Non-destructive analysis of samples with a complex geometry by NRTA
The use of Neutron Resonance Transmission Analysis to characterise samples with a complex geometry is discussed. Analytical expressions for such samples have been derived and implemented in the resonance shape analysis code REFIT. They were validated by experiments at the time-of-flight facility GELINA using a set of metallic natural copper samples and pellets made of silver mixed with uranium-oxide powder. The expressions were used to derive sample characteristics by a least squares adjustment to experimental transmission data. In addition, the resonance parameters of 63Cu and 65Cu for energies below 6.5 keV, which are reported in the literature and recommended in evaluated data libraries, were verified.