Tests of nuclear half-lives as a function of the host medium and temperature: Refutation of recent claims

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 12 K. 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 19 K; and (2) the electron-capture decay of 97Ru in ruthenium, for which we find any half-life difference to be <0.1%.