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仪器中子活化分析是一种非破坏性的分析方法。一些元素辐照后产生短半衰期(<60 s)放射性核素,其他元素既产生长寿命核素也产生短寿命核素。这些短寿命核素,单次测量误差较大。为了减少误差,提高灵敏度,可采用循环中子活化分析的方法。通过一个连接到样品传送器、探测器以及微型反应堆辐照管道,并可自动控制照射时间和计数时间的装置,根据某些元素的核参数,试验确定了照射时间、计数时间和循环周期次数,从而建立了基于微型堆的循环活化分析方法。研究了17种元素的循环活化分析条件,并应用于实际样品的测定。探讨了循环超热中子活化分析的方法实验。通过对国家标准参考物质的分析,证实了该方法的可靠性和灵敏度高、精度好、分析周期短的优点。循环中子活化分析是只有短寿命核素元素的有效分析方法,其精度优于单次短照活化分析。对同时有短寿命和长寿命核素的元素,该方法可以缩短分析周期,从几天到几周缩短至几分钟。
Instrumental neutron activation analysis is a nondestructive analytical method. Some elements produce short half-life (<60 s) radionuclides after irradiation, while others produce both long-lived and short-lived nuclides. These short-lived nuclides, a single measurement error. In order to reduce the error and increase the sensitivity, we can adopt the method of circulating neutron activation analysis. Through a device connected to the sample transmitter, detector and the reactor’s irradiation pipe and automatically controlling the irradiation time and counting time, the irradiation time, the counting time and the number of cycles are determined experimentally according to the nuclear parameters of some elements, Thus, a micro-reactor-based cycle activation analysis method is established. 17 kinds of elements of the cycle of activation analysis conditions, and applied to the actual sample determination. The method experiment of circulating superheated neutron activation analysis was discussed. Through the analysis of the national standard reference material, the method has the advantages of high reliability, high sensitivity, good precision and short analysis period. Cyclic neutron activation analysis is an effective method for analyzing only short-lived nuclide elements with better accuracy than single-shot activation analysis. For elements that have both short-lived and long-lived nuclides, this approach can shorten the analysis cycle from a few days to a few weeks to a few minutes.