Stefania Dede (Aprahamian Group)

Targetry with Actinides: Electrospraying

April 21, 2021

Stefania Dede 1

Stefania Dede is a visiting scholar advised by Prof. Ani Aprahamian, Frank M. Freimann Professor of Physics at the University of Notre Dame. Stefania presented her research titled, “Targetry with Actinides: Electrospraying" in April 2021 during ND Energy’s monthly seminar series for postdoctoral scholars and graduate students.

While Stefania’s home institution is Texas A&M University, she found a unique path to Notre Dame two years ago. Her advisor took a new position at a university in Canada, effectively halting the progress of her research project. After completing the preliminary experiments and defending her master’s, Stefania and her advisor agreed it was a good time for her to start something new.

After meeting Prof. Michael Wiescher, Frank M. Freimann Professor of Physics at Notre Dame, at a Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements (JINA-CEE) conference, Stefania was able to connect with Prof. Aprahamian and Prof. Khachatur Manukyan, research assistant professor in the Department of Physics at Notre Dame. Interested in their research project, Stefania was offered an opportunity to complete her Ph.D. work at Notre Dame as a visiting scholar.

Stefania’s project has two parts. She is developing a novel technique for preparing actinide targets for nuclear physics and chemistry measurements, ensuring their stability through materials characterization and testing.  The second part includes running a reaction to take measurements and analyze the data. Most likely, this experiment will be done at Notre Dame with a neutron beam, which is currently being developed in the physics department.

“In the past, a lot of progress has been made with the detectors, but less effort and focus has been put on the targets,” Stefania said. “Even if you have the best detectors and a well-defined beam, if your target is not good, your results will not be good.”

Beyond creating the targets, characterization is critical for gaining a complete knowledge of the materials. For example, Stefania is checking for uniformity in the sample and analyzing the surface.

“We’re determining if the layer is crystalline, amorphous, or if it is porous inside,” Stefania said. Current targets are being created from uranium, and future work will include americium and thorium.

“Actinides have an extra level of difficulty that you don’t have with materials that are not radioactive,” Stefania said. “You also have a very specific amount of material that you can’t just throw away.”

Although she is a physicist, Stefania’s research interests are focused more on real-world applications. She earned her bachelor’s degree in applied mathematics and physical sciences at the National Technical University of Athens in Greece. Referencing the uranium clusters being synthesized in the Actinide Center for Excellence (ACE), she noted that this type of research could lead to reducing the size of nuclear fuel rods in reactors.

“I was interested in being in a laboratory creating actinide targets and not just sitting in front of a computer all day,” she said, contrasting it with her previous research experience which was focused more on coding.

Measurements for this project are taken at several facilities across campus, including the Center for Environmental Science and Technology (CEST), Notre Dame Integrated Imaging Facility (NDIIF), and ND Energy’s Materials Characterization Facility (MCF).

“We are mostly using the XPS to determine exactly what kind of uranium oxide we have,” Stefania said of her use of the instrumentation in the MCF. “Lately we have been using it to give us a depth profile of our target, which gives us a sense of variations within the sample.”

Unlike conventional methods that may only provide a nominal thickness, this extensive characterization provides a clearer picture of the material’s properties and minimizes the risk of errors associated with the target.

For Stefania, having access to a combination of facilities and gaining guidance and support from several individuals make Notre Dame the right place to conduct her research. She lauded the University’s commitment to continually upgrading instrumentation to produce better data and praised the experience and knowledge of Aprahamian and Manukyan.

“Notre Dame strives for perfection,” she concluded. “I don’t think I could do this kind of research at any other university.”