Physics – Nuclear Physics – Nuclear Experiment
Scientific paper
2006-10-26
Phys.Rev.C74:025807,2006
Physics
Nuclear Physics
Nuclear Experiment
10 pages, 5figures, recently published in Phys. Rev. C
Scientific paper
10.1103/PhysRevC.74.025807
The neutron capture cross section of Bi209 has been measured at the CERN n TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Additional experimental sources of systematic error, such as the electronic threshold in the detectors, summing of gamma-rays, internal electron conversion, and the isomeric state in bismuth, have been taken into account. Gamma-ray absorption effects inside the sample have been corrected by employing a nonpolynomial weighting function. Because Bi209 is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha-decays. In the relevant stellar range of thermal energies between kT=5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. At this low temperature an important part of the heavy Pb-Bi isotopes are supposed to be synthesized by the s-process in the He shells of low mass, thermally pulsing asymptotic giant branch stars. With the improved set of cross sections we obtain an s-process fraction of 19(3)% of the solar bismuth abundance, resulting in an r-process residual of 81(3)%. The present (n,gamma) cross-section measurement is also of relevance for the design of accelerator driven systems based on a liquid metal Pb/Bi spallation target.
No associations
LandOfFree
New measurement of neutron capture resonances of 209Bi does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with New measurement of neutron capture resonances of 209Bi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and New measurement of neutron capture resonances of 209Bi will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-114746