Nuclear Approach May Help Climate Researchers Pinpoint Volcanic Eruptions

Nuclear Approach May Help Climate Researchers Pinpoint Volcanic Eruptions: "Source: Penn State
Date: 2005-05-25
URL: http://www.sciencedaily.com/releases/2005/05/050525104903.htm
Nuclear Approach May Help Climate Researchers Pinpoint Volcanic Eruptions

There's gold in them thar rings. Tree rings that is, and Penn State researchers are using the Breazeale Nuclear Reactor to measure gold and link the rings to volcanic eruptions.

'Initially, when we began this work at Cornell University, we were simply looking to see what elements in tree rings could be measured using neutron activation analysis,' says Dr. Kenan Unlu, professor of nuclear engineering and associate director for research of Penn State's Radiation Science and Engineering Center. 'We can see a lot of elements, but it is easy to see the gold peak.'

When Peter I. Kuniholm, professor of archaeology and dendrochronology and director of the Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology at Cornell, saw which tree rings held the highest gold levels, he quickly recognized that they dated to years of known volcanic eruptions.

Because trees add a ring a year to their trunks, if researchers know the cutting date of a tree or can calibrate the tree's rings against a previously dated tree, researchers can assign each ring accurately to a specific year. By isolated wood from just one ring, neutron activation analysis can measure the gold that the tree took up during that year with parts per billion sensitivity.

Neutron activation analysis uses the neutrons produced by a nuclear reactor to create temporary radioactive isotopes in a sample. Because each isotope has its own gamma radiation signal, the gamma radiation signal strength indicates the amount of that element present.

When Cornell's nuclear reactor at the Ward Center for Nuclear Sciences was shut down, Unlu moved the project, which was funded in part by the National Science Foundation, to Pe"