Albedo

  Backscattering originally of light, more generally of energy; used also as a measure for reflectivity, and named thus from the white appearance of planets due to backscattered light. In the context of particle detectors, albedo arises when a particle enters a material, and is of relevance when a hadronic particle enters a calorimeter. The (small) fraction of energy in this albedo has its origin in the breakup of nuclei; the angular distribution of particles in backscattering is more or less isotropic; the amount of energy is a few percent of incident energy, up to about 1 GeV; it settles to a constant value of 150 to 200 MeV for higher-energy incident particles ([Dorenbosch87]).  also Hadronic Shower.