Reference-free measurement of photon emission intensities in the decay of standard radionuclides

Reliable X-ray emission intensities are essential for quantitative material analysis using X-ray spectrometry and for the efficiency calibration of energy-dispersive spectrometers. In order to improve the reliability of data, reference-free measurements were performed to determine X-ray emission intensities, along with their associated uncertainties, for a set of standard radionuclides in the energy range from 5.4 keV to 53.13 keV. Partial K X-ray emission intensities were determined for nine radionuclides, resulting in total K emission intensities, I_XK, of 24.06(49)% for ⁵⁴Mn, 27.59(48)% for ⁵⁵Fe, 55.8(10)% for ⁵⁷Co, 37.4(9)% for ⁶⁵Zn, 60.0(7)% for ⁸⁵Sr, 59.0(7)% for ⁸⁸Y, 100.5(15)% for ¹⁰⁹Cd, 117.3(12)% for ¹³³Ba and 77.7(9)% for ¹³⁹Ce. In addition, γ-ray emission intensities were measured as 8.77(12)% for the 14.41 keV transition of ⁵⁷Co and 2.199(29)% for the 53.16 keV transition of ¹³³Ba. The results are in good agreement with existing data, although some differences were observed for a few radionuclides. For all investigated radionuclides, a fully traceable and reliable uncertainty budget has been provided.