Definitions for "Spallation"
The shattering of a nucleus by a highly energetic cosmic-ray particle.
is the production of light nuclei in collisions between either an energetic heavy nucleus and a low energy proton of the interstellar medium or an energetic proton and a low energy heavy nucleus of the interstellar medium. This process accounts for the relatively high abundance of Be, Li and B in cosmic rays.
(physics) a nuclear reaction in which a bombarded nucleus breaks up into many particles; "some astronomers believe that the solar system was formed by spallation when the sun was a very young star"