Few would have guessed that huge particle accelerators would today be some of the most promising new tools in art history and archaeology! Fueling these new investigations are the copious x-rays produced by particle accelerators that power new types of “microscopes” to record detailed images of chemical and atomic composition - all without damaging or altering precious historical artifacts.
X-ray techniques can be applied to discover details about art and artifacts, otherwise invisible to the human eye, such as ancient inscriptions in two-thousand year old stone tablets have mostly eroded away due weathering. Elements like iron and lead, which were buried in the stone during chiseling, carving and subsequent painting, can be detected. Other researchers have begun projects at CHESS to analyze slices of trees, which can hold clues to atmospheric conditions present when they grew, and to characterize Native American ornamental stone artifacts to learn about trade routes and quarry practices during early periods of USA colonization.
When high-energy x-rays hit an object, the atoms in the material create “fluorescence” and give off light. The colors of this light, or its wavelength spectrum, are unique to the particular atoms being struck. In this way x-ray fluorescence (XRF) has proven itself a versatile tool to “fingerprint” materials. Collaborators from numerous museums have ongoing projects to uncover mysteries in painting held in their collections. The facilities at CHESS allow scientists to hold specimens, and translate them through x-ray beams, all while analyzing the XRF light to identify elemental composition. Both the x-ray beams and the XRF light travel easily through dense materials, so XRF can serve as both a surface and a bulk analysis tool. Once a yardstick only used by physicists, chemists and materials scientists, synchrotron x-ray facilities now have easy-to-use XRF microscopes for new customers, such art historians and archaeologists, along with many others.