High-Resolution Neutron Capture and Total Cross-Section Measurements, and the Astrophysical 95Mo(n,gamma) Reaction Rate at s-process Temperatures
- ORNL
Abundances of Mo isotopes predicted by stellar models of the s process are, except for {sup 95}Mo, 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 {sup 95}Mo, 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 {sup 95}Mo(n,{gamma}) reaction rate via high-resolution measurements of the neutron-capture and total cross sections of {sup 95}Mo at the Oak Ridge Electron Linear Accelerator. These data were analyzed with the R-matrix code SAMMY to obtain parameters for resonances up to E{sub n} = 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 {sup 95}Mo(n,{gamma}) reaction rate at s-process temperatures. We compare the currently recommended rate to our new results and discuss their astrophysical impact.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oak Ridge Electron Linear Accelerator
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 951925
- Resource Relation:
- Conference: 10th International Symposium on Nuclei in the Cosmos (NIC-X), Mackinac Island, MI, USA, 20080727, 20080801
- Country of Publication:
- United States
- Language:
- English
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