Evaluation of neutron nuclear data for gallium

Abstract

Neutron nuclear data on 69,71 Ga have been evaluated for the next version of the Japanese Evaluated Nuclear Data Library (JENDL) general purpose file in the energy region from 10 −5 eV to 20 MeV. The resolved resonance parameters at negative energies were adjusted so as to reproduce measured thermal capture cross sections. The statistical model was applied to calculate the cross sections above the resolved resonance region. In the calculations, coupled-channel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present evaluation is consistent with available experimental data. The evaluated data are compiled into an ENDF-formatted data file.

Evaluation of neutron nuclear data on iodine isotopes

“…and WID V were adjusted together with the β 2 values for 127, 129 I, while the rest of the parameters remain unchanged from the original ones [20]. Concerning charged particles, the spherical parameters of Koning and Delaroche [23] for protons, those of Lohr and Haeberli [24] for deuterons, those of Becchetti and Greenlees [25] for tritons and 3 He, and those of Lemos [26] modified by Arthur and Young [27] for α-particles were used. The transmission coefficients, which are required by CCONE to calculate charged-particle emission, are obtained from the charged-particle parameters.…”

“…The Version 0.8.4 of CCONE incorporates preequilibrium process for the (n, γ ) and first-step binary reactions such as (n, n ), (n, p), (n, d), (n, t), (n, 3 He) and (n, α). In the two-exciton pre-equilibrium formalism, the single-particle state densities for protons and neutrons in a residual nucleus are described [36] by…”

“…More experimental data are available for (n, 2n) than for (n, n ) in the nuclides presently concerned. In addition to the C 0 's, the pre-equilibrium parameters for complexparticle emission [37] were determined, i.e., those for the deuteron pickup reaction from the 127 I(n, t) reaction and those for the 3 He pickup and the α knockout reactions from the 127 I(n, α) reaction. These parameters for the complex particles were used for all iodine targets.…”

“…Hence, the fast-neutron cross sections for the rest of the fission-product nuclides may need improvements for the next version of JENDL general-purpose file. Under such circumstances, re-evaluations have been actually performed for the data on Er [2], Ga [3], Ru [4], Sb [5] and Te [6], after the release of JENDL-4.0. Iodine is the next target to be dealt with.…”

“…Moreover, the data on 128 I were newly evaluated, since the (n, γ ) reaction on 128 I yields a long-life (T 1/2 = 1.57 × 10 7 y) nucleus 129 I. The total, elastic and inelastic scattering, (n, γ ), (n, p), (n, d), (n, t), (n, 3 He), (n, α), (n, np), (n, nd), (n, nα), (n, 2n), (n, 3n), (n, 2np) reaction cross sections, the angular distributions of elastically and inelastically scattered neutrons, and the energy distributions of emitted particles and γ -rays in the energy region from 10 −5 eV to 20 MeV are evaluated. The Q-values of the reactions were calculated from the 2012 version of the mass table (AME2012 [12]), and are listed in Table 1, together with abundance and half-lives [13].…”