New Short-Lived Isotope 221U and the Mass Surface Near N =126
Abstract
Two short-lived isotopes 221U and 222U were produced as evaporation residues in the fusion reaction 50Ti + 176Yb at the gas-filled recoil separator TASCA. An α decay with an energy of Eα=9.31 (5 ) MeV and half-life T1 /2=4.7 (7 ) μ s was attributed to 222U. The new isotope 221U was identified in α -decay chains starting with Eα=9.71 (5 ) MeV and T1 /2=0.66 (14 ) μ s 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.
- Publication:
-
Physical Review Letters
- Pub Date:
- December 2015
- DOI:
- 10.1103/PhysRevLett.115.242502
- Bibcode:
- 2015PhRvL.115x2502K
- Keywords:
-
- 23.60.+e;
- 25.70.Jj;
- 27.90.+b;
- Alpha decay;
- Fusion and fusion-fission reactions;
- 220<
- =A