Analytical application of total reflection and polarized X-rays

摘要: Detection limits in photon induced X-ray fluorescence analysis (XRF) using energy dispersive spectrometer systems (ED) can be improved by the application of special excitation conditions. 1. Total reflection primary beam plane and smooth surface a reflector reduces radiation background. In total geometry scarcely penetrates into medium. Taking as substrate, only an extremely thin layer (20–70 nm) acts scatterer photons. The allows efficient sample optimal detection fluorescent signal detector mounted close to sample. Thin film samples are placed on reflector-substrate. volume needs few microliter. Concentrations ppb level or absolute amounts pg detected cases. Total XRF will method choice if low concentrations small volumina have detected. 2. Linear polarized X-rays used orthogonal (x-y-z) reduce background from scattered substrate. Several possibilities produce discussed proposals made increase intensity after 90° Bragg single crystal. Samples any kind shape. at present under good conditions sub ppm range about 100 absolute. may therefore extended practically all kinds care preparation technique is taken.