Precise measurement of the thermal and stellar Fe 54 (n,γ) Fe 55 cross sections via accelerator mass spectrometry

Wallner, A.; Buczak, K.; Belgya, T.; Bichler, M.; Coquard, L.; Dillmann, I.; Golser, R.; Käppeler, F.; Karakas, A.; Kutschera, W.; Lederer, C.; Mengoni, A.; Priller, A.; Reifarth, R.; Steier, P.; Szentmiklosi, L.; Kaeppeler, F.; Pignatari, M.

Abstract

© 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Accelerator mass spectrometry (AMS) represents a complementary approach for precise measurements of neutron capture cross sections, e.g., for nuclear astrophysics. This technique, completely independent of previous experimental methods, was applied for the measurement of the Fe54(n,γ)Fe55 reaction. Following a series of irradiations with neutrons from cold and thermal to keV energies, the produced long-lived Fe55 nuclei (t1/2=2.744+-0.009) yr) were analyzed at the Vienna Environmental Research Accelerator. A reproducibility of about 1% could be achieved for the detection of Fe55, yielding cross-section uncertainties of less than 3%. Thus, this method produces new and precise data that can serve as anchor points for time-of-flight experiments. We report significantly improved neutron capture cross sections at thermal energy (σth=2.30±0.07 b) as well as for a quasi-Maxwellian spectrum of kT=25 keV (σ=30.3±1.2 mb) and for En=481±53 keV (σ=6.01±0.23 mb). The new experimental cross sections have been used to deduce improved Maxwellian-averaged cross sections in the temperature regime of the common s-process scenarios. The astrophysical impact is discussed by using stellar models for low-mass asymptotic giant branch stars.

Citation

Wallner, A., Buczak, K., Belgya, T., Bichler, M., Coquard, L., Dillmann, I., Golser, R., Käppeler, F., Karakas, A., Kutschera, W., Lederer, C., Mengoni, A., Priller, A., Reifarth, R., Steier, P., Szentmiklosi, L., Kaeppeler, F., & Pignatari, M. (2017). Precise measurement of the thermal and stellar Fe 54 (n,γ) Fe 55 cross sections via accelerator mass spectrometry. Physical Review C, 96(2), Article ARTN 025808. https://doi.org/10.1103/PhysRevC.96.025808

• Journal Article Type: Article
• Acceptance Date: Aug 28, 2017
• Online Publication Date: Aug 28, 2017
• Publication Date: Aug 28, 2017
• Deposit Date: Sep 15, 2017
• Publicly Available Date: Sep 15, 2017
• Journal: Physical review C
• Print ISSN: 2469-9985
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 96
• Issue: 2
• Article Number: ARTN 025808
• DOI: https://doi.org/10.1103/PhysRevC.96.025808
• Keywords: Neutron physics; Nuclear astrophysics; Nuclear reactions; Nucleosynthesis in explosive environments; Radiative capture
• Public URL: https://hull-repository.worktribe.com/output/454797
• Publisher URL: https://journals.aps.org/prc/abstract/10.1103/PhysRevC.96.025808
• Additional Information: Copy of article first published in: Physical review C, 2017, v.96, issue 2
• Contract Date: Sep 15, 2017