Investigation of radioactive samples for neutron capture reaction measurements using energy-resolved neutron imaging

•Shape effects for samples are critical for analysis using neutron-capture reactions.•Three non-destructive imaging methods estimated shape effects of sealed samples.•The energy-resolved neutron imaging could evaluate the non-uniformity of the samples quantitatively.•The energy-resolved neutron imaging is effective for improving the accuracy of analysis using neutron capture reactions. To determine neutron capture cross-sections and elemental/isotopic compositions accurately via neutron capture reactions, shape effects caused by uniformity of samples must be considered. However, the estimation of shape effects is difficult to verify in some cases: sealed samples and valuable objects. In this study, the effects on sealed radioactive samples were estimated experimentally. A capability of energy-resolved neutron imaging enabled us to confirm significant localization of the sealed 129I sample non-destructively. It is revealed that shape effects should be corrected for obtaining accurate experimental results. Consequently, we conclude that energy-resolved neutron imaging will be effective to improve analytical accuracy.