ALPHA-DECAY STUDIES OF PROTACTINIUM ISOTOPES (thesis)

Publisher Website
Google Scholar
Abstract
The alpha decay of Pa/sup 231/, Pa/sup 229/, Pa/sup 227/, and Ac/sup 223/ w as studied by an alpha-particle ---gamma-ray coincidence technique. A 180 deg double-focusing spectrograph or goldsilicon solid-state detectors for alpha analysis and a sodium iodide (Tl-activated) scintillation crystals for gamma-ray detection were used. The ground states of Pa/sup 227/ and Pa/sup 229/ are shown to be populated by 5.46- and 5.73-Mev alpha particles, respectively. The rotational bands populated in the decay of Pa/sup 231/ are interpreted as being based on octupole vibrational levels predicted by the Bohr -Mottelson strong- coupling model. Modified decay schemes are presented. It is suggested that in odd-proton nuclei, the permanent nuclear deformation starts closer to the closed shell than in the even-even nuclei. A new alpha group at 5.47 Mev is noted in the alpha decay of Ac/sup 233/. No rotational structure is observed in the levels populated. Evidence is presented for the presence of two additional levels populated in the alpha decay of Pa/sup 231/. 40 references. (auth)

This publication has 0 references indexed in Scilit: