Lifetime measurements of excited states in 17C: Possible interplay between collectivity and halo effects
Lifetime measurements of excited states in 17C: Possible interplay between collectivity and halo effects
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DOI：
10.1016/j.physletb.2008.07.055
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发表时间：
2008-08
影响因子：
4.4
通讯作者：
D. Suzuki;H. Iwasaki;H. Ong;N. Imai;H. Sakurai;T. Nakao;N. Aoi;H. Baba;S. Bishop;Y. Ichikaw
中科院分区：
文献类型：
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作者：
D. Suzuki;H. Iwasaki;H. Ong;N. Imai;H. Sakurai;T. Nakao;N. Aoi;H. Baba;S. Bishop;Y. Ichikaw
使用反冲阴影法对富中子同位素C17的低激发态进行了寿命测量。212 keV下第一激发态的γ衰变平均寿命为583±21（stat）±35（syst）ps，333 keV下第二激发态的γ衰变平均寿命为18.9±0.6（stat）±4.7（syst）ps。基于与电磁跃迁强度的经验上限的比较，这些衰变的结论是主要是M1过渡。对第一和第二激发态，M1到基态的约化跃迁几率分别为（1.0±0.1）×10−2μ N2和（8.2−1.8+3.2）×10−2μN2.强烈受阻的M1强度以及较低的激发能代表了212 keV态的独特性质。
Lifetime measurements were performed on low-lying excited states of the neutron-rich isotope C17 using the recoil shadow method. The γ-decay mean lifetimes were determined to be 583±21(stat)±35(syst) ps for the first excited state at 212 keV and 18.9±0.6(stat)±4.7(syst) ps for the second excited state at 333 keV. Based on a comparison with the empirical upper limits for the electromagnetic transition strengths, these decays are concluded to be predominantly M1 transitions. The reduced M1 transition probabilities to the ground state were deduced to be (1.0±0.1)×10−2μN2and (8.2−1.8+3.2)×10−2μN2, respectively, for the first and second excited states. The strongly hindered M1 strength as well as the lowered excitation energy represents unique nature of the 212-keV state.