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Idaho Accelerator Center leads the way in research and education

Enables uranium detection, safer mammograms, material failure prediction

In partnership with the INEEL, the State of Idaho, and Idaho State University, the Idaho Accelerator Center was created to advance accelerator applications research, teaching and industrial/governmental collaborations.

The pyramids rise from the rounded hills like a monument to some civilization, but not an ancient civilization. The Idaho Accelerator Center stands as a monument to the future.

At the Accelerator Center, the nature of physics is studied and solutions to global human problems - polluted soils, brain cancers, smuggled nuclear weapons, and aging and failing superstructures - are discovered and sent out into the world. Bright-eyed students and gray-headed researchers work side-by-side studying fundamental radiation science and developing practical accelerator applications.

Born of an alliance between the Idaho National Engineering and Environmental Laboratory and Idaho State University, the Accelerator Center acquires the strengths of both. From the university, the Accelerator Center takes basic nuclear research capabilities and the fresh ideas of students, led by seasoned researchers. From the INEEL, the Center takes nuclear engineering experience forged from 50 years of designing, building and testing reactors. Add to this an array of small accelerators not seen elsewhere in the world and the result is, according to Associate Director James Jones, a major, world-class research center.

Jones, an INEEL physicist, has worked with the Idaho Accelerator Center alliance since its inception in 1994 and has seen it continue to evolve through acquisition, expansion and imagination. In 1999, he was instrumental in bringing a one-of-a-kind, 30 million electron volt linear accelerator to the shining, new university facility built into the foothills just north of the university's main campus.

But even Jones is surprised by the versatility and capabilities of the Center. "It's much more extensive than I ever envisioned," says Jones. "I thought it would be more R and D, but instead it's very problem focused." Driven by the INEEL deliverable approach, students, faculty and INEEL researchers tackle challenging short-term projects. "A program manager comes to us and says 'can you do this?' and we get the students, faculty, engineers and scientists figuring out a way."

The Accelerator Center, however, owns another whole set of deliverables unlike any encountered by the INEEL. It is still an integral part of Idaho State University, and Director Frank Harmon and Jones never lose sight of student needs - education and diplomas. "The students get more than a great university education," says Jones. "They get unparalleled research opportunities and pragmatic problem-solving projects."

A description of the Idaho Accelerator Center is not a simple litany of the myriad accelerators and neutron generators housed within its confines, nor is it images of the architecturally stimulating headquarters. An accurate picture of the Idaho Accelerator Center must include at least some glimpses into the research enfolding there and the solutions created there. Here are just a few.

Foiling smugglers

It could have been taken from a chapter of a Tom Clancy thriller. A Frenchman and two cohorts were arrested in Paris trying to smuggle 80 percent-enriched uranium out of the country. They encased a glass vial in a lead cylinder and transported the package in a mundane delivery van. Fortunately, they were caught.

Investigators believe they stymied the delivery of a sample to potential buyers. Even with this arrest, customs service officials are worried. Who isn't caught? How much weapons grade uranium is being smuggled around the globe?

Certain types of radioactive materials, like medical, commercial and research isotopes are legal and transported every day. Smugglers attempt to shield illegal materials with lead and plastics.

To make matters worse, 70 percent of manufactured goods are imported/exported in gigantic 40-foot cargo containers, an easy place to bury a wrapped and shielded package.

Jones and a team of researchers have proposed a solution. They use a pulsing electron accelerator to produce high-energy photons and aim them at a target. The energetic photons penetrate the target and stimulate photonuclear processes within the inspected object. The neutrons that result from this process are detected between each accelerator pulse and are used to identify any nuclear materials inside - whether shielded or not.

But to differentiate between legally shipped medical or commercial isotopes and perhaps terrorist-bound uranium, Jones shoots two different beam energies (from the same accelerator) at the target and analyzes the ratio of neutron counts that result.

Initial tests have successfully identified several types of nuclear material in various shielding configurations. Jones is conducting additional research in differentiating nuclear materials using a specialized photoneutron source that will preferentially induce neutrons in only highly enriched uranium. He sees the next steps as incorporating these active interrogation methods into existing inspection systems.

X-ray vision - Accelerator superpowers

Moving from international borders to those closer to home, accelerator applications are supporting the INEEL's signature research focus, subsurface science.

Elements migrate through the subterranean labyrinth of rock and aquifer. How, at what speeds, and in which direction are just three of the innumerable questions scientists at the Laboratory are trying to answer. Theories and models are tested against samples taken from the subsurface. The sampling is meticulous and laborious. Accelerators might make it just a little easier.

Nowadays, scientists draw long columns of soil into the light, remove the material, and transport it to a lab for testing. Researchers at the Accelerator Center have developed a new nondestructive technique, called accelerator X-ray fluorescence or XRF, to identify potentially migrating elements like lead, mercury or plutonium. They do this within the bulk sample, without removing the soil from the columns.

The tiny accelerator, not much longer than a clarinet, creates penetrating X-rays. But instead of seeing through the material, atomic fluorescence is produced by the process and is measured. Simultaneously, a germanium detector picks up the decaying positrons.

The combination of these subatomic processes has allowed the researchers to detect heavy metals in bulk media of soil and sand in parts-per-million. The post-doc and ISU student working on this Inland Northwest Research Alliance-funded project are seeing just how far they can push the technique. Right now, XRF easily penetrates the soil columns. Can it assay a 55-gallon drum? More research will bring more answers.

Making waves

Moving from the subsurface to the subcutaneous, another accelerator application may make mammograms safer and clearer.

Conventional X-rays are generated with up to about 80 kilovolts of energy and subject patients to a small amount of radiation. That's how the image is made. So annual mammograms and dental X-rays all add up to a small dose. What if you could cut that dose in half while dramatically enhancing the X-ray image? Could you spot a tumor sooner?

These are the questions and the problem that another team of researchers are working on, but this time, using not just an accelerator but a laser, too.

Waves of energy emit colors, some visible to the human eye, some not. The higher the energy, the shorter the wavelength, the less visible the color. But it's still there. Accelerators and lasers emit energy of certain wavelengths. Laser light - think of a laser pointer - is just on the edge of visible.

When the waves of energy from a laser crash into the waves of electron energy from an accelerator, they convert the light to a new wavelength, a new color. This inelastic collision is likened to a baseball player hitting a ball. Lots of energy is released. And some of it is released as X-rays. This process, called Compton Backscattering, generates very clear X-rays in the 1- to 50-kilovolt range.

Creating this effect is not as simple as hitting that baseball. The laser pulses at 10 nanoseconds and the electrons from the accelerator pulse at 30 picoseconds or 3/10,000th of a microsecond. The collision must occur dead on, at exactly the right time. A hair right or left, a picosecond behind and only "jitters" are produced.

A "positron" influence

No industry wants to pay the cost of unpredicted material failure - in money, in downtime or in human life. To avoid failures and stay safe, many industries replace expensive parts well before the end of their productive life. A new INEEL process will not only predict material failure, it can determine remaining useful life, saving money and extending uninterrupted operation for critical components such as those used in airplanes, bridges and utilities.

A team of scientists is producing positrons with electron linear accelerators and using them to detect and measure subatomic structural defects. In July, Positron Systems, Inc., of Boise, Idaho, licensed the technology for commercial applications.

Scientists point a portable linear accelerator - similar to those systems used in cancer therapies - at a steel bridge support, an airplane wing spar or a plastic valve used in a human heart and shoot a beam of accelerator-produced, energetic photons at the material.

This process produces short-lived radiation in the material and gives off positrons - electrons with a positive charge. Positrons are attracted to the nano-sized defects of the material and as they decay, release their energy as unique gamma rays. The energy spectrum of the gamma rays creates a distinct and readable signature of the size, quantity and type of the defect.

Not satisfied with leaving well enough alone, researchers at the Accelerator Center are investigating another positron inspection process that uses photons produced from lower energy electron accelerators which completely avoids producing any short-lived radiation in the inspected material.

Using these processes, engineers could determine how long aircraft wings can be used, and bridge supports will stand. Medical manufacturers could confirm the quality of valves before doctors implant them into patients.



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