Neutron tomographic investigations of boron-alloyed steels

Boron-alloyed steel sheets are used in nuclear engineering as neutron shielding for radioactive waste disposal equipment. The 10B isotope is a strong absorber of thermal neutrons but the transmission is enhanced by beam hardening of the polyenergetic neutrons in boron-alloyed steels. Therefore an algorithm for the correction of beam hardening was applied to the tomographic reconstruction of strong absorbing steel rods. We present tomographic studies on 10B enriched steels and compare different reconstruction techniques, the filtered backprojection with and without beam hardening correction, and the maximum-likelihood method.