Neutron capture cross sections on /sup 138/Ba, /sup 140,142/Ce, /sup 175,176/Lu, and /sup 181/Ta at 30 keV:Prerequisite for investigation of the /sup 176/Lu cosmic clock

Journal Article · Thu Jan 31 23:00:00 EST 1980 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.21.534· OSTI ID:5754822

Beer, H; Kaeppeler, F

The capture cross sections of /sup 138/Ba, /sup 140,142/Ce, /sup 176/Lu, /sup 181/Ta and the capture cross section of /sup 175/Lu to the 3.68 h isomeric state in /sup 176/Lu have been determined at 30 keV neutron energy using the activation technique. Neutrons were generated via the /sup 7/Li( p,n) reaction just above the reaction threshold at a 3 MV pulsed Van de Graaff accelerator. The capture cross sections are of importance to stellar nucleosynthesis. With the /sup 138/Ba and /sup 140/Ce cross sections the time integrated average neutron flux for the s process was determined to 0.22 mb/sup -1/. This result, the capture cross section of /sup 176/Lu and the /sup 175/Lu cross section to the 3.68 h isomeric state in /sup 176/Lu were used to analyze the /sup 176/Lu cosmic clock. The mean s process age of solar matter before the solidification of the solar system was estimated to 6 x 10/sup 9/ yr. In addition the Hf/Lu abundance ratio was determined.

• Research Organization: Kernforschungszentrum Karlsruhe GmbH, Institut fuer Angewandte Kernphysik, Postfach 3640, D-7500 Karlsruhe, Federal Republic of Germany
• OSTI ID: 5754822
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 21:2; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABUNDANCE
ACCELERATORS
BARIUM 138 TARGET
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CAPTURE
CERIUM 140 TARGET
CERIUM 142 TARGET
CROSS SECTIONS
ELECTROSTATIC ACCELERATORS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
GAMMA SPECTRA
HADRON REACTIONS
HAFNIUM
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOTOPES
KEV RANGE
KEV RANGE 10-100
LUTETIUM 175 TARGET
LUTETIUM 176
LUTETIUM 176 TARGET
LUTETIUM ISOTOPES
METALS
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEOSYNTHESIS
ODD-ODD NUCLEI
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
REFRACTORY METALS
SPECTRA
TANTALUM 181 TARGET
TARGETS
TRANSITION ELEMENTS
VAN DE GRAAFF ACCELERATORS
YEARS LIVING RADIOISOTOPES
ZIRCONIUM