Angular properties of 6.13 MeV gamma rays penetrating lead, steel and concrete shields

Experimentally determined angular flux spectra for 6.13 MeV source photons from disc geometry penetrating shielding slabs of lead, steel and concrete are analysed. For all three shield materials, the proportion of photons scattered in a forward direction increases with increasing penetration thickness. At any given polar angle, the scattered photon properties decrease exponentially with increasing shield thickness. An angular exposure dose buildup factor is defined and angular contributions to the scalar buildup factor are presented. (orig.)