The scattering of neutrons occurs in two ways, either through interaction with the nucleus (nuclear
scattering) or through interaction of unpaired electrons (and hence the resultant magnetic moment)
with the magnetic moment of the neutron (magnetic scattering). It is the former of these that this
introduction will address.
Let us consider the elastic scattering of a beam of neutrons from a single nucleus. In this case
we treat the nucleus as being rigidly fixed at the origin of coordinates and there is no exchange of
energy (Figure (1)). The scattering will depend upon the interaction potential V(r) between the
neutron and the nucleus, separated by r. This potential is very short range and falls rapidly to
zero at a distance of the order of 10−15 m. This is a much shorter distance than the wavelength