Accession Number : AD0858007

Title :   Calculation of Neutron and Neutron Induced Gamma Fluences from a Point Source in the Atmosphere.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Winchester, Robert O.

Report Date : JUN 1969

Pagination or Media Count : 88

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)

Descriptors :   *NEUTRON FLUX), (*NUCLEAR EXPLOSIONS, (*NEUTRON CAPTURE GAMMA RAYS, NUCLEAR EXPLOSIONS), AIRBURST, NEUTRON CROSS SECTIONS, ATMOSPHERE MODELS, ALTITUDE, NEUTRON TRANSPORT THEORY, DIFFUSION, PARTIAL DIFFERENTIAL EQUATIONS, COMPUTER PROGRAMS, THESES.

Subject Categories : Radioactiv, Radioactive Wastes & Fission Prod
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE