Transient Ionization Effects from Neutron-Secondary Gamma Radiation in the Upper Atmosphere.
Abstract
The transport of neutrons and secondary gamma radiation produced by the interactions of these neutrons with the atmosphere has been studied to determine transient ionization effects for two source energy spectra (a 14-MeV band and fission) as a function of time for unit impulse sources at 45-km altitude. These Monte Carlo calculations using the FASTER III code included altitude-dependent density, curvature of the earth, ENDF/B III neutron point-cross-section data, and Rayleigh scattering and polarization of the photons. Data were obtained on energy, angle, and time distributions for 20 detector positions for each source spectrum. One important result is observed. A large contribution to ionization production rates occurs at late (approximately 1 to 10 ms) local times, primarily due to the arrival of the neutrons with their attendant secondary gamma production in a volume near the detectors. this contribution exceeds that of earlier times by as much as an order of magnitude or more. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1975
- Accession Number
- ADA020288
Entities
People
- John P. Roberts
- John S. Wicklund
Organizations
- Harry Diamond Laboratories