Title:              The Prompt Cosmic-Ray-Induced Background in the
                     Orbiting Compton Telescope COMPTEL
 Authors:            RYAN,J.M.; KAPPADATH,S.; MCCONNELL,M.; MORRIS,D.;
                     SCHOENFELDER,V.; VARENDORFF,M.; WEIDENSPOINTNER,G.;
                     HERMSEN,W.; BENNETT,K.
 Affiliation:        AA(New Hampshire Univ.), AB(New Hampshire Univ.),
                     AC(New Hampshire Univ.), AD(New Hampshire Univ.),
                     AE(New Hampshire Univ.), AF(Max-Planck-Inst. fuer
                     Extraterrestrische Physik), AG(Max-Planck-Inst. fuer
                     Extraterrestrische Physik), AH(Space Research
                     Organization Netherlands), AI(European Space Research
                     and Technology Centre)
 Journal:            Conference on the High Energy Radiation Background in
                     Space, p. 85-87
 Publication Date:   01/1997
 Category:           Space Radiation
 Origin:             STI
 NASA/STI Keywords:  GAMMA RAY OBSERVATORY, CONTINUUMS, EARTH ATMOSPHERE,
                     GAMMA RAYS, OBSERVATORIES, EXCITATION, TELESCOPES,
                     PHOTONS
 Bibliographic Code: 1997herb.conf...85R

                                  Abstract

One of the major objectives of the COMPTEL experiment on the Compton Gamma
Ray Observatory is the measurement of the cosmic diffuse gamma ray flux. One
of the advantages enjoyed by COMPTEL is that it experiences a varying
background environment that, in principle, can be extrapolated to zero.
Another paper in this session deals with the portion of the background that
either builds up or is not modulated. As it orbits the earth on the Compton
Observatory, COMPTEL often views (toward the local zenith) the high galactic
latitude portions of the sky free from contamination of gamma rays emerging
from the earth's atmosphere. It is these data that we use to measure the
cosmic diffuse gamma ray flux. However, because of other particles hitting
either the instrument or the spacecraft, multiple gamma rays are generated
that 'simultaneously' interact with the independent detectors that
constitute the COMPTEL instrument. These coincident gamma ray interactions
in the independent detectors of COMPTEL give rise to gamma-ray events that
pass all the logic and electronic criteria for a legitimate event. The
gamma-ray emissions fall into two categories. The first is the decay of
metastable nuclei that are activated by bombardment by cosmic rays. The
other, the topic of this paper, is the photons that come from cascading
de-excitation of nuclei excited by cosmic rays. In this latter case nuclei
are excited into high quantum states (or the continuum) and they de-excite
by multiple photon emission on very short time scales. The photon emission
from this process should closely track the local and instantaneous cosmic
ray intensity.