Direct observation of long-lived isomers in 212Bi.
Direct observation of long-lived isomers in 212Bi.
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DOI：
10.1103/physrevlett.110.122502
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发表时间：
2013-03
影响因子：
8.6
通讯作者：
L. Chen;P. Walker;H. Geissel;Y. Litvinov;K. Beckert;P. Beller;F. Bosch;D. Boutin;L. Caceres;J. Carroll;D. Cullen;I. Cullen;B. Franzke;J. Gerl;M. Gorska;G. Jones;A. Kishada;R. Knöbel;C. Kozhuharov;J. Kurcewicz;S. Litvinov;Z. Liu;S. Mandal;F. Montes;G. Münzenberg;F. Nolden;T. Ohtsubo;Z. Patyk;W. Plaß;Z. Podolyák;S. Rigby;N. Saito;T. Saito;C. Scheidenberger;E. Simpson;M. Shindo;M. Steck;B. Sun;S. Williams;H. Weick;M. Winkler;H. Wollersheim;T. Yamaguchi
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文献类型：
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作者：
L. Chen;P. Walker;H. Geissel;Y. Litvinov;K. Beckert;P. Beller;F. Bosch;D. Boutin;L. Caceres;J. Carroll;D. Cullen;I. Cullen;B. Franzke;J. Gerl;M. Gorska;G. Jones;A. Kishada;R. Knöbel;C. Kozhuharov;J. Kurcewicz;S. Litvinov;Z. Liu;S. Mandal;F. Montes;G. Münzenberg;F. Nolden;T. Ohtsubo;Z. Patyk;W. Plaß;Z. Podolyák;S. Rigby;N. Saito;T. Saito;C. Scheidenberger;E. Simpson;M. Shindo;M. Steck;B. Sun;S. Williams;H. Weick;M. Winkler;H. Wollersheim;T. Yamaguchi
研究了670 MeV/核子的（238）U射弹碎裂后（212）Bi的长寿命异构体。碎裂产物作为高电荷离子注入储存环，从而获得质量和半衰期。虽然确认了（212）Bi的第一种异构体的激发能，但观察到第二种异构体的激发能为1478（30）keV，而先前接受的值为>1910 keV。还发现它具有延长的洛伦兹校正的环内半衰期>30分钟，而中性原子为7.0（3）分钟。能量和半衰期的差异都可以理解为是由于中性原子的内部衰变分支造成的，尽管以前没有认识到。较早的壳模型计算，现在发现给异构体激发能很好的协议。此外，这些和新的计算预测存在的国家在略高的能量，可以促进异构体去激发研究。
Long-lived isomers in (212)Bi have been studied following (238)U projectile fragmentation at 670 MeV per nucleon. The fragmentation products were injected as highly charged ions into a storage ring, giving access to masses and half-lives. While the excitation energy of the first isomer of (212)Bi was confirmed, the second isomer was observed at 1478(30) keV, in contrast to the previously accepted value of >1910 keV. It was also found to have an extended Lorentz-corrected in-ring half-life >30 min, compared to 7.0(3) min for the neutral atom. Both the energy and half-life differences can be understood as being due a substantial, though previously unrecognized, internal decay branch for neutral atoms. Earlier shell-model calculations are now found to give good agreement with the isomer excitation energy. Furthermore, these and new calculations predict the existence of states at slightly higher energy that could facilitate isomer deexcitation studies.