Characterisation of the IAEA-375 soil intercomparison material for radioactivity with assigned values traceable to the SI units

IRMM participated in an IAEA co-ordinated research project (CRP) entitled "Upgrading of Analytical Quality Control Services (AQCS) intercomparison materials to reference materials with assigned property values traceable to the International System of Units". The aim of the work was to establish full traceability to the International System of Units (SI) of the activity concentrations of the radionuclides 40K, 134Cs, 137Cs, 90Sr, 226Ra, 234U, 235U, 238U, 238Pu and 239+240Pu in the soil RM. In addition, the activity concentrations of 212Pb, 212Bi, 214Pb, 214Bi, 230Th and 232Th were determined. The choice of the particular reference material was dictated by the particular concern about radioactivity levels in the environment. This report describes the sample preparation and the assaying of the activity concentrations in the soil RM. The methods used to achieve instrument calibrations and measurements traceable to the SI units, the data reduction and analysis and, finally, the results obtained are presented.