Cosmic-ray origin in OB associations and preferential acceleration of
  refractory elements: Evidence from abundances of elements 26Fe through 34Se
  We report abundances of elements from 26Fe to 34Se in the cosmic radiation
measured during fifty days of exposure of the Trans-Iron Galactic Element
Recorder (TIGER) balloon-borne instrument. These observations add support to
the concept that the bulk of cosmic-ray acceleration takes place in OB
associations, and they further support cosmic-ray acceleration models in which
elements present in interstellar grains are accelerated preferentially compared
with those found in interstellar gas.
