Angular exposure build up factors for combined energy source photons penetrating aluminium, steel and lead shielding slabs

Experimentally determined angularflux spectra for 6.13 and 7.12 MeV photons emitted from a disc geometry source penetrating single shielding slabs of Al, Fe and Pb were analysed. The angular exposure dose build up factor for combined source energies is defined and angular contribution to the scalar build up factor are presented. The in¯uence of the com- bined energy approximation to the angular build up factor in comparison to single energy consideration is discussed.