The prompt cosmic-ray-induced background in the orbiting Compton telescope COMPTEL

The authors report the spectrum of background events that the COMPTEL instrument on Compton Gamma Ray Observatory experiences due to the instantaneous effects of cosmic rays. Other backgrounds are present in the data of this Compton telescope, but the components that closely follow the instantaneous flux of cosmic rays are the most identifiable. The background varies approximately linearly with the cosmic-ray intensity and exhibits a broad feature from about 1 to 10 MeV suggestive of the nuclear nature of the events. Above 10 MeV there is a marked change in the nature of the background that is not understood. It appears that the background changes from nuclear to electromagnetic in nature.