Neutron Optics – ORNL

Neutron Optics

Cold neutrons have wavelengths comparable to atomic separations in solid materials. As a result they interact coherently with atoms in a lattice and their behavior can be described using optical formulae and an index of refraction.
For most materials, the index of refraction is less than one, so neutrons that approach a surface at an angle less than the critical angle can reflect off the surface.