Half-life measurements of ${}^{212}$Po with thorium-loaded liquid scintillator

Abstract

Precise measurement of half-life of ${}^{212}$Po (one of the daughter nuclides in radioactive chain of ${}^{232}$Th) was realized by means of liquid scintillator based on toluene doped by complex of thorium and trioctylphosphine oxide with concentration of Th $\sim 0.1$ mass %. Fast photomultiplier tube and high frequency oscilloscope were used to acquire the scintillation signals waveforms. The algorithms were developed to find pairs of ${}^{212}$Bi beta-decays and subsequent ${}^{212}$Po alpha-decays, to calculate time differences between the events in the pair, and to build ${}^{212}$Bi beta-decay and ${}^{212}$Po alpha-decay energy spectra. Preliminary the ${}^{212}$Po half-life is $T_{1/2}=(294.8\pm 1.9)$ ns. The experiment is in progress aiming at reduction of the statistical and systematic uncertainties.

7 pages, in Ukrainian, 7 figures