Review about old and new imaging signals for neutron computerized tomography

Absorption is just one of a number of imaging signals used in neutron tomography. Within the last years, phase contrast, refraction and ultra small-angle scattering as imaging signals have been investigated as well as real-time radiography or energy-dispersive absorption. The use of cold neutrons ( λ > 0.3 nm ) implies for many neutron tomograms a better absorption contrast, larger refraction angles, larger small-angle scattering angles and better phase contrast. The reconstruction procedures for refraction and ultra small-angle scattering tomographies are different from other signals, however, they can be transformed to data sets and then be reconstructed with well-known programs. Examples will be given of all these techniques.