Structure of Mg Isotope Studied by β-Decay Spectroscopy of Spin-Polarized Na Isotopes

• Published in: Progress of theoretical physics. Supplement Vol. 196; pp. 310 - 315
• Main Authors: Shimoda, Tadashi, Tajiri, Kunihiko, Odahara, Atsuko, Suga, Masaki, Hamatani, Noriaki, Nishibata, Hiroki, Takatsu, Jun, Yokoyama, Rin, Hirayama, Yoshikazu, Imai, Nobuaki, Miyatake, Hiroari, Pearson, Mathew, Levy, C. D. P., Jackson, K. P., Leguillon, Romain, Petrache, Costel
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.01.2012
• ISSN: 0375-9687
• DOI: 10.1143/PTPS.196.310

Abstract We have been studying the structure of Mg isotopes in the region of the N = 20 island of inversion, to clarify the structure change as a function of the neutron number. The experiments are being performed by our unique method of β-decay spectroscopy taking advantage of highly-spin-polarized radioactive nuclear beams at TRIUMF. The β-decay asymmetry in the Na-isotope decay enables unambiguous spin-parity assignments of the levels in the daughter Mg isotope, and it becomes possible to compare the experimental data and theoretical predictions on a level-by-level basis. The present paper reports on the results of the β decay of 30Na→30Mg. From the detailed decay scheme of 30Na, it is suggested that the 30Mg levels at 1.788 MeV [(0+2)], 3.460 MeV [(2)+], 4.967 MeV [1+], and 5.414 MeV [2+] have deformed shapes with intruder configurations, whereas the level at 2.466 MeV [(2+2)] has different nature both from the spherical ground state and the deformed four levels. It is proposed that the 2+2 level is the band-head of the predicted γ-band.