  Be abundances at low metallicities have major implications on cosmic ray
origin, requiring acceleration out of fresh supernova ejecta. The observed,
essentially constant Be/Fe fixes the Be production per SNII, allowing the
determination of the energy supplied to cosmic rays per SNII. The results rule
out acceleration out of the metal-poor ISM, and favor Be production at all
epochs of Galactic evolution by cosmic rays having the same spectrum and source
composition as those at the current epoch. Individual supernova acceleration of
its own nucleosynthetic products and the collective acceleration by SN shocks
of ejecta-enriched matter in the interiors of superbubbles have been proposed
for such origin. A new Monte-Carlo based evolutionary code, into which the
concept of Be and Fe production per supernova is explicitly built in, yields
the supernova acceleration efficiency, 2% for the refractory metals and 12% for
all the cosmic rays.
