Absence of low-temperature dependence of the decay of 7Be and 198Au in metallic hosts

TL;DR

This study measures the decay rates of 7Be and 198Au in metallic hosts across a wide temperature range, finding no significant temperature dependence, challenging existing theoretical models like Debye-Huckel.

Contribution

The paper provides the first precise measurements showing no low-temperature dependence of decay rates in metallic hosts, questioning prior assumptions and models.

Findings

Decay rates of 7Be and 198Au are temperature-independent within experimental error.

No change in half-life of 198Au from 12.5 K to 293 K.

The results challenge the applicability of the Debye-Huckel model for such decay measurements.

Abstract

The electron-capture (EC) decay rate of 7Be in metallic Cu host and the beta-decay rate of 198Au in the host alloy Al-Au have been measured simultaneously at several temperatures, ranging from 0.350 K to 293 K. No difference of the half-life of 198Au between 12.5 K and 293 K is observed to a precision of 0.1%. By utilizing the special characteristics of our double-source assembly, possible geometrical effects that influence the individual rates could be eliminated. The ratio of 7Be to 198Au activity thus obtained also remains constant for this temperatures range to the experimental precision of 0.15(0.16)%. The resulting null temperature dependence is discussed in terms of the inadequacy of the often-used Debye-Huckel model for such measurements.