Results of a search for daily and annual variations of the Po-214 half-life at the two year observation period

TL;DR

This study monitored the half-life of Po-214 over 590 days, detecting small but statistically significant daily and annual variations possibly linked to Earth's motion and external influences.

Contribution

It presents long-term measurements of Po-214 half-life and reports the first observation of multiple periodic variations in its value.

Findings

Detected annual and daily variations in Po-214 half-life.

Measured half-life value of 163.46 ± 0.04 μs.

Observed amplitudes of variations correlated with Earth's motion.

Abstract

The brief description of installation TAU-2 intended for long-term monitoring of the half-life value $\tau$ ($\tau_{1/2}$) of the $^{214}$Po is presented. The methods of measurement and processing of collected data are reported. The results of analysis of time series values $\tau$ with different time step are presented. Total of measurement time was equal to 590 days. Averaged value of the $^{214}$Po half-life was obtained $\tau=163.46\pm0.04$ $\mu$s. The annual variation with an amplitude $A=(8.9\pm2.3)\cdot10^{-4}$, solar-daily variation with an amplitude $A_{So}=(7.5\pm1.2)\cdot10^{-4}$, lunar-daily variation with an amplitude $A_L=(6.9\pm2.0)\cdot10^{-4}$ and sidereal-daily variation with an amplitude $A_S=(7.2\pm1.2)\cdot10^{-4}$ were found in a series of $\tau$ values. The maximal values of amplitude are observed at the moments when the projections of the installation Earth location velocity vectors toward the source of possible variation achieve its maximal magnitudes.