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标题：270Ds and its decay products â€“ K-isomers, Î±-sf competition and masses
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作者：D. ACKERMANN
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2012
卷号：2012
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：In the period August - October 2010, we investigated the even-even superheavy nucleus 270Ds, employing the reaction 64Ni + 207Pb−!270Ds. In a first attempt, published in 2001, a total of eight decay chains of type evaporation residue (ER)-a-a-sf (270Ds−!266Hs 262Sg) was observed. Now, in a period of 40 days of beam on target, we accumulated 25 decay chains of 270Ds, for which we measured in addition to the decay pattern observed in the first experiment, also ER-a-sf and (ER)-a-a-a-sf correlations. For eight of the collected decay chains we detected spontaneous fission of 266Hs. With this we could establish the sf branch of 266Hs. The resulting branching ratio is 0.24±0.09. More importantly, however, also the searched for K-isomer in 266Hs and the a-decay branch of 262Sg was found. For the latter we detected a total of two a-decays, resulting in a 262Sg a-decay branching ratio of 0.06±0.04. The observation of this a-decay establishes the missing link to 254No for which a precise mass value employing the Penning trap system SHIPTRAP was measured recently. Using the experimentalQa -values we are now able to provide an experimentalmass for the even-even nucleus 270Ds. This is an important parameter for theoretical models which are used to predict masses and binding energies for the heaviest nuclei.