The Application of Linear Polarized X-rays After Bragg Reflection for X-ray Fluorescence Analysis

Abstract

AbstractPolarized x-rays are used to excite samples of any kind and shape to emit characteristic radiation. In the appropriate geometry, where source-sample-ED detector are in any orthogonal position to each other, the exciting poLarized x-rays will be practically not scattered from sample and substrate into the detector. This reduces the background considerably and hence improves the lower limits of detection. The production of intensive polarized x-rays is done by using a single crystal-where Bragg reflection occurs at an angle 2 θ = 90° instead of amorphous low Z scatterers. The result is a linear polarized and monochromatic beam. The use of curved crystals instead of plane single crystals further increases the intensity of the exciting radiation. The lower limits of detection attainable with the recently constructed compact polarizer device are in the sub ppm range or in absolute amounts around 150 pg for medium Z elements.