The Preliminary Cosmic Di use - Ray Spectrum from 800 keV to 30 MeV Measured with COMPTELS

We report a preliminary Cosmic Diiuse-ray (CDG) spectrum from 800 keV to 30 MeV obtained with the COMPTEL instrument, the Imaging Compton Telescope on-board the Compton Gamma Ray Observatory. The spectrum is constructed by measuring the count rate of rays from high galactic latitudes and rst extrapolating the rate to a zero cosmic-ray ux environment to eliminate the prompt background. The prompt background is produced primarily by the interactions of protons and neutrons with the spacecraft. Second, this rate is then corrected for the eeects of delayed internal radioactivity to arrive at the-ray count rate due to the CDG radiation. The preliminary measurements of the CDG ux in the 2{10 MeV range is 5{10 times lower than earlier reports. The 2{30 MeV ux is consistent with power-law extrap-olations from lower and higher energies. The preliminary measurements show no evidence of a `MeV bump' above 2 MeV. The bump, if present, is restricted to energies less than 2 MeV.