New neutron capture and transmission measurements for 134,136Ba at ORELA and their impact on s-process nucleosynthesis calculations

Koehler, P.; Spencer, R.R.; Winters, R. R.; Guber, K. H.; Harvey, J.; Hill, N.W.; Smith, M. S.

doi:10.1016/s0375-9474(97)00250-9

Cited by 3 publications

(1 citation statement)

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“…A prominent example was the Oak Ridge Electron Linear Accelerator (ORELA) [223], where important experimental techniques have been developed [138,224] and where most of the initial MACS data for s-process studies have been determined in numerous measurements by Macklin and collaborators (see, e.g., [225,226,227,228], including first studies on unstable isotopes [229,230,231,232]. After an update of the experimental setup, astrophysics at ORELA was resumed by Koehler et al with (n, γ) and (n, α) measurements on isotopes of Sr, Mo, Ba, Sm, and Pt [233,234,235,236,237,238].…”

Section: White Neutron Sourcesmentioning

confidence: 99%

Neutron reactions in astrophysics

Reifarth

Lederer

Käppeler

2014

J. Phys. G: Nucl. Part. Phys.

157

141

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The quest for the origin of matter in the Universe had been the subject of philosophical and theological debates over the history of mankind, but quantitative answers could be found only by the scientific achievements of the last century. A first important step on this way was the development of spectral analysis by Kirchhoff and Bunsen in the middle of the 19 th century, which provided first insight in the chemical composition of the sun and the stars. The energy source of the stars and the related processes of nucleosynthesis, however, could be revealed only with the discoveries of nuclear physics. A final breakthrough came eventually with the compilation of elemental and isotopic abundances in the solar system, which are reflecting the various nucleosynthetic processes in detail.This review is focusing on the mass region above iron, where the formation of the elements is dominated by neutron capture, mainly in the slow (s) and rapid (r) processes. Following a brief historic account and a sketch of the relevant astrophysical models, emphasis is put on the nuclear physics input, where status and perspectives of experimental approaches are presented in some detail, complemented by the indispensable role of theory.

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Section: White Neutron Sourcesmentioning

confidence: 99%

Neutron reactions in astrophysics

Reifarth

Lederer

Käppeler

2014

J. Phys. G: Nucl. Part. Phys.

157

141

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Neutron capture studies on unstableCs135for nucleosynthesis and transmutation

Patronis

Dababneh²,

Assimakopoulos

et al. 2004

Phys. Rev. C

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The neutron capture cross section of the unstable isotope 135 Cs was measured relative to that of gold by means of the activation method. The sample was produced by ion implantation in a high resolution mass separator and irradiated with quasimonoenergetic neutrons at 30 keV and 500 keV, using the 7 Li͑p , n͒ 7 Be reaction. An additional irradiation with thermal neutrons has been carried out for defining the sample mass and for measuring the half-life of 136 Cs. The neutron capture cross sections were determined as 164± 10 mb and 34.8± 3.0 mb at 30 keV and 500 keV, respectively, and were used to normalize the theoretically derived cross section shape. Based on these data, refined statistical model calculations were performed to obtain the ͑n , ␥͒ cross sections of the short-lived isotopes 134 Cs and 136 Cs as well. Updated Maxwellian-averaged capture cross sections of all unstable Cs isotopes were calculated for a range of thermal energies characteristic of helium burning scenarios for an improved s-process analysis of the Xe-Cs-Ba region.

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