2009 JSA Postdoctoral Research Fellowship Awarded

Patricia Solvignon
Argonne National Lab Postdoc
2009 JSA Postdoctoral Research Fellowship Recipient

The Jefferson Lab Users Group Board of Directors selected Patricia Solvignon as the winner of the 2009 JSA Postdoctoral Research Fellowship. Solvignon is a postdoctoral appointee at Argonne National Lab.

Fellowship applicants were judged on their records of accomplishment in physics, proposed uses of the research grant in a high-impact physics program and the likelihood of further accomplishments in the Jefferson Lab research fields.

"It is a pleasure that we have many excellent postdocs working on Jefferson Lab physics, even though it makes our job of evaluating them difficult," said Ron Gilman, board chairman and a professor at Rutgers University. "They were all very good, so it was hard work for us to select a single, best individual."

JSA President and Jefferson Lab Director Hugh Montgomery congratulated the winner, adding, "Patricia is a worthy recipient and an outstanding young physicist. The grant continues our commitment to providing the next generation of scientists with challenging and rewarding research opportunities, which ultimately benefits all of society."

Although Solvignon represents postdoctoral researcher interests on the board, she was not privy to fellowship deliberations. "It was a big surprise, and I was very happy to get it. I'm fortunate that I work with people who are very supportive, and in particular, John Arrington, my supervisor," she said. "I'm honored to receive the fellowship."

Solvignon has a broad range of interests. For example, she is lead author on a recent publication concerning the spin of the neutron, and she continues to work in this field. She is also investigating how the distributions of quarks in protons and neutrons (nucleons) are changed when the nucleon is put into a nucleus, through what is called the EMC effect, named after the collaboration to first discover it.

In addition, Solvignon studies how correlations between nucleons within a nucleus lead to these nucleons having high momentum, several times as much as one would expect if there were no correlations. "We are looking at how the nuclear force is working between protons and neutrons inside the nucleus," she explained.

It is this last experiment that will benefit in particular from the $10,000 fellowship research grant. The grant will go toward the purchase of a stainless steel vacuum glove box for handling calcium-48.

Planned for use as a target material in the experiment, this rare calcium isotope oxidizes when exposed to air. "To prepare it for the experiment, we need to put it into a vacuum glove box that is very good at keeping oxygen out. We can not do the experiment without the box," Solvignon said.

Due to its rarity, calcium-48 is expensive, at about $150,000 per gram. By purchasing and using the specialized box, she and her colleagues can borrow a sample of calcium-48 and return it after the experiment is completed, saving more than $100,000 in costs for the experiment. "Jefferson Lab will not have to pay as much at this difficult budgetary time," Solvignon added.

Approved at the 2008 meeting of the Program Advisory Committee, PAC 33, the experiment is scheduled to run in 2011 in Hall A. One part of the experiment is aimed at revealing how the intrinsic spin of nucleons and their constituents plays a role in short-range correlations.

"What we want to look at is the isospin dependence of short-range correlations," Solvignon said.

In previous experiments, additional nuclear effects clouded measurements of this particular property. Solvignon and her colleagues hope to get a better measurement by comparing the results they get using calcium-48 versus another isotope of calcium to be used in the experiment, calcium-40.

"A lot of these effects cancel in the ratio, so we should have a cleaner measurement," Solvignon explained. In addition, calcium-48 contains more neutrons in its nucleus than more common isotopes of calcium. "With more neutrons, you should get more reactions."

The goal is a better understanding of the different interactions that take place between proton-proton, neutron-neutron, and proton-neutron pairs in the nucleus.

The JSA Postdoctoral Research Fellowship was initiated by the Users Group Board of Directors. The research grant is provided by Jefferson Science Associates, LLC, through the JSA Initiatives Fund.