Portable Systems for Energy‐DispersiveX‐Ray Fluorescence

Abstract

AbstractPortable energy‐dispersive X‐ray fluorescence (EDXRF) spectrometers are becoming very popular in many fields for the on‐site analysis of elements. This is mainly because EDXRF is a nondestructive, multielemental technique that is extremely well suited for the analysis of any material.An EDXRF spectrometer mainly consists of an X‐ or γ‐ray excitation source, an X‐ray detector with electronics, and a pulse height analyzer. Recent technological developments have resulted in small, low‐power, dedicated X‐ray tubes, thermoelectrically cooled semiconductor detectors, and small pulse height analyzers. Therefore, completely portable EDXRF spectrometers are available that can be assembled on‐site, having the size of a book and a weight ranging from as light as 500 g (using a radioactive source) to a few kilograms (using an X‐ray tube). These spectrometers can be employed for on‐site analysis in various fields, such as works of art, alloys, soil, environmental samples, forensic medicine, paper, waster materials, mineral ores and their products, or anywhere a portable apparatus would be required.This paper reviews the present status of the development and application of EDXRF portable systems. The various components of a portable system are described: the radiation source, i.e. small, low‐power, dedicated X‐ray tubes or alternatively radioactive sources that emit X‐rays or low‐energy γ‐rays; and X‐ray detectors, i.e. scintillators, proportional gas counters and semiconductor detectors, with special emphasis on the recent thermoelectrically cooled X‐ray detectors: Si‐PIN (silicon positive–intrinsic– negative), Si‐strip and CZT (cadmium–zinc–telluride).Commercial systems are considered, and finally the most common and significant applications are described.