CURRENT STATE-OF-THE-ART IN PORTABLE X-RAY ANALYZERS AND THEIR APPLICATION FOR NONDESTRUCTIVE INVESTIGATION OF OBJECTS OF ART AND CULTURAL HERITAGE

摘要

The first portable XRF analyzers were built in the mid sixties of the past century, when small radioisotope sources became commercially available. The momentum behind the design of the first portable instrument were the needs of geological prospecting. However, these first attempts were not successful due to many technological limitations. A major change took place in the early nineties, with the advent of powerful microprocessor chips. Development of electro-thermally cooled semiconductor detectors was another breakthrough that made the design of the first ever hand-held analyzer feasible. The last few years brought us miniature, low power x-ray sources to replace the radioisotopes traditionally used in portable x-ray analyzers. This latest development resulted in the design of a hand-held, lightweight (1.5 kg), tube excited XRF analyzer with analytical performance rivaling that of many bench-top and laboratory systems. In this paper we report on the current state-of-the-art in the design of portable XRF analyzers, and discuss their performance in typical applications such as alloy analysis. Since these analyzers are designed for field and harsh environment use, they are exceptionally well suited for requirements of an archeologist who - for example - can take it for an on-site inspection of hard to transport objects. Another practical example of the use is on-site testing the authenticity of print or inspection of an object of art such as bronze sculpture, before making purchase decision. These and other examples of practical applications will be described to illustrate the wide range of possibilities offered by portable XRF analyzers in testing and diagnostics of objects of cultural heritage. Truly portable XRF analyzers are an excellent complement to the less mobile, transportable, micro focused x-ray tube based systems designed for microscopic investigations of objects of art.