微量铀的快速超热中子活化法测定

Epithermal neutron activation analysis of trace uranium using short half life nuclide 239 U

选用２３８Ｕ（ｎ，γ）２３９Ｕ反应，通过测定半衰期为２３．５ｍｉｎ的２３９Ｕ对铀进行定量分析。采用氮化硼屏蔽的超热中子活化法，使铀的探测极限达到８ｎｇ／ｇ（生物样品）和０．１５μｇ／ｇ（地质样品），且每个样品的分析时间小于１ｈ。对１５种生物和地质标准物质中的铀进行了测定，结果表明测定值与推荐值是吻合的。

The epithermal neutron activation analysis of uranium was studied to deter mining trace uranium via 239 U(T 1/2 =23 5min) produced by the 238 U(n, γ) reaction with boron nitride (BN) as shielding material to reduce the interference from major elements Al, Cl and Na The detection limits of uranium are 8ng/g for biological materials and 0 15μg/g for geological samples, respectively An analytical time of less than one hour per sample is possible The contents of uranium in 15 biological and geological standard reference materials were determined, with a good agreement with the certified values