High-precision measurement of ${}^{215}$Po half-life via delayed-coincidence analysis

We performed a high-precision study of the ${}^{215}$ Po $\alpha$-decay using a LaBr${}_3$ scintillating detector in a low-background environment. The ${}^{227}$Ac intrinsic contamination in the LaBr${}_3$ crystal undergoes a decay chain, producing the intermediate pair of ${}^{219}$Rn${\to }^{215}$Po${\to }^{211}$Pb decays. The fast time response and good energy resolution of the detector allow for extracting the short half-life of ${}^{215}$Po from the time correlation of the two subsequent $\alpha$-decays by using the delayed coincidence method. Thanks to high statistics and a comprehensive uncertainty assessment, we obtain the most precise half-life value to date of ${}^{215}$Po, corresponding to $1.77804\pm 0.00091$(stat.)$\pm 0.00067$(syst.) ms.