Uranium-235 Isotope Abundance Standard Reference Materials for Gamma Spectrometry Measurements

摘要

The accurate determination of isotope abundances by any method requires that the measuring systems be calibrated using well characterized isotope reference materials. The National Bureau of Standards (NBS) and the Central Bureau for Nuclear Measurements (CBNM) have jointly produced and certified U3O8 nondestructive assay (NDA) reference samples to be used for calibrating gamma measurements. Five different uranium abundances have been certified (0.31, 0.71, 1.95, 2.95, and 4.46 nominal mass percent, (235)U/U). In the 260 series publication, the material fabrication and certification are described and a discussion of the measurement results affecting the accuracy of gamma spectrometry is given. These certified standards represent the first example of an international effort that establishes traceability to NBS, CBNM, and the basic SI units.