Disproof of solar influence on the decay rates of90Sr/90Y

Abstract

A custom-built liquid scintillation counter was used for long-term measurements of 90Sr/90Y sources. The detector system is equipped with an automated sample changer and three photomultiplier tubes, which makes the application of the triple-to-double coincidence ratio (TDCR) method possible. After decay correction, the measured decay rates were found to be stable and no annual oscillation could be observed. Thus, the findings of this work are in strong contradiction to those of Parkhomov [1] who reported on annual oscillations when measuring 90Sr/90Y with a Geiger-M\"uller counter. Sturrock et al. [2] carried out a more detailed analysis of the experimental data from Parkhomov and claimed to have found correlations between the decay rates and processes inside the Sun. These findings are questionable, since they are based on inappropriate experimental data as is demonstrated in this work. A frequency analysis of our activity data does not show any significant periodicity.Comment: 11 pages, 9 figures, 1 tabl

Generalized Lomb–Scargle analysis of $$\mathrm {^{90}Sr/^{90}Y}$$ 90 Sr / 90 Y

“…These results were contested by Kossert and Nahle [2] (hereafter, KN15). They showed using long-term measurements of the decay rates with a custom-built liquid scintillator at the Physikalisch-Technische Bundesanstalt (PTB), that there is no evidence for any periodic modulations in the decay rates of 90 Sr/ 90 Y.…”

“…[26]. To recover the LS powers in KN15 [2] and Sturrock [1], one needs to multiply by (N − 1)/2. The dotted horizontal line corresponds to a false alarm probability (FAP) of a random fluctuation equal to 17.2% and represents the FAP of the largest peak in the LS periodogram.…”

“…This is supplemented by a blank sample (S1) for monitoring the background effects. The radioactivity estimates have been made using the Triple-ToDouble coincidence ratio method [2]. The beta decay rates are parameterized by the normalized activity rates as shown in Figures 4, 5 and 6 of KN15.…”

Evidence against solar influence on nuclear decay constants

“…Evidence has been collected to demonstrate instabilities in the decay of other radionuclides [10,11] and by means of time-frequency analysis periodicity at shorter and longer term than 1 year have been claimed [11–13]. However, this interpretation is being challenged by the publication of data sets confirming a close adherence to exponential decay with residuals in the 10 −5 range [16,18,20,21,23]. …”

“…Authors of both convictions expressed the need for collecting evidence for different radionuclides measured with different detection techniques [7,11,13,18,23]. At national metrology institutes (NMIs) taking responsibility for establishing the unit becquerel, mono-radionuclide sources are kept and regularly measured for standardisation purposes as well as for determining half-lives.…”