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Review of alpha-decay data from doubly-even nuclei

Description: Alpha-decay data from doubly-even nuclei throughout the periodic table are reviewed and evaluated. From these data, nuclear radius parameters are calculated by using the Preston formula for {alpha}- decay probabilities. The radius parameters for each element behave rather regularly as a function of neutron number. The show minima at the major closed shells, increase sharply for parents just above the closed shells, and decrease smoothly toward the next shell closure. The same trend is observed for {alpha} reduced widths calculated using the Rasmussen formalism. Any irregularity or large departure from this behavior indicates probable incorrect input data. This systematic behavior can also be utilized to estimate partial half- lives.
Date: September 1, 1996
Creator: Akovali, Y.A.
Partner: UNT Libraries Government Documents Department

Calculation of the {alpha}-particle ground state

Description: The Correlated Hyperspherical Harmonic expansion method is used to calculate alpha-particle properties with a realistic hamiltonian consisting of the Argonne V14 two nucleon and Urbana model VIII three nucleon potentials. The calculated binding energy, mass radius and wave percentages are close to the corresponding quantities obtained with Green's Function Monte Carlo and Faddeev-Yakubovsky techniques.
Date: October 1, 1994
Creator: Viviani, M.; Kievsky, A. & Rosati, S.
Partner: UNT Libraries Government Documents Department

Relativistic charge form factor of the deuteron

Description: Relativistic integral representation in terms of experimental neutron-proton scattering phase shifts alone is used to compute the charge form factor of the deuteron G{sub Cd}(Q{sup 2}). The results of numerical calculations of {vert_bar}G{sub Cd}(Q{sup 2}){vert_bar} are presented in the interval of the four-momentum transfers squared 0 {<=} Q{sup 2} {<=} 35 fm{sup {minus}2}. Zero and the prominent secondary maximum in {vert_bar}G{sub Cd}(Q{sup 2}){vert_bar} are the direct consequences of the change of sign in the experimental {sup 3}S{sub 1} - phase shifts. Till the point Q{sup 2} {approx_equal} 20 fm{sup {minus}2} the total relativistic correction to {vert_bar}G{sub Cd}(Q{sup 2}){vert_bar} is positive and reaches the maximal value of 25% at Q{sup 2} {approx_equal} 14 fm{sup {minus}2}.
Date: December 1, 1997
Creator: Afanasev, Andrei V.; Afanasev, V.D. & Trubnikov, S.V.
Partner: UNT Libraries Government Documents Department

Nuclear structure research. Annual progress report

Description: The most significant development this year has been the realization that EO transition strength is a fundamental manifestation of nuclear mean-square charge radius differences. Thus, EO transitions provide a fundamental signature for shape coexistence in nuclei. In this sense, EO transitions are second only to E2 transitions for signaling (quadrupole) shapes in nuclei and do so when shape differences occur. A major effort has been devoted to the review of EO transitions in nuclei. Experiments have been carried out or are scheduled at: ATLAS/FMA ({alpha} decay of very neutron-deficient Bi isotopes); MSU/NSCL ({beta} decay of {sup 56}Cu); and HRIBF/RMS (commissioning of tape collector, internal conversion/internal-pair spectrometer; {beta} decay of {sup 58}Cu). A considerable effort has been devoted to planning the nuclear structure physics that will be pursued using HRIBF. Theoretical investigations have continued in collaboration with Prof. K. Heyde, Prof. D.J. Rowe, Prof. J.O. Rasmussen, and Prof. P.B. Semmes. These studies focus on shape coexistence and particle-core coupling.
Date: December 31, 1996
Creator: Wood, J.L.
Partner: UNT Libraries Government Documents Department

ASPECTS OF COULOMB DISSOCIATION AND INTERFERENCE IN PERIPHERAL NUCLEUS - NUCLEUS COLLISIONS.

Description: Coherent vector meson production in peripheral nucleus-nucleus collisions is discussed. These interactions may occur for impact parameters much larger than the sum of the nuclear radii. Since the vector meson production is always localized to one of the nuclei, the system acts as a two-source interferometer in the transverse plane. By tagging the outgoing nuclei for Coulomb dissociation it is possible to obtain a measure of the impact parameter and thus the source separation in the interferometer. This is of particular interest since the life-time of the vector mesons are generally much shorter than the impact parameters of the collisions.
Date: October 16, 2002
Creator: Nystrand, J.; Baltz, A. J. & Klein, S. R.
Partner: UNT Libraries Government Documents Department

TABLE OF ELECTRON WAVE FUNCTIONS AT THE NUCLEAR SURFACE

Description: The beta and gamma radiations of 21-hr I/sup 133/ were investigated by single-crystal and multicrystal scintillation spectrometers, and a scheme is proposed for the energy levels of Xe/sup 133/. The level scheme of Ge/sup 74/ was obtained by means of single-crystal and multicrystal beta- and gammaray spectrometry using sources of Ga/sup 74/ and As/sup 74/. The angular correlation for the 0.60-0.60-Mev cascade was measured. Both beta- and gamma-ray single- crystal measurements and gamma-beta and gamma-gamma coincidence experiments were performed on the decay of I/sup 132/. Also, gamma-gamma angular correlations were measured for all the prominent gamma rays. This information has led to a level scheme in Xe/sup 132/ involving excited states at 0.673, signments of 2, 4, 3, and 4 for the first four of these. A study of 2.7-hr Pm/sup 150/ established that the most energetic beta ray, at 3.16 plus or minus 0.11 Mev, decays to the first excited state of Sm/sup 150/ at 0.333 Mev. A partial decay scheme based on beta-gamma coincidence spectrometry was formulated with excited states in Sm/sup 150/ at 0.333, 1.18, 1.66, and 2.08 Mev. The measurement of the neutron- absorption cross sections of Ce/sup 141/ and Ce/sup 144/ by the activation method is in progress. Separation of the 5.9-hr Pr/sup 145/ daughter of the 3-min Ce/ sup 145/ produced by the (n, gamma ) reaction on Ce/sup 144/ from the associated cerium isotopes was accomplished by the extraction of tetravalent cerium with di(2-ethyl-hexyl)phosphoric acid in n-heptane. Preliminary results of several irradiations of Ce/sup 144/ in the LITR indicate an effective neutron cross section of (6 plus or minus 2) x 10/sup -24/ cm/sup 2/atom. Flux depressions in the vicintty of and within infinite cadmium slabs were calculated using the SNG reactor code on the IBM-704 computer at K-25. These results are pertinent ...
Date: October 1, 1960
Creator: Bhalla, C. P. & Rose, M. E.
Partner: UNT Libraries Government Documents Department

EBIT - Electronic Beam Ion Trap: N Divison experimental physics annual report 1995

Description: The multi-faceted research effort of the EBIT (Electron Beam Ion Trap) program in N-Division of the Physics and Space Technology Department at Lawrence Livermore National Laboratory (LLNL) continues to contribute significant results to the physical sciences from studies with low energy very highly charged heavy ions. The EBIT program attracts a number of collaborators from the US and abroad for the different projects. The collaborations are partly carried out through participating graduate students demonstrating the excellent educational capabilities at the LLNL EBIT facilities. Moreover, participants from Historically Black Colleges and Universities are engaged in the EBIT project. This report describes EBIT work for 1995 in atomic structure measurements and radiative transition probabilities, spectral diagnostics for laboratory and astrophysical plasmas, ion/surface interaction studies, electron-ion interactions studies, retrap and ion collisions, and instrumental development.
Date: October 1, 1996
Creator: Schneider, D.
Partner: UNT Libraries Government Documents Department

Magnetic radius of the deuteron

Description: The root-mean square radius of the deuteron magnetic moment distribution, r{sub Md}, is calculated for several realistic models of the NN-interaction. For the Paris potential the result is r{sub Md} = 2.312 {+-} 0.010 fm. The dependence of r{sub Md} on the choice of NN model, relativistic effects and meson exchange currents is investigated. The experimental value of r{sub Md} is also considered. The necessity of new precise measurements of the deuteron magnetic form factor at low values of Q{sup 2} is stressed.
Date: August 1, 1998
Creator: Afanasev, Andrei; Afanasev, V.D. & Trubnikov, S.V.
Partner: UNT Libraries Government Documents Department

Aspects of Coulomb dissociation and interference in peripheral nucleus-nucleus collisions

Description: Coherent vector meson production in peripheral nucleus-nucleus collisions is discussed. These interactions may occur for impact parameters much larger than the sum of the nuclear radii. Since the vector meson production is always localized to one of the nuclei, the system acts as a two-source interferometer in the transverse plane. By tagging the outgoing nuclei for Coulomb dissociation it is possible to obtain a measure of the impact parameter and thus the source separation in the interferometer. This is of particular interest since the life-time of the vector mesons are generally much shorter than the impact parameters of the collisions.
Date: October 21, 2001
Creator: Nystrand, Joakim; Baltz, Anthony & Klein, Spencer R.
Partner: UNT Libraries Government Documents Department

Effect of deformation and the neutron skin on RMS charge radii

Description: Droplet Model predictions for nuclear RMS charge radii are compared with measured values in order to determine whether or not there is any evidence for volume shell effects. After corrections for deformation, diffuseness, and the central depression have been applied, some evidence for such effects remains, but it is at about the same level as the experimental uncertainty.
Date: May 1, 1981
Creator: Myers, W. D. & Schmidt, K. H.
Partner: UNT Libraries Government Documents Department

Marginal densities of radially symmetric densities in two and three dimensions

Description: Necessary and sufficient conditions are given for a function p(x) on 0 < absolute value (x) < R to be the marginal density of a radially symmetric density f(r) in the case of two and three dimensions. The first case relies on an integral transform due to Bell (CERN/MPS/DL 73-3), while for 3-space the theory is considerably simpler. The two cases appear to be quite different, and no generalization to n-space is known.
Date: May 1, 1978
Creator: Everett, C.J. & Cashwell, E.D.
Partner: UNT Libraries Government Documents Department

ENAM'04 Fourth International Conference on Exotic Nuclei and Atomic Masses

Description: The conference can trace its origins to the 1950s and 1960s with the Atomic Mass and Fundamental Constants (AMCO) and the Nuclei Far From Stability (NFFS) series of conferences. Held jointly in 1992, the conferences officially merged in 1995 and the fourth conference was held at Callaway Gardens in Pine Mountain, GA and was organized by the Physics Division at Oak Ridge National Laboratory. The conference covered a broad list of topics consisting of a series of invited and contributed presentation highlighting recent research in the following fields: Atomic masses, nuclear moments, and nuclear radii; Forms of radioactivity; Nuclear structure, nuclei at the drip lines, cluster phenomena; Reactions with radioactive ion beams; Nuclear astrophysics; Fundamental symmetries and interactions; Heaviest elements and fission; Radioactive ion beam production and experimental developments; Applications of exotic nuclei
Date: January 1, 2005
Creator: Gross, C. J.; Nazarewicz, W. & Rykaczewski, K. P.
Partner: UNT Libraries Government Documents Department

Spectroscopy at the high-energy electron beam ion trap (Super EBIT)

Description: The following progress report presents some of the x-ray measurements performed during the last year on the Livermore SuperEBIT facility. The measurements include: direct observation of the spontaneous emission of the hyperfine transition in ground state hydrogenlike holmium, {sup 165}Ho{sup 66{plus}}; measurements of the n {equals} 2 {r_arrow} 2 transition energies in neonlike thorium, Th{sup 80{plus}}, through lithiumlike thorium, Th{sup 87{plus}}, testing the predictions of quantum electrodynamical contributions in high-Z ions up to the 0.4{percent} level; measurements of the isotope shift of the n= 2 {r_arrow} 2 transition energies between lithiumlike through carbonize uranium, {sup 233}U{sup 89{plus}...86{plus}} and {sup 238}U{sup 89{plus}...86{plus}}, inferring the variation of the mean- square nuclear charge radius; and high-resolution measurements of the K{alpha} radiation of heliumlike xenon, Xe{sup 52 {plus}}, using a transmission-type crystal spectrometer, resolving for the first time the ls2p{sup 3}P{sub 1} {r_arrow} 1S{sup 2} {sup 1}S{sub 0} and ls2s{sup 3}S{sub 1} {r_arrow} 1S{sup 2} {sup 1}S{sub 0} transitions individually. 41 refs., 9 figs., 1 tab.
Date: July 10, 1996
Creator: Widmann, K.; Beiersdorfer, P. & Crespo Lopez-Urrutia, J.R.
Partner: UNT Libraries Government Documents Department

Droplet-model predictions of charge moments

Description: The Droplet Model expressions for calculating various moments of the nuclear charge distribution are given. There are contributions to the moments from the size and shape of the system, from the internal redistribution induced by the Coulomb repulsion, and from the diffuseness of the surface. A case is made for the use of diffuse charge distributions generated by convolution as an alternative to Fermi-functions.
Date: April 1, 1982
Creator: Myers, W.D.
Partner: UNT Libraries Government Documents Department

Neutron-photon multigroup cross sections for neutron energies less than or equal to400 MeV. Revision 1

Description: For a variety of applications, e.g., accelerator shielding design, neutrons in radiotherapy, radiation damage studies, etc., it is necessary to carry out transport calculations involving medium-energy (greater than or equal to20 MeV) neutrons. A previous paper described neutron-photon multigroup cross sections in the ANISN format for neutrons from thermal to 400 MeV. In the present paper the cross-section data presented previously have been revised to make them agree with available experimental data. 7 refs., 1 fig.
Date: January 1, 1986
Creator: Alsmiller, R.G. Jr.; Barnes, J.M. & Drischler, J.D.
Partner: UNT Libraries Government Documents Department

Dependence of rms charge radii on the neutron skin and on deformation

Description: When the measured rms radii of nuclei throughout the periodic table are compared with each other, and the result is plotted in a certain way, there seems to be evidence for significant shell effects. A closer look, however, suggests that the rms radii are predicted quite accurately by the Droplet Model (a macroscopic model that contains provisions for the possible formation of a neutron skin), if proper account is taken of the nuclear deformation. 3 figures. (RWR)
Date: January 1, 1981
Creator: Myers, W.D.
Partner: UNT Libraries Government Documents Department

Nuclear mass formula with a neutron skin degree of freedom and finite-range model for the surface energy

Description: We study the possibility of extending the model used by Moeller and Nix in 1980 to calculate nuclear masses and fission barriers for nuclei throughout the periodic system, to describe compressibility effects and the existence of a neutron skin. 9 references. (WHK)
Date: March 1, 1984
Creator: Moeller, P. & Myers, W.D.
Partner: UNT Libraries Government Documents Department

Molecular degrees of freedom: resonances and orbiting

Description: Studies of orbiting and other gross features of heavy ion induced reactions show that molecular degrees of freedom play a significant role. The formation of a rotating dinuclear molecule appears as a general feature, and the radii derived for these dinuclear systems are larger than the radii of the conventional nucleus-nucleus potential. These large radii for the molecular bonding potential are similar to those derived from systematic studies performed recently on resonances in the /sup 12/C + /sup 12/C + /sup 16/O systems.
Date: January 1, 1983
Creator: Shapira, D. & Erb, K.A.
Partner: UNT Libraries Government Documents Department

Relativistic heavy ion physics

Description: The main objective of the study of nuclear physics is pointed out to be the study of nuclear properties under conditions far from normal nuclear densities and excitations. Another objective in relativistic heavy ion physics is to study conventional nuclear properties such as the limits of nuclear stability, ground state correlations, and the excitation of high multipole giant resources. Exotic phenomena, inclusive interactions, reaction mechanisms, and the types of experimental facilities and planning are briefly noted. 15 references. (JFP)
Date: June 1, 1979
Creator: Westfall, G.D.
Partner: UNT Libraries Government Documents Department