A central calorimeter outside and two end calorimeters capping the solenoid contained separate sections for measuring electromagnetic particles and hadrons. Uranium was chosen for the inert absorber plates owing to its very high density. The active gaps contained liquid argon with a strong electric field applied to collect the ionization of traversing particles on finely segmented planes of copper electrodes. These signals were ganged into 50,000 signals that measured the particle energies and the transverse and longitudinal shower shapes which helped identify the particle type. Each calorimeter contained about sixty uranium-liquid argon modules with a total weight of 240 to 300 metric tons. The total thickness of a calorimeter was about 175 cm so as to fully absorb the showers of the most energetic particles from a collision. The stainless steel vessels needed to contain the modules at liquid argon temperature (-190 C) were relatively thick, so scintillation detectors were inserted between central and end calorimeters to correct for energy lost in the cryostat walls.