ECU accelerator used to trace pirates and more
(July 29, 1999)
When it comes to the study of old artifacts, new tools evolve slowly, but one that is making a name for itself can be found at the East Carolina University Department of Physics.
It's a tandem Van Der Graaf accelerator and there is nothing new about it except in the way it is being used to study such things as medicine, the environment, sea creatures, ancient cultures and even Blackbeard the pirate.
"We still use it to do basic physics research," said Dr. Larry Toburen, director of the Physics Accelerator Laboratory, "but over the last three years we have begun to develop the analytic type of studies that contribute to the research in a number of other departments."
When the state department of Cultural Resources called about using the accelerator -- the only one in the state -- to examine 50 artifacts from mostly Native American sites, the lab was more than happy to oblige. And one of the artifacts turned out to be a thin piece of copper removed from beneath the barrel of a cannon that was recovered from a shipwreck near Beaufort that that may have belonged to the pirate Edward Teach, better known Blackbeard.
The shipwreck is believed to be the Queen Anne's Revenge that sank in 1718. The wreck was discovered about three years ago, but so far, the remains at the wreck site have not been positively identified.
While the physicists have no way of proving that the artifact is from Blackbeard's ship, they can use their accelerator to find out some other things about it. The accelerator enables them to perform a proton induced x-ray emissions (PIXE) analysis of the artifact to learn what went into the making of the metal itself. It's done like this. The metal artifact is placed in a vacuum container, a 10-gallon aluminum barrel covered with portholes and blasted with a beam of accelerated protons that cause the atoms in the different elements in the metal to fly off in a scattering of X-rays.
The X-rays, produced by elements such as iron, copper, arsenic and antimony, are measured to show the parts per million. The artifact suffers no damage in the process. One of the things that the physicists have noticed is that the shipwreck artifact contains a high amount of arsenic.
The early Native American copper tested at the lab contains no arsenic. Does this help the physicists identify the shipwreck? "No!" said Toburen. But he said the information might be useful to the historians who have researched the making of metal in Europe and other places. He said the historians will assemble the clues and try to put them into proper relationships.
"It will be an advantage if we can make this work in a way where the trace element signatures can indicate where the items come from," he said. The trace element signatures could help the archaeologists track such things as trade route and possibly the areas where the metal ores were mined. The physics lab uses the accelerator in research projects involving several ECU departments. Geology has a graduate student using the machine to look at mineral samples. Medicine uses it to examine the trace elements in the blood of cancer patients. Biologists study the elements in fish bones and archaeologists continue to look at copper and pottery shards from prehistoric Native American sites.
"We want to make it an active part of university life," said Toburen. "In today's funding and research environment, the multi-disciplinary projects have a much higher probability of being funded." "And besides," he said, "from my point of view it is interesting to find out more ways to apply physics to other disciplines."