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20.01.2022 | 

The FAIR-GSI PhD Award 2021 went to Dr. Daria Kostyleva. The award was presented recently during a virtual colloquium by Professor Paolo Giubellino, Scientific Managing Director of FAIR and GSI, and Daniel Sälzer, Managing Director of Pfeiffer Vacuum GmbH. This annual award is sponsored by Pfeiffer Vacuum and endowed with 1000 euros.

In her doctoral thesis, which she completed at the Justus Liebig University of Giessen in the research group of Professor Christoph Scheidenberger, Dr. Daria Kostyleva used a novel experimental method that allowed her to study atomic nuclei at the limits of stability, their internal structure as well as some of their characteristic properties such as lifetime, ground state and excited levels. To this end, nuclear reactions at the fragment separator FRS at GSI were used to produce very neutron-deficient argon, potassium, and chlorine isotopes, which are extremely short-lived: some of them have lifetimes as short as 10^-12 seconds (which is a trillionth of a second) or even shorter.

Because of their short lifetimes, these atomic nuclei decay in flight, emitting one, two, or three protons while transitioning to a more stable, longer-lived configuration. The protons can be detected with a special detector arrangement that Dr. Kostyleva contributed to develop. For the first time, this experimental method was used to detect the three-proton decay of an atomic nucleus: on ³¹K, a potassium atom with mass number 31, consisting of 19 protons and only 12 neutrons. Also for the first time, the detection of some previously unknown isotopes — ²⁸Cl, ³⁰Cl, ²⁹Ar, and the aforementioned nuclide ³¹K — was successful. For other nuclides, two-proton radioactivity was observed, a particular decay mechanism discovered at GSI in the early 2000s. For some of the studied nuclei, it was even possible to derive a level scheme, i.e., to describe the internal structure that forms under these extreme conditions.

Half-lives, binding energies and a wealth of other information could also be determined in a single experiment. These findings are particularly noteworthy because Dr. Kostyleva's experiments, to date, extend the farthest beyond the so-called proton dripline. As such, they provide a first insight into areas far beyond nuclear stability and into novel phenomena with the potential to our picture of the structure of atomic nuclei. The experiments open a perspective to gain a deeper understanding of the transition from the ordering effect of nuclear forces in atomic nuclei to a structureless assembly of nucleons at the dripline. The super-conducting Fragment Separator (Super-FRS), currently under construction at the international FAIR facility, is expected to provide further insights.

The annual FAIR-GSI PhD Award honors an excellent PhD thesis completed during the previous year. Eligible for nominations are dissertations that were supported by GSI in the context of its strategic partnerships with the universities of Darmstadt, Frankfurt, Giessen, Heidelberg, Jena, and Mainz, or through the research and development program. In the framework of the Graduate School HGS-HIRe (Helmholtz Graduate School for Hadron and Ion Research), more than 300 PhD students currently perform research for their PhD theses on topics closely related to GSI and FAIR. GSI has a long-standing partnership with the award sponsor, Pfeiffer Vacuum GmbH, which offers vacuum technology and pumps. Vacuum solutions from Pfeiffer Vacuum have been successfully used in GSI's facilities for decades. (CP)