Neutron capture yields and resonance parameters of dysprosium isotopes measured at Japan Proton Accelerator Research Complex

Abstract

Neutron capture yields of dysprosium isotopes (161Dy, 162Dy, 163Dy, and 164Dy) were measured using the time-of-flight method with a NaI(Tl) spectrometer locate at 27.9m from the spallation neutron target in the ANNRI beamline at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. The resonance parameters were determined using the multilevel R-matrix Bayesian code SAMMY in the neutron energy range of 1 to 300eV. Five resonances of the 161Dy isotope, reported by Shin et al. but not presented in ENDF/B-VII.1, were confirmed in this study. One resonance of the 164Dy isotope presented in ENDF/B-VII.1 was not observed in this study. The measured average level spacings were $2.31\pm 0.23$ eV for 161Dy and $6.91\pm 0.69$ eV for 163Dy. The statistical distributions of the resonance parameters reasonably agreed with the Porter-Tomas distributions and multiple exit channel theory.