Calorimetry in Astrophysics

Astrophysical environments produce charged particles and photons over an enormous range of energies. Single particles have been detected with energies in excess of 10²⁰eV. Studying these particles and photons requires a range of calorimetry techniques which are matched to the intensities and shower properties at various energies. At lower energies where the particle intensity is large, straight-forward techniques can be used on spacecraft or high altitude balloons. At the highest energies, the atmosphere itself is used as an interaction medium because of the huge effective collecting area required. Weakly interacting particles require low background detectors with even larger mass. Experiments are underway to use deep water volumes, the Antarctic ice, and even the Moon for neutrino detection.