ADVANCING SCIENCE AT NEAR LIGHT SPEED

Two groups of researchers from Montana Technological University were able to secure beam time at the Stanford Synchrotron Radiation Lightsource (SSRL) this summer, a highly competitive achievement that only 1,700 users get to experience each year. The researchers will use data collected and experience gained at the facility to develop fuel cell technology and understand the origins of sphalerite, a critical mineralcontaining ore found in southwestern Montana.

Celine Beaucamp is an Earth Science and Engineering Ph.D. student working with Dr. Chris Gammons on a $365,000 National Science Foundation (NSF) grant to study sphalerite. Beaucamp has been conducting research in the Philipsburg Mining District since 2020, and the grant was awarded in Spring 2024. The pair want to understand how the ore forms, as it contains elevated amounts of gallium, tungsten, germanium, and indium, some of
which are critical metals.

“For part of the NSF grant, we want to run the samples through the synchrotron lab because we want to know how the trace elements get into the sphalerite’s lattice. One major criterion is the valence they have. For instance, copper (Cu) can be Cu2+ or Cu1+. We are the first in the world mentioning tungsten in sphalerite in meaningful amounts, and tungsten (W) can be W4+ or W6+. The amount of protons changes the atom’s size, and it impacts the crystal’s structure. Furthermore, the charge balance has to stay equal. Therefore, we are looking into what atom association is needed to achieve all these requirements. To be able to do so, you need to run the sample through a synchrotron to know each atom’s valence.”

Beaucamp and Gammons submitted a proposal to run her samples through the Stanford Synchrotron Radiation
Lightsource. Earlier in June, a colleague at the U.S. Geological Survey offered to have Beaucamp volunteer for one of the agency’s projects being run through the synchrotron. She jumped at the chance to participate in order to learn how the machine works. Projects at the synchrotron run 24 hours a day, so teams need both a dayside scientist and a nightside scientist to monitor their experiments. Beaucamp served as the nightside scientist. For three nights she completed her shift and paid close attention to the process so that she could write the best
proposal possible for her own sphalerite research.

“I didn’t have the pressure of decision making because it was not my project,” Beaucamp said. “I could just be an observer and learn. It was an amazing opportunity.”

The Stanford Synchrotron Radiation Lightsource is a directorate of the SLAC National Accelerator Laboratory, and
is a Department of Energy Office of Science User Facility. These facilities exist to promote advances in a wide range of scientific fields that would not be possible with only lab-scale experimentation. Researchers do not pay for beam time at the lab because user facilities are funded by the Department of Energy.

The x-rays at SSRL are produced in the synchrotron, a roughly circular particle accelerator called the Stanford Positron Electron Asymmetric Ring (SPEAR3). Inside SPEAR 3, electrons travel around at relativistic speeds just under the speed of light, accelerated and steered by a series of magnetic devices.

There is a fresh pulse of electrons every five minutes, and one of the byproducts created is broad-spectrum x-rays that can be extracted and fine-tuned by insertion devices and monochromators for use in diffraction, scattering, and imaging experiments. The product that researchers obtain at SSRL varies, depending on the experimental technique used.

The x-rays produced by the SSRL are of far higher intensity than those that can be produced using the laboratory-based tools at Montana Tech. The Center for Advanced Materials Processing (CAMP) at Montana Tech maintains and supervises an x-ray diffractometer that researchers can experiment with, and provides good data, but sometimes researchers need more.

CAMP Materials Testing Lab Manager Dr. Julie Muretta and Associate Professor of Chemistry and Geochemistry Dr. John Kirtley had very specific needs that only the synchrotron could fulfill as they researched whether the synthesis gas released during the gasification of biochar might be used to power a fuel cell. The presence of sulfur in the synthesis gas would be a huge problem for the project, as the sulfur eventually will deactivate the fuel cell.

“For our research goals, very low levels of sulfur is very detrimental,” Kirtley said. “The detection limit is critical.”

After researching other techniques, the team submitted a detailed proposal that scored high
enough to earn time at SSRL.

“X-ray absorption near-edge spectroscopy (XANES) was the technique John and I used at beamline 4-3 at SSRL,” Muretta said. “Beamline 4-3 produces ‘tender x-rays,’ meaning fairly low energy compared to other beamlines. This low energy was necessary to ‘see’ the sulfur (S) in our samples.”

During the experiment, Muretta experienced a situation where she was working alone on the beamline when the electronics within the synchrotron glitched due to the intense heat outside (it was >100°F), and the machine stopped collecting data. She said the beamline staff went above and beyond to get everything running again within half an hour.

“It was a Herculean effort on their part,” Muretta said. “The beamline scientists are experts in their field. I cannot say enough good things about SSRL. It was a fantastic experience.”

For Muretta, time at the SSRL was about more than this project. It was about growing as a
scientist.

“Conducting experiments at a synchrotron or neutron facility has always been on my radar as a researcher,” Muretta said. “The science they do at these facilities is phenomenal and it is really fun to be part of that. I attended the 2020 National School for Neutron and X-ray Scattering, put on jointly by Oak Ridge and Argonne National Labs, and that in itself was an awesome experience. It only piqued my interest. I am so happy to have had the opportunity to travel to SSRL and to collaborate with John on these experiments. I look forward to returning in the future.”

Kirtley and Muretta hope to publish a paper in spring about their findings. They are being assisted in their research by Chemistry senior Thea McCurdy and Worcester Polytechnic Institute Chemical Engineering senior Paige Agostini, who spent the summer of 2024 enrolled in Montana Tech’s Research Experience for Undergraduates.

Kirtley spoke highly of the facility and the staff at SSRL, who helped move the team’s research forward.

“The whole institution really seems focused on serving their clients,” Kirtley said. “We went into
this with a lot of unknowns and we did as much as we could to learn about the technique. At
the end of the day there is so much we didn’t know. The scienti sts there were very helpful
and will do their best to help you succeed.”