Imagine a machine that could generate enough information from analyzing mud from car tires to tell where the car had previously been. Imagine a machine that could help researchers figure out when and where ancient pottery and ceramics were produced.
USM is now the home of just such a machine. It’s called an “X-ray Powder Diffractometer,” and it arrived on the Gorham campus on April 2.
The machine will greatly influence the capability of USM faculty and students to do research and training. In fact, a team led by Cindy Henry, a junior geoscience major, will begin work soon on a project having to do with analyzing pottery and mangrove swamp clays found in the Caribbean.
According to Steve Pollock, chair of the Department of Geosciences, the uses of the machine are very broad.
“Some people like to think this is just a tool for geology,” said Pollock, “but it’s much broader than that.” The machine is “a tool for identification and characterization of solids.”
The machine can identify over 15,000 solids including metal alloys, explosives, archaeological stone artifacts, pottery, and ceramics, modern ceramics, alloys, pigments, synthetic chemicals, minerals, and rocks, Pollock said.
“This just ain’t your grandparents’ ‘model-t’ mineral identifier,” Pollock said.
The machine analyzes solids that are turned into powder through various steps beginning with a sledgehammer, then rock crusher, small ball mill and finally an agate mortar and pestle. Once the sample is ready, it is put into a circular plastic disc holder which is inserted into a long, slim tray that holds up to nine samples at once. The tray slides along a track until the sample reaches the examination point.
X-rays from a tube on the left diffract, or bend, off of the sample, and into a “scintillation” tube on the right. The scintillation tube picks up the X-rays and transforms them into an electric signal that is processed by a nearby computer.
The diffraction isn’t visible to the human eye because X-ray wavelengths fall outside the visible light range. Each sample can take up to an hour to be analyzed by the machine. Then, the composition of the sample can be printed in chart format from the computer.
The results are represented on the chart with peaks. If the sample is a mixture, the substance found in greatest proportion is represented by the strongest peaks. Strong peaks also mean the sample has a high density.
This may sound like a minimal amount of machinery, but including its protective case, the X-ray Powder Diffractometer weighs in at almost 1,200 pounds. The actual instrument sits inside a case with glass doors, on a metal cabinet. The weight is mostly due to the lead shielding the instrument and the glass. With the shielding present, no protective wear needs to be worn in the room while the machine is running. Pollock said that if the glass doors or the cabinet are opened during operation, the machine will automatically shut off.
The weight was a problem when getting the machine into Bailey Hall. Originally, the machine was supposed to go in Bailey 216 near the 1957 model. However, because of its weight, it had to go on the ground level.
Also, because the protective crates that it was shipped in from Germany made the machine much larger than the actual unit, it had to be brought in through the ground level handicap entrance and up the elevator. Then, workers had to take the crates and some of the machine’s panels off to fit it into Bailey 14A.
Pollock and his colleagues are very excited about the opportunities that lie ahead.
“A machine like this expands the research capabilities’ horizons,” Pollock said.
In January of 2001 Pollock and two of his colleagues wrote a proposal to the Major Research Instrumentation Program, part of the National Science Foundation, asking for the machine. They received notification last July that they had been awarded an external grant for $122,000, and USM supplemented this with $8,600. Pollock believes that they were awarded the grant due to the fact that they were able to show the National Science Foundation that the machine could be used here at USM across disciplines.
Staff Writer Natalie Frye can be contacted at [email protected]