Calculation of cross sections for metastable state production in the (n, γ), (n, n′), (n, 2n) and (n, 3n) reactions of ⁹³Nb

Abstract

Toward the revision of 93 Nb data in the Japanese Evaluated Nuclear Data Library JENDL-4.0, we calculated cross sections for metastable state production (MSP) in the (n, γ), (n, n), (n, 2n) and (n, 3n) reactions in the incident energy (E n) range from 7 keV to 20 MeV. The cross sections were evaluated using nuclear reaction models such as the spherical optical model, the multi-step statistical model, preequilibrium models, and the distorted-wave Born approximation (DWBA). By adjusting parameters of nuclear level densities, we could obtain the MSP cross sections which are almost consistent with the experimental data.

Optical potential for incident and emitted low-energy $α$ particles. III. Non-statistical processes induced by neutrons on Zr, Nb, and Mo nuclei

“…by analysis of the sand p-wave neutron strength functions S 0 and S 1 , respectively, the potential scattering radius R ′ [22] (Table II), and the energy dependence of the neutron total crosssection σ T (E) [32]. Thus, we found that the global parameter set [33] provides a better agreement between the measured and calculated σ T (E) of 93 Nb within this energy range, in comparison to the related local parameter set [Fig. 1(a)].…”

“…For nuclei without resonance data, the smooth-curve method [34] was used, in which an average of fitted a-values for nearby nuclei is adopted while the ∆ value is obtained by fit of the low-lying discrete levels. [32] and calculated neutron total cross-sections of (a) 93 Nb, using the global (dashed curve) and local (dash-dotted curve) OMP parameters of Koning and Delaroche [33], and (b) 95 Mo (thick, lower curves) and 97 Mo (thin, upper curves) with global (dashed curves) as well as the corresponding modified values of v1 parameters given in Table II (solid curves).…”

“…The same OMP parameters have been involved within DWBA assessment of the collective inelastic scattering, using the deformation parameters [39][40][41] of the first 2 + and 3 − collective states. Typical direct inelasticscattering cross-sections increase to, e.g., ∼7% of σ R for neutrons on 93 Nb and 98 Mo at incident energies around 4 MeV and then decrease to slightly less than 5% at energies above 20 MeV. They were then involved in a subsequent decrease of σ R that has been taken into account within the PE+HF analysis.…”

“…II along with items of the DR analysis by the distorted-wave Born approximation (DWBA) method and code FRESCO [19]. A comparison of HF+PE results and (i) recent (α, γ) and (α, n) crosssections of Zr and Mo nuclei, for α-particle OPM additional proof, (ii) available data of neutron-induced activation by nucleon-emission for 93 Nb and 92 Mo, as for Zr nuclei [5], and (iii) α-emission for all Zr, Nb, and Mo isotopes including eventual excited-nucleus like-GQR decay, are discussed in Sec. III.…”

93Nb(n,2n)92mNb, 93Nb(n,α)90mY and 92Mo(n,p)92mNb reactions at 14.78 MeV and covariance analysis

“…The neutron induced reaction cross sections are very useful in various field such as in the nuclear technology, for the investigation of nuclear theory, to explain the nuclear reaction mechanism and in fusion reactor facility [1][2][3][4]. The cross section of 93 Nb(n,2n) 92m Nb reaction is used as a flux monitor for the 14 MeV neutron generator [5][6][7]. The natural niobium metal has high-melting point and thus is used as an element of superconductor alloys in fusion reactors, as a structural material in thermonuclear reactors and for the advance reactor design [8][9][10].…”