At first glance, it can be seen from these figures that steel–magnetite
concrete with highest density has higher attenuation (lowest
transmission) than other concretes. Although barite concrete
includes high atomic number elements in compare with other
studied concretes, but higher density of steel–magnetite concrete
overcomes its higher effective atomic number.
For all three photon energies, it can be deduced that for reduction
of gamma ray intensity below a certain rate, ordinary concrete
with minimum density (about 2.3 g cm1) is required in more
thickness than other concretes.
Also for these materials and this selection of thicknesses, it is
found that the transmission factors (for example in Co-60 gamma
rays) for the ordinary, serpentine, barite and steel–magnetite
shields span from 1 to less than 102, 3 103, 103 and 105
respectively.