Calorimeters

The determination of the energy of particles is called ‘calorimetry’ and the corresponding detectors are called calorimeters. The particle energy is deposited in a calorimeter through inelastic reactions leading to the formation of particle showers. The deposited energy is measured either through the charge generated by ionisation or through scintillation or Cherenkov light. Depending on the particle type initiating a shower one distinguishes electromagnetic calorimeters from hadronic calorimeters. In this chapter the formation of showers for both cases is explained and the corresponding construction principles are discussed. For hadron calorimeters special attention is given to the different response to electromagnetically and hadronically deposited energy and the possible compensation of invisible energy. This is followed by a description of typical implementations of electromagnetic and hadronic calorimeters as well as of systems combining both types. Special emphasis is given to the discussion of the energy resolution of the different detectors and detector systems.