Neutron radiograph of a flower corsage shows the method's ability to image thin biological samples. Photo courtesy of Nray Services. The ways that neutrons interact with matter are very different from the way x rays interact with matter.
X rays interact with the electron cloud surrounding the nucleus of an atom.
Neutrons interact with the nucleus itself. The methods can be used in a complementary fashion. Patrick Doty, Senior Scientist at Sandia National Labs. This article concentrates on thermal and fast neutrons. Radioisotopes such as californium and amerecium-beryllium can generate fast neutrons as well, although this is not generally used for radiography.