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通过重离子引起的融合蒸发反应 92 Mo (40 Ca ,p2n)合成了稀土区未知核素 12 9Pm ,并且配合氦喷嘴快速带传输系统利用X γ符合方法对它进行了首次鉴别 .实验观测到了经 12 9Pm的 (EC +β+ )衰变产生的对应于子核 12 9Nd中 5 2 -→ 1 2 -跃迁的一条 99keVγ线 .根据这条 99keVγ线的时间衰变曲线 ,提取出 12 9Pm的半衰期为 (2 .4± 0 .6 )s .
The rare earth nuclide 12 9Pm was synthesized by heavy ion-induced fusion evaporation 92 Mo (40 Ca, p2n), and was first identified by the X γ coincidence method with the helium nozzle rapid belt transfer system. The (EC + β +) decay of 12 9Pm produces a 99keVγ line corresponding to a 5 2 - → 1 2 - transition in 9 9N of the nucleus.According to the time decay curve of 99keVγ line, the half-life of 12 9Pm extracted is ( 2 .4 ± 0 .6) s.