Quenched E1 transition rates in ²³¹Th

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• 作者：Aas ; A.J. ; Mach ; H. ; Kvasil ; J. ; Borge ; M.J.G. ; Fogelberg ; B. ; Grant ; I.S. ; Gulda ; K. ; Hagebø ; E. ; et. al.
• 关键词：21.10.&minus ; k ; 21.10.Tg ; 21.10.Re ; 23.20.&minus ; g ; 23.20.Lv ; 27.90.+b ; Radioactivity ; ²³¹Ac ; β ; ^&minus ; ; Measured E_γ ; ; I_γ ; ; γ ; -γ ; coincidences ; T ; Deduced ²³¹Th levels
• 刊名：Nuclear Physics A
• 出版年：1999
• 期刊代码：44_03759474
• 类别：ph
• 出版时间：August 2, 1999
• 卷：654
• 期：3-4
• 页码：499-522
• 文件大小：1018 K

摘要

The fast timing βγγ(t) method has been used to measure lifetimes of the low-lying levels in ²³¹Th populated in the β⁻ decay of ²³¹Ac. The half-life of the K^π = band-head at 185.7-keV was measured as T = 1073(79) ps, yielding D₀ = 1.76(8) × 10⁻² e·fm and 1.65(6) × 10⁻² e·fm for the E1 transitions to the and members respectively of the K^π = ground state band. Furthermore, T ≤ 74 ps and ≤ 74 ps were measured for the K^π = and band-heads at 221.4- and 247.6-keV, and T = 503(12) ps and 98(36) ps for the and states at 554.7- and 593.6-keV, members of the K^π = band. The latter results consistently yield D₀ values of the order of 1.1 × 10⁻² e·fm for three transitions connecting the K^π = bands. The observed transition rates have been interpreted within the quasiparticle-phonon model with the inclusion of Coriolis coupling.