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.