Isotopic neon cross sections for a study of neutron balance and temperature during s-process nucleosynthesis

Journal Article · Tue Feb 01 00:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160686· OSTI ID:6085926

Almeida, J; Kaeppeler, F

The neutron source of the s-process is believed to the /sup 22/Ne(..cap alpha.., n) reaction, taking place in the He-burning shell of a pulsating red giant. Such a periodic neutron irradiation leads to an exponential distribution of neutron fluences for the seed nuclei, which can be deduced from the observed solar system abundances. Using this empirically determined distribution of neutron fluences and the abundances and the cross sections of the elements present in the He shell, the number of neutrons captured by each nuclear species during the s-process has been calculated. The /sup 22/Ne has as progenitors the C, N, and O isotopes involved in the CNO cycle, and is the most abundant nuclear species (apart from /sup 4/He and /sup 12/C) in the He shell; it was therefore anticipated that it would be a major neutron absorber. We have thus measured the capture cross sections of the three stable neon isotopes in the energy range 5--400 keV, and we determined the 30 keV Maxwellian averaged cross sections with an accuracy of better than 1 mb; the total cross sections were also measured, between 5 and 800 keV.

• OSTI ID: 6085926
• Journal Information: Astrophys. J.; (United States), Vol. 265:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
NUCLEOSYNTHESIS
S PROCESS
RED GIANT STARS
HELIUM BURNING
STAR MODELS
ALPHA REACTIONS
CAPTURE
CROSS SECTIONS
NEON 22 TARGET
NEUTRON DETECTION
NEUTRONS
NUCLEAR REACTIONS
BARYONS
CHARGED-PARTICLE REACTIONS
DETECTION
ELEMENTARY PARTICLES
FERMIONS
GIANT STARS
HADRONS
MATHEMATICAL MODELS
NUCLEONS
RADIATION DETECTION
STAR BURNING
STAR EVOLUTION
STARS
TARGETS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources