Measurement of total attenuation coefficients for 6- to 10- MeV photons

Abstract

Total attenuation cross sections for five different elements (Al, Fe, Cu, Zr, and Pb) were measured in the energy interval of 6 to 10 MeV photons. This was accomplished by using the discrete energy gamma rays produced by radiative capture of neutrons in various elements (6.02, 7.279, and 9.3 MeV in Fe(n,γ); 7.72 MeV in Al(n, γ); 8.49 and 9.33 MeV in Se(n, γ)). The nuclear resonance scattering method was used in the attenuation of photons for the two energies, 7.27 MeV in Pb and 8.49 MeV in Zr. For other energies, direct narrow beam measurements were made. The cross sections were measured within an average uncertainty of 0.6% and appeared to be in better agreement with the calculated values of Hubbell and Berger than the later calculations of Storm and Israel.