Pyroelectric X-ray Generator for XRF in Combination with Optical Microscopy

Abstract

X-ray fluorescence spectroscopy (XRF) is a method for elemental analyses of materials. In comparison to other analysing methods such as energy dispersive X-Ray spectroscopy (EDS) within a scanning electron microscope (SEM) or optical emission spectroscopy (OES) there are several advantages. This paper contains experimental investigations to improve the emission behaviour of a pyroelectric X-ray source regarding X-ray energy and output intensity. Pyroelectric lithiumtantalate (LiTaO3) was used to emit and accelerate electrons and to generate primary X-rays subsequently. Geometrical conditions were altered and the design of the X-ray source was optimized. All steps of optimization have been performed with respect to an application in a spectroscopic device in combination with an optical microscope (OM). Based on this purpose, the miniaturization of all applied components is of major importance. Different pure metals, alloys, and a coated specimen were analysed to demonstrate potential applications and current limitations of the designed system. Materials with a wide range of necessary excitation energy for chemical analyses of 1.5 to 10 keV for the Kα and Lα X-ray fluorescent lines were used to demonstrate the technical relevance of this type of application. As a result, a prototype of a spectrometer that combines XRF and OM was designed and tested.