Decay data measurements on 213Bi using recoil atoms

In this work, 213Bi has been separated from an open 225Ac source by collecting recoil atoms onto a glass plate in vacuum. The activity of such recoil sources has been measured as a function of time, using an ion-implanted planar Si detector in quasi-2π geometry. From these measurements, a new half-life value of T1/2(213Bi)=45.62 (6) min was derived. Additionally, high-resolution alpha-spectrometry measurements were performed at a solid angle of 0.4% of 4π sr, to verify the energies and emission probabilities of the α-emissions from 213Bi. Using 225Ac, 221Fr, 217At and 213Po peaks as reference peaks, the measured 213Bi α-peak energies at Eα,0=5878 (4) keV and Eα,1=5560 (4) keV were about 10 keV higher than validated data. The relative α-particle emission probabilities of 213Bi, Pα,0=0.9155 (11) and Pα,1=0.0845 (11), and the 213Bi alpha branching factor, Pα=1−Pβ=2.140 (10)%, are compatible with recommended values, but have a higher accuracy.

► Measured half-life of 213Bi is 45.62 (6) min.
► 213Bi α-emission energies at Eα,0=5878 (4) keV and Eα,1=5560 (4) keV.
► Literature data are off by about 10 keV.
► Alpha branching factor is Pα=2.140 (10)%.
► Relative emission probabilities are Pα,0=0.9155 (11) and Pα,1=0.0845 (11).