Determination of k0-related nuclear parameters-precise determination of 97Zr half-life

The half-life of 97Zr, used for the calculation of thermal/epithermal neutron flux ratio in k0-NAA, is re-determined using three measurement systems with different pulse processing principles. The result of (16.755 ± 0.013) h clarifies the discrepancy between two widely used literature values, (16.744 ± 0.011) h and (16.90 ± 0.05) h. Different dead-time correction methods used on various measurement systems are evaluated. Factors influencing precise measurement of relative peak counting rates are discussed in time-series measurements over a dynamic range of 1000-fold radioactive intensities (10 half-lives). (authors)