Quasistellar spectrum for neutron activation measurements at kT=5 keV

Journal Article · Tue Feb 01 04:00:00 EST 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.71.025803· OSTI ID:20695964

Heil, M; Dababneh, S; Juseviciute, A; Kaeppeler, F; Plag, R; Reifarth, R; O'Brien, S ^[1]

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1. Forschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany)

We have measured the neutron energy spectrum of the {sup 18}O(p,n){sup 18}F reaction at a proton energy of 2582 keV, 8 keV above the reaction threshold. At this energy the resulting neutron spectrum resembles almost perfectly a Maxwellian distribution at a thermal energy of kT=5.1{+-}0.1 keV. Since all neutrons are emitted in a forward cone of 140 degrees opening angle, this reaction can be used for neutron activation measurements similar to the {sup 7}Li(p,n){sup 7}Be reaction, which is known for producing a thermal spectrum with kT=25 keV. Measured neutron capture cross sections at kT=5.1 keV and kT=25 keV can be used to interpolate to kT=8 keV, which characterizes the dominant neutron exposure during s-process nucleosynthesis in thermally pulsing low-mass AGB stars. In a first application of this new method the Maxwellian-averaged neutron capture cross section of {sup 138}Ba was measured to be <{sigma}v>/v{sub T}=13.0{+-}0.5 mb at kT=5.1 keV.

• OSTI ID: 20695964
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 2 Vol. 71; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARIUM 138
CAPTURE
CROSS SECTIONS
DISTRIBUTION
ENERGY SPECTRA
GIANT STARS
KEV RANGE
NEUTRON EMISSION
NEUTRON REACTIONS
NEUTRON SPECTRA
NEUTRONS
NUCLEOSYNTHESIS
OXYGEN 18 TARGET
PROTON REACTIONS
PROTON-NUCLEON INTERACTIONS
PROTONS
S PROCESS