用4πX(PPC)-γ符合方法测量^(75)Se核素溶液活度

ACTIVITY MEASUREMENT OF ^(75)Se RAKIONUCLIDE SOLUTION WITH 4πX(PPC)-γ COINCIDENCE METHOD

用４πＸ（ＰＰＣ）－γ符合方法测量来自国际计量局（ＢＩＰＭ）的￣（７５）Ｓｅ放射性溶液，测得的活度是（１．２５８±０．０２２）ＭＢｑ／ｇ（参考时间为１９９２年６月１日），与参加比对的１９个实验室的２３个结果的加权平均值（１．２５３±０．００３）ＭＢｑ／ｇ偏离０．４％，在误差范围内相一致。由衰变谱计算得到￣（７５）Ａｓ的亚稳态内转换电子影响的修正系数Ｋ＿（ｄｅ）＝１．０７４９±０．０１５０。

The activity of ￣(75)Se radionuclide Solution which is supplied by BIPM is measured with 4πX(PPC)-γ coincidence. The final result obtained is(1.258 ± 0. 002)MBq/g(reference time 1992-06-01),The difference between the result and the weighted average is 0.4%,the weighted aver-age of 23 results provided by 19 participant laboratories is(1.253 ± 0. 003)MBq/g and the twovalues are coincident within the given error limits, K_(de) the correction,is1.0749 ± 0.0150 whichis a result of the effect of conversion electrons of ￣(75)As￣m metastable state