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中子照射稳定核素产生的放射性核素,其中有些与铀的裂变产物中的放射性核素是相同的,例如由(n,γ)反应产生的放射性核素:~(140)La、~(141)Ce、~(143)Ce、~(147)Nd等几十种核素都可在铀的裂变链中找到。因此,如果样品中含有铀,就会干扰这些核素的测定。地质样品中的花岗岩,其平均铀含量是3～4ppm;主要类型沉积岩中铀含量也在0.1～10ppm;铀在水中含量为1.5～8μg/l;就是在正常人的血液中还含铀0.9～1.8ng/l。因此,用中子活化分析测定质量数为70～160之间的核素时,必须注意裂变产物的可能干扰。
The neutrons irradiate radionuclides produced by stable radionuclides, some of which are the same as the radionuclides in the fission products of uranium, such as the radionuclides produced by the (n, γ) reaction: ~ (140) La, ~ 141) Ce, ~ (143) Ce, ~ (147) Nd and other nuclides can be found in the fission chain of uranium. Therefore, if the sample contains uranium, it will interfere with the determination of these nuclides. Geological samples of granite, the average uranium content is 3 ~ 4ppm; the main types of sedimentary rock uranium content is also in the 0.1 ~ 10ppm; uranium in the water content of 1.5 ~ 8μg / l; that is, in normal human blood also contains uranium 0.9 ~ 1.8ng / l. Therefore, when neutron activation analysis is used to determine nuclides with a mass of 70 to 160, attention must be paid to possible interference with fission products.