Smolek Stephan, Streli Christina, Zoeger Norbert, Wobrauschek Peter
Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria.
Rev Sci Instrum. 2010 May;81(5):053707. doi: 10.1063/1.3428739.
Since most available micro x-ray fluorescence (micro-XRF) spectrometers operate in air, which does not allow the analysis of low-Z elements (Z <or = 14), a special micro-XRF spectrometer has been designed to extend the analytical range down to light elements (Z > or = 6). It offers improved excitation and detection conditions necessary for light element analysis. To eliminate absorption of the exciting and fluorescent radiation, the system operates under vacuum condition. Sample mapping is automated and controlled by specialized computer software developed for this spectrometer. Several different samples were measured to test and characterize the spectrometer. The spot size has been determined by scans across a 10 microm Cu wire which resulted in a full width at half maximum of 31 microm for Mo Kalpha line (17.44 keV) and 44 microm effective beam size for the Cu K edge and 71 microm effective beam size for the Cu L edge. Lower limits of detection in the picogram range for each spot (or microg/cm(2)) were obtained by measuring various thin metal foils under different conditions. Furthermore, detection limits in the parts per million range were found measuring NIST621 standard reference material. Area scans of a microscopic laser print and NaF droplet were performed to show mapping capabilities.
由于大多数现有的微X射线荧光（micro-XRF）光谱仪在空气中运行，而这无法对低Z元素（Z≤14）进行分析，因此设计了一种特殊的微XRF光谱仪，以将分析范围扩展到轻元素（Z≥6）。它提供了轻元素分析所需的改进的激发和检测条件。为了消除激发辐射和荧光辐射的吸收，该系统在真空条件下运行。样品映射是自动化的，并由为此光谱仪开发的专用计算机软件控制。测量了几种不同的样品以测试和表征该光谱仪。通过扫描一根10微米的铜丝来确定光斑尺寸，结果对于Mo Kα线（17.44 keV），半高宽为31微米，对于铜K边，有效束斑尺寸为44微米，对于铜L边，有效束斑尺寸为71微米。通过在不同条件下测量各种薄金属箔，获得了每个光斑（或微克/平方厘米）皮克范围内的检测下限。此外，通过测量NIST621标准参考物质，发现了百万分之几范围内的检测限。对微观激光打印和NaF液滴进行了区域扫描，以展示映射能力。
