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MS: Fachverband Massenspektrometrie
MS 5: Poster
MS 5.7: Poster
Mittwoch, 4. März 2026, 17:00–19:00, Philo 1. OG
Mass Measurements near N=126 with the FRS Ion Catcher — •Kriti Mahajan1, 2 and Daler Amanbayev3, 1 for the Super-FRS Experiment collaboration — 1Justus-Liebig-Universität Gießen, Germany — 2Helmholtz Research Academy Hesse for FAIR (HFHF), Campus Gießen, Germany — 3GSI Darmstadt, Germany
Studying the r-process requires nuclear data of very neutron-rich nuclei. This data is still scarce and modern r-process network calculations rely on theoretical models that give divergent predictions as one moves away from the valley of stability. Nuclear masses help to determine the r-process path and shed light on the nucleosynthesis environment.
The use of high-energy heavy-ion beams with the Fragment Separator (FRS) at GSI facilitates the study of neutron-rich nuclei in the r-process region. An experiment was performed within FAIR Phase-0, where these nuclei were produced at the FRS using fragmentation of 1 GeV/u 208Pb beam on a 4 g/cm2 thick 9Be target and precise mass measurements were performed using the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The MR-TOF-MS features a high resolving power of up to 1,000,000, short cycle times of a few tens of milliseconds, and mass accuracy down to 2×10−8.
During the experiment, masses of sixteen nuclides around N = 126 were measured, of which four masses were measured for the first time. The results of this experiment will be presented, including the first mass measurements of 204Au and 205Au, where significant deviations from the AME2020 extrapolations indicate a change in nuclear structure around the N = 126 shell closure.
Keywords: Exotic nuclei; Mass measurements; MR-TOF-MS; Cryogenic Stopping Cell (CSC); FRS Ion Catcher