Lifetime measurements of ~(214)Po and ~(212)Po with the CTF liquid scintillator detector at LNGS Borexino Collaboration

摘要

We have studied the α-decays of ~(214)Po into ~(210)Pb and of ~(212)Po into ~(208)Pb tagged by the coincidence with the preceding β-decays from ~(214)Bi and ~(212)Bi, respectively. The ~(222)Rn, ~(232)Th, and~(220)Rn sources used were sealed inside quartz vials and inserted in the Counting Test Facility at the underground Gran Sasso National Laboratory in Italy. We find that the mean lifetime of ~(214)Po is (236.00 ± 0.42(stat) ± 0.15(syst)) μs and that of ~(212)Po is (425.1 ± 0.9(stat) ± 1.2(syst)) ns. Our results, obtained from data with signal-to-background ratio larger than 1000, reduce the overall uncertainties and are compatible with previous measurements.