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Title: {Enhancement of Neutron Capture Rates for Deformed Nuclei and Impact on the r-process Nucleosynthesis Calculations

Authors:
 [1];  [1];  [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1324574
Report Number(s):
LA-UR-16-26785
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: Nuclei in the Cosmos XIV ; 2016-06-20 - 2016-06-24 ; Niigata, Japan
Country of Publication:
United States
Language:
English
Subject:
Atomic and Nuclear Physics

Citation Formats

Kawano, Toshihiko, Mumpower, Matthew Ryan, and Ullmann, John Leonard. {Enhancement of Neutron Capture Rates for Deformed Nuclei and Impact on the r-process Nucleosynthesis Calculations. United States: N. p., 2016. Web.
Kawano, Toshihiko, Mumpower, Matthew Ryan, & Ullmann, John Leonard. {Enhancement of Neutron Capture Rates for Deformed Nuclei and Impact on the r-process Nucleosynthesis Calculations. United States.
Kawano, Toshihiko, Mumpower, Matthew Ryan, and Ullmann, John Leonard. 2016. "{Enhancement of Neutron Capture Rates for Deformed Nuclei and Impact on the r-process Nucleosynthesis Calculations". United States. doi:. https://www.osti.gov/servlets/purl/1324574.
@article{osti_1324574,
title = {{Enhancement of Neutron Capture Rates for Deformed Nuclei and Impact on the r-process Nucleosynthesis Calculations},
author = {Kawano, Toshihiko and Mumpower, Matthew Ryan and Ullmann, John Leonard},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 9
}

Conference:
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  • We have made high-resolution neutron capture and transmission measurements on isotopically enriched samples of {sup 134}Ba and {sup 136}Ba at the Oak Ridge Electron Linear Accelerator (ORELA) in the energy range from 20 eV to 500 keV. Previous measurements had a lower energy limit of 3 - 5 keV, which is too high to determine accurately the Maxwellian-averaged capture cross section at the low temperatures (kT {approx} 6 - 12 keV) favored by the most recent stellar models of the {ital s}-process. Our results for the astrophysical reaction rates are in good agreement with the most recent previous measurement atmore » the classical {ital s}-process temperature, kT = 30 keV, but show significant differences at lower 40 temperatures. We discuss the astrophysical implications of these differences.« less
  • The neutron capture cross sections of /sup 112/Sn, /sup 130/Ba, /sup 146/Nd, /sup 148/Nd, /sup 186/W, /sup 190/Os, and /sup 192/Os at 24 keV neutron energy were measured with respect to /sup 197/Au by activation in a 24 keV neutron beam at the Brookhaven High Flux Beam Reactor. The reliability of this technique was verified by remeasuring the cross section of /sup 186/W and comparing it to previous measurements. This continuing series of measurements will provide a more reliable data base for nucleosynthesis calculations. 12 references.
  • We summarize results from a detailed parameter study of the s-process in models which produce an exponential distribution of exposures by sequential irradiations and dredge up in the stellar environment. The calculations are based on a complete network of measured and calculated neutron capture and beta-decay rates as well as estimates for their temperature dependence. In the framework of these models we identify and systematically vary the astrophysical variables which affect the observed solar-system sigmaN (cross section times abundance) curve. Constraints are placed on the s-process neutron exposure and flux as well as the temperatures, densities, neutron pulse shape andmore » inter-pulse period. The results also highlight important needs for better nuclear data in various mass regions.« less