Buildup factors of ? radiation with energy 6?10 MeV in large depths of lead shielding

Effect of Exposure Buildup Factors on Reactor Shielding

“…Figs. (7,8,9) show that exposure buildup factor for double layer of lead & water( lead closer to the source) is higer than that for water & lead (water closer to the source).The same behavior was shown in iron and water. For both cases exposure buildup factor has a higher value for low energy and its value decreases as energy increases [8].…”

“…(4,5,6) at different mean free path, which show that exposure buildup factor increases with the increasing of mean free path. Exposure buildup factor for water and lead have a high value at low energy and their values decreases with increasing energy .The exposure buildup for UO 2 increases with energy, while in iron the exposure buildup factor increases with energy up to a bout 1 MeV then it decreases when energy increases for different mean free path [6,7]. Most shields contain a mixture of different element so the exposure buildup factor for a mixture of iron and water, and a mixture of water and lead was studied for different orders.…”

“…First when element of a high atomic number is closer to the source, second when element of low atomic number is closer to the source for energies 0.1, 1 and 10 MeV as shown in Figs. (7,8,9).…”