17. PhD Interview

“I just liked the idea to be able to contribute some small pieces to the large and challenging puzzle.”

Janine Schwestka, doctoral candidate at the Institute of Applied Physics (TU Wien)

What is the topic of your Ph.D. thesis?

“Ion irradiation of thin carbon films - from fundamental understanding to material properties”

What is the focus of research? 

To extend the present basic knowledge on mechanisms responsible for surface erosion, sputtering, electron emission and other ion-surface-interaction processes. The main focus is on the understanding of these processes which play an important role when a hot fusion plasma comes into contact with the surrounding wall.

What is the benefit for fusion research?

Material erosion by energetic ion sputtering limits the lifetime of plasma facing components. It is therefore of crucial importance to understand the mechanisms on energy deposition of the ions (both kinetic and potential energy) during the interaction with the atoms at the surface. Ion-induced electron emission from the plasma wall changes the plasma potential and thus in turn influences the impact energy of the plasma ions on the wall. To understand the underlying processes, I have built an ion spectrometer, which allows to measure the energy loss and charge exchange of singly and multiply charged ions during their interaction with a single layer of material (e.g. graphite) as well as the resulting emission of electrons and photons. We use scanning transmission electron microscopy to inspect the nanoscopic damage induced by the impacting ions.

What are the biggest challenges? 

For this kind of investigations, a well-defined surface has to be prepared. Finding a suitable cleaning procedure was among one of the many challenges I had to face within my thesis. To master the complexity of a multi-coincidence experiment for recording ions and electrons or photons at the same time was another.

Which plans do you have for your future? What will you do in 5 years? Would you like to continue research or are you going to work in industry?

As I am just about to complete my dissertation, I have been dealing with this question for quite some time. A career in research was always my dream. Even though I know by now that it is not one of the easiest ways to go, I would still like to face new challenges and extend my insight into the scientific world.

What was your motivation to write a fusion relevant Ph.D. thesis? What is fascinating about nuclear fusion?

ITER is the world's largest research project aimed at paving the way to environmentally friendly energy from the fusion of hydrogen atoms to Helium. However, to achieve this goal, still many problems have to be solved. I just liked the idea to be able to contribute some small pieces to the large and challenging puzzle.