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During the last days of September to the first days of October in 2017, a unique detection of 106 Ru was observed in air filters sampled at different locations in Sweden via the national air monitoring network. Furthermore, measurements of precipitation also showed the presence of 106 Ru. This initiated soil sampling and in situ gamma-ray spectrometry at one of the locations. [ABSTRACT FROM AUTHOR]

Abstract: In this work we present new improved experimental limits for the partial half-lives of the double beta processes of 96Ru and 104Ru, obtained by means of a γ-ray spectrometry measurement. A disc of metallic Ru of natural isotopic abundance was sandwiched between two HPGe-detectors in the 225m deep underground laboratory HADES. After 108 days of measurement, the lower bounds for the partial half-lives were up to 6.9×1019 yr for 96Ru and 1.9×1020 yr for 104Ru. [Copyright &y& Elsevier]

Abstract: When radioactive isotopes that decay by α, β−, β+ and electron-capture transitions are placed in a conducting host material, it has recently been claimed that their half-lives show a significant dependence on temperature—up to a 6% difference between room temperature and 12K. We have refuted two of these claims by measuring: (1) the β− decay of 198Au in gold, for which we find the half life to be the same within 0.04% between room temperature and 19K; and (2) the electron-capture decay of 97Ru in ruthenium, for which we find any half-life difference to be <0.1%. [Copyright &y& Elsevier]

Abstract: We have measured the systematic influence of coincidence summing between electrons and gamma-rays on the calculated activity of 106Ru and developed a simple model for assessing this influence. In the model it is supposed that the number of electrons penetrating the attenuating layer of a material exponentially decreases with the thickness of the layer. When thin samples are measured close to a detector having a beryllium window, the influence may reach 20%. However, for homogeneous samples measured in plastic canisters the influence may be only a few percent. [Copyright &y& Elsevier]