Recommended standards for gamma-ray energy calibration (1979)

A consistent set of γ-ray energies, all with uncertainties of at most 10 ppm, is recommended for use in the energy calibration of γ-ray spectra. Almost all γ rays listed are from commercially available sources. The half-lives of the isotopes selected are generally at least 30 days. The γ-ray energies, in the range E_γ = 60–6100 keV, are all based on the value of 411 804.4 ± 1.1 eV for the γ-ray from the decay of ¹⁹⁸Au. The energy of the 6129-keV line in ¹⁶O, which is the γ-ray with the highest energy of the present set, has also been measured relative to another standard; the two values are consistent.