Northern Illinois University

NIU Office of Public Affairs

News Release

Contact: Tom Parisi, Office of Public Affairs
(815) 753-3635

October 7, 2004

Research of NIU astrophysicist has sponsors beaming

DeKalb, Ill. — Technology being developed in the laboratory of NIU Physicist Court Bohn might someday help U.S. Navy fleets defend themselves against cruise missiles. Then again, it could also help keep your sandwich fresh.

Bohn, who holds a Ph.D. in astrophysics from the University of Chicago, has dedicated the past 16 years of his career to understanding the dynamics of electron beams created by high tech particle accelerators.

The extensive astrophysics background actually meshes quite nicely with Bohn’s study of tiny particles. He discovered some years ago that the intense accelerator-driven beams evolve in much the same way as galaxies and now is developing mathematical techniques that explain the forces at work in both systems. The research is attracting the attention of some high powered sponsors.

In recent months, Bohn received grants totaling nearly $1 million from the U.S. Department of Defense and the Department of Energy. For the military, his research group is creating simulation tools and software needed for the development of high powered lasers that could help Navy fleets respond at the speed of light to cruise missile attacks.

"You don’t have much time, so you need the speed of light," says Bohn, a former officer in the U.S. Air Force, where he directed laser and accelerator programs. (High powered lasers extract their light from accelerator beams.)

Before coming to NIU in 2002, Bohn also worked as a physicist at the Thomas Jefferson National Accelerator Facility in Virginia, Argonne National Laboratory and Fermi National Accelerator Laboratory. He currently holds a joint position at Fermilab and NIU and directs a research group of three NIU postdoctoral students. Two hold Ph.D.s in astrophysics.

"What we’re developing now is a completely new technique for simulating intense charged-particle beams," Bohn says. "We’ll benchmark these simulation tools against real experiments performed in accelerators at Fermilab. Ultimately, our computerized models will allow for quicker improvement and expansion of laser technologies."

The simulations require newly developed algorithms that must explain both how galaxies evolve and how intense beams degrade. "A high-brightness beam typically is comprised of trains of bunches, with each bunch containing 10 billion to 100 billion particles. That’s comparable to the number of stars in a large galaxy—and it’s no coincidence," Bohn says.

"We now know that beam dynamics parallel that of large galaxies," he adds. "So our research encompasses a totally new and important aspect of laboratory astrophysics in which beams are analogous to large stellar systems, for which experiments are otherwise impossible."

The research into beam dynamics could lead to scientific studies of new applications for intense laser probes. Lasers can be used by manufacturers to modify the surface of a wide variety of materials. For instance, fabrics such as polyester can be made to look and feel like silk; clear plastic wrap used for sandwiches can be modified to be bacteria resistant.

"Industries would use such lasers to process materials in bulk quantities," Bohn says. "What’s needed is a very intense electron beam to produce a high powered laser that could be spread out to cover a broad area and rapidly process large quantities of material. Generating intense electron beams is challenging because the electrons repel each other and want to fly apart. The thrust of our research is to understand in detail how to focus the beam and preserve its quality."

Unlike electrons, stars in a galaxy attract each other. But the force between two stars is inversely proportional to the square of their separation, and this is also true for the force between two electrons.

"So a focused beam evolves similarly to a galaxy," Bohn says. "This means what we learn about intense electron beams generated in a lab will tell us much about our universe."