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长寿命裂变产物核素￣（７９）Ｓｅ的半衰期还没有被准确地测量过，文献中一直引用１９４９年测定的值：Ｔ＿（１／２）≤６．５×１０￣４ａ。本工作应用放化法测量了￣（７９）Ｓｅ的半衰期。从中子照射的铀靶中分出放化纯的￣（７９）Ｓｅ，并用液闪谱仪测量其活度。利用￣（９０）Ｓｒ、￣（１３７）Ｃｓ作为监测核计算出铀靶的裂变数，然后根据裂变产额得到￣（７９）Ｓｅ核数。得到的￣（７９）Ｓｅ的半衰期为（４．８±０．４×１０￣５ａ。）
The half-life of selenium (79), a long-lived fission product, has not been accurately measured and has been quoted in the literature for 1949 as T 1/2 (1/2) ≤ 6.5 × 10 -4a. In this work, the half-life of ~ (79) Se was measured by radiochemical method. Radiochemical purity ~ (79) Se was fractionated from neutron-irradiated uranium targets and its activity was measured by liquid-state spectrometry. The fission number of uranium target was calculated using ~ (90) Sr and ~ (137) Cs as monitoring nuclei, and then the ~ (79) Se nucleus was obtained according to the fission yield. The half-life of Se (79) obtained was (4.8 ± 0.4 × 10-5a.)