New nuclide 139Tb and (EC+ ) decay of 138,139Gd
Xie Yuanxiang - Xu Shuwei - Li Zhankui - Yu Yong - Pan Qiangyan - Wang Chunfang - Zhang Tianmei
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, P.R. China
Received: 2 June 1999 / Revised version: 4 August 1999 Communicated by D. Schwalm
The unknown isotope 139Tb and the known isotopes 138,139Gd were produced in the 36Ar+106Cd reaction and studied by using a He-jet tape transport system in combination with X- and - coincidence measurements. The half-lives of 139Tb, 139gGd, 139mGd and 138Gd were determined to be 1.6(2), 5.8(9), 4.8(9) and 4.7(9) s, respectively. Partial (EC+ ) decay schemes of 139gGd, 139mGd and 138Gd were proposed for the first time.
23.40.-s decay; double decay; electron and muon capture - 21.10.Tg Lifetimes - 27.60.+j