Accession Number : AD0628982

Title :   GAMMA-RAY ENERGY PSEUDOSPECTRA FOR U235 FISSION PRODUCTS AND FOR VARIOUS TIMES AFTER FISSION,

Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Personal Author(s) : Ksanda,C. F. ; Laumets,E. ; Hogan,M. A.

Report Date : 16 DEC 1965

Pagination or Media Count : 99

Abstract : The gamma-ray energy spectrum of U-235 fission products following a nuclear explosion is made up of hundreds of different photon energies whose relative contributions to the spectrum change with time after fission. Gammaradiation attenuation and shielding calculations can be greatly simplified by the use of 'pseudospectra' that closely approximate the attenuation obtained with the 'true' spectra. A technique for computing pseudospectra weighting fractions to obtain such simplified spectra composed of only 5 representative photon energies is described. Pseudospectra weighting fractions and pseudospectra for air and iron attenuation are presented. A flow chart and an IBM-704 computer program of the technique are also presented, along with the input data and examples of the printed output values. Throughout the time range considered (from 1.7 sec to 301 days after fission), the maximum attenuation error is less than plus or minus 5%. The technique is valid for resolving almost any spectral attenuation data into five or fewer energy components, and may be used to solve problems involving five simultaneous equations in five unknowns with prescribed constraints. (Author)

Descriptors :   (*URANIUM, FISSION PRODUCTS), (*FISSION, GAMMA RAY SPECTRA), (*GAMMA RAY SPECTRA, MATHEMATICAL ANALYSIS), NUCLEAR EXPLOSIONS, PHOTONS, ENERGY, ATTENUATION, SHIELDING, AIR, IRON, COMPUTER PROGRAMMING, FLOW CHARTING

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE