Properties of the β-Delayed Proton Decay of 147Er

The β-delayed proton decay of ¹⁴⁷Er is studied experimentally using the ⁵⁸Ni+⁹²Mo reaction at a beam energy of 383 MeV. Based on a He-jet apparatus coupled with a tape transport system, theβ-delayed proton radioactivities both from the νs_1/2 ground state and the νh_11/2 isomer in ¹⁴⁷Er are identified by proton-γ coincidence measurements. By analyzing the time distribution of the 4^+_→ 2^+_γ transition in the grand-daughter nucleus ¹⁴⁶Dy, a half-life of 1.6±0.2 s is determined for the νh_11/2 isomer in ¹⁴⁷Er. The half-life for the ground state of ¹⁴⁷Er is estimated to be 3.2±1.2 s.