Fluorescence correction for activity measurement of ^93mNb in niobium dosimeters: Calculation and experimental validation

Niobium is a dosimeter used to characterize fast-neutron reaction rates monitor nuclear reactor vessels. Its characterization based on the activity of 93m Nb resulting from 93 Nb(n,n’) activation reaction. The decay results mainly in emission niobium K X-rays which are determine Nb. Direct measurement using X-ray spectrometry does not require any sample preparation, but fluorescence effects, due impurities activated during irradiation, must be taken into account. Indeed, some these radioactive impurities, particular 182 Ta, and other isotopes remain present measurements disturb spectra. effect induces additional that alone, leads an overestimation activity, especially if expected shortly after end irradiation. It therefore necessary assess contribution effects provide accurate values activity. Fluorescence correction factors were established by Monte Carlo simulation. calculated validated experimental approach, dosimeters with different tantalum concentrations.