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).