Hydrogen detection in metals by neutron interferometry

The neutron interferometer is used to determine the H and D concentration in V and Nb samples. The hydrogen content changes the average coherent scattering length and, therefore, the phase shift of the coherent beams which can be measured precisely. The results are compared with the weighing and the epithermal neutron scattering method. Characteristic values for the sensitivity obtained with the interferometer method are 0.02–0.06 at.% or 6–12 ppm by weight. As soon as precipitation occurs in the sample, a loss of contrast indicates additional small-angle scattering.