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In this artist's rendering, the Mars Rover scouts the planet with a Raman spectrometer out front, identifying minerals. UA researchers are currently developing mineral profiles that can be loaded onto the device.
Jeffry scott / Arizona Daily Star
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Nation

UA mineral-ID device bound for space

By Susan Bonicillo
Arizona Daily Star
Tucson, Arizona | Published: 04.17.2006
Science fiction is on the verge of becoming reality as part of work being done at the University of Arizona.
UA researchers are working toward developing their own "tricorder," like the fictional device of "Star Trek" fame that could identify the chemical composition of a mineral simply by "scanning" it.
Commissioned by NASA, the UA device will be used on the Mars Rover 2009 mission.
The device first must be programmed to recognize the chemical composition of all known minerals.
Robert Downs, a UA professor of geosciences, is working on cataloging all 4,000 known minerals. Assisted by a team of undergraduate and postgraduate students, he has about 1,300 officially in the database.
The cataloging project is funded by the founding president of Apple computers, Michael Scott. The project, called RRUFF, is named after his cat.
Working with the UA group, Caltech in Pasadena, Calif., is assisting with the technical and engineering aspects of the device.
"They have more instruments, but they don't have the personnel that we do," Downs said of Caltech. "We have 31 people working with about 20 to 25 undergraduates."
The goal for the UA is to accurately identify the chemical signature of minerals, a process that can take up to a month for a single mineral sample using methods such as X-ray powder diffraction and electron microprobe analysis.
Once all the information on mineral composition is recorded, all that will remain is to complete the device itself.
"Part of the NASA obligation was to create this instrument with over-the-counter parts so anyone can make them," Downs said.
Though the device on the Mars Rover will operate on a retractable robotic arm, the team is also developing a hand-held version powered by 3 AA batteries.
The mineral database will be stored on a single computer chip in a device that is projected to be about the size of a handgun. Research partner and UA chemistry professor M. Bonner Denton is in charge of the device's construction.
The mineral database will serve as a library that can be searched against a test sample.
Rather than harsher techniques where minerals are ground into powder for identification, Downs hopes to let Raman spectroscopy do the work.
This technique is based on the Raman effect. When light hits a molecule, the refracted light will reflect at the same energy level. However, a small fraction of light will radiate at a different frequency. That frequency is an analog for the chemical bonds of the sample and is unique for each substance, serving as a sort of chemical fingerprint.
The first part of the project lies in analyzing samples through traditional, though time-consuming, methods. After the data are recorded, Raman spectroscopy is used to get a reading verifying the chemical composition with the other method's results. The difference is that the Raman spectroscopy gives a complete analysis in a matter of seconds, while traditional methods can take weeks, Downs said.
Some materials are unable to give off a Raman reading, Downs said. Cubic metals (like gold and platinum) and rock salts give off a signal that cancels out any possible reading from the Raman effect. These only account for about 200 of the known minerals, but they will also be recorded in the database.
"Knowing that they are flat is meaningful because it can only be one of 200 things," Downs said.
Potential applications for the device are not limited to rock samples. Organic materials can be identified as well.
In medical field tests, bacterial infection or abnormalities like cancer could be identified quickly rather than waiting days for laboratory analysis, Downs said.
● Contact NASA Space Grant intern Susan Bonicillo at 307-0815 or at sbonicil@ azstarnet.com.