Restricted spin-range correction in the Oslo method: The example of nuclear level density and γ-ray strength function from Pu 239 (d,pγ) Pu 240
© 2019 American Physical Society. The Oslo method has been applied to particle-γ coincidences following the Pu239(d,p) reaction to obtain the nuclear level density (NLD) and γ-ray strength function (γSF) of Pu240. The experiment was conducted with a 12 MeV deuteron beam at the Oslo Cyclotron Laboratory. The low spin transfer of this reaction leads to a spin-parity mismatch between populated and intrinsic levels. This is a challenge for the Oslo method as it can have a significant impact on the extracted NLD and γSF. We have developed an iterative approach to ensure consistent results even for cases with a large spin-parity mismatch, in which we couple Green's function transfer calculations of the spin-parity dependent population cross-section to the nuclear decay code rainier. The resulting γSF shows a pronounced enhancement between 2-4 MeV that is consistent with the location of the low-energy orbital M1 scissors mode.
Zeiser, F.; Tveten, G. M.; Potel, G.; Larsen, A. C.; Guttormsen, M.; Laplace, T. A.; Siem, S.; Bleuel, D. L.; Goldblum, B. L.; Bernstein, L. A.; Bello Garrote, F. L.; Crespo Campo, L.; Eriksen, T. K.; Görgen, A.; Hadynska-Klek, K.; Ingeberg, V. W.; Midtbø, J. E.; Sahin, E.; Tornyi, T.; Voinov, A.; Wiedeking, M.; and Wilson, J., "Restricted spin-range correction in the Oslo method: The example of nuclear level density and γ-ray strength function from Pu 239 (d,pγ) Pu 240" (2019). Physics & Astronomy Open Access Publications. 23.