THE PRELIMINARY COSMIC DIFFUSE GAMMA-RAY SPECTRUM FROM 800 KEV TO 30 MEV MEASURED WITH COMPTEL

We report a preliminary Cosmic Diffuse gamma-ray (CDG) spectrum from 8 00 keV to 30 MeV obtained with the COMPTEL instrument, the Imaging Com pton Telescope onboard the Compton Gamma Ray Observatory. The spectrum is constructed by measuring the count rate of gamma rays from high ga lactic latitudes and first extrapolating the rate to a zero cosmic-ray flux environment to eliminate the prompt background. The prompt backg round is produced primarily by the interactions of protons and neutron s with the spacecraft. Second, this rate is then corrected for the eff ects of delayed internal radioactivity to arrive at the gamma-ray coun t rate due to the CDG radiation. The preliminary measurements of the C DG flux in the 2-10 MeV range is 5-10 times lower than earlier reports . The 2-30 MeV flux is consistent with power-law extrapolations from l ower and higher energies. The preliminary measurements show no evidenc e of a 'MeV bump' above 2 MeV. The bump, if present, is restricted to energies less than similar to 2 MeV.