LiBeB Energetics and Cosmic Ray Origin
  Three different models have been proposed for LiBeB production by cosmic rays: the CRI model in which the cosmic rays are accelerated out of an ISM of solar composition scaled with metallicity; the CRS model in which cosmic rays with composition similar to that of the current epoch cosmic rays are accelerated out of fresh supernova ejecta; and the LECR model in which a distinct low energy component coexists with the postulated cosmic rays of the CRI model. These models are usually distinguished by their predictions concerning the evolution of the Be and B abundances. Here we emphasize the energetics which favor the CRS model. This model is also favored by observations showing that the bulk (80 to 90%) of all supernovae occur in hot, low density superbubbles, where supernova shocks can accelerate the cosmic rays from supernova ejecta enriched matter. 
Reuven Ramaty (NASA/GSFC) and Richard Lingenfelter (UCSD)