|
Natural-Matrix SRM's: Program Summary and ApplicationsThe radioactivity group at NIST provides radioactive natural-matrix Standard Reference Materials to groups and organizations with a variety of application interests. Geoscience applications include research in geochronology, biological systems, and geochemistry. These standards are also important to laboratories and agencies that monitor and remediate contaminated nuclear power and national defense sites.The need for natural-matrix SRM's was brought to the forefront of the metrology community in 1977 at a meeting of the International Committee on Radionuclide Metrology held in Paris, France. At that meeting Professor V.T. Bowen of Woods Hole Oceanographic Institute outlined to the Committee his view of the need for natural-matrix SRM's versus natural-matrix materials that were spiked with radionuclides. It was agreed by the Committee that the environmental radiochemistry community was in need of very large homogeneous natural-matrix samples, each naturally contaminated by a variety of longer-lived radionuclides, at several ranges of concentrations. These materials were needed for use in analytical intercomparisons and as Standard Reference Materials. In response to this need the Radioactivity Group at NIST embarked to produce a variety of natural-matrix SRM's, each naturally contaminated with actinides and fission products and also containing naturally-occurring radionuclides in the uranium and thorium decay chains. These SRM's include:
|
