[en] Previously published and unpublished analyses of neutron scattering data for several even-A tin isotopes show that either a Spherical Optical Model (SOM) or a Coupled Channel (CC) model describes the scattering data quite well. The dispersion relation was used to convert the scattering potential for ¹¹⁶Sn + n into a mean field, which should then provide a description of negative energy or bound states as well as of scattering. Only the mean field resulting from the CC analysis is successful in fitting the data at both positive and negative neutron energies. The CC mean field predicts single particle states calculated from the SOM mean field are very weakly bound, and are badly ordered. The results of both CC and SOM analyses will be presented

[en] Electron energy spectra and angular distributions were measured using magnetic spectrometer techniques, at isocenter, for two clinical linear accelerators: one scanning beam (Theratronics T20) and one scattering-foil (Philips SL25) machine. The energy spectra of the T20 were all of nearly Gaussian shape and energy full-width-at-half-maximum-intensity (FWHM) of about 5%. The energy distributions of the SL25 were of varied and unusual shapes, including shapes even with double peaks, and had energy FWHM from 9-22%. Peak spectral shapes for the SL25, in some cases, were observed to change over time. The effect of these varied spectra on depth-dose curves can be characterized by the spectral quantity < E₀ >^*, which is defined here as the mean energy of the incident spectral peak, termed the 'peak-mean-energy'. An analytical model shows that, in the absence of electrons at the patient plane with energies outside about < E₀ >^* ±0.1 < E₀ >^*,R_p and R₅₀ are both determined by < E₀ >^*. This is confirmed by a Monte Carlo calculation comparing depth-dose curves from two different idealized incident spectra. In addition, Monte Carlo depth-dose simulations based on the measured linac energy spectra show that the energy spread has only a small effect on the shape of the central axis depth-dose curve, even for FWHM as large as 20%. Furthermore, there is a much better correlation between the MC-derived R_p's and the peak-mean-energies (< E₀ >^*'s) than between the R_p's and the most probable energies (E_p,0's). These results imply that the peak-mean-energy is a more appropriate spectral quantity to use when describing electron beams at the surface compared to the most probable energy, E_p,0

[en] Fast neutron scattering from medium mass nuclei will be reviewed, with discussion of i-spin dependence. A survey of small angle elastic scattering provides cross sections consistent with experiments at larger angles. Inelastic scattering cross sections were measured near 3 MeV incident energy with both neutron and γ-ray detection, and are in good agreement

[en] At 2.5 MeV incident neutron energy the elastic scattering and inelastic scattering cross sections to the 2⁺ level can be reproduced with the addition of the C.C. model and WHF contributions, although the structure in the calculated angular distribution for the 2⁺ level is too small to match that in the measurements. However, the model which works to that extent in ¹⁵²Sm would fail to represent the elastic scattering cross sections for ¹⁴⁸Sm. If one expands the model space to include measurements to the 4⁺ and 6⁺ levels, all of these data cannot be satisfactorily fit even if the potential parameters are varied to attempt to achieve a fit. If one includes differential scattering cross sections for incident neutron energies of 6 MeV or greater, where WHF model calculations are insignificant, and also includes sigma/sub t/-values over a large range of energies together with low energy scattering properties, these measurements are all well described in a coupled-channels model which takes nuclear deformations explicitly into account. The quadrupole parameter, β₂, extracted from the analysis is significantly smaller than that implied by analysis of coulomb excitation cross sections for the same 2⁺ levels of /sup 152,154/Sm

[en] The energy levels and the decay schemes of ⁷⁶Se, ⁷⁸Se, ⁸⁰Se, ⁸²Se and ⁷⁶Ge have been studied through the measurements of (n,n'γ) differential cross sections. Gamma-ray excitation functions have been measured between 2.0- and 4.1-MeV incident neutron energy, and angular distribution have been observed for all of these isotopes

[en] Differential cross sections for neutron elastic and inelastic scattering from ⁷⁶Se, ⁷⁸Se, ⁸⁰Se and ⁸²Se, have been measured at 8-MeV incident neutron energy and from ⁷⁶Se and ⁸²Se at 6- and 10-MeV incident energies. The differences observed in the elastic scattering cross sections are interpretable as the effects of isospin term in the scattering potentials. A full analysis of the elastic scattering data are presented

No abstract available

[en] Neutron inelastic scattering cross sections can be obtained conveniently from (n,n'ß) yields provided a good normalization standard is available. Measurements from independent neutron and ß-ray detection experiments are compared to confirm the use of the ₅₆Fe(n,n'ß) ₅₆Fe - 846.7-keV production cross section as a normalization standard

[en] The large difference of the effective interaction for unlike nucleons from that for like nucleons in complex nuclei provides a powerful means of separating target proton from target neutron roles in collective excitations in nuclei when neutron scattering is combined with electromagnetic excitations or decay strengths. Results obtained for ⁴⁸Ca excitations are presented to illustrate the power of this separation method. Combining α-ray detection with neutron detection in neutron inelastic scattering enhances the ability to separate levels and identify varieties of collective excitations; lifetime measurements made with DSAM techniques in neutron scattering are a powerful means of fixing the needed electromagnetic strengths. The power of α-ray methods is illustrated by presenting multi-phonon multiplets for ⁹⁶Zr and for ¹⁴⁴Sm

No abstract available