Point Isotropic Buildup Factors of Gamma Rays, Including Bremsstrahlung and Annihilation Radiation for Water, Concrete, Iron, and Lead

Gamma-ray exposure buildup factors are calculated using a discrete ordinates direct integration code, PALLAS-PL, SP-Br, for water, concrete, iron, and lead for point isotropic sources. These data include the effects of secondary photon sources arising from Compton scattering, bremsstrahlung, and annihilation. Comparisons of these results without bremsstrahlung to values obtained earlier by moments calculations show reasonable agreement, except in some instances of deep penetration. The calculated buildup factors are tabulated for incident energies of 0.1 to 15 MeV (except for lead, where the lower energy is 0.4 MeV) and for penetration depths as great as 40 mfp.