Publikationen

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

Autor(en)
A. Wallner, K. Buczak, Tamás Belgya, M. Bichler, L Coquard, I Dillmann, R. Golser, F. Kaeppeler, A. Karakas, W. Kutschera, C. Lederer, Alberto Mengoni, M Pignatari, A. Priller, Rene Reifarth, P. Steier, L. Szentmiklosi
Abstrakt

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 Fe-54(n,gamma) Fe-55 reaction. Following a series of irradiations with neutrons from cold and thermal to keV energies, the produced long-lived Fe-55 nuclei (t(1/2) = 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 Fe-55, 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 (sigma(th) = 2.30 +/- 0.07 b) as well as for a quasi-Maxwellian spectrum of kT = 25 keV (sigma = 30.3 +/- 1.2 mb) and for E-n = 481 +/- 53 keV (sigma = 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.

Organisation(en)
Isotopenphysik
Externe Organisation(en)
Australian National University, Hungarian Academy of Sciences, Technische Universität Wien, Karlsruher Institut für Technologie, TRIUMF Canada's National Laboratory for Particle and Nuclear Physics, Monash University, University of Edinburgh, European Organization for Nuclear Research (CERN), University of Hull, Johann Wolfgang Goethe-Universität Frankfurt am Main
Journal
Physical Review C
Band
96
Anzahl der Seiten
13
ISSN
0556-2813
DOI
https://doi.org/10.1103/PhysRevC.96.025808
Publikationsdatum
08-2017
Peer-reviewed
Ja
ÖFOS 2012
103014 Kernphysik, 103004 Astrophysik
Schlagwörter
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/precise-measurement-of-the-thermal-and-stellar-fe54ngamma-fe55-cross-sections-via-accelerator-mass-spectrometry(80bab83d-3ac7-4062-baed-d8ecfe2f34ce).html