DEVELOPMENT OF A RANGE OF GAMMA-RAY EMITTING RADIOACTIVE SPIKED REFERENCE MATERIALS FOR ENVIRONMENTAL MONITORING .1.

A EUROMET project was initiated between LPRI (France), ENEA (Italy), P TB (Federal Republic of Germany) and NPL (United Kingdom) to provide a range of spiked reference materials (low density silica, microballoon s, zeolite, milk, resin, soil and kaolin) covering the bulk density ra nge 200-1700 kg m(-3) for the calibration of gamma-ray spectrometers. The materials were spiked with mixtures of Cs-134/(CS)-C-137 or (CS)-C -137/Am-241, using a number of techniques developed for this project. It is intended to extend this to include a mixture of radionuclides co vering the energy range 60-1836 keV. A procedure for homogeneity testi ng was developed and used in the characterisation of these materials a t each laboratory. The technology has now been established to synthesi se spiked reference materials and the first batches are now available to the user community. This paper reports on progress to date.