Stefanescu I, Georgiev G, Ames F, Aystö J, Balabanski D L, Bollen G, Butler P A, Cederkäll J, Champault N, Davinson T, De Maesschalck A, Delahaye P, Eberth J, Fedorov D, Fedosseev V N, Fraile L M, Franchoo S, Gladnishki K, Habs D, Heyde K, Huyse M, Ivanov O, Iwanicki J, Jolie J, Jonson B, Kröll Th, Krücken R, Kester O, Köster U, Lagoyannis A, Liljeby L, Lo Bianco G, Marsh B A, Niedermaier O, Nilsson T, Oinonen M, Pascovici G, Reiter P, Saltarelli A, Scheit H, Schwalm D, Sieber T, Smirnova N, Van De Walle J, Van Duppen P, Zemlyanoi S, Warr N, Weisshaar D, Wenander F
Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
Phys Rev Lett. 2007 Mar 23;98(12):122701. doi: 10.1103/PhysRevLett.98.122701.
We report on the first low-energy Coulomb excitation measurements with radioactive Ipi=6- beams of odd-odd nuclei 68,70Cu. The beams were produced at ISOLDE, CERN and were post-accelerated by REX-ISOLDE to 2.83 MeV/nucleon. Gamma rays were detected with the MINIBALL spectrometer. The 6- beam was used to study the multiplet of states (3-, 4-, 5-, 6-) arising from the pi2p3/2 nu 1g9/2 configuration. The 4- state of the multiplet was populated via Coulomb excitation and the B(E2;6--->4-) value was determined in both nuclei. The results obtained illustrate the fragile stability of the Z=28 shell and N=40 subshell closures. A comparison with large-scale shell-model calculations using the 56Ni core shows the importance of the proton excitations across the Z=28 shell gap to the understanding of the nuclear structure in the neutron-rich nuclei with N approximately 40.
我们报道了首次使用放射性(I^{\pi}=6^{-})的奇奇核(^{68,70}Cu)束流进行的低能库仑激发测量。束流在欧洲核子研究组织（CERN）的ISOLDE装置上产生，并由REX-ISOLDE后加速至(2.83)兆电子伏每核子。使用MINIBALL谱仪探测伽马射线。(6^{-})束流用于研究由(\pi2p_{3/2}\nu1g_{9/2})组态产生的态多重态（(3^{-})、(4^{-})、(5^{-})、(6^{-})）。通过库仑激发填充多重态的(4^{-})态，并在两个核中确定了(B(E2;6^{-}\to4^{-}))值。所获得的结果说明了(Z = 28)壳层和(N = 40)次壳层闭壳的脆弱稳定性。与使用(^{56}Ni)核心的大规模壳模型计算的比较表明，质子穿过(Z = 28)壳层间隙的激发对于理解(N)约为(40)的富中子核中的核结构具有重要意义。
