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UT Arlington Ph.D. student honored for plutonium research

Tuesday, October 14, 2014

Media Contact: Traci Peterson

News Topics: awards, physics, research

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A UT Arlington student who began her studies through a National Science Foundation-funded program to increase underrepresented groups in the sciences recently was honored at an international conference of plutonium experts.

Sarah Hernandez

Sarah Hernandez

Sarah Hernandez presented her research on the stabilization of delta phase plutonium by the element gallium at the American Nuclear Society’s Plutonium Futures – The Science conference in September. She took home the prize for best poster presentation on plutonium materials.

In addition, she was lead author on a paper published this summer in the Journal of Physics: Condensed Matter.

“I never once dreamed I would be sitting here at this moment. When I won that award I felt like a celebrity,” said Hernandez, who has a bachelor’s degree from Texas Christian University and master’s degree from Miami University in Oxford, Ohio.

A figure from the paper was also selected as the front cover picture for the June 11, 2014 printed issue.

Hernandez enrolled in the Ph.D. program in UT Arlington’s Department of Physics in 2010 with the help of the UT Arlington Louis Stokes Alliance for Minority Participation Bridge to the Doctorate Fellowship, which provides up to $30,000 annual stipends for two years and intensive mentoring.  In the summer of 2011, she went on to win a prestigious Seaborg Institute Summer Research Fellowship at Los Alamos National Laboratory.

Hernandez said her interest in the plutonium-gallium system blossomed while at Los Alamos. She decided to examine it further with encouragement and support from Asok Ray, a UT Arlington physics professor who died in 2013. Besides its use in weapons, plutonium is a valuable source for fuel in scientific missions such as NASA’s Cassini spacecraft. 

“Plutonium is arguably the most complicated element in the periodic table and it is due to the behavior of its 5f electrons,” said Hernandez.  In the low temperature phases of plutonium, the 5f electrons roam around and strongly interact with each other within the material. In the high temperature phases, individual 5f electrons tend to stay by themselves with little or no interactions between them. This dual behavior is the origin of the chemical complexities of plutonium.

“The delta phase of plutonium exists at high temperatures but the addition of small amounts of gallium to it stabilizes it to room temperature and no one seems to fully understand why.  I want to know why?” Hernandez said.

The Los Alamos Laboratory Directed Research & Development (LDRD) program currently supports Hernandez’s research. She hopes to graduate in spring 2015 and continue her research at the post-doctoral level.

Raymond Atta-Fynn, one of two faculty members mentoring Hernandez, says her current success is due in large part to a strong combination of self-motivation and intellectual curiosity. Muhammad N. Huda, associate professor of physics at UT Arlington, also mentors Hernandez.   Her mentor at Los Alamos is Tom Venhaus.

 “Sarah works hard and is dedicated to her craft as a physicist,” said Atta-Fynn, who is a visiting assistant professor. “She’s also a source of inspiration to young women who are interested in science in general and physics in particular.”

About The University of Texas at Arlington

The University of Texas at Arlington is a comprehensive research institution and the second largest institution in The University of Texas System. The Chronicle of Higher Education ranked UT Arlington as the seventh fastest-growing public research university in 2013. U.S. News & World Report ranks UT Arlington fifth in the nation for undergraduate diversity. Visit to learn more. Follow #UTAdna on Twitter. 


The University of Texas at Arlington is an Equal Opportunity and Affirmative Action employer.