Phys. Rev. C 67, 015807 (2003) [9 pages]Cross section measurements of the 181Ta(γ,n)180Ta reaction near neutron threshold and the p-process nucleosynthesisReceived 9 October 2002; published 31 January 2003 New measurements of the photoneutron reaction on 181Ta have been conducted with the AIST-LCS (laser Compton scattering) beam in the 7.8≲E[MeV]≲12 energy range. The major advantage of the present γ-ray experiment is its intense peaking in the energy window of astrophysical interest, i.e., close to the neutron threshold. Details on photon beams from the laser Compton scattering, neutron counting, and experimental determination of the 181Ta photoneutron cross section are given. The present experimental data are in good agreement with the IAEA evaluation. Reaction rate calculations in the Hauser-Feshbach statistical model are performed and confronted with the experimental data. The data provide constraints on the low-energy tail of the dipole strength function. It is found that among the three different models for the E1-strength considered, only the microscopic quasiparticle random phase approximation model can reproduce the extra strength observed in the 181Ta(γ,n)180Ta reaction at energies of about 8.5 MeV. Such an experiment helps to improve the determination of the corresponding stellar photodisintegration rate of 181Ta which directly influences the p-process production of 180Ta. © 2003 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevC.67.015807
DOI:
10.1103/PhysRevC.67.015807
PACS:
25.20.-x, 26.30.+k, 27.70.+q, 97.10.Tk
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