Persistence of octupole correlations in 231Ra

✍ Scribed by L.M. Fraile; M.J.G. Borge; H. Mach; R. Boutami; A.J. Aas; B. Fogelberg; L.M. Garcı́a-Raffi; I.S. Grant; K. Gulda; E. Hagebø; W. Kurcewicz; J. Kvasil; M.J. López; G. Løvhøiden; T. Martı́nez; B. Rubio; J.L. Taı́n; O. Tengblad

• Book ID: 104333899
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 492 KB
• Volume: 686
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(00)00572-8

✦ Synopsis

The structure of 231 Ra, the heaviest odd Ra nucleus currently accessible for detailed spectroscopic investigation, has been studied in the β -decay of 231 Fr. The main purpose has been to verify whether fast B(E1) rates and significant octupole correlations recently established in 229 Ra persist in 231 Ra. The excited states in 231 Ra have been determined for the first time. Spins and parities have been deduced from conversion electron measurements, while level half-lives in the ps and ns ranges have been measured with the Advanced Time Delayed βγ γ (t) method. The moderately fast B(E1) rates found for transitions connecting the lowest-lying K π = 5/2 ± and K π = 1/2 ± bands, reveal the persistence of octupole collective effects in 231 Ra, although the B(E1) rates are lower than in 229 Ra. These findings reinforce the differences in the B(E1) systematics between isotonic Ra and Th nuclei.