08.12.2022; Vortrag
Seminar: Measuring Neutron Capture Cross Section of Short-lived Isotopes (Heinrich Wilsenach)
01069 Dresden
About half of the elements heavier than iron are created in the universe via the rapid (r) neutron capture process. Their abundance distribution is not fully understood, and the r-process astrophysical sites are still under investigation. The neutron-star merger observation via gravitational waves and electromagnetic radiation provides astrophysical insights into this question, whereas nuclear properties of neutron-rich unstable nuclei are critical inputs to r-process nucleosynthesis calculations that predict abundance distributions and constrain creation sites.
Neutron capture cross-sections of neutron-rich unstable nuclei are invaluable for nuclear reactions and nuclear structure in general. Their measurement is currently considered impossible due to the instability of the targets and projectile. A joint project between Justus-Liebig-Universität Gießen and Tel-Aviv University is currently underway to overcome this limitation. The main goal of this project is to select and store fission fragments in an RF system (coined ‘NG-Trap’ [1]), which will form a trapped ‘cloud target’ that will consequently be irradiated by an intense neutron beam. The reacted ions will be mass-selected, identified and counted using a multiple-reflection time-of-flight mass-spectrometer (MR-TOF-MS), thus extracting (n,g) cross sections.
This talk will mainly focus on the NG-Trap system that will be developed for the Soreq Applied Research Accelerator Facility (SARAF) [2], currently under construction in Yavne, Israel. An existing triple-RFQ system [3], which is presently being set up at Tel-Aviv University for research and development of the cloud target concept, and preliminary estimations of event rates for numerous radioactive target isotopes will also be presented.
[1] T. Dickel et al., Eur. Phys. J. Web of Conferences 260, 11021 (2022)
[2] I. Mardor et al., Eur. Phys. Jour. A 54: 91 (2018)
[3] E. Haettner et al., Nucl. Instr. Meth. A 880, 138