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The Thickness Distortion of Fe 57 Backscatter Mossbauer Spectra

Description: The thickness distortion of a backscatter 14.41 keV {gamma}-ray Mossbauer spectrum is calculated for the case of isotropic {gamma}-ray re-emission in the absorber, and a method of extracting the true absorber material resonant scattering cross section from experimental data is suggested and demonstrated. Some other features of backscatter and transmission Fe{sup 57} Mossbauer spectra are compared.
Date: August 1, 1980
Creator: Fultz, B. & Morris, J. W., Jr.
Partner: UNT Libraries Government Documents Department
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ANALYZING POWERS OF {sup 3}He({vector p},p){sup 3}He ELASTIC SCATTERING BETWEEN 30 AND 50 MeV

Description: Analyzing power data have been obtained for {sup 3}He({vector p},p){sup 3}He elastic scattering at seven energies between 30 and 50 MeV at laboratory angles between 20° and 160°. Errors are typically less than 0.01. These results supplement earlier differential and total reaction cross-section and analyzing power data and new data obtained with a polarised {sup 3}He target.
Date: June 1, 1980
Creator: Birchall, J.; Oers, W.T.H. van; Conzett, H.E.; Rossen, P. von; Larimer, R.M.; Larimer, R.M. et al.
Partner: UNT Libraries Government Documents Department
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THE DISASSEMBLY OF NUCLEAR MATTER

Description: A statistical model is applied for multi-fragment final states in nuclear collisions with bombarding energies E/A ≈ 100 MeV. A portion of the intermediate system formed is assumed to decay according to the available classical non-relativistic phase space, calculated in a grand canonical ensemble. The model correlates and predicts many experimental observables in terms of three parameters: the available energy per nucleon, the isospin asymmetry, and the effective interaction volume.
Date: August 1, 1980
Creator: Randrup, J. & Koonin, S.E.
Partner: UNT Libraries Government Documents Department
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GFMC calculations of electromagnetic moments and M1 transitions in A {<=} 9 nuclei

Description: We present recent Green’s function Monte Carlo calculations of magnetic moments and M1 transitions in A{<=}#20;9 nuclei, which include corrections arising from two-body meson-exchange electromagnetic currents. Two-body effects provide significant corrections to the calculated observables, bringing them in excellent agreement with the experimental data. In particular, we find that two body corrections are especially large in the A = 9, T = 3/2 systems, in which they account for up to ~#24; 20% (~#24; 40%) of the total predicted value for the {sup 9}Li ({sup 9}C) magnetic moment.
Date: August 1, 2013
Creator: Pastore, Saori; Pieper, Steven C.; Schiavilla, Rocco & Wiringa, Robert Bruce
Partner: UNT Libraries Government Documents Department
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Neutron Emission in Relativistic Nuclear Collisions

Description: Previously reported differences between the measured proton and neutron energy spectra for the reaction ~400 MeV/nucleon {sup 20}Ne + U {yields} p, n + x are discussed. A parameter-free cascade-coalescence model of heavy ion collisions is shown to account for these differences. Such measurerrents are shown to be sensitive to the degree of projectile-target equilibration in relativistic nuclear collisions.
Date: December 1980
Creator: Stevenson, J. D.
Partner: UNT Libraries Government Documents Department
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Polarized {sup 3}He(e,e'n) Asymmetries in Three Orthogonal Measurements

Description: Asymmetry measurements were conducted in Jefferson Lab's experimental Hall A through electron scattering from a polarized {sup 3}He target in the quasi-elastic polarized-{sup 3}He(e,e'n) reaction. Measurements were made with the target polarized in the longitudinal direction with respect to the incoming electrons A_L, in a transverse direction that was orthogonal to the beam-line and parallel to the q-vector A_T, and in a vertical direction that was orthogonal to both the beam-line and the q-vector (A_y^0). The experiment measured $A_y^0$ at four-momentum transfer squared Q^2 of 0.127 (GeV/c)^2, 0.456 (GeV/c)^2, and 0.953 (GeV/c)^2. The A_T and A_L asymmetries were both measured at Q^2 of 0.505 (GeV/c)^2 and 0.953 (GeV/c)^2. This is the first time that three orthogonal asymmetries have been measured simultaneously. Results from this experiment are compared with the plane wave impulse approximation (PWIA) and Faddeev calculations. These results provide important tests of models that use 3He as an effective neutron target and show that the PWIA holds above Q^2 of 0.953 (GeV/c)^2.
Date: September 1, 2012
Creator: Long, Elena
Partner: UNT Libraries Government Documents Department
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Photodisintegration of Light Nuclei with CLAS

Description: We report preliminary results of photodisintegration of deuteron and {sup 3}He measured with CLAS at Jefferson Lab. We have extracted the beam-spin asymmetry for the {vector {gamma}}d {yields} pn reaction at photon energies from 1.1 GeV to 2.3 GeV and proton center-of-mass (c.m.) angles between 35{degrees}#14; and 135{degrees}#14;. Our data show interesting evolution of the angular dependence of the observable as the photon energy increases. The energy dependence of the beam-spin asymmetry at 90#14; shows a change of slope at photon energy of 1.6 GeV. A comparison of our data with model calculations suggests that a fully non-perturbative treatment of the underlying dynamics may be able to describe the data better than a model based on hard scattering. We have observed onset of dimensional scaling in the cross section of two-body photodisintegration of {sup 3}He at remarkably low energy and momentum transfer, which suggests that partonic degrees of freedom may be relevant for the description of nuclei at energies lower than previously considered.
Date: August 1, 2013
Creator: Ilieva, Yordanka Yordanova & Zachariou, Nicholas
Partner: UNT Libraries Government Documents Department
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ONE- AND TWO-PROTON INCLUSIVE SPECTRA IN 800 MeV PROTON-NUCLEUS COLLISIONS AND THE MEAN FREE PATH OF PROTONS IN NUCLEI

Description: One- and two-proton inclusive spectra have been measured in collisions of 800 MeV protons with C, NaF, KCl, Cu, and Pb targets. The single proton inclusive yield increases monotonically with target mass, while the two-proton yield at {theta}{sub Lab}=± 40° associated with pp quasi-elastic scatterings shows a maximum at a mass number of about 50. A model calculation reproduces the observed target mass dependence with a mean free path of ~2.5 fm for 800 MeV protons inside the nucleus.
Date: October 1, 1980
Creator: Tanihata, I.; Nagamiya, S.; Schnetzer, S. & Steiner, H.
Partner: UNT Libraries Government Documents Department
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ADIABATICITY CRITERION FOR CHARGE EQUILIBRATION WITH APPLICATION TO FISSION

Description: The dispersion of a quantal oscillator with a time-dependent inertial mass is considered. For a special class of time dependence, an empirical method is formulated for predicting the asymptotic behavior of such a system. This method is then applied to the prediction of charge widths in strongly damped nuclear collisions and in fission.
Date: September 1, 1980
Creator: Myers, W. D.; Mantzouranis, G. & Randrup, J.
Partner: UNT Libraries Government Documents Department
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Measurement of single-target spin asymmetries in the electroproduction of negative pions in the semi-inclusive deep inelastic reaction n{up_arrow}(e,e'{pi}{sup -})X on a transversely polarized {sup 3}He target

Description: The experiment E06010 measured the target single spin asymmetry (SSA) in the semiinclusive deep inelastic (SIDIS) n{up_arrow}(e, e'{pi}{sup -})X reaction with a transversely polarized {sup 3}He target as an e#11;ective neutron target. This is the very #12;rst independent measurement of the neutron SSA, following the measurements at HERMES and COMPASS on the proton and the deuteron. The experiment acquired data in Hall A at Je#11;erson Laboratory with a continuous electron beam of energy 5.9 GeV, probing the valence quark region, with x = 0.13 {rt_arrow} 0.41, at Q{sup 2} = 1.31 {rt_arrow} 3.1 GeV{sup 2}. The two contributing mechanisms to the measured asymmetry, viz, the Collins effect and the Sivers effect can be realized through the variation of the asymmetry as a function of the Collins and Sivers angles. The neutron Collins and Sivers moments, associated with the azimuthal angular modulations, are extracted from the measured asymmetry for the very #12;first time and are presented in this thesis. The kinematics of this experiment is comparable to the HERMES proton measurement. However, the COMPASS measurements on deuteron and proton are in the low-x region. The results of this experiment are crucial as the first step toward the extraction of quark transversity and Sivers distribution functions in SIDIS. With the existing results on proton and deuteron, these new results on neutron will provide powerful constraints on the transversity and Sivers distributions of both the u and d-quarks in the valence region.
Date: June 1, 2010
Creator: Dutta, Chiranjib
Partner: UNT Libraries Government Documents Department
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