Half-lives of 221Fr, 217At, 213Bi, 213Po and 209Pb from the 225Ac decay series

The half-lives of 221Fr, 217At, 213Bi, 213Po, and 209Pb were measured by means of an ion-implanted planar Si detector for alpha and beta particles emitted from weak 225Ac sources or from recoil sources, which were placed in a quasi-2 pi counting geometry. Recoil sources were prepared by collecting atoms from an open 225Ac source onto a glass substrate. The 221Fr and 213Bi half-lives were determined by following the alpha particle emission rate of recoil sources as a function of time. Similarly, the 209Pb half-life was determined from the beta particle count rate. The shorter half-lives of 217At and 213Po were deduced from delayed coincidence measurements on weak 225Ac sources using digital data acquisition in list mode. The resulting values: T1/2(221Fr)=4.806 (6) min, T1/2(217At)=32.8 (3) ms, T1/2(213Bi)=45.62 (6) min, T1/2(213Po)=3.708 (8) micro s and T1/2(209Pb)=3.232 (5) h were in agreement only with the best literature data.

SULIMAN Gabriel;  POMME Stefaan;  MAROULI Maria;  VAN AMMEL Raf;  STROH Heiko;  JOBBAGY Viktor;  PAEPEN Jan;  DIRICAN A.;  BRUCHERTSEIFER Frank;  APOSTOLIDIS Christos;  MORGENSTERN Alfred; 

2013-03-21

PERGAMON-ELSEVIER SCIENCE LTD

JRC79966

0969-8043,   

http://www.sciencedirect.com/science/article/pii/S0969804313000584,    https://publications.jrc.ec.europa.eu/repository/handle/JRC79966,   

10.1016/j.apradiso.2013.02.008,