Calorimetry and Cherenkov radiation

Cherenkov radiation has been frequently used to measure the energy of electromagnetic showers, for instance in lead-glass calorimeters, and now it becomes increasingly useful for hadronic calorimetry as well. A sizable fraction of cascades initiated by hadrons in an absorber is quickly transformed into γ rays, giving e ± as final products. In a transparent active medium, these charged particles can radiate Cherenkov light which, detected with appropriate photosensitive devices, provides a measure of the energy of high energy showering particles. The state of the art in Cherenkov calorimetry and prospects for new types of calorimeters with high granularity and energy resolution are reviewed.