14C和129I的无化学制样快速加速器质谱分析研究

Due to the extremely high sensitivity, Accelerator Mass Spectrometry (AMS) has been widely used for determination of 14C and 129I in environmental and biomedical studies. However, a time consuming chemical procedure for separation of the target nuclides from the sample matrix and preparation of target significantly limited its application, especially for rapid analysis in the emergency situation and for the analysis of large number of samples. This project aims to develop a rapid AMS method for rapid determination of 14C and 129I in environmental samples and biomedical samples for the monitoring of environmental nuclear safety, especially for the emergency analysis, as well as tracer studies of 14C for investigating the metabolism of compounds and drugs in animal body. This will be implemented by eliminate the step of chemical separation of target nuclides, the samples will be directly packed into target holder after dried and homogenized, and the prepared target is directly used for AMS analysis. By this approach, the analytical time can be shorten to a few hours for a batch of samples (10-50 samples). The major research activities will focus on an efficient AMS target preparation procedure, ion source geometry modification and optimization, the special needs in AMS data acquisition, and the special needs in data analysis and normalization. In the end, an optimized replicable analytical procedure shall be determined, and one or two typical applications shall be demonstrated using this rapid AMS assay method. This method has not been well reported in the literature, it will significantly promote the application of AMS in biomedical studies and as well as nuclear emergency analysis, or even a new specific instrument of AMS.

加速器质谱仪（AMS）对超微量的14C、129I等核素的超高灵敏度探测能力极大地拓展了这些核素的应用范围，但是极长的化学制样时间制约了AMS分析能力，从而限制了其应用。本项目针对14C生物医学示踪研究，和利用14C、129I进行核事故以及核设施周边放射性水平重建和安全评估等研究中要求分析速度快、样品量大、目标核素含量水平不低于现代环境水平且对数据精度和本底水平要求不高等特点，拟尝试跳过化学制样环节，将干燥固体样品粉末与相应导电导热介质混合后直接制靶进行AMS测试，从而开发一种能在小时量级时间内实现批量14C或129I的无化学制样快速AMS分析的创新方法。类似方法在国外虽有初步涉及，但尚未有详细的、全面的专题研究报道。本项目拟从理论研究、离子源结构优化和实验研究等多方面对此方法作较为全面的研究。该工作将极大的推动一大批相关应用研究，并有希望促成一类专用于此类样品快速检测的AMS设备研发。

加速器质谱仪对超微量的14C、129I等放射性核素的超高灵敏度探测能力极大的拓展了这些核素的应用范围，在大多数AMS实验室，极长的制样时间是制约AMS应用的主要瓶颈之一。本项目针对部分AMS应用如14C生物医学示踪，利用14C、129I进行核事故以及核设施周边安全评估等研究中要求测试周期短、样品量大而且对数据的精度和本底水平要求不高等特点，从AMS靶源制备、离子源改造与优化以及AMS测试与数据处理等三个方面来开展，尝试了对这类样品跳过制样环节，将干燥粉碎后的样品与相应导电导热介质混匀后直接制靶进行AMS测试，开发了一种能在小时量级时间内实现批量14C或129I的无制样快速AMS检测的创新方法。在国际上首次报道，本项目理论研究和实验实测同时进行，该方法有望推动一大批相关应用研究并促成一类专用于此类样品快速检测的AMS设备研发。为将来大规模开展利用14C做生物医学标记的Microdosing研究，以及利用14C和129I等监测核设施的运行和周边环境所受辐射的影响研究提供基础技术支撑。