Niedermaier O, Scheit H, Bildstein V, Boie H, Fitting J, von Hahn R, Köck F, Lauer M, Pal U K, Podlech H, Repnow R, Schwalm D, Alvarez C, Ames F, Bollen G, Emhofer S, Habs D, Kester O, Lutter R, Rudolph K, Pasini M, Thirolf P G, Wolf B H, Eberth J, Gersch G, Hess H, Reiter P, Thelen O, Warr N, Weisshaar D, Aksouh F, Van den Bergh P, Van Duppen P, Huyse M, Ivanov O, Mayet P, Van de Walle J, Aystö J, Butler P A, Cederkäll J, Delahaye P, Fynbo H O U, Fraile L M, Forstner O, Franchoo S, Köster U, Nilsson T, Oinonen M, Sieber T, Wenander F, Pantea M, Richter A, Schrieder G, Simon H, Behrens T, Gernhäuser R, Kröll T, Krücken R, Münch M, Davinson T, Gerl J, Huber G, Hurst A, Iwanicki J, Jonson B, Lieb P, Liljeby L, Schempp A, Scherillo A, Schmidt P, Walter G
Max-Planck-Insitut für Kernphysik, Heidelberg, Germany.
Phys Rev Lett. 2005 May 6;94(17):172501. doi: 10.1103/PhysRevLett.94.172501. Epub 2005 May 4.
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient gamma spectrometer MINIBALL. Using 30Mg ions accelerated to an energy of 2.25 MeV/u together with a thin (nat)Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation gamma-ray yields the B(E2;0(+)gs-->2(+)1) value of 30Mg was determined to be 241(31)e2 fm4. Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope 30Mg resides outside the "island of inversion."
我们报告了首次在欧洲核子研究中心（CERN）最近启用的REX - ISOLDE设施上进行的放射性束流实验，该实验与高效伽马能谱仪MINIBALL联合进行。使用加速到2.25 MeV/u能量的30Mg离子以及薄的天然镍（nat）Ni靶，观察到弹核和靶核的第一激发2 +态在远低于库仑势垒处的库仑激发。根据测量的相对退激伽马射线产额，确定30Mg的B（E2；0（+）gs→2（+）1）值为241（31）e2 fm4。我们的结果低于使用中能库仑激发方法在弹核碎裂设施上获得的值，并证实了理论推测，即富中子镁同位素30Mg位于“反转岛”之外。
