Searches for solar-influenced radioactive decay anomalies using Spacecraft RTGs

TL;DR

This paper investigates potential solar influences on radioactive decay rates by analyzing data from spacecraft RTGs, extending previous analyses to set broader constraints and discussing the feasibility of future experiments.

Contribution

It extends previous work by modifying and broadening the analysis of decay anomalies in $^{238}$Pu from spacecraft RTGs, providing new constraints on such effects.

Findings

Constraints on anomalous $^{238}$Pu decay rates established

High sensitivity needed for terrestrial detection of anomalies

Future spacecraft experiments could improve detection capabilities

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.