Resonance parameters of Gd isotopes derived from capture measurements at GELINA

Abstract

Neutron capture yields for $^{{155}}\hbox {Gd}$, $^{{156}}\hbox {Gd}$, $^{{157}}\hbox {Gd}$, $^{{158}}\hbox {Gd}$, and $^{{160}}\hbox {Gd}$ were determined applying the total energy detection principle technique using four $\hbox {C}_{{6}}\hbox {D}_{{6}}$ liquid scintillators and a $^{{10}}\hbox {B}$-loaded ionization chamber. Time-of-flight experiments were carried out at a 30 m flight path station of the GELINA facility using enriched samples. Parameters for resonances in the energy region between 5 and 500 eV were obtained from a resonance shape analysis with REFIT. Resonance integrals for $^{{155}}\hbox {Gd}$ and $^{{157}}\hbox {Gd}$ derived from the parameters are 1511 (25) b and 801 (19) b, respectively. Average level spacings, average radiation widths and neutron strength functions were derived. The results were compared with data that are reported in the literature and recommended in evaluated data libraries.

Appendix

We list resonance parameters derived from a resonance shape analysis with REFIT. All resonances were supposed to be s-wave resonances and the spin was adopted from the ENDF/B-VIII.0 library [11]. The resonance energy, neutron width and radiation width are denoted by ${E}_{{0}}$, $\Gamma _{\mathrm{n}}$, $\Gamma _{\upgamma }$, respectively. The uncertainties of the resonance parameters derived in this work are only due to propagating the uncertainties due to counting statistics (Tables 8, 9, 10, 11, 12, 13 and 14).

Table 8 Resonance parameters of $^{{155}}\hbox {Gd}$ isotope compared with those of ENDF/B-VIII.0 [11]

Table 9 Resonance parameters of $^{{156}}\hbox {Gd}$ isotope compared with those of ENDF/B-VIII.0 [11]

Table 10 Resonance parameters of $^{{157}}\hbox {Gd}$ isotope compared with those of ENDF/B-VIII.0 [11]

Table 11 Resonance parameters of $^{{158}}\hbox {Gd}$ isotope compared with those of ENDF/B-VIII.0 [11]

Table 12 Resonance parameters of $^{{160}}\hbox {Gd}$ isotope compared with those of ENDF/B-VIII.0 [11]

Table 13 Resonance energies and capture kernels of $^{{155}}\hbox {Gd}$ resonances that are not included in the main evaluated libraries and were observed in this work. The energies and kernels are compared with those observed by Baramsai et al. [13], Kang et al. [14], and Mastromarco et al. [15]

Table 14 Resonance energies and capture kernels of $^{{157}}\hbox {Gd}$ resonances that are not included in the main evaluated libraries and were observed in this work. The energies and kernels are compared with those observed by Kang et al. [14] and Mastromarco et al. [15]