Journal Article

Neutron capture measurements and resonance parameters of dysprosium

Cho, M. H., Danon, Y., Ro, T. -I., Kye, Y. U., Williams, D., Rapp, M. J., Leinweber, G., Block, R. C., Lee, M. W., Kim, G. N., Barry, D. P., Namkung, W., Shin, S. G., Kang, Y. -R.

2017

Overview

. Neutron capture yields of dysprosium isotopes ( 161 Dy, 162 Dy, 163 Dy, and 164 Dy were measured using the time-of-flight method with a 16 segment sodium iodide multiplicity detector. The measurements were made at the 25m flight station at the Gaerttner LINAC Center at Rensselaer Polytechnic Institute. Resonance parameters were obtained using the multilevel R-matrix Bayesian code SAMMY. The neutron capture data for four enriched dysprosium isotopes and one natural dysprosium sample were sequentially fitted. New resonances not listed in ENDF/B-VII.1 were observed. There were 29 and 17 new resonances from 161 Dy and 163 Dy isotopes, respectively. Six resonances from 161 Dy isotope, two resonances from 163 Dy, and four resonances from 164 Dy were not observed. The capture resonance integrals of each isotope were calculated with the resulting resonance parameters and those of ENDF/B-VII.1 in the energy region from 0.5eV to 20MeV and were compared to the capture resonance integrals with the resonance parameters from ENDF/B-VII.1. A resonance integral value of the natural dysprosium calculated with present resonance parameters was 1405 ± 3 . 5 barn. The value is ∼ 0 . 3 % higher than that obtained with the ENDF/B-VII.1 parameters. The distributions of the present and ENDF/B-VII.1 neutron widths were compared to a Porter-Thomas distribution. Neutron strength functions for 161 Dy and 163 Dy were calculated with the present resonance parameters and both values were in between the values of “Atlas of Neutron Resonances” and ENDF/B-VII.1. The present radiation width distributions of 161 Dy and 163 Dy were fitted with the χ 2 distribution by varying the degrees of freedom.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Bayesian analysis / Dysprosium / Dysprosium isotopes / Hadrons / Heavy Ions / Integrals / Isotopes / Mathematical analysis / Multilevel / Nuclear capture / Nuclear Fusion / Nuclear Physics / Particle and Nuclear Physics / Physics / Physics and Astronomy / Regular Article - Experimental Physics