Title:              The Preliminary Cosmic Diffuse Gamma-Ray Spectrum
                     from 800 keV to 30 MeV Measured with COMPTEL
 Authors:            KAPPADATH,S.C.; RYAN,J.; FORREST,D.;
                     KIPPEN,R.M.; MCCONNELL,M.; BENNETT,K.;
                     WINKLER,C.; BLOEMEN,H.; HERMSEN,W.; VAN DIJK,R.;
                     DIEHL,R.; SCHONFELDER,V.; VARENDORFF,M.;
                     WEIDENSPOINTER,G.
 Affiliation:        AA(UNH), AF(SSD-ESA/ESTEC), AH(SRON-Utrecht), AK(MPE)
 Journal:            Bull. American Astron. Soc., 187, #58.01
 Publication Date:   12/1995
 Origin:             AAS
 Abstract Copyright: (c) 1995: American Astronomical Society
 Bibliographic Code: 1995AAS...187.5801K

                                  Abstract

We report a preliminary Cosmic Diffuse gamma-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 gamma rays from
high galactic latitudes and first extrapolating the rate to a zero
cosmic-ray flux 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 effects of delayed internal radioactivity to arrive at the
gamma-ray count rate due to the CDG radiation. The preliminary
measurements of the CDG 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 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.