Stellar 78,80,84,86Kr(n,γ) Reactions Studied by Activation at SARAF-LiLiT, Atom Trap Trace Analysis and Decay Counting

• Published in: Journal of physics. Conference series 2020-10, Vol.1668 (1)
• Main Authors: Tessler, M., Paul, M., Weissman, L., Zappala, J., Baggenstos, D., Halfon, S., Heftrich, T., Jiang, W., Kreisel, A., Lu, Z., Mueller, P., Purtschert, R., Reifarth, R., Shor, A., Veltum, D., Weigand, M.
• Format: Article
• Language: English
• Subjects: Atom Trap Trace Analysis (ATTA); Atom traps; Decay; Fluence; high-intensity neutron source; Isotopes; Kr(n,g); liquid-lithium target; Lithium; Low Level Counting (LLC); Maxwellian Averaged Cross Section (MACS); Metal foils; Natural gas; Nuclear capture; Nuclear fusion; Physics; process; Proton beams
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1668/1/012043

We report on (n,γ) neutron capture experiments performed with the Liquid-Lithium Target (LiLiT) and the mA-proton beam at 1.92 MeV (2-3 kW) from the Soreq Applied Research Accelerator Facility (SARAF). The setup yields high-intensity 30-keV quasi-Maxwellian neutrons (3-5 × 1010 n/s) closely reproducing the conditions of s-process stellar nucleosynthesis. The 78,80,8486Kr(n,γ) reactions at the border between weak- and strong- s-process were studied. A Ti sphere filled with 107.7 mg of natural Kr gas was placed in an irradiation chamber downstream of LiLiT with a gold foil used as a neutron fluence monitor during the activation. The activities of the short-lived Kr isotopes (7985m87Kr) were measured by γ decay counting with a HPGe detector. The long-lived Kr isotopes (81,85gKr) were measured by atom counting via Atom Trap Trace Analysis (ATTA) at Argonne and Low-Level Counting (LLC) at Bern.