Portable Systems for Energy‐Dispersive X ‐Ray Fluorescence Analysis

Abstract

Abstract Portable energy‐dispersive X‐ray fluorescence (EDXRF) spectrometers are very useful and popular in many fields for the on‐site analysis of elements because EDXRF is a nondestructive, multielemental, and inexpensive technique that is extremely well suited for the analysis of inorganic materials. 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, with the size of a book and a weight that is as light as 300 g (using an X‐ray tube) or less (using a radioactive source). These spectrometers can be employed for on‐site analysis in various fields, such as works of art, alloys, soil, environmental samples, forensic medicine, paper, waste materials, mineral ores and their products, or anywhere a portable apparatus would be required. This article reviews the present status of the development and application of portable EDXRF systems. The various components of a portable system are described, including 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. semiconductor detectors, with a special emphasis on the more recent thermoelectrically cooled X‐ray detectors (Si‐Positive–Intrinsic–Negative [Si‐PIN], Si‐drift detector (SDD), CdTe, HgI 2 , and others). Commercial systems are considered, and the most common and significant applications are described, with particular emphasis on the analysis of works of art.