THE RESPONSE OF THE CGRO COMPTEL DETERMINED FROM MONTE-CARLO SIMULATION STUDIES

The COMPTEL collaboration has carried out an extensive series of Monte Carlo simulation studies to examine the response of the Imaging Compt on Telescope COMPTEL (energy range 0.8 to 30 MeV) aboard the Compton O bservatory. These investigations employed the CERN GEANT Monte Carlo p ackage, using a detailed model of the mass distribution within the COM PTEL experiment. We have derived the absolute efficiency of the COMPTE L experiment as a function of photon energy and incidence angle, and p resent a comparison of simulation results with pre-launch calibration measurements. Also, we report on a comprehensive study of the types of photon interactions leading to accepted COMPTEL telescope events. We briefly describe a new library of monoenergetic instrument-response fu nctions, individual elements of which can now be combined to produce t he response of COMPTEL to an input source of arbitrary spectral shape, for use in scientific analysis. A more detailed, complete report on t hese simulation studies is currently in preparation and will complemen t parallel reports on the instrument calibration and performance, and background methods and modeling techniques.