Accurate determination of the parameters of the 292.4-eV resonance of ⁹¹Zr and the 301.1-eV resonance of ⁹⁶Zr

Abstract

High-resolution transmission measurements of zirconium" metal samples have been carried out at ORELA using the 80-m flight path and an improved 6 Li-glass scintillation neutron detector. Four different thicknesses of the pura zirconium metal and one sample of zircalloy were used in four separate experiments. The transmission data for these samples were measured at room temperature, and one sample was cooled to liquid nitrogen temperature. These data were analyzed using the multilevel R-matrix computer code SAMMY. The resonance parameters obtained for the 292.4-eV resonance of 91 Zr (including both statistical and systematic uncertainties) are: J*»3 + , E o =292.40±0.10 eV, r n =665±5 meV, r T =131±10 meV, and cc(r n ,r Y )=0.14. The parameters obtained for the 301.1-eV resonance in 96 Zr are: J=1/2 S E o =301.14±0.10 eV, r n =223±7 meV, iy=285±38 meV, and cc(r n ,r Y )=0.80.

Neutron Capture and Total Cross-Section Measurements and Resonance Parameters of Gadolinium

“…The present assignment of J ϭ 3 for the 292.5-eV s-wave resonance in 91 Zr is especially significant as it clarifies decades of conflict as shown in Table I. The present measurements confirm the J ϭ 3 assignment of Salah et al 8 for this resonance. Figure 2 contrasts the best fits possible with each J value.…”

“…The spin assignment for this resonance has a conflicting history, as Table I shows. The most recent work is that of Salah et al 8 who found this to be an s-wave resonance with J ϭ 3. The historical work on the 301.1-eV p-wave resonance in 96 Zr was less extensive.…”