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Neutron scattering and models: Silver

Description: Differential neutron elastic-scattering cross sections of elemental silver were measured from 1.5 {r_arrow} 10 MeV at {approx} 100 keV intervals up to 3 MeV, at {approx} 200 keV intervals from 3 {r_arrow} 4 MeV, and at {approx} 500 keV intervals above 4 MeV. At {le} 4 MeV the angular range of the measurements was {approx} 20{sup 0} {r_arrow} 160{sup 0} with 10 measured values below 3 MeV and 20 from 3 {r_arrow} 4 MeV at each incident energy. Above 4 MeV {ge} 40 scattering angles were used distributed between {approx} 17{sup 0} and 16{sup 0} All of the measured elastic distributions included some contributions due to inelastic scattering. Below 4 MeV the measurements determined cross sections for ten inelastically-scattered neutron groups corresponding to observed excitations of 328 {+-} 13, 419 {+-} 50, 748 {+-} 25, 908 {+-} 26, 115 {+-} 38, 1286 {+-} 25, 1507 {+-} 20, 1632 {+-} 30, 1835 {+-} 20 and 1944 {+-} 26 keV. All of these inelastic groups probably were composites of contributions from the two isotopes {sup 107}Ag and {sup 109}Ag. The experimental results were interpreted in terms of the spherical optical model and of rotational and vibrational coupled-channels models, and physical implications are discussed. In particular, the neutron-scattering results are consistent with a ground-state rotational band with a quadrupole deformation {Beta}{sub 2} = 0.20 {+-} {approx} 10% for both of the naturally-occurring silver isotopes.
Date: July 1, 1996
Creator: Smith, A.B.
Partner: UNT Libraries Government Documents Department

Target dependence of proton source sizes at 14.6 A GeV/c

Description: Relative-momentum correlations have been measured for pairs of protons from central collisions of 14.6 A-GeV/c {sup 28}Si with {sup 27}Al, {sup 107}Ag, and {sup 197}Au nuclei. The protons were detected in a region centered near a laboratory rapidity of 1.2. Theoretical correlation functions are convoluted with the spectrometer response function and fitted to the data to derive the source volume. The fitted radii are corrected for small relativistic effects. The extracted volumes are consistent with a crude geometrical overlap model and depart from {pi} - {pi} and K-K data trends which suggest a source size closer to that of the projectile.
Date: May 1, 1994
Creator: Stephans, G. S. F.
Partner: UNT Libraries Government Documents Department

Doppler broadening effect to neutron resonance cross sections for Ag, AgCl, and Ag/sub 2/O. [Yield, Debye temperature]

Description: The neutron capture yield of the 16.3 eV resonance in /sup 107/Ag was measured, using targets of Ag metal, AgCl and Ag/sub 2/O at room, liquid N/sub 2/ and He temperatures. The effective temperature T' defined by Lamb for weak binding, and subsequently the Debye temperature theta/sub D/, were extracted for each case by a least squares shape fit. For Ag metal the measured theta/sub D/ values agree with both the simple Debye theory and a prediction of the Ag lattice dynamics. The theta/sub D/ values for AgCl and Ag/sub 2/O show some variations with temperature. The results for AgCl at 77.2 and 4.066/sup 0/, however, agree with the inelastic scattering and calorimetric data. 12 references.
Date: January 1, 1979
Creator: Liou, H.I.; Chrien, R.E. & Moreh, R.
Partner: UNT Libraries Government Documents Department

Deep-inelastic processes: a workbench for large scale motion in nuclear matter

Description: The most prominent collective modes excited in deep-inelastic reactions are reviewed, and the natural hierarchy provided by their characteristic relaxation times is described. A model is presented which treats the relaxation of the mass asymmetry mode in terms of a diffusion process. Charge distributions and angular distributions as a function of Z calculated with this model are in good agreement with experimental data. An extension of this diffusion model which treats the transfer of energy and angular momentum in terms of particle transfer is described, and is successfully compared with experimental ..gamma..-ray multiplicities as a function of both Q-value and mass asymmetry. The problem of angular momentum transfer is again considered in connection with the sequential fission of heavy, deep-inelastic fragments and the excitation of collective modes in the exit channel is suggested. Lastly, the role of the giant E1 mode in the equilibration of the neutron-to-proton ratio is discussed. 14 figures, 39 references.
Date: July 1, 1978
Creator: Moretto, L.G. & Schmitt, R.P.
Partner: UNT Libraries Government Documents Department

16. 3 eV neutron capture in /sup 107/Ag: nuclear structure of /sup 108/Ag. [Transitions, J correlations,. pi. ]

Description: The ..gamma.. rays from neutron capture in the 0- resonance of /sup 107/Ag at 16.3 eV were studied. Thirteen primary transitions populate spin 1 levels in /sup 108/Ag below an energy of 1.5 MeV. Transitions from low lying levels change in intensity by as much as a factor of 2 between thermal neutron capture (largely spin 1) and the 0- resonance, indicating a strong correlation of the population with level spin. 7 references.
Date: January 1, 1978
Creator: Orr, G.B.; Kane, W.R. & Smith, G.J.
Partner: UNT Libraries Government Documents Department