244Pu是潜在的早期核武器试验“指纹特征”核素，237Np是环境放射性监测和放射性废物处置中重点关注的核素。然而环境中244Pu浓度极低，237Np无可靠的同位素示踪剂，目前缺乏准确的分析方法。本研究基于小型（300 kV）加速器质谱，通过对化学分离中难熔锕系核素的提取、Pu/Np同步分离、超低水平样品制备的本底控制等关键技术难题进行研究，并通过进一步提高锕系核素AMS的离子化效率，实现埃克量级（10-17 g）244Pu的超灵敏测量，量化Pu/Np的分馏系数，建立大质量环境样品中超痕量244Pu和237Np的加速器质谱分析方法。用该方法对核试验场所附近及环境中244Pu和237Np进行分析，初步获得哈萨克斯坦核污染土壤及我国环境中244Pu和237Np的浓度水平信息，服务于环境中Pu和Np的精细来源解析及其环境迁移行为研究。

244Pu is a potential fingerprint radionuclide of atmospheric nuclear weapons tests, 237Np is one of the most important radionuclides in environmental radioactivity monitoring and nuclear waste repository. Due to extremely ultra-trace levels of 244Pu in the environment and no reliable isotope yield tracer of 237Np, no reliable method for their accurate determination in the environmental samples is available. Based on the compact accelerator mass spectrometry (300 kV), this study aim to develop a sensitive and reliable method for the accurate determination of 244Pu and 237Np in large size environmental samples. A total sample dissolution method for separation of refractory actinide from solid sample matrix, simultaneous separation of Pu/Np, background control, the AMS target preparation, and improvement of ionization efficiency in the AMS measurement will be implemented, with these efforts, a detection limit down to 10-17 g for 244Pu, and quantify the fractionation coefficient of Pu/Np will be achieved. The developed methods will be applied on determination of 244Pu and 237Np in the samples collected in the vicinities of nuclear test sites and in the ordinary environment, aiming to investigate 244Pu and 237Np in the nuclear-contaminated soil at Semipalatinsk nuclear test site and the environment samples in China, which will provide an important basic data for nuclear forensics and migration research of Pu and Np.