Calorimeter

A calorimeter is a part of a detector for measuring the energy of particles. Typically electromagnetic calorimeters measure the energy of photons and charged particles (in particular, electrons and positrons), while hadronic calorimeters measure the energy of charged and neutral hadrons. Calorimeters consist of dense material, with which the primary particles interact, causing a shower of secondary particles. These cause ionization in an active material (scintillator, gaseous detector, etc.), creating a signal that is read out. The strength of the signal is used to infer the energy of the primary particles.