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

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.

Qualification of a precision pattern dispenser

In order to automate sample preparation processes, a precision pattern dispenser was designed to reproducibly dispense radioactive solutions at pre-defined positions. It is composed of an automatic liquid sample handling unit coupled to an XYZ table. Qualification tests were conducted to evaluate the performance of the instrument and to assess the compliance with the requirements, in particular trueness (< 2%) and repeatability (< 1%). The instrument allows preparing sources in different source holders and on air filters, in a fast and accurate way.

Determination of the (241)Am activity in real contaminated slag

One of the main tasks of the EMRP IND04 MetroMetal project "Ionising Radiation Metrology for the Metallurgical Industry" was to develop sets of reference sources in various matrices such as cast steel, slag and fume dust for the calibration of the gamma spectrometric detector prototypes developed in the frame of the project. This work is focused on the characterisation of real contaminated slag material with (241)Am using the transmission measurements in combination with Monte-Carlo simulations. The method and the results are presented and discussed.