Solar influence on radon decay rates: irradiance or neutrinos?

Abstract

Radon decay rate data from 2007-2011, measured in a closed canister with one gamma counter and two alpha detectors, were made available for analysis by the Geological Survey of Israel (GSI). Sturrock et al. have published several papers in which they claim that decay rate variations in the gamma counter can be associated with solar rotation. They assert influences by solar and cosmic neutrinos on beta decay and draw unsubstantiated conclusions about solar dynamics. This paper offers an alternative explanation by relating the daily and annual patterns in the radon decay rates with environmental conditions. Evidence is provided that the radon measurements were susceptible to solar irradiance and rainfall, whereas there is no indication that radioactive decay is influenced by the solar neutrino flux. Speculations about solar dynamics based on the concept of neutrino-induced beta decay are ill-founded.

Possible Indications of Variations in the Directionality of Beta-Decay Products

“…for the probability of obtaining by chance a power of S or more at a selected frequency [13] from normally distributed random measurements, this value of the power corresponds to a falsealarm probability of less than 10 −1700 . (This obviously rules out any environmental effect, such as has been suggested by Pommé [11]. We see from Figure 1B and Table 4 that the two strongest oscillations in the frequency band 6-16 year −1 (which covers the frequency band expected for solar rotation) are found in the midnight data at 11.35 year −1 with S 65.5 and at 12.63 year −1 with S 61.4.…”

“…Pommé et al concluded that "the observed seasonal modulations could be attributed to instrumental instability" [10]. For a recent publication and guide to earlier articles, see [11].…”

On the recent claim of correlation between radioactive decay rates and space weather

“…A complex scheme of daily and annual variations of radon decay rates inside a closed canister was presented as the best evidence of solar and cosmic neutrinos influencing the directionality of radiation emitted after neutrino-induced decay [20,26]. In response, it was shown that this interpretation was prone to many inconsistencies [45], and an alternative and more plausible explanation was given through the mobility of the radon along temperature gradients inside the air-filled canister [46,47]. The set-up was exposed to sunshine and rain, and the activity measurements were strongly correlated with outside weather conditions.…”

Generalized Lomb–Scargle analysis of $${^{123}\mathrm{I}}$$ and $${^{99\mathrm{m}}\mathrm{Tc}}$$ decay rate measurements

“…However, other groups have failed to confirm these results, while analyzing the same data, or offered more prosaic explanations for the variability observed in the decay rate measurements. A review of some of the rejoinders and countera e-mail: ep17btech11008@iith.ac.in b e-mail: shntn05@gmail.com (corresponding author) rejoinders can be found in [10][11][12][13][14][15][16][17][18][19] and references therein. Other groups have also refuted the results related to an association between the beta decay rates and solar flares [20,21].…”