Publications

Determination of the stellar (n,gamma) cross section of 40Ca with Accelerator Mass Spectrometry

Author(s)
Iris Dillmann, César Domingo-Pardo, Michael Heil, Franz Käppeler, Anton Wallner, Oliver Forstner, Robin Golser, Walter Kutschera, Alfred Priller, Peter Steier, Alberto Mengoni, Roberto Gallino, Michael Paul, Christof Vockenhuber
Abstract

The stellar (n, y) cross section of 40Ca at kT = 25 keV has been measured with a combination of the activation technique and accelerator mass spectrometry (AMS). This combination is required when direct off-line counting of the produced activity is compromised by the long half-life and/or missing ?-ray transitions. The neutron activations were performed at the Karlsruhe Van de Graaff accelerator using the quasistellar neutron spectrum of kT = 25 keV produced by the 7Li(p,n)7Be reaction. The subsequent AMS measurements were carried out at the Vienna Environmental Research Accelerator (VERA) with a 3 MV tandem accelerator. The doubly magic 40Ca is a bottle-neck isotope in incomplete silicon burning, and its neutron capture cross section determines the amount of leakage, thus impacting on the eventual production of iron group elements. Because of its high abundance, 40Ca can also play a secondary role as "neutron poison" for the s-process. Previous determinations of this value at stellar energies were based on time-of-flight measurements. Our method uses an independent approach, and yields for the Maxwellian-averaged cross section at kT = 30 keV a value of (?)30keV = 5.73 ± 0.34 mb.

Organisation(s)
Isotope Physics
External organisation(s)
Universität Basel, Universitat de València, Karlsruher Institut für Technologie, International Atomic Energy Agency (IAEA), Istituto Nazionale di Fisica Nucleare (INFN), Roma, Hebrew University Jerusalem, Eidgenössische Technische Hochschule Zürich
Journal
Physical Review C
Volume
79
No. of pages
8
ISSN
0556-2813
DOI
https://doi.org/10.1103/PhysRevC.79.065805
Publication date
2009
Peer reviewed
Yes
Austrian Fields of Science 2012
1030 Physics, Astronomy
Portal url
https://ucris.univie.ac.at/portal/en/publications/determination-of-the-stellar-ngamma-cross-section-of-40ca-with-accelerator-mass-spectrometry(2efe0406-1bfb-44e9-bf9e-63f7b75ec04c).html