Figure 2, attenuation coefficient of gamma-ray
increases with increasing of the atomic number of element while attenuation coefficients of
neutron are high for light elements like hydrogen(H), lithium (Li) and boron(B) as well as
some heavy elements such as gadolinium (Gd), cadmium(Cd) and dysprosium (Dy). In
contrast, lead (Pb) has very high attenuation coefficient for gamma-ray but very low for
neutron. Neutron radiography therefore can make parts containing light elements; such as
polymer, plastic, rubber, chemical; visible even when they are covered or enveloped by
heavy elements.
Neutrons may interact with matter in one or more of the following reactions.