1. New Short-Lived Isotope ^{221}U and the Mass Surface Near N=126
- Author
-
Khuyagbaatar, J., Yakushev, A., Düllmann, Ch. E., Ackermann, D., Andersson, L.-L., Block, M., Brand, H., Cox, D. M., Even, J., Forsberg, Ulrika, Golubev, Pavel, Hartmann, W., Herzberg, R.-D., Heßberger, F. P., Hoffmann, J., Hübner, A., Jäger, E., Jeppsson, J., Kindler, B., Kratz, J. V., Krier, J., Kurz, N., Lommel, B., Maiti, M., Minami, S., Mistry, A. K., Mrosek, Ch. M., Pysmenetska, I., Rudolph, Dirk, Sarmiento, Luis, Schaffner, H., Schädel, M., Schausten, B., Steiner, J., De Heidenreich, T. Torres, Uusitalo, J., Wegrzecki, M., Wiehl, N., and Yakusheva, V.
- Subjects
Shell Structure ,Heavy Elements Shell Structure Sampling Electronics ,Heavy Elements ,Sampling Electronics ,Subatomic Physics - Abstract
Two short-lived isotopes ^{221}U and ^{222}U were produced as evaporation residues in the fusion reaction ^{50}Ti+^{176}Yb at the gas-filled recoil separator TASCA. An α decay with an energy of E_{α}=9.31(5) MeV and half-life T_{1/2}=4.7(7) μs was attributed to ^{222}U. The new isotope ^{221}U was identified in α-decay chains starting with E_{α}=9.71(5) MeV and T_{1/2}=0.66(14) μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N=126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α-decay reduced width.
- Published
- 2015