TY - JOUR
T1 - High-resolution neutron capture and total cross-section measurements, and the astrophysical 95Mo(n,γ) reaction rate at s-process temperatures
AU - Koehler, P. E.
AU - Harvey, J. A.
AU - Guber, K. H.
AU - Wiarda, D.
PY - 2008
Y1 - 2008
N2 - Abundances of Mo isotopes predicted by stellar models of the s process are, except for 95Mo, in good agreement with data from single grains of mainstream presolar SiC. Because the meteorite data seemed sound and no reasonable modification to stellar theory resulted in good agreement for 95Mo, it has been suggested that the recommended neutron capture reaction rate for this nuclide is 30% too low. Therefore, we have made a new determination of the 95Mo(n,γ) reaction rate via high-resolution measurements of the neutron-capture and total cross sections of 95Mo at the Oak Ridge Electron Linear Accelerator. These data were analyzed with the R-matrix code SAMMY to obtain parameters for resonances up to En = 10 keV. Also, a small change to our capture apparatus allowed us to employ a new technique to vastly improve resonance spin and parity assignments. These new resonance parameters, together with our data in the unresolved range, were used to calculate the 95Mo(n,γ) reaction rate at s-process temperatures. We compare the currently recommended rate to our new results and discuss their astrophysical impact.
AB - Abundances of Mo isotopes predicted by stellar models of the s process are, except for 95Mo, in good agreement with data from single grains of mainstream presolar SiC. Because the meteorite data seemed sound and no reasonable modification to stellar theory resulted in good agreement for 95Mo, it has been suggested that the recommended neutron capture reaction rate for this nuclide is 30% too low. Therefore, we have made a new determination of the 95Mo(n,γ) reaction rate via high-resolution measurements of the neutron-capture and total cross sections of 95Mo at the Oak Ridge Electron Linear Accelerator. These data were analyzed with the R-matrix code SAMMY to obtain parameters for resonances up to En = 10 keV. Also, a small change to our capture apparatus allowed us to employ a new technique to vastly improve resonance spin and parity assignments. These new resonance parameters, together with our data in the unresolved range, were used to calculate the 95Mo(n,γ) reaction rate at s-process temperatures. We compare the currently recommended rate to our new results and discuss their astrophysical impact.
UR - http://www.scopus.com/inward/record.url?scp=84887273849&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:84887273849
SN - 1824-8039
JO - Proceedings of Science
JF - Proceedings of Science
T2 - 10th Symposium on Nuclei in the Cosmos, NIC 2008
Y2 - 27 July 2008 through 1 August 2008
ER -