Determination of the content of natural radionuclides in furnace slag used for the preparation of standard sources

On the equivalence between homogeneously prepared sources and sources prepared by seeding in layers for different geometries, energies and matrix parameters

Measuring the radioactive content of environmental samples requires the use of appropriate reference materials with the same composition and density as the matrices to be measured. If they are not available, ad hoc artificially spiked reference materials are an alternative. Spiking in layers requires a detailed study of the drop distribution, as energy and decay scheme of the component radionuclides must be taken into account to produce a reference material that represents, in efficiency terms, a real sample. A method based on Monte Carlo simulation has been developed to find the optimal distribution of drops in layers for the combination of two typical soil samples and four radionuclides. Results have been validated by comparison with samples prepared by two techniques: methanol bath and spiking in layers.

Preparation and characterisation of a (226)Ra spiked slag as reference material for radioactive control of steelworks

One of the issues of the European Research Project MetroMetal is to develop reference materials in order to provide SI-traceable radioactivity monitoring in foundries. For this purpose, a protocol for preparing a set of identical standard slag samples, containing known activity concentrations of (226)Ra, has been developed. This paper describes the preparation of the raw material, the characterisation in terms of its mineralogical, chemical and radiological features, the spiking procedure and the homogeneity testing of the spiked samples.