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Signature Inversion in Odd-odd Nuclei

Description: Trends in the energy staggering of the {pi}h{sub 11/2}{nu}i{sub 13/2} and {pi}h{sub 11/2} {nu}h{sub 11/2} bands in the mass 160 and 130 regions, respectively, have been investigated in order to better understand the origin of signature inversion. While the A {approx} 160 nuclei behave in a consistent manner, a more complicated scenario is observed in the mass 130 region. As a result of our experiments on the lightest Pr nuclei, the systematics of these Z = 59 nuclei have been extended, which aids in the understanding of the latter region. Triaxial deformation, a pn interaction, and quadrupole pairing are considered as possible contributors to this effect. As all the chiral-twin bands that are known have signature inversion in the favored band, a possible link between the two phenomena should be considered.
Date: September 10, 2001
Creator: Riedinger, L.L.
Partner: UNT Libraries Government Documents Department

Shell-model Monte Carlo studies of nuclei

Description: The pair content and structure of nuclei near N = Z are described in the frwnework of shell-model Monte Carlo (SMMC) calculations. Results include the enhancement of J=0 T=1 proton-neutron pairing at N=Z nuclei, and the maxked difference of thermal properties between even-even and odd-odd N=Z nuclei. Additionally, a study of the rotational properties of the T=1 (ground state), and T=0 band mixing seen in {sup 74}Rb is presented.
Date: February 1, 1997
Creator: Dean, D.J.
Partner: UNT Libraries Government Documents Department

Shell-model Monte Carlo calculations near N = Z

Description: The pairing and structure of nuclei near N = Z is described in the framework of shell-model Monte Carlo (SMMC) calculations. Principal results include the enhancement of J=0, T=1 proton-neutron pairing at N=Z nuclei, and the marked difference of thermal properties between even-even and odd-odd N=Z nuclei. Additionally I will present a study of the rotational properties for the T=1 (ground state), and T=0 band mixing seen in {sup 74}Rb.
Date: October 1, 1996
Creator: Dean, D.J.
Partner: UNT Libraries Government Documents Department

Nuclear structure considerations for gamma-ray lasers

Description: Presented are initial results in our investigation of the nuclear physics issues of gamma-ray lasers. These include the questions of what is known from existing experimental data, where does one optimally search for nuclei displaying simultaneously both closely lying levels and nuclear isomerism, and which theoretical models does one employ for systematic searches for candidate nuclei and for calculation of detailed candidate level properties.
Date: January 1, 1985
Creator: Strottman, D.; Arthur, E.D. & Madland, D.G.
Partner: UNT Libraries Government Documents Department

Survey of odd-odd deformed nuclear spectroscopy

Description: In this paper, we survey the current experimental data that support assignment of rotational bands in odd-odd deformed nuclear in the rare earth and actinide regions. We present the results of a new study of {sup 170}Mt nuclear structure. In a comparing experimental and calculated Gallagher-Moszkowski matrix elements for rare earth-region nuclei, we have developed a new approach to the systematics of these matrix elements.
Date: September 14, 1993
Creator: Hoff, R. W.
Partner: UNT Libraries Government Documents Department

(Mechanism of hydrogen incorporation in coal liquefaction)

Description: Our approach has been to study the thermally-induced reaction of various coal model compounds, including 1,2-diphenylethane with molecular deuterium (D{sub 2}). In reviewing the literature regarding these reactions, it appeared to us that all of the reported exchange studies using D{sub 2} as a source of deuterium had involved metal reactor vessels. This raised the question of whether the initial process for introduction of deuterium atoms into the thermolysis milieu might be metal catalyzed. As we wished to use the noncatalyzed reaction as a starting point for our studies, we employed a glass reaction vessel.
Date: January 1, 1991
Partner: UNT Libraries Government Documents Department

Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses

Description: The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.
Date: January 1, 1992
Creator: Epstein, S. & Stolper, E.
Partner: UNT Libraries Government Documents Department

Calibrations of a tritium extraction facility

Description: A tritium extraction facility has been built for the purpose of measuring the absolute tritium concentration in neutron-irradiated lithium metal samples. Two independent calibration procedures have been used to determine what fraction, if any, of tritium is lost during the extraction process. The first procedure compares independently measured /sup 4/He and /sup 3/H concentrations from the /sup 6/Li(n,..cap alpha..)T reaction. The second procedure compared measured /sup 6/Li(n,..cap alpha..)T//sup 197/Au (n,..gamma..)/sup 198/Au thermal neutron reaction rate ratios with those obtained from Monte Carlo calculations using well-known cross sections. Both calibration methods show that within experimental errors (approx. 1.5%) no tritium is lost during the extraction process.
Date: January 1, 1983
Creator: Bretscher, M.M.; Oliver, B.M. & Farrar, H. IV
Partner: UNT Libraries Government Documents Department

Development of an ion source for long-pulse (30-s) neutral beam injection

Description: This paper describes the development of a long-pulse positive ion source that has been designed to provide high brightness deuterium beams (divergence approx. = 0.25/sup 0/ rms, current density approx. = 0.15 A cm/sup -2/) of 40 to 45 A, at a beam energy of 80 keV, for pulse lengths up to 30 s. The design and construction of the ion source components are described with particular emphasis placed on the long-pulse cathode assembly and ion accelerator.
Date: January 1, 1982
Creator: Menon, M.M.; Barber, G.C.; Blue, C.W.; Dagenhart, W.K.; Gardner, W.L.; Haselton, H.H. et al.
Partner: UNT Libraries Government Documents Department

Performance of a developmental 120-keV, 10-A deuterium (14-A hydrogen) neutral beam system

Description: We have recently operated the LBL 120-keV neutral beam test facility on deuterium. This facility consists of a large (170,000 l) vacuum system, a plasma source, a multiple-aperture electrostatic accelerator structure, an ion sweep magnet, ion and neutral beam dumps, and a computer diagnostic and control system. The total length of the beamline is about 8.5m. Operation of this test facility on deuterium has produced beams with an energy of 120 keV, a total (ion plus neutral) beam current of 10 A, and a pulse length of 0.5 sec. The beam profile at the location of the dump is bi-gaussian, with 1/e halfwidths of about 1.28 and 0.42 degrees. Deuterium operation has been very limited because of the high neutron production rate (about 10/sup 11/ sec/sup -1/ when the beam is on) and the lack of radiation shielding around the facility.
Date: October 1, 1977
Creator: Berkner, K.H.; Cooper, W.S.; Ehlers, K.W. & Pyle, R.V.
Partner: UNT Libraries Government Documents Department

Stereoselective disposition of R-(-)- and S-(+)-methadone in man

Description: Deuterium-labeled methadone has been used to study the urinary excretion of racemic methadone, R-(-)- and S-(+)-methadone in adult maintenance patients. In three cases studied, the pharmacologically active enantiomer, R-(-)-methadone, had a significantly longer elimination half-life (51.7 to 61.8 hours) than did the inactive S-(+)-methadone (31.8 to 37.0 hours). The ratio of drug elimination half-lives, R-(-)-/S-(+)-, ranged between 1.39 and 1.94.
Date: January 1, 1978
Creator: Hachey, D.L.; Kreek, M.J. & Klein, P.D.
Partner: UNT Libraries Government Documents Department

Field-reversed configuration formation, translation, and confinement studies on the FRX-C/T experiment

Description: The field-reversed configuration (FRC) is a high ..beta.. (>50%), prolate compact toroid plasma contained primarily by poloidal magnetic fields. FRC plasmas with parameters, anti n = (1-5)x10/sup 15/cm/sup -3/, T/sub i/ = 0.1-0.8 keV, T/sub e/ = 0.1-0.2 keV, R approx. = 7 cm, B = 5-8 kG, lifetimes less than or equal to300 ..mu..s, are studied on the FRX-C/T experiment at Los Alamos. FRX-C/T consists of a 0.5-m-dia, 1.0-m-long field-reversed theta-pinch coil, and a 0.4-m-dia, 5-m-long translation region into which FRC's are launched, translated, and trapped. A 5-20 mtorr pressure D/sub 2/ fill is introduced into the device by either a gas puff (localized in the theta-pinch source) or static fill system.
Date: January 1, 1985
Creator: Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.; Hugrass, W.N.; McKenna, K.F.; Rej, D.J. et al.
Partner: UNT Libraries Government Documents Department

Operating and maintenance experience in tritium environments

Description: This presentation is a summary of practical experience gained over more than twenty years from analyzing failures of process equipment operated in tritium and deuterium environments. Significant improvements have been achieved in design and procurement of new equipment, testing and selection of materials, and gradually more favorable maintenance experience. Preferred materials and inspection methods are described. 6 tabs.
Date: January 1, 1987
Creator: Tuer, G.L.
Partner: UNT Libraries Government Documents Department

Optimization of the fission--fusion hybrid concept

Description: One of the potentially attractive applications of controlled thermonuclear fusion is the fission--fusion hybrid concept. In this report we examine the possible role of the hybrid as a fissile fuel producer. We parameterize the advantages of the concept in terms of the performance of the fusion device and the breeding blanket and discuss some of the more troublesome features of existing design studies. The analysis suggests that hybrids based on deuterium--tritium (D--T) fusion devices are unlikely to be economically attractive and that they present formidable blanket technology problems. We suggest an alternative approach based on a semicatalyzed deuterium--deuterium (D--D) fusion reactor and a molten salt blanket. This concept is shown to emphasize the desirable features of the hybrid, to have considerably greater economic potential, and to mitigate many of the disadvantages of D--T-based systems.
Date: April 1, 1979
Creator: Saltmarsh, M.J.; Grimes, W.R. & Santoro, R.T.
Partner: UNT Libraries Government Documents Department

Utilization of the catalyzed-DD fuel cycle in reversed-field pinch reactors (RFPRs)

Description: The utilization of deuterium-based fuels offers the potential advantages of greater flexibility in blanket design, significantly reduced tritium inventory, potential reduction in radioactivity level, and utilization of an inexhaustible fuel supply. The extension of the conventional DT-fueled Reversed-Field Pinch Reactor (RFPR) designs to advanced-fuel (catalyzed-DD) operation has recently been reported. Attractive and economically competitive DD/RFPR systems are identified having power densities and plasma parameters comparable to the DT systems. These designs are compared to other fusion reactor designs.
Date: January 1, 1981
Creator: Hagenson, R.L. & Krakowski, R.A.
Partner: UNT Libraries Government Documents Department

Flux and energy of deuterium incident on a limiter-like probe in PLT

Description: The radial dependence of the flux and energy of deuterium incident on a probe in PLT has been determined from analysis of deuterium retained in the probe. From this data and the assumption of a poloidal symmetry it is concluded that deuterium ion impacts on the limiters can account for an impurity generation rate via sputtering of .5 - 3 x 10/sup 19/ s/sup -1/ and a power flow onto the limiters of 11 to 18% of the ohmic heating.
Date: January 1, 1979
Creator: McCracken, G.M.; Cohen, S.A.; Dylla, H.F.; Rossnagel, S.M.; Magee, C.W.; Picraux, S.T. et al.
Partner: UNT Libraries Government Documents Department

A laser-driven source of polarized hydrogen and deuterium

Description: A novel laser-driven polarized source of hydrogen and deuterium which operates on the principle of spin-exchange optical pumping is being developed. This source is designed to operate as an internal target in an electron storage ring for fundamental studies of spin-dependent structure of nuclei. It has the potential to exceed the flux from existing conventional sources (3 /times/ 10/sup 16//s) by an order of magnitude. Currently, the source delivers hydrogen at a flux of 8 /times/ 10/sup 16/ atoms/s with an atomic polarization of 24% and deuterium at 6 /times/ 10/sup 16/ atoms/s with a polarization of 29%. Technical obstacles which have been overcome, with varying degrees of success are complete Doppler-coverage in the optical-pumping stage without the use of a buffer gas, wall-induced depolarization and radiation-trapping. Future improvements should allow achievement of the design goals of 4 /times/ 10/sup 17/ atoms/s with a polarization of 50%. 8 refs., 2 figs.
Date: January 1, 1989
Creator: Young, L.; Holt, R.J.; Gilman, R.A.; Kowalczyk, R. & Coulter, K.
Partner: UNT Libraries Government Documents Department

Neutron production by neutral beam sources

Description: Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments.
Date: November 1, 1979
Creator: Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V. & Ruby, L.
Partner: UNT Libraries Government Documents Department

Intense field non-resonant multiphoton absorption of diatomic molecules

Description: We report on the results of nonlinear ionization and dissociation of gas-phase diatomic molecules, H{sub 2}, D{sub 2}, O{sub 2}, and Cl{sub 2}, in an intense (10{sup 11{minus}14} W/cm{sup 2}) laser field. Measurements include energy and angularly resolved vibrational photoelectron spectroscopy, as well as mass spectroscopy. 5 refs., 2 figs.
Date: January 1, 1991
Creator: Yang, B.; Saeed, M.; Breeden, T. & DiMauro, L.F.
Partner: UNT Libraries Government Documents Department

Thermotransport of hydrogen and deuterium in vanadium, niobium and tantalum alloys

Description: Heats of transport have been determined for thermotransport of hydrogen and deuterium in pure vanadium, niobium and tantalum; in vanadium alloyed with either niobium, titanium or chromium; and in niobium-tantalum alloys. In all cases, thermotransport was toward colder regions and was significantly greater for deuterium than for hydrogen. A mass spectrometric technique was used to simultaneously measure heats of transport for hydrogen and deuterium in a single specimen containing both isotopes. This technique greatly increased the precision with which isotope effects in the heat of transport could be measured. The predominant effect of alloying was to dramatically increase thermotransport; however, thermotransport decreased as niobium was added to tantalum.
Date: October 1, 1981
Creator: Smith, M.F.
Partner: UNT Libraries Government Documents Department

Density separation of boron particles. Final report

Description: A density distribution much broader than expected was observed in lots of natural boron powder supplied by two different sources. The material in both lots was found to have a rhombohedral crystal structure, and the only other parameters which seemed to account for such a distribution were impurities within the crystal structure and varying isotopic ratios. A separation technique was established to isolate boron particles in narrow densty ranges. The isolated fractions were subsequently analyzed for B/sup 10/ and total boron content in an effort to determine whether selective isotopic enrichment and nonhomogeneous impurity distribution were the causes for the broad density distribution of the boron powders. It was found that although the B/sup 10/ content remained nearly constant around 18%, the total boron content varied from 37.5 to 98.7%. One of the lots also was found to contain an apparently high level of alpha rhombohedral boron which broadened the density distribution considerably. During this work, a capability for removing boron particles containing gross amounts of impurities and, thereby, improving the overall purity of the remaining material was developed. In addition, the separation technique used in this study apparently isolated particles with alpha and beta rhombohedral crystal structures, although the only supporting evidence is density data.
Date: April 1, 1980
Creator: Smith, R.M.
Partner: UNT Libraries Government Documents Department

Advanced-fuel reversed-field pinch reactor (RFPR)

Description: The utilization of deuterium-based fuels offers the potential advantages of greater flexibility in blanket design, significantly reduced tritium inventory, potential reduction in radioactivity level, and utilization of an inexhaustible fuel supply. The conventional DT-fueled Reversed-Field Pinch Reactor (RFPR) designs are reviewed, and the recent extension of these devices to advanced-fuel (catalyzed-DD) operation is presented. Attractive and economically competitive DD/RFPR systems are identified having power densities and plasma parameters comparable to the DT systems. Converting an RFP reactor from DT to DD primarily requires increasing the magnetic field levels a factor of two, still requiring only modest magnet coil fields (less than or equal to 4 T). When compared to the mainline tokamak, the unique advantages of the RFP (e.g., high beta, low fields at the coils, high ohmic-heating power densities, unrestricted aspect ratio) are particularly apparent for the utilization of advanced fuels.
Date: October 1, 1981
Creator: Hagenson, R.L. & Krakowski, R.A.
Partner: UNT Libraries Government Documents Department