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DOE Physicists at Work
Profiles of representative DOE-sponsored physicists
doing research at universities and national laboratories
Compiled by the Office of Scientific and Technical Information
Dr. Peter Beiersdorfer
It was just a simple iron wire, strung across the ceiling, that when heated by a current expanded and dropped lower. But that wire, along with a professor willing to take a different approach, confirmed in Peter Beiersdorfer's mind that experimental physics was the way to go.
"When trying to decide what field to study after high school, I simply faced too many possibilities," says Dr. Beiersdorfer, group leader of the Radiative Properties Group at Lawrence Livermore National Laboratory's High Temperature and Astrophysics Division. The choice became clear when his German high school took a field trip to Darmstadt University. The professors in chemistry, mathematics, philosophy, and psychology detailed for the young students how long graduate school would take, what courses would be required, and what jobs might be available. "But the professor in physics took a different approach," says Dr. Beiersdorfer, who was born in California, then spent most of his early school years in Germany. "He performed live experiments in the lecture hall."
One of the experiments entailed that iron wire, expanding and dropping when heated. "When the current was turned off, the wire contracted," says Dr. Beiersdorfer. "But before it went to its original position, it surprised everyone and expanded again - a phase transition," the professor explained. "That really caught my fancy."
Beiersdorfer's mind was made up. He wanted to study physics. "Physics is the key to understanding the world we live in because any speculation about how the world works can be rigorously tested and proven or refuted by experiment."
His fascination with experimental physics started in earnest as an undergraduate at Auburn University. "Professor Gene Clothiaux really got me started in experimental physics," says Dr. Beiersdorfer, who worked on magnetic field measurements and x-ray timing experiments on a vacuum spark plasma while at Auburn.
In graduate school at Princeton, Dr. Beiersdorfer built particle energy analyzers and x-ray spectrometers for use with the tokamaks at the Princeton Plasma Physics Laboratory. For his thesis he built diagnostics to study heavy-ion impurities in the Princeton Large Torus (PLT), tokamak working with Schwick von Goeler and Manfred Bitter. Introducing exotic elements such as gadolinium, europium, and ytterbium into PLT plasmas, he held the record for looking at the highest charged ions in a magnetic fusion plasma.
After graduate school Beiersdorfer joined the electron beam ion trap (EBIT) group at the Lawrence Livermore National Laboratory. "EBIT produces a plasma of ions of any element imaginable by using a magnetically focused electron beam," says Dr. Beiersdorfer. The machine now holds the record for making ions as high as Cf96+ (californium with all but two electrons removed) in a plasma device. Dr. Beiersdorfer built spectrometers to study EBIT plasmas, test x-ray laser schemes, and calibrate and develop spectral diagnostics. His work spilled over into testing the fundamental forces of nature. "With this device and the right diagnostics we were able to perform tests of quantum electrodynamics in the strong electric fields of heavy nuclei, such as uranium, with a better precision than anyone else could do," says Dr. Beiersdorfer. "In fact, this plasma device has outdone even the most powerful heavy-ion accelerators by more than an order of magnitude in precision."
His fascination with physics, especially with experimental physics, continues unabatedly, and he finds the time for hands-on experiments. His diagnostics have found homes on the National Spherical Torus Experiment (NSTX) at Princeton, the Compact Torus Injection Experiment at Livermore, and the Alcator tokamak at Massachusetts Institute of Technology. "It's rewarding to be able to help different projects succeed," says Dr. Beiersdorfer.
It is also exciting. At NSTX, Beiersdorfer uses tokamak plasmas to learn about stellar coronae and x-ray emission from comets. "Fusion is about bringing the energy of the stars to earth. But these terrestrial plasmas can also teach us a lot about the stars. There is always something new to study. We live in an era of tremendous breakthrough and insight, and it's fantastic to live in the middle of it and contribute to it."
Dr. Peter Beiersdorfer's articles accessed via OSTI: