Search for correlations between solar flares and decay rate of radioactive nuclei

TL;DR

This study monitored the decay rates of three radioactive isotopes during major solar flares to investigate potential correlations, finding no significant effects and setting sensitivity limits at a few parts in 10,000.

Contribution

It provides the first high-sensitivity measurements of radioactive decay rates during solar flares, challenging previous claims of decay rate variations linked to solar activity.

Findings

No significant decay rate deviations observed during solar flares

Sensitivity of measurements reached a few parts in 10,000

Results do not support claims of decay rate changes during solar events

Abstract

The deacay rate of three different radioactive sources 40K, 137Cs and natTh has been measured with NaI and Ge detectors. Data have been analyzed to search for possible variations in coincidence with the two strongest solar flares of the years 2011 and 2012. No significant deviations from standard expectation have been observed, with a few 10-4 sensitivity. As a consequence, we could not find any effect like that recently reported by Jenkins and Fischbach: a few per mil decrease in the decay rate of 54Mn during solar flares in December 2006.