Neutron phase contrast tomography on isotope mixtures

Perfect crystal neutron interferometry is an extreme sensitive instrument for the detection of phase shifts induced in materials or magnetic fields. The utilisation of neutron beams and phase signals in tomography permits the investigation of weakly absorbing substances and isotope mixtures. Due to the larger fluctuation of count numbers and phases, an optimised maximum-likelihood algorithm has to be engaged. We present the analysis of isotope mixtures, which are nearly transparent to thermal neutrons, with a sensitivity of about 1% in the detection of isotopic density differences.