Calculation of Neutron and Neutron Induced Gamma Fluences from a Point Source in the Atmosphere.
Abstract
Neutron fluences (nvt) and neutron induced gamma fluences in the atmosphere were calculated for an isotropic point source of 10 to the 20th power neutrons with an energy of 14.1 Mev. Point sources at altitudes of 25, 30, 40 and 500 kilometers were considered. Atmospheric density was assumed to vary exponentially to an altitude of 100 kilometers. Fluences from unscattered particles were calculated by multigroup diffusion theory. Multigroup diffusion equations were written in difference form for two-dimensional (r,z) cylindrical geometry and a computer program for an IBM 7094 was written to solve the difference equations. An exact solution of the difference equations was obtained by the use of a tri-diagonal algorithm. Neutron fluences were calculated for 22 energy groups and gamma fluences for 12 groups. Extensive graphical results are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1969
- Accession Number
- AD0858007
Entities
People
- Robert O. Winchester
Organizations
- Air Force Institute of Technology