimeter of the CMS detector for the CERN LHC accelerator is designed to measure the energy of hadron jets: single hadrons as well as observe single mu 's. It has six segments. The Central Barrel and the two End Caps are made of brass and scintillators. Two Forward calorimeters made of iron and quartz fibers cover the \eta\ range of 3.0 to 5.0. Since the barrel of the calorimeter is only 6.5 interaction lengths, an Outer calorimeter made of one layer (two near \eta\ = 0) of scintillator will be placed outside of the magnet coil and cryostat to sample the energy leakage. Progress has been made on all the subsystems and full size prototypes have been constructed and placed in the CERN test beam.