Calculations have been made of the new Rice University gamma ray astronomical telescope, over the energy interval 0.1 MeV-5.0MeV. A computer program, ACCEPT, was used and simulations performed on the Rice University's AS-9000 mainframe. For gamma ray fluxes at 3.5 g cm\sp−2 atmospheric depth over Palestine, Texas, efficiency curves for the principal detector have been obtained. Energy deposition profiles have been calculated and compared to previous simulations and observations. The study shows the simulation code ACCEPT to be more machine dependent than previously believed.