PhD project: Mass measurements of the most exotic isotopes at the FRS Ion Catcher, GSI/FAIR

Project description

The study of radioactive isotopes is of high interest to understand the interplay between the electromagnetic, strong and weak interactions inside a nucleus. High precision mass measurements play an important role in the study of the structure of nuclei far from stability, but are also important inputs for nuclear astrophysics applications.

In recent years a new type of mass spectrometer (so called multiple-reflection time-of-flight mass spectrometer) has been introduced and very successfully brought into operation at almost all major radioactive beam facilities. In these devices long flight path (up to a km of path length) are achieved by storing ions between two electrostatic ion mirrors. Further, these devices are not only capable of performing mass measurements, but can also be used to indentify and quantify reaction products or daughter nuclides following radioactive decays [1].

The FRS Ion Catcher experiment [2,3] at the current GSI facility, Darmstadt, Germany serves as the test bench for the future LEB and allows precision studies already now. As part of this thesis you will join the efforts at the FRS Ion Catcher collaboration in the search for new isotopes being produced via Pb fragmentation at relativistic energies or via multinucleon transfer reactions [4]. The main goal of these experiments will be to produce and identify new neutron-rich isotopes in the element range between terbium and lead and to measure their production cross sections, masses and half-lives. Particular the new mass values will be highly relevant for the third peak of the rapid neutron capture process (r-process), which is believed to be responsible for the creation of half of the stable isotopes beyond iron.

The Phd project will be offered to a student with a strong academic background in nuclear physical, a high degree of independence and the aspiration to work within an international collaboration. You will further develop the analysis method for high precision mass or decay data and study the impact of the new measurements on the production of isotopes in astrophysical environments. You will lead the discussions on your results within the collaboration and prepare publication in peer-reviewed journals. Additionally you will work on further technical developments to improve the precision, resolving power or operation of the Ion Catcher. You will commission a new position-sensitive fast ion detector at the FRS Ion Catcher online. This detector will allow to correct the time-of-flight of each single ion based on its respective trajectory inside the time-of-flight analyzer and will boost the achievable resolving power and precision of the mass spectrometer. Hands-on and computer-based work will be required and adjusted for the incumbent's interests and operational needs. This project includes traveling to GSI, Germany, and, as a member of the FRS-Ion-Catcher collaboration, offers you the opportunity to present your results at international conferences or workshops.

Research Council scholarships cover UK/EU fees and provide tax free stipends for living costs for 42 months. The initial application deadline is 20 January 2023, however, applications reached after the deadline will continue to be considered until all the positions are filled (see how to apply and funding options).

[1] I. Miskun, et al. Eur. Phys. J. A (2019) 55: 148
[2] W. R. Plass et al., NIMB (2013) 317 B, 457-462
[3] FRS Ion Catcher experiment web page -
[4] W. R. Plaß et al. Hyperfine Interactions 240:111 (2019)

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