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Physics at the National Lab

Learning at the Speed of Light

Physicist involves students in research at national lab

Longwood physicist Tim Holmstrom and his students are conducting research at the same facility that draws leading scientists from around the country and the world.

The Thomas Jefferson National Accelerator Facility in Newport News, Va., is the only one of its kind in the world. One of 17 national laboratories funded by the U.S. Department of Energy, the lab's primary mission is research on the atom's nucleus. Hall A, where Holmstrom works, has collaborators from more than 70 institutions and 18 countries.

Holmstrom, assistant professor of physics, has collaborated on eight experiments over the last eight years at the facility. Six current or former Longwood students also have participated in the research since Holmstrom joined the Longwood faculty in 2008.

"Jefferson Lab is unique; no other lab does exactly what we do," said Holmstrom, whose field is experimental nuclear physics. "Nobody has an electron beam at our intensity and energy. Our advantage is this intensity, the number of electrons per second, which enables us to carry out experiments with high statistical precision.

"What we're looking at in these experiments is the structure of the neutron and the structure of the proton. The lab has an accelerator that accelerates electrons up to near the speed of light. We produce massive amounts of energy and use the electron as a probe, essentially as a giant microscope, to examine the neutrons and protons."

The accelerator, which is shaped like a racetrack and is seventh-eights of a mile long, directs an electron beam into one of three experimental halls, each located in a different part of the lab. Holmstrom collaborates on experiments in Hall A, the largest of the three staging areas.

As the electron beam makes up to five successive orbits, its energy is increased up to a maximum of six billion electron volts. The accelerator and all three halls are underground, to avoid any possible exposure to radiation (the walls of the accelerator tunnels are two feet thick), though the researchers and lab staff monitoring the experiments are aboveground.

Holmstrom has worked on two types of experiments: four experiments related to Helium-3 and four involving what is called parity. "The Helium-3 experiments are trying to understand the ‘strong force,' which holds the nucleus together and is one of the main focuses of the Jefferson Lab. All of these experiments are finished collecting data, and a number have published results. I am currently doing analysis on two of the experiments. Most of these experiments have 50 to 80 collaborators. On some experiments, I contributed a lot, and on some a little," he said.

Learn more about Longwood’s Chemistry and Physics program