Browsing by Author "S.W. Yates"

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A study of measured neutron elastic differential neutron cross sections for 23Na
(Kluwer Academic Publishers, 2014) A. Kumar; M. Balasubramaniam; A. Chakraborty; B.P. Crider; S.F. Hicks; C. Karthikraj; L.J. Kersting; C.J. Luke; P.J. McDonough; M.T. McEllistrem; E.E. Peters; F.M. Prados-Estévez; A.J. Sigillito; M.M. Upadhyay; J.R. Vanhoy; S.W. Yates
Elastic neutron scattering angular distributions from 23Na have been measured for incident neutron energies between 1.0 and 4.0 MeV at the University of Kentucky Accelerator Laboratory using neutron time-of-flight techniques for the scattered neutrons. This is an energy region in which existing data are very sparse. Measurements are compared with the predictions of the light particle-induced reaction code TALYS. The calculations reproduce forward angle scattering but have difficulty with relative minima in the differential cross section and large-angle scattering. © Akadémiai Kiadó, Budapest, Hungary 2014.
Emerging collectivity from the nuclear structure of Xe 132: Inelastic neutron scattering studies and shell-model calculations
(American Physical Society, 2019) E.E. Peters; A.E. Stuchbery; A. Chakraborty; B.P. Crider; S.F. Ashley; A. Kumar; M.T. McEllistrem; F.M. Prados-Estévez; S.W. Yates
Inelastic neutron scattering was used to study the low-lying nuclear structure of Xe132. A comprehensive level scheme is presented, as well as new level lifetimes, multipole mixing ratios, branching ratios, and transition probabilities. Comparisons of these data as well as previously measured E2 strengths and g factors are made with new shell-model calculations for Xe132,134,136 to explore the emergence of collectivity in the Xe isotopes with N<82 near the closed shell. © 2019 American Physical Society.
Inelastic neutron scattering studies of Se 76
(American Physical Society, 2019) S. Mukhopadhyay; B.P. Crider; B.A. Brown; A. Chakraborty; A. Kumar; M.T. McEllistrem; E.E. Peters; F.M. Prados-Estévez; S.W. Yates
The low-lying, low-spin levels of Se76 were studied with the (n,n′γ) reaction. Gamma-ray excitation function measurements were performed at incident neutron energies from 2.0 to 3.5 MeV, and γ-ray angular distributions were measured at neutron energies of 2.4, 3.0, and 3.7 MeV. From these measurements, level spins, level lifetimes, branching ratios, and multipole mixing ratios were determined. We established the 02+ band, which supports the shape coexistence in Se76 predicted by large-scale shell model calculations and the interacting boson model. © 2019 American Physical Society.
Level lifetimes and the structure of Xe 134 from inelastic neutron scattering
(American Physical Society, 2017) E.E. Peters; A. Chakraborty; B.P. Crider; S.F. Ashley; E. Elhami; S.F. Hicks; A. Kumar; M.T. McEllistrem; S. Mukhopadhyay; J.N. Orce; F.M. Prados-Estévez; S.W. Yates
The level structure of Xe134 was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a 0+ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The 3- octupole phonon has been confirmed, and the complete negative-parity multiplet resulting from the ν(1h11/22d3/2) configuration has also been tentatively identified for the first time in the N=80 isotones. © 2017 American Physical Society.
Neutron scattering differential cross sections for 23Na from 1.5 to 4.5 MeV
(Elsevier, 2015) J.R. Vanhoy; S.F. Hicks; A. Chakraborty; B.R. Champine; B.M. Combs; B.P. Crider; L.J. Kersting; A. Kumar; C.J. Lueck; S.H. Liu; P.J. McDonough; M.T. McEllistrem; E.E. Peters; F.M. Prados-Estévez; L.C. Sidwell; A.J. Sigillito; D.W. Watts; S.W. Yates
Measurements of neutron elastic and inelastic scattering cross sections from 23Na have been performed for sixteen incident neutron energies between 1.5 and 4.5 MeV. These measurements were complemented by γ-ray excitation functions using the (n, n'γ) reaction to include excited levels not resolved in the neutron detection measurements. The time-of-flight (TOF) technique was employed for background reduction in both neutron and γ-ray measurements and for energy determination in neutron detection measurements. Previous reaction model evaluations relied primarily on neutron total cross sections and four (n, n0) and (n, n1) angular distributions in the 5 to 9 MeV range. The inclusion of more inelastic channels and measurements at lower incident neutron energies provide additional information on direct couplings between elastic and inelastic scattering as a function of angular momentum transfer. Reaction model calculations examining collective direct-coupling and compound absorption components were performed. © 2015 Elsevier B.V.
Seniority structure of Xe82 136
(American Physical Society, 2018) E.E. Peters; P. Van Isacker; A. Chakraborty; B.P. Crider; A. Kumar; S.H. Liu; M.T. McEllistrem; C.V. Mehl; F.M. Prados-Estévez; T.J. Ross; J.L. Wood; S.W. Yates
The level structure of the N=82 nucleus Xe136 was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of the spins and parities were reassigned, and many level lifetimes were determined for the first time using the Doppler-shift attenuation method. New shell-model calculations were also performed using both the full Z=50-82 model space, and a reduced model space including only the 1d5/2 and 0g7/2 orbitals. This new information characterizing Xe136 was used to identify the seniority structure of the low-lying levels and to assign (π0g7/2)υ=04, (π0g7/2)υ=24, (π0g7/2)υ=44, (π1d5/2)(π0g7/2)υ=13, and (π1d5/2)2(π0g7/2)υ=02 configurations to describe all observed states below 2.8 MeV. © 2018 American Physical Society.