On the road to the basement of the periodic table

The courier from Dresden arrives once a week, and for Kristina Kvashnina it is the most important connection across 1,200 kilometers of Europe. “They send us sealed containers in special vehicles, which is a logistical masterpiece,” says the physicist. The special vehicles have stickers on all sides warning of radioactive radiation: Plutonium, neptunium, americium and all the other materials from which Kvashnina extracts her secrets.

Kristina Kvashnina has worked at the European Synchrotron Radiation Facility (ESRF) in Grenoble for more than a decade where she manages the measuring station, which is operated by the Helmholtz Center Dresden-Rossendorf. “We combine the best of both worlds,” she explains: “In Dresden, we have the best laboratories in the world, where chemists can synthesize the materials we work with, and here in Grenoble we have the perfect synchrotron radiation source to study them.”

When Kvashnina talks about her research, she usually begins with the basics: “A central problem of nuclear power plants is radioactive waste. That is where our work starts,” she says: What happens when the material comes into contact with water, for example, where does the uranium go, how fast does it move? “We study the interactions at the atomic and molecular level,” explains Kristina Kvashnina. She talks about the “basement of the periodic table” when she talks about her research, about the so-called actinoids, which are actually at the bottom of the periodic table. Her hope is that if we can learn more about these little-known elements, it may one day be possible to use chemical reactions to neutralize some of the dangerous substances and solve the problem of radioactive waste.

The 47-year-old researcher was introduced to physics while still at school. That was in Russia, in the rural Ural region near Yekaterinburg. Born in Ukraine, her parents moved to Russia when she was four years old. It was in high school that she first attracted national attention: She came third in a physics competition for students, and that was from a regular high school, not one of the science hotbeds in Moscow or St. Petersburg. At 16, the high-flyer graduated from high school with top grades in all subjects and enrolled in the local university. Again, she graduated in record time and with top grades-and made a far-reaching decision: “I was tired of theory, I wanted to experiment,” she says, looking back. And while Russia was fantastic for theoretical training, there was hardly any equipment for experiments, so she went to Upsala, Sweden, for her Ph.D., from where she often traveled to Berkeley for experiments.

Those years marked the beginning of her biggest breakthrough to date: “At that time, soft X-rays were mainly used for investigations,” she explains: The samples were bombarded with the rays to make their hidden properties visible. Soon after, Kristina Kvashnina moved to Grenoble to try out her experiments with hard X-rays, “and then I had the idea to go a different way,” she says: She developed a completely new method, high-energy resolution X-ray spectroscopy. Put simply, it uses a mid-frequency range of X-rays. “When I presented this at conferences, the audience couldn’t believe the amount of data that could be obtained with this approach,” she says with a smile. Today, researchers at many synchrotrons around the world are taking advantage of her discovery.

Kristina Kvashnina, who joined the HZDR in Grenoble in 2015, has also rediscovered her enthusiasm for theory. Although she goes to the lab every day, which is just a few corridors away from her office, much of her work takes place on the computer: She enters the measurement results into spreadsheets, into highly complex predictive models of the behavior of the little-studied materials “in the basement of the periodic table”. Little by little, she hopes to unlock their secrets.

In addition to the scientific infrastructure, Grenoble offers her another advantage. Thanks to the French Alps, she has similar conditions to those she used to have in the Urals, “even if they are higher and steeper”, she says. As a child, she went skiing once a week. Today, she is still often on the slopes with her three sons and her Belgian husband. In summer, the family switches to racing bikes.