藉助核反应92 Mo( 3 2 S ,3n)产生了未知的缓发质子先驱核12 1Ce ,并利用氦喷嘴快速带传输系统和“p γ”符合方法对它进行了鉴别 .测定了12 1Ce的半衰期 ( 1 1±0 .1 )s,观测了它的β缓发质子能谱 ,粗略地估计了它的 β缓发质子衰变道的分支比约为 1 % .首次观测了先驱核119Ba,12 1Ba和12 2 La经过β缓发衰变在“子核”中产生的低位能级到基态的γ跃迁 . An unknown delayed proton nucleus, 12 1Ce, was generated by means of the 92 Mo (3 2 S, 3n) reaction and was identified using the helium nozzle rapid belt transport system and the “p γ” coincidence method. The half-life of 12 1Ce (1 1 ± 0. 1) s, its β-delayed proton energy spectrum was observed and its branching ratio of β-delayed proton decay was roughly estimated to be about 1%. For the first time, the precursor nuclei 119Ba and 12 1Ba And 12 2 La undergoes γ-transitions from the lower level to the ground state produced by β-delayed decay in the “nucleus.”