New trends in calorimetry for particle physics
The first calorimeters we meet while studying physics are tanks filled with water and instrumented with a thermometer. Calorimeters for general purpose collider experiments in high energy particle physics are huge, heavy systems with up to a few million readout channels using the newest available technology. Both detectors have a common purpose: they measure energy. The list of differences is much longer, for example: microscopic particles interact with the materials in the detector in many different ways, eventually producing a shower of a large number of lower energetic particles and being destroyed in the process; in particle physics measurements need to be performed at a high rate (up to millions per second) and the detector should have no memory of the previous measurements; the direction of the shower also needs to be measured, requiring spatial granularity in a calorimeter for particle physics; the energy measurement of particles requires much more complex algorithms than just adding up the signals from all the channels. Current research and development for future detectors aims additionally at "looking inside" the showers in space and time to identify single components and to reach the best possible resolution in the energy measurement. The ultimate detector will provide five-dimensional measurements of spatial coordinates, time and energy for each readout channel and be supported by reconstruction algorithms combining traditional calorimetry techniques with tracking and timing. Starting from similar technologies, with dedicated optimisations, these calorimeters can be used in neutrino and beam-dump experiments looking for very rare events, as well as at a future collider at the energy frontier.