  EGRET data on the Gamma ray emission from the inner Galaxy have shown a
rather flat spectrum, extending to about 50 GeV. It is usually assumed that
these gamma-rays arise from the interactions of cosmic ray nuclei with ambient
matter. Cosmic Ray particles have been observed up to 3 10^20 eV, with many
arguments suggesting, that up to about 3 10^18 eV they are of Galactic origin.
Cosmic ray particles get injected by supernova explosions. Their injected
spectrum is steepened by diffusive losses from the Galaxy to yield the observed
spectrum. As cosmic ray particles roam around in the Galactic disk, they
encounter molecular clouds and through p-p collisions produce gamma rays from
pion decay. The flux and spectrum of these gamma rays is then a clear signature
of cosmic rays throughout the Galaxy. Star formation activity peaks in the
central region of the Galaxy, around the Galactic Center. Looking then at the
gamma ray spectrum of the central region of our Galaxy yields clues as to where
the cosmic ray particles interact, and with what spectrum. Using the FLUKA
Monte-Carlo, we have modelled this spectrum, and find a best fit for a powerlaw
spectral index of 2.34, rather close to the suggested injection spectrum for
supernovae which explode into their own winds. This suggests that most cosmic
ray interaction happens near the sources of injection; this is consistent with
the spectrum of cosmic ray nuclei derived from spallation. One consequence is
that cosmic ray heating and ionization should be strong in the Galactic Center
region.
