Radiochemical Measurement Of Np-237 In A Solution Of Mixed Radionuclides: Experiences In Chemical Separation And Alpha-Spectrometry

A radiochemical procedure is described for the measurement of 0.1 Bq Np-237 in a solution containing similar activity concentrations of Th, U, Pu and Am as well as activity concentrations of Co-60, Sr-90 and Cs-137 one hundred times higher. A tracer of Np-239 (milked from Am-243) was used as an isotopic spike for chemical yield determination. The relationship between gamma-counting geometries for ampoule (liquid) and NdF3 (solid) Np-239 sources was established so that Np chemical yields could be measured by a comparative method. Efficiencies of alpha-spectrometers for Np-237 in NdF3 sources were measured by a bootstrap technique. Two sets of experiments were designed and used to test out the procedure.