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Experiments on Polarization in Scatterig Deuterons from Complex Nuclei and in Proton-Proton Scattering (Thesis)

Description: Abstract: "The elastic double scattering of deuterons by complex nuclei has been investigated experimentally. Measurements were made on carbon, aluminum, and copper at around 157 Mev; on lithium, beryllium, and carbon at around 125 Mev; and on carbon and aluminum at 94 Mev. The expected tensor components of the deuteron polarization have not been observed. Measurements have been made of the differential cross section and vector-type polarization as a function of angle for the scattering of deuterons from the above elements, at the above energies. The observed polarizations were larger than would be expected on the basis of the individual nucleon-nucleus interactions. In a second experiment we measured the 169-Mev proton-proton polarization at 10, 15, 22.5, 30, and 35 in the laboratory system. The results indicate that partial waves up to and including L = 3 are important at this energy."
Date: May 11, 1956
Creator: Baldwin, John A., Jr.
Partner: UNT Libraries Government Documents Department


Description: Calculational procedures oriented toward computer application are preserted to evaluate the neutron inelastic scattering cross section in the incoherent approximation for a simple cubic Bravais lattice. The differential scattering cross section, the scattering law, or inelastic scattering matrices and transport cross sections for multigroup calculations are evaluated using the contributions of 25 phonons. The inelastic scattering cross section for graphite is calculated as an example of polycrystalline media where the phonon-frequency distribution is dependent on the direction of polarization. (H.D.R.)
Date: September 1, 1962
Creator: Jankus, V.Z.
Partner: UNT Libraries Government Documents Department

2009 International Conference on Neutron Scattering (ICNS 2009)

Description: The ICNS provides a focal point for the worldwide neutron user community to strengthen ties within this diverse group, while at the same time promoting neutron research among colleagues in related disciplines identified as “would-be” neutron users. The International Conference on Neutron Scattering thus serves a dual role as an international user meeting and a scientific meeting. As a venue for scientific exchange, the ICNS showcases recent results and provides forums for scientific discussion of neutron research in diverse fields such as hard and soft condensed matter, liquids, biology, magnetism, engineering materials, chemical spectroscopy, crystal structure, and elementary excitations, fundamental physics and development of neutron instrumentation through a combination of invited talks, contributed talks and poster sessions. Each of the major national neutron facilities (NIST, LANSCE, ANL, HFIR and SNS), along with their international counterparts, has an opportunity to exchange information with each other and to update users, and potential users, of their facility. This is also an appropriate forum for users to raise issues that relate to the facilities.
Date: August 5, 2010
Creator: Rao, Gopal & Gillespie, Donna
Partner: UNT Libraries Government Documents Department

Gamma Rays from Inelastic Scattering of 14-Mev Neutrons on Pb²⁰⁸

Description: Abstract: "The cross section for the production of 2.61-Mev gamma rays from the Pb-208(n, n')Pb-208* reaction has been measured for five different angles from 50 to 130 degrees. The angular distribution appears to be isotropic within the precision of the experiments, and leads to an integrated cross section of 25.5 +/- 4.6 millibarns."
Date: August 25, 1959
Creator: Hallett, Edward & Jensen, Roger
Partner: UNT Libraries Government Documents Department

Application of Scattering Theory to the Measurement of Turbulent Density Fluctuations by an Optical Method

Description: "An analysis shows that the scattering of unpolarized plane light waves which penetrate turbulent, transparent gases provides a measure of the average integral scale and intensity of the turbulent density fluctuations. The analysis is based upon the scattering coefficient deduced by Booker and Gordon and, thus, assumes isotropic fluctuations having an exponentially decaying (Markoffian) correlation function. Photometric data taken through turbulent boundary layers in air are found to conform functionally with the analytical prediction" (p. 1).
Date: June 1956
Creator: Stine, Howard A. & Winovich, Warren
Partner: UNT Libraries Government Documents Department

Compton Scattering on Nucleons

Description: From introduction: "The present paper deals with a classical calculation in which some of the meson effects can be included to all orders in the meson-nucleon coupling coupling constant, in particular those having to do with the gyration of the nucleon spin and isotopic spin. Such a treatment leads to results qualitatively different from the weak coupling calculations."
Date: May 24, 1954
Creator: Huddlestone, Richard Harold
Partner: UNT Libraries Government Documents Department

Elastic Scattering of 7 Mev Neutrons (Theoretical Curves)

Description: Abstract: "Theoretical differential cross-sections computed from the optical model for 7 Mev neutrons are presented for a large number of nuclei. The parameters used for the calculations were selected on the basis of best fit to existing experimental data."
Date: July 1957
Creator: Bjorklund, F. & Fernbach, Sidney, 1917-1991
Partner: UNT Libraries Government Documents Department

Elastic Scattering of 14 Mev Neutrons (Theoretical Curves)

Description: Abstract: "Theoretical differential cross-sections computed from the optical model for 14 Mev neutrons are presented for a large number of nuclei. The parameters used for the calculations were selected on the basis of best fit to existing experimental data."
Date: July 1957
Creator: Bjorklund, F. & Fernbach, Sidney, 1917-1991
Partner: UNT Libraries Government Documents Department

Direct Interaction Neutrons from 14-Mev Inelastic Neutron Scattering

Description: Abstract: "Neutron nonelastic cross sections measured at different detector biases have been used to determine the cross sections for inelastically scattering 14 Mev neutrons into 9- to 14-Mev energy range. The cross section for producing these high energy neutrons, which may be attributed to direct interaction processes, is roughly 10% of the nonelastic cross section, for all elements. A comparison is made with data of Coon and co workers, who measured angular distributions for the same high-energy inelastically scattered-neutron group."
Date: May 19, 1958
Creator: MacGregor, Malcolm H.
Partner: UNT Libraries Government Documents Department

Angular distribution of neutrons from a plane surface

Description: From introduction: "This report determines lattice losses by considering the angular distribution of the neutrons emitted from the interior faces of the lattice and the exterior faces of the target. The purpose of this report is to investigate this problem by considering the dimensions of the faces to be large compared to the total mean free path."
Date: 1951
Creator: Harker, Wesley H.
Partner: UNT Libraries Government Documents Department

Implementation of exterior complex scaling in B-splines to solve atomic and molecular collision problems

Description: B-spline methods are now well established as widely applicable tools for the evaluation of atomic and molecular continuum states. The mathematical technique of exterior complex scaling has been shown, in a variety of other implementations, to be a powerful method with which to solve atomic and molecular scattering problems, because it allows the correct imposition of continuum boundary conditions without their explicit analytic application. In this paper, an implementation of exterior complex scaling in B-splines is described that can bring the well-developed technology of B-splines to bear on new problems, including multiple ionization and breakup problems, in a straightforward way. The approach is demonstrated for examples involving the continuum motion of nuclei in diatomic molecules as well as electronic continua. For problems involving electrons, a method based on Poisson's equation is presented for computing two-electron integrals over B-splines under exterior complex scaling.
Date: November 18, 2003
Creator: McCurdy, C. William & Martin, Fernando
Partner: UNT Libraries Government Documents Department

Thomson Scattering Density Calibration by Rayleigh and Rotational Raman Scattering on NSTX

Description: The multi-point Thomson scattering (MPTS) diagnostic measures the profiles of the electron temperature Te(R) and density ne(R) on the horizontal midplane of NSTX. Normal operation makes use of Rayleigh scattering in nitrogen or argon to derive the density profile. While the Rayleigh scattering ne(R) calibration has been validated by comparison with other density measurements and through its correlation with plasma phenomena, it does require dedicated detectors at the laser wavelength in this filter polychromator based diagnostic. The presence of dust and/or stray laser light precludes routine use of these dedicated spectral channels for Thomson scattering measurement. Hence it is of interest to investigate the use of Raman scattering in nitrogen for the purpose of density calibration, since it could free up detection equipment, which could then be used for the instrumentation of additional radial channels. In this paper the viewing optics "geometrical factor" profiles obtained from Rayleigh and Raman scattering are compared. While both techniques agree nominally, residual effects on the order of 10% remain and will be discussed.
Date: July 16, 2008
Creator: LeBlanc, B.P.
Partner: UNT Libraries Government Documents Department


Description: BS>Graphs were prepared as basic inelastic neutron data requested for neutron age calculations to be made using the compositions NaF-ZrF/sub 4/, BeF/ sub 2/, LiF-BeF/sub 2/, and ZrH. Nuclear temperature as a function of incident neutron energy was obtained for F, Be, and Zr. (W.D.M.)
Date: June 1, 1956
Creator: Copenhaver, C.M.
Partner: UNT Libraries Government Documents Department

Measurements of Scattering Processes in Negative Ion- Atom Collisions

Description: The main research activity is to study various scattering processes which occur in H{sup -} collisions with atomic (specifically, noble gas and atomic hydrogen) targets in the intermediate energy region. These processes include: elastic scattering, single- and double-electron detachment, and target excitation/ionization.
Date: December 22, 2000
Creator: Kvale, T. J.
Partner: UNT Libraries Government Documents Department

Final Report LDRD 02-ERD-013 Dense Plasma Characterization by X-ray Thomson Scattering

Description: We have successfully demonstrated spectrally-resolved x-ray scattering in a variety of dense plasmas as a powerful new technique for providing microscopic dense plasma parameters unattainable by other means. The results have also been used to distinguish between ionization balance models. This has led to 10 published or to be published papers, 8 invited talks and significant interest from both internal and external experimental plasma physicists and the international statistical plasma physics theory community.
Date: February 11, 2005
Creator: Landen, O L; Glenzer, S H; Gregori, G; Pollaine, S M; Hammer, J H; Rogers, F et al.
Partner: UNT Libraries Government Documents Department

Variational Calculations of Positronium Scattering with Hydrogen

Description: Positronium-hydrogen (Ps-H) scattering is of interest, as it is a fundamental four-body Coulomb problem. We have investigated low-energy Ps-H scattering below the Ps(n=2) excitation threshold using the Kohn variational method and variants of the method with a trial wavefunction that includes highly correlated Hylleraas-type short-range terms. We give an elegant formalism that combines all Kohn-type variational methods into a single form. Along with this, we have also developed a general formalism for Kohn-type matrix elements that allows us to evaluate arbitrary partial waves with a single codebase. Computational strategies we have developed and use in this work will also be discussed.With these methods, we have computed phase shifts for the first six partial waves for both the singlet and triplet states. The 1S and 1P phase shifts are highly accurate results and could potentially be viewed as benchmark results. Resonance positions and widths for the 1S-, 1P-, 1D-, and 1F-waves have been calculated.We present elastic integrated, elastic differential, and momentum transfer cross sections using all six partial waves and note interesting features of each. We use multiple effective range theories, including several that explicitly take into account the long-range van der Waals interaction, to investigate scattering lengths for the 1,3S and 1,3P partial waves and effective ranges for the 1,3S-wave.
Date: December 2015
Creator: Woods, Denton
Partner: UNT Libraries