CLEMSON — Luiz Jacobsohn of Clemson University said that his research into “electronic traps” could mean that patients would be exposed to less radiation when they go to the doctor for certain tests and treatments.

Jacobsohn, an assistant professor of materials science and engineering, is doing his research as part of a $546,243 award he has received through the National Science Foundation’s Faculty Early Career Development Program.

Luiz Jacobsohn works in a lab in Olin Hall at Clemson University.

Luiz Jacobsohn works in a lab in Olin Hall at Clemson University.

It’s commonly called the NSF CAREER award and is one of the nation’s most prestigious honors for junior faculty members.

“I feel very honored,” he said. “I see it as recognition of my work in this field, so I’m really happy.”

Jacobsohn’s work will be aimed at making scintillators and dosimeters work more efficiently. Both devices detect ionizing radiation but do it in different ways and have different practical uses.

Scintillators are used in medical equipment, including those that do PET and CT scans, and in security devices that help search for nuclear weapons. Dosimeters measure radiation exposure over time and are typically worn by X-ray technicians and others who work with radiation.

To understand how Jacobsohn plans to improve scintillators and dosimeters, it helps to understand how the material inside them works.

When an X-ray or gamma ray hits the material, it liberates a bunch of electrons. The electrons, in a scintillator, recombine and immediately emit light. In a dosimeter, the electrons are caught in electronic traps, and those electrons are later measured to tell the radiation dose.

Jacobsohn said that by honing his research on electronic traps, it could be possible to improve both scintillators and dosimeters.

Scintillators work more efficiently when traps are removed, because fewer electrons get caught up and are free to recombine. That enhances their light output.

Better scintillators could mean medical patients would be exposed to less radiation when they go for certain tests and treatments, Jacobsohn said.

“By increasing the quality of the detector through a better scintillator, you can decrease the amount of radiation a patient has to go through in CT scans,” he said. “You can improve accuracy of radiotherapy as well because you know precisely how much radiation is needed.”

Making dosimeters work better requires just the opposite of what it takes to make scintillators better. In dosimeters, the traps should capture electrons more effectively, Jacobsohn said.

Researchers are now very limited in controlling electronic traps, he said.

“In effect, the discovery of any new scintillator or dosimeter is by chance,” Jacobsohn said.  “You’re guided by previous results and you try to make small modifications in the hope of achieving a better result. But there is no model.”

Jacobsohn and his team will experiment with the composition and structure of metal oxides in hopes of finding a general rule that guides the fabrication of the metal oxides to help control for the presence of electronic traps.

Rajendra Bordia, chair of the materials science and engineering department at Clemson, congratulated Jacobsohn on the grant.

“This award is a well-deserved significant national recognition of Dr. Jacobsohn’s contributions and potential,” Bordia said. “He will be well positioned to contribute to research and education and mentoring students for years to come. He is helping reinforce Clemson’s excellence as a leader in advanced materials.  We are very happy to have him as a colleague in the department.”

Also as part of the grant, Jacobsohn plans to develop tools and strategies aimed at introducing materials science and engineering concepts to high school students. He and his team will distribute kits that are designed by the Optical Society of America and include LED lights, lenses, color filters and other items.

Schools involved include D.W. Daniel High School and McCormick High School.

Anand Gramopadhye, dean of the College of Engineering, Computing and Applied Sciences, said the award is among the most prestigious honors given by the NSF to early-career faculty members.

“The NSF CAREER award affirms Dr. Jacobsohn’s accomplishments as a teacher and a scholar,” Gramopadhye said. “It also underscores Clemson’s growing strength as a research university, creating jobs and finding solutions to some of the world’s toughest challenges.”


This material is based upon work supported by the National Science Foundation under award number 1653016 . Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.