Searches for solar-influenced radioactive decay anomalies using Spacecraft RTGs

Abstract

Experiments showing a seasonal variation of the nuclear decay rates of a number of different nuclei, and decay anomalies apparently related to solar flares and solar rotation, have suggested that the Sun may somehow be influencing nuclear decay processes. Recently, Cooper searched for such an effect in ${}^{238}$Pu nuclei contained in the radioisotope thermoelectric generators (RTGs) on board the Cassini spacecraft. In this paper we modify and extend Cooper's analysis to obtain constraints on anomalous decays of ${}^{238}$Pu over a wider range of models, but these limits cannot be applied to other nuclei if the anomaly is composition-dependent. We also show that it may require very high sensitivity for terrestrial experiments to discriminate among some models if such a decay anomaly exists, motivating the consideration of future spacecraft experiments which would require less precision.

8 pages, 4 figures (to appear in Astroparticle Physics)

References in corpus (4)

• Searching for modifications to the exponential radioactive decay law with the Cassini spacecraft
• Further Evidence Suggestive of a Solar Influence on Nuclear Decay Rates
• Influence of Relic Neutrinos on Beta Radioactivity
• Periods Detected During Analysis of Radioactivity Measurements Data

Cited by in corpus (6)

• An Analysis of Apparent r-Mode Oscillations in Solar Activity, the Solar Diameter, the Solar Neutrino Flux, and Nuclear Decay Rates, with Implications Concerning the Solar Internal Structure and Rotation, and Neutrino Processes
• Analysis of beta-decay data acquired at the Physikalisch-Technische Bundesanstalt: evidence of a solar influence
• Spectral Content of 22Na/44Ti Decay Data: Implications for a Solar Influence
• Anomalies in Radioactive Decay Rates: A Bibliography of Measurements and Theory
• Influence of solar flares on behavior of solar neutrino flux
• Test of Nuclear Decay Rate Variation due to an Antineutrino Flux