The separation of Pa from a Th target by means of ion-exchange chromatography

An ion-exchange method is presented to separate the radioisotope 227Pa from a Th target after bombardment with 66 MeV protons. Several sources of 227Pa were prepared to be used as generators of 223Ac, concluding the first stage (or radiochemistry stage) of an exotic radioactive decay experiment to determine whether the emission of 14C and 15N clusters is observed in the decay of 223Ac. The second stage (or nuclear physics stage) of the experimental investigation involves the search for tracks of 14C and 15N clusters in solid-state nuclear track detectors exposed to the emissions from these sources. While the nuclear physics stage is still in progress, we report here on the completed radiochemistry stage and the development work. As the half-life of 227Pa is relatively short (38.3 minutes) it was imperative to perform the necessary chemical separation of this radioisotope as well as the preparation of dry sources as quickly as possible. By means of the methods developed, the period from the end of bombardment (EOB) of a Th target until completion of a dry source, could be kept below two half-lives of 227Pa. The resulting source strengths were sufficient for the purposes of the nuclear physics part of the investigation.