126Ce的EC/β+衰变

利用187 MeV的40Ca离子轰击同位素靶92Mo， 由熔合蒸发反应生成目标核126Ce。 藉助氦喷嘴快速带传输系统和X-X-t与X-γ-t符合测量， 首次建立了126Ce的EC/β+衰变纲图。 建议了可能属于126Ce一个高自旋同核异能态的衰变， 其β衰变后布居在与126La的高自旋同核异能态相关的低位能级区， 测定的半衰期是57(9) s。 也建议了可能属于126Ce基态的衰变， 其β衰变后布居在与126La的低自旋同核异能态相关的低位能级区，它的半衰期被测定为12(4) s。 但偶偶核126Ce存在高自旋同核异能态的物理原因还有待进一步探究。 Ce was produced by bombarding an enriched target of 92Mo with 187 MeV 40Ca beam and studiedby using a helium jet fast tape transport system in combination with X-γ and γ-γ coincidencemeasurements. An EC/β+ decay scheme of 126Ce was proposed for the first time. A group of low lying states associated with the low spin isomer in 126La feeding by β decay was possibly from the ground state EC/β+ decay of 126Ce with the measured half-life 12(4) s. Another group of low lying states associated with the high spin isomer in 126La feeding by β decay was possibly from a high spin isomer EC/β+ decay of 126Ce with the measured half-life 57(9) s. However， the physical reason for the existence of a high spin isomer in even-even nucleus 126Ce is still an open problem.