The very neutron-deficient nuclei ^145,147Er were produced via the reaction of ⁵⁸Ni+⁹²Mo at beam energy of 383 MeV at the Institute of Modern Physics, CAS. Using the He-jet apparatus coupled with a tape transport system, the ß-delayed proton radioactivities both from the ns_1/2 ground state and the nh_11/2 isomer in ^145,147Er were observed by proton-g coincidence measurements. The decay schemes of ^145,147Er, deduced from this work, are shown in Fig.1. 

Fig. 1. Decay schemes of (a) 145Er and (b) 147Er (Image by IMP)

The calculation of the statistical model indicated that the 4⁺ states in the granddaughter nuclei ^144,146Dy were mainly produced by the b-delayed proton decays of the nh_11/2 isomers in ^145,147Er. Therefore, the half-lives of the isomers in ^145,147Er can be obtained by analyzing the time distributions of the 4⁺→2⁺ g transitions in ^144,146Dy. As shown in Fig.2, the half-lives of 1.0 ± 0.3 s and 1.6 ± 0.2 s have been deduced for the nh_11/2 isomers in ^145,147Er by fitting the decay curves of the 673 and 926 keV transitions, respectively.

The results were published in Physical Review C81,047301(2010).

Fig. 2. Delayed proton spectra gated by the (a) 673 keV and (b) 926 keV transitions and their decay curves. (Image by IMP)