The re-evaluation of the 234mPa's 1001.03 keV gamma emission absolute intensity for the precise assessment of 238U.

In this study the commonly used f-value for the 1001.03 keV (0.835 ± 0.004%) energy transition of the 234mPa was re-evaluated due to an obvious consistent overestimation of the 238U activity concentration. Different calibration protocols, samples' matrices and geometries, and gamma-ray spectrometers were exploited in order to assure the accuracy of the derived data. An average positive relative bias of about 24% from the currently used f-value was estimating leading to newly adopted f-value of 1.037 ± 0.052%. This newly suggested f-value will lead to an improvement in the accurate assessment process of the 238U using gamma-ray spectrometry in both environmental and nuclear safeguard fields.