Chris Conolly looks at the concrete floor of Wilson Lab, eyeing up the numerous holes drilled by one of the contractors for the upgrade project. These one-inch holes pockmark the 10,000sf experimental hall of the Wilson Synchrotron Laboratory. In a way, these holes represent the numerous experiments conducted over the past 50 years.

The morning session consisted of lecture-style presentations delivered by Arthur Woll, covering theoretical background and practical considerations regarding XRF signal generation, x-ray detection, and data analysis. For the afternoon portion, Louisa Smieska led a hands-on demonstration of the GeoPIXE software used with the CHESS Maia detector.

For the past year, Louisa has been working with X-ray fluorescence to scan manuscripts from the Johnson Museum, mining deposits from deep below earth, and other samples to train users on the benefits of using the high energy x-rays at CHESS to peer inside, or through their samples.

Louisa Smieska and Ruth Mullet were surprised to find barium in the azurite blues of medieval illuminated manuscript pages. Azurite, a soft, deep blue copper mineral produced by weathering of copper ore deposits, has been recognized since ancient time. However, the trace element barium is more often associated with modern paints, and, according to the researchers, has never been reported in illuminated manuscripts before.

This was the year his “Blue Period” began, and remains a time of great interest to art historians and enthusiasts alike. Technical analysis of paintings made during this period are one approach to finding clues into as-yet understood aspects of Picasso’s experience and process. The recent discovery of a buried portrait below one of his first blue period paintings, “The Blue Room,” (The Phillips Collection, 1600 21st St NW, Washington DC) offers an example of two paintings, each by Picasso, that represent snapshots of this transition.

However, one of main properties of x-rays that makes them powerful -- their high penetrating power – also limits the scope of application of this imaging technique. In particular, imaging thick or heterogeneous samples at the micron scale generally requires that the sample be thinned, which is often impractical or impossible.

The origins of the trace elements observed by SXRF in inscribed regions are unclear, but are speculated being derived from the tools and paints used in the original inscriptions. Although SXRF is effective for naturally worn surfaces, the measurement has also been complicated by object surface curvature or relief, such as incised letters.

Louisa Smieska and Ruth Mullett studied manuscript pages from Cornell University Library’s Division of Rare and Manuscript Collections (RMC), dating from the 13th to the 16th centuries, using X-ray fluorescence (XRF) and spectral imaging analysis.

“Our initial goal was to learn more about Cornell’s fragments and about trends in pigment use,” said Mullett, a medieval studies doctoral student. “An initial survey using a portable point XRF [p-XRF] instrument uncovered several things we weren’t expecting.”