Nuclear-level densities in the 49V and 57Co nuclei on the basis of evaporated-neutron spectra in (p, n) and (d, n) reactions

Resumo

The spectra of neutrons from the reactions ⁴⁹Ti(p, n)⁴⁹V and ⁵⁷Fe (p, n)⁵⁷Co were measured in the range of proton energies between 8 and 11 MeV along with their counterparts from the reactions ⁴⁸Ti(d, n)⁴⁹V and ⁵⁶Fe (d, n)⁵⁷Co at the deuteron energies of 2.7 and 3.8 MeV. These measurements were conducted with the aid of a time-of-flight fast-neutron spectrometer on the basis of the EGP-15 pulsed tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations based on the Hauser–Feshbach formalism of statistical theory were carried out with nuclear-level densities given by the generalized superfluid model of the nucleus, the backshifted Fermi-gas model, and the Gilbert–Cameron composite formula. The nuclear-level densities of ⁴⁹V and ⁵⁷Co and their energy dependences were determined. The results were discussed together with available experimental data and data recommended by model systematics.