A team of scientists from the Institute of Nuclear Chemistry at Johannes Gutenberg University Mainz, Germany has analyzed glass beads found in former Rhaetian settlements in Bavaria, and concluded that the beads, dating from the 1st through 4th centuries, must have originated "somewhere near a soda lake like those in Wadi El Natrun in Egypt." (photo)
The beads were found during excavations of a "cult site" near Oberammergau. The scientists used radiation to analyze the glass.
With the help of a technique called neutron activation analysis (NAA), it proved possible to identify the various elements present in the beads from Oberammergau and the other sites at Heimstätten, Auerberg, and Neubiberg. The technique involved exposing the specimens to radiation in the TRIGA research reactor. When bombarded by neutrons, the atomic nuclei of the material under investigation initially become unstable. As they return to their normal state, the nuclei emit characteristic gamma radiation that has a unique profile for each element and can thus be used for identification. "TRIGA as a radiation facility offers the ideal conditions for obtaining a chemical fingerprint of specimens by completely non-destructive means," stated Dr. Gabriele Hampel, operations manager of the research reactor.