Do Radioactive Half-Lives Depend on the Earth-Sun Distance?

In recent articles [1-4], Jenkins \textit{et al}. claim to have evidence that radioactive half-lives vary as a function of the earth-to-sun distance. They base their claims on data obtained by others over the space of several years -- the decay of $^{32}$Si as measured at Brookhaven National Laboratory [5] from 1982-85 and that of $^{226}$Ra as measured at the Physikalisch Technische Bundesanstalt in Germany [6] from 1984-88 -- in which the decay rates show a small but statistically significant oscillation with a period of one year and approximately correlated with the earth-sun distance (and with the seasons). Here we report a series of seven measurements of the $^{198}$Au half-life (see [7] for a description of two of these) made by us at various intervals over a period of one aphelion-aphelion cycle. Each measured half-life has a precision of about 0.02{\%}. There is no evidence of any deviation from a constant half-life. [1] J. H. Jenkins \textit{et al}., Astropart. Phys. \textbf{31} 407 (2009) [2] J. H. Jenkins \textit{et al}., Astropart. Phys. \textbf{32}, 42 (2010) [3] E. Fischbach \textit{et al}., Space Sci. Rev. \textbf{145}, 285 (2009) [4] J. Jenkins \textit{et al}., arxiv:0912:5385v1 [5] D. Alburger \textit{et al}., Earth and Planet. Sci. Lett. \textbf{78}, 168 (1986) [6] H. Siegert \textit{et al}., Appl. Radiat. Isot.\textbf{ 49}, 1397 (1998) [7] J. R. Goodwin \textit{et al}., Eur. Phys. J. A \textbf{34}, 271 (2007).