The standardization of plutonium-241 and nickel-63

Measurement of the shape-factor functions of the long-lived radionuclides 87Rb, 40K and 10Be

“…In last few years, a substantial improvement has been achieved in activity determinations by including the CIEMAT/NIST (Centro de Investigaciones Energe´ticas Medioambientales y Tecnolo´gicas/National Institute of Standards and Technology) method [4][5][6][7] in the analyses of liquid-scintillation counting measurements. This method is now used extensively by many reference laboratories for the standardization of solutions of b-and b-g-ray nuclides with uncertainties of less than 0.5% [8][9][10].…”

New advances in the determination of the 87Rb shape factor function

“…The Centro de Investigaciones Energéticas Medioambientales y Tecnológicas/National Institute of Standards and Technology (CIEMAT/NIST) method [5][6][7][8] is an efficiency tracing method for beta-ray nuclides. It considers two steps.…”

Beta shapefactor determinations by the cutoff energy yield method

“…The radionuclide activity concentrations in the third column of Table 1 were determined by the CIEMAT/NIST method [10][11][12] from an Amersham tritiated water standard.…”