Partial cross sections of the Mo92(p,γ) reaction and the γ strength in Tc93

J. Mayer, S. Goriely, L. Netterdon, S. Péru, P. Scholz, R. Schwengner, and A. Zilges
Phys. Rev. C 93, 045809 – Published 20 April 2016

Abstract

Background: Mo92 is the most abundant nucleus of the p nuclei, with an isotopic abundance of more than 14 %. The γ-process nucleosynthesis is believed to produce Mo92 but fails to explain its large abundance, especially with respect to the other p nuclei produced in the same stellar environment. Further studies require precise nuclear models for the calculation of reaction cross sections.

Purpose: A measurement of the total and partial cross sections of the Mo92(p,γ)Tc93 reaction allows for a stringent test of statistical-model predictions. Not only different proton+nucleus optical model potentials, but also the γ-ray strength function of Tc93 can be investigated. In addition, high-resolution in-beam γ-ray spectroscopy enables the determination of new precise nuclear structure data for Tc93.

Method: Total and partial cross-section values were measured by using the in-beam method. Prompt γ rays emitted during the irradiation of Mo92 with protons at seven different energies between 3.7  and 5.3 MeV were detected by using the high-purity germanium (HPGe) detector array HORUS at the Institute for Nuclear Physics, University of Cologne. The γγ-coincidence method was applied to correlate γ-ray cascades in Tc93 with their origin in the Mo92+p compound state.

Results: The measured cross sections are compared to Hauser–Feshbach calculations by using the statistical-model code talys on the basis of different nuclear physics input models. Using default settings based on standard phenomenological models, the experimental values cannot be reproduced. A shell-model calculation was carried out to predict the low-energy M1 strength in Tc93. Together with Gogny–Hartree–Fock–Bogoliubov (Gogny-HFB) or Skyrme-HFB plus quasi-particle random-phase approximation (QRPA) models for the γ-ray strength function, the agreement between experimental data and theoretical predictions could be significantly improved. In addition, deviations from the adopted level scheme were found.

Conclusions: By using Gogny- or Skyrme-HFB+QRPA E1 and shell-model M1 strength functions, statistical-model predictions can be significantly improved. Partial cross sections provide a valuable testing ground for γ-ray strength functions for nuclear astrophysics applications. In addition, they can be used to investigate nuclear-structure properties of the compound nucleus.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
3 More
  • Received 28 November 2015

DOI:https://doi.org/10.1103/PhysRevC.93.045809

©2016 American Physical Society

Physics Subject Headings (PhySH)

Nuclear Physics

Authors & Affiliations

J. Mayer1,*, S. Goriely2, L. Netterdon1, S. Péru3, P. Scholz1, R. Schwengner4, and A. Zilges1

  • 1Institute for Nuclear Physics, University of Cologne, Zülpicher Str. 77, 50937 Cologne, Germany
  • 2Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles, CP226, 1050 Brussels, Belgium
  • 3CEA, DAM, DIF, F-91297 Arpajon, France
  • 4Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany

  • *jan.mayer@ikp.uni-koeln.de

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 93, Iss. 4 — April 2016

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review C

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×