Stellar Neutron Capture Cross Sections of the Lu and Hf Isotopes

Journal Article · Tue May 24 00:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.1945247· OSTI ID:20722423

Wisshak, K; Voss, F; Kaeppeler, F ^[1]; Kazakov, L ^[2]; Krticka, M ^[3]

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1. Forschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany)
2. Institute for Physics and Power Engineering, Obninsk (Russian Federation)
3. Faculty of Mathematics and Physics, Charles University, CZ-180 00 Prague (Czech Republic)

The neutron capture cross sections of 175,176Lu and 176,177,178,179,180Hf have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator relative to the gold standard. Neutrons were produced by the 7Li(p,n)7Be reaction and capture events were detected by the Karlsruhe 4{pi}BaF2 detector. The cross section ratios could be determined with uncertainties between 0.9 and 1.8% about a factor of five more accurate than previous data. A strong population of isomeric states was found in neutron capture of the Hf isotopes, which are only partially explained by CASINO/GEANT simulations based on the known level schemes.Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 keV and 100 keV. Severe differences up to40% were found to the data of a recent evaluation based on existing experimental results. The new data allow for a much more reliable analysis of the important branching in the s-process synthesis path at 176Lu which can be interpreted as an s-process thermometer.

• OSTI ID: 20722423
• Journal Information: AIP Conference Proceedings, Vol. 769, Issue 1; Conference: International conference on nuclear data for science and technology, Santa Fe, NM (United States), 26 Sep - 1 Oct 2004; Other Information: DOI: 10.1063/1.1945247; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BERYLLIUM 7
BRANCHING RATIO
C CODES
CAPTURE
COMPUTERIZED SIMULATION
CROSS SECTIONS
ENERGY LEVELS
G CODES
HAFNIUM 176 TARGET
HAFNIUM 177 TARGET
HAFNIUM 178 TARGET
HAFNIUM 179 TARGET
HAFNIUM 180 TARGET
HAFNIUM ISOTOPES
KEV RANGE
LITHIUM 7 TARGET
LUTETIUM 175 TARGET
LUTETIUM 176 TARGET
LUTETIUM ISOTOPES
NEUTRON REACTIONS
NEUTRONS
NUCLEOSYNTHESIS
PROTON REACTIONS
S PROCESS
VAN DE GRAAFF ACCELERATORS