Which Resolution can be Achieved in Practice in Neutron Imaging Experiments? – A General View and Application on the Zr - ZrH2 and ZrO2 - ZrN Systems

Current methodical developments improve the spatial resolution of neutron imaging facilities. Objects with dimensions down to several microns should be detectable. However, the minimum object size detectable depends not only on the facility hardware like detector resolution or neutron optics, but also on the attenuation contrast. In this paper the relation between illumination time needed, neutron contrast of the objects and their minimal size detectable is derived and an analysis of the minimal dimension of an object can be detected in neutron radiography and tomography is discussed at two examples: zirconium hydride ZrH₂ in Zircaloy-4 as a high contrast system and zirconium nitride ZrN in zirconium oxide ZrO₂ as a low contrast system. It is concluded which minimal sizes of the precipitates can be detected in realistic times.