Imaging Neutron Activation Analysis

小企业创新研究（SBIR）第一阶段项目 在分析和表面化学的一般领域和在 痕量表面分析子领域。 这项活动的主旨是 是建造和测试成像中子活化 能够辨别元素浓度的分析检测器 一点一点的基础上。 中子活化分析是一种 测量大调、小调和微量的一种非常强大的方法 各种样品中的元素浓度。 在这 方法，分析物元素吸收中子以形成放射性核素 其通常通过发射B粒子和伽马射线而衰变。 伽马射线能量是分析物元素的特征 并且它们通常用锗检测器测量。 作为B粒子在样品表面产生的二次电子 薄样品的通过可以被加速和成像。 当 伽马射线和B粒子是同时被探测到的， 射线能量回答了“是什么”的问题， 位置回答了一个人“在哪里”的问题， 放射性核素衰变 这些信息将被组织 元素分布图和局部伽马射线谱。 这项研究的成功进行将有助于 成像中子活化分析在 非均质固体的表征。 在一对 成功的第二阶段工作，广泛的应用领域， 地质学、生物学、材料科学和粒子分析可以 被期待。

This Small Business Innovation Research (SBIR) Phase I project is in the general area of analytical and surface chemistry and in the subfield of trace surface analysis. The thrust of this activity is the construction and testing of an imaging neutron activation analysis detector capable of discerning element concentrations on a point by point basis. Neutron activation analysis is an extremely powerful method for measuring major, minor, and trace element concentrations in a wide variety of samples. In this method, analyte elements absorb a neutron to form a radionuclide which usually decays by emitting a B particle and a gamma ray. The gamma ray energies are characteristic of the analyte element and they are normally measured with a germanium detector. Secondary electrons produced at a sample surface as a B-particle passes out of a thin sample can be accelerated and imaged. When gamma rays and B-particles are detected in coincidence, the gamma ray energy answers the question "what" and the secondary electron position answers the question "where" for an individual radionuclide disintegration. This information will be organized into element maps and local area gamma ray spectra. Successful pursuit of this research should facilitate the application of imaging neutron activation analysis to the characterization of heterogeneous solids. Following a coupled successful Phase II effort, widespread applications in fields such as geology, biology, materials science, and particle analysis can be anticipated.