Gamma-ray emission probabilities of the daughters of 238U

Abstract

A wealth of decay data has been obtained and reported in recent years, much of it in “Decay Data of the Transactinium Nuclides”. IAEA Technical Reports Series No. 261 (1986). The decay data for the daughters of 238U have been notable by their absence in such compilations and, since there is a need for such data, a set of experiments has been performed to measure their gamma-ray emission probabilities. Uranium samples of known mass and isotopic concentration were dissolved in aqueous solution, and analyzed with a high-purity germanium gamma-ray spectrometer. Some of these samples also contained multi-line calibration nuclides with well-known relative emission probabilities and the well-known emission probabilities of the 235U gamma rays were also used to provide an absolute emission probability reference. Since self-absorption of the sample was included in the effective detector efficiency, there was no need for a separate calculation of this absorption. Gamma-ray emission probabilities for the energy range 63 to 1937 keV are reported, and sources of error are discussed, including those in the efficiency curve.