When Rebecca Lalk learned that earning her PhD in the Department of Materials Science and Engineering would give her a chance to conduct research at the University of Tennessee’s Scintillation Materials Research Center (SMRC), she knew UT was the clear choice.
“I am fascinated by the physics of light production,” said Lalk, who now works in Associate Professor Mariya Zhuravleva’s lab. “Researching scintillators not only aligns with my interest in optical materials but provides an exciting way to connect that scientific curiosity with practical, real-world applications.”
Three years into her PhD, Lalk has focused her research on rare earth aluminum garnet scintillators, which possess a unique combination of stability, efficiency, and versatility that makes them highly desirable in fields like medical imaging, nuclear security, and environmental monitoring.
Engineering Better Scintillators
Lalk is working to identify more efficient, stable, and durable scintillators that other researchers can scale up for use in real-world applications.
Aluminum garnet-based scintillators have an inherently robust crystal structure, which gives them long productive lifetimes and resistance to numerous environmental stressors. Lalk’s crystals also include small amounts of cerium, which produces a very bright light and has fast decay time.
Lately, Lalk has been investigating compositionally complex garnets, scintillators in which the garnet lattice contains an assortment of rare earth cations instead of just one. This type of compositional engineering could impact the interaction between charge carriers and electronic defect states, which can slow down a scintillator’s visible signals or reduce its light output.
“Understanding the location and distribution of electronic defect states, as well as how concentrations of different cations in the lattice affect energy transfer processes, lets us evaluate the extent to which changes in composition impact scintillation performance,” Lalk explained.
Lalk is passionate about her scintillator research and can see herself pursuing it further at a national laboratory after earning her PhD. She’s also open to exploring opportunities in nonproliferation policy.
“Ultimately, I hope to contribute to the development of technologies and strategies that enhance radiation protection and support efforts in national security and nonproliferation,” she said.
Balancing Lab and Life
Just as her scintillators include a balanced mix of cations, Lalk is sure to balance her work in the laboratory with self-care activities. She paints, plays multiple musical instruments, hikes, and recently started running on Knoxville’s many trails.
“Hiking and trail running are great ways for me to stay physically active while disconnecting from the demands of research,” she said, “and all my hobbies provide me valuable time to recharge and think creatively.”
Lalk also devotes much of her time to helping other engineers in the UT community. She mentors undergraduate engineering students through UT’s Society of Women Engineers (SWE), serves on the SMRC safety committee, and earned a 2024 Graduate Student Senate Award for Excellence in Service for her activities as the treasurer of the Materials Research Society at UT—an organization of which she is now president.
“While these activities aren’t directly related to my research, they contribute to my wellbeing,” said Lalk. “They are important for helping me clear my mind and gain fresh perspectives. They help me stay engaged, motivated, and balanced, allowing me to be my best self both in and out of the lab.”
Contact
Izzie Gall (865-974-7203, egall4@utk.edu)