Measurement of the 226Th and 222Ra half-lives

The half-lives of 226Th and 222Ra were measured by counting alpha-particle emissions from sources as a function of time. The 226Th sources were prepared from an open 230U source, capturing recoil atoms after alpha-particle decay on glass disks or even directly on to a detector. Similarly, the 222Ra sources were obtained by self-transfer of recoil atoms from 226Th sources. The activity measurements were performed in (nearly-)2pi geometry with an ion-implanted silicon detector. The decay curves were analysed in different ways, incl. moment analysis, trying to avoid the pitfalls of bias of least-squares fits to Poisson distributed data. The observed half-life values are T1/2(226Th)=30.70 (3) min and T1/2(222Ra)=33.6 (4) s. Literature values show some inconsistency.

POMME Stefaan;  SULIMAN Gabriel;  MAROULI Maria;  VAN AMMEL Raf;  JOBBAGY Viktor;  PAEPEN Jan;  STROH Heiko;  APOSTOLIDIS Christos;  ABBAS Kamel;  MORGENSTERN Alfred; 

2012-12-05

PERGAMON-ELSEVIER SCIENCE LTD

JRC65539

0969-8043,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC65539,   

10.1016/j.apradiso.2012.02.117,