Dipole strength functions in the actinide mass region (open access)

Dipole strength functions in the actinide mass region

We have calculated a number of neutron- and photon-induced reactions for the actinide nuclei /sup 232/Th, /sup 238/U, and /sup 237/Np. By fitting average resonance capture (ARC) measurements and total neutron capture data, we deduced absolute dipole strength functions for /sup 233/Th and /sup 239/U. We have found that the M1/E1 ratio is the same as in the /sup 176/Lu case, but the total transition strength was larger by about 27%. 17 refs., 4 figs., 1 tab.
Date: July 15, 1987
Creator: Gardner, D. G.; Gardner, M. A. & Hoff, R. W.
System: The UNT Digital Library
Calculated cross sections for production and destruction of some long-lived nuclides of importance in fusion energy applications (open access)

Calculated cross sections for production and destruction of some long-lived nuclides of importance in fusion energy applications

Knowledge of the production and destruction of long-lived species via neutrons, photons, and charged-particles is required in many fusion energy applications, such as reactor first-wall and blanket design, radioactive waste management, etc. Here we describe our calculational results for the production, via the (n,2n) reaction, of the following long-lived species: {sup 150}Eu(t{sub 1/2} = 36 y), {sup 152}Eu(t{sub 1/2} = 13 y), and {sup 192m2}Ir(t{sub 1/2} = 241 y). Some comments on calculations that we`ve made for destruction reactions of these species are also included.
Date: July 8, 1993
Creator: Gardner, M. A. & Gardner, D. G.
System: The UNT Digital Library
Search for W-prime boson production in the top quark decay channel (open access)

Search for W-prime boson production in the top quark decay channel

We present a search for the production of a new heavy gauge boson W' that decays to a top quark and a bottom quark. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W bosons at the 95% confidence level for several different W' boson masses. We exclude masses below 610 GeV for a W' boson with standard-model-like couplings, below 630 GeV for a W' boson with right-handed couplings that is allowed to decay to both leptons and quarks, and below 670 GeV for a W' boson with right-handed couplings that is only allowed to decay to quarks.
Date: July 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Hydrotreating studies involving NiMo/silica-doped hydrous titanium oxide (HTO:Si)-coated alumina catalysts (open access)

Hydrotreating studies involving NiMo/silica-doped hydrous titanium oxide (HTO:Si)-coated alumina catalysts

For hydrotreating a petroleum-derived liquid feed at 400 C, LHSV = 2. 5 g/g{sub cat}/h, and 1500 psig hydrogen (H) pressure, both HDS and HDN activities were roughly equivalent for a name/TO:Si-coated Amocat catalyst and a commercial alumina-supported name catalyst (Amocat 1C). Superior HDN performance was exhibited by the name/TO: Si-coated Amocat catalyst at low H pressure (500 psig) and after H pressure cycling (1500-500-1500 psig) relative to Amocat 1C. Consistent with previous results obtained on a coal-derived liquid feed, the HDS/HDN results with the petroleum-derived liquid showed that the performance of the name/TO:Si-coated Amocat catalyst on an active metals weight basis exceeded the performance of Amocat 1C at all test conditions. The name/TO:Si-coated Amocat catalyst also showed potentially increased hydrogenation activity, increased resistance to deactivation, and increased yields of lower boiling point distillate fractions, although further work is needed.
Date: July 1, 1996
Creator: Gardner, T.J.; Miller, J.E.; McLaughlin, L.I. & Trudell, D.E.
System: The UNT Digital Library
A standardized approach for determining radiological sabotage targets (open access)

A standardized approach for determining radiological sabotage targets

The US Department of Energy has required radiological sabotage vulnerability assessments to be conducted for years. However, the exact methodology to be used in this type of analysis still remains somewhat elusive. Therefore, there is tremendous variation in the methodologies and assumptions used to determine release levels and doses potentially affecting the health and safety of the public. In some cases, there are three orders of magnitude difference in results for dispersal of similar materials under similar meteorological conditions. To address this issue, the authors have developed an approach to standardizing radiological sabotage target analysis that starts by addressing basic assumptions and then directs the user to some recommended computerized analytical tools. Results from different dispersal codes are also compared in this analysis.
Date: July 1, 1993
Creator: Gardner, B. H. & Snell, M. K.
System: The UNT Digital Library
Accumulator ring design for the NSNS project (open access)

Accumulator ring design for the NSNS project

The goal of the proposed National Spallation Neutron Source (NSNS) is to provide a short pulse proton beam of about 0.5 {mu}s with average beam power of 1 MW. To achieve such purpose, a proton storage ring operated at 60 Hz with 1 x 10{sup 14} protons per pulse at 1 GeV is required. The Accumulator Ring (AR) receives 1 msec long H{sup {minus}} beam bunches of 28 mA from a 1 GeV linac. Scope and design performance goals of the AR are presented, other possible technological choices and design options considered, but not adopted, are also briefly reviewed.
Date: July 1, 1997
Creator: Weng, W. T.; Alessi, J. & Beebe-Wang, J.
System: The UNT Digital Library
UNDERSTANDING FLOW OF ENERGY IN BUILDINGS USING MODAL ANALYSIS METHODOLOGY (open access)

UNDERSTANDING FLOW OF ENERGY IN BUILDINGS USING MODAL ANALYSIS METHODOLOGY

It is widely understood that energy storage is the key to integrating variable generators into the grid. It has been proposed that the thermal mass of buildings could be used as a distributed energy storage solution and several researchers are making headway in this problem. However, the inability to easily determine the magnitude of the building’s effective thermal mass, and how the heating ventilation and air conditioning (HVAC) system exchanges thermal energy with it, is a significant challenge to designing systems which utilize this storage mechanism. In this paper we adapt modal analysis methods used in mechanical structures to identify the primary modes of energy transfer among thermal masses in a building. The paper describes the technique using data from an idealized building model. The approach is successfully applied to actual temperature data from a commercial building in downtown Boise, Idaho.
Date: July 1, 2013
Creator: Gardner, John; Heglund, Kevin; Wymelenberg, Kevin Van Den & Rieger, Craig
System: The UNT Digital Library
Crystal fields, disorder, and antiferromagnetic short-range order in (Yb{sub 0.24}Sn{sub 0.76})Ru (open access)

Crystal fields, disorder, and antiferromagnetic short-range order in (Yb{sub 0.24}Sn{sub 0.76})Ru

We report extensive measurements on a new compound (Yb{sub 0.24}Sn{sub 0.76})Ru that crystallizes in the cubic CsCl structure. Valence band photoemission and L{sub 3} x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb{sup 3+} is split by the crystalline electric field (CEF) into a Γ{sub 7} doublet ground state and a Γ{sub 8} quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ{sub 6} excited state resides at 32 meV; however, the Γ{sub 8}/Γ{sub 6} transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K, there is a peak in specific heat that is too broad to represent a magnetic phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand, this peak also is too narrow to represent …
Date: July 18, 2011
Creator: Klimczuk, T.; Wang, C. H.; Lawrence, J. M.; Xu, Q.; Durakiewicz, T.; Ronning, F. et al.
System: The UNT Digital Library
Dominance of strong absorption in /sup 9/Be + /sup 28/Si elastic scattering. [121 and 201. 6 MeV: angular distribution, optical model] (open access)

Dominance of strong absorption in /sup 9/Be + /sup 28/Si elastic scattering. [121 and 201. 6 MeV: angular distribution, optical model]

Because the character of the scattering changes markedly from /sup 6/Li to /sup 12/C projectiles, a study of the /sup 9/Be + /sup 28/Si system was undertaken to examine the transition region. Data were measured at 121.0 and 201.6 MeV. Low-energy data of other investigators were used to carry out global optical model searches. It was found that the elastic scattering of /sup 9/Be from /sup 28/Si is dominated at all energies by relatively strong absorption. This removes much of the sensitivity to the real potential, and even elastic scattering data spanning a range of energies from 13 to 201 MeV do not allow a unique determination of the potential parameters. There is at least circumstantial evidence that /sup 6/Li scattering at low energies (and by implication also /sup 9/Be scattering) may be strongly influenced by breakup processes, although it is not clear that the mechanism is the same. 3 figures, 1 table. (RWR)
Date: July 1, 1979
Creator: Zisman, M. S.; Cramer, J. G.; DeVries, R. M.; Goldberg, D. A. & Watson, J. W.
System: The UNT Digital Library
A superconducting short period undulator for a harmonic generation FEL experiment (open access)

A superconducting short period undulator for a harmonic generation FEL experiment

A three stage superconducting (SC) undulator for a high gain harmonic generation (HGE) FEL experiment in the infrared is under construction at the NSLS in collaboration with Grumman Corporation. A novel undulator technology suitable for short period (6--40mm) undulators will be employed for all three stages, the modulator, the dispersive section and the radiator. The undulator triples the frequency of a 10.4{mu}m CO{sub 2} seed laser. So far a 27 period (one third of the final radiator) prototype radiator has been designed, built and tested.
Date: July 1, 1993
Creator: Ingold, G.; Solomon, L.; Ben-Zvi, Ilan; Krinsky, S.; Li, D.; Lynch, D. et al.
System: The UNT Digital Library
Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms (open access)

Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms

We describe modeling and simulation of long-range terrestrial laser communications links between static and mobile platforms. Atmospheric turbulence modeling, along with pointing, tracking and acquisition models are combined to provide an overall capability to estimate communications link performance.
Date: July 29, 2003
Creator: Scharlemann, E T; Breitfeller, E F; Henderson, J R; Kallman, J S; Morris, J R & Ruggiero, A J
System: The UNT Digital Library
Monte Carlo simulations of plutonium gamma-ray spectra (open access)

Monte Carlo simulations of plutonium gamma-ray spectra

Monte Carlo calculations were investigated as a means of simulating the gamma-ray spectra of Pu. These simulated spectra will be used to develop and evaluate gamma-ray analysis techniques for various nondestructive measurements. Simulated spectra of calculational standards can be used for code intercomparisons, to understand systematic biases and to estimate minimum detection levels of existing and proposed nondestructive analysis instruments. The capability to simulate gamma-ray spectra from HPGe detectors could significantly reduce the costs of preparing large numbers of real reference materials. MCNP was used for the Monte Carlo transport of the photons. Results from the MCNP calculations were folded in with a detector response function for a realistic spectrum. Plutonium spectrum peaks were produced with Lorentzian shapes, for the x-rays, and Gaussian distributions. The MGA code determined the Pu isotopes and specific power of this calculated spectrum and compared it to a similar analysis on a measured spectrum.
Date: July 16, 1993
Creator: Koenig, Z. M.; Carlson, J. B.; Wang, Tzu-Fang & Ruhter, W. D.
System: The UNT Digital Library
Application of RAD-BCG calculator to Hanford's 300 area shoreline characterization dataset (open access)

Application of RAD-BCG calculator to Hanford's 300 area shoreline characterization dataset

Abstract. In 2001, a multi-agency study was conducted to characterize potential environmental effects from radiological and chemical contaminants on the near-shore environment of the Columbia River at the 300 Area of the U.S. Department of Energy’s Hanford Site. Historically, the 300 Area was the location of nuclear fuel fabrication and was the main location for research and development activities from the 1940s until the late 1980s. During past waste handling practices uranium, copper, and other heavy metals were routed to liquid waste streams and ponds near the Columbia River shoreline. The Washington State Department of Health and the Pacific Northwest National Laboratory’s Surface Environmental Surveillance Project sampled various environmental components including river water, riverbank spring water, sediment, fishes, crustaceans, bivalve mollusks, aquatic insects, riparian vegetation, small mammals, and terrestrial invertebrates for analyses of radiological and chemical constituents. The radiological analysis results for water and sediment were used as initial input into the RAD-BCG Calculator. The RAD-BCG Calculator, a computer program that uses an Excel® spreadsheet and Visual Basic® software, showed that maximum radionuclide concentrations measured in water and sediment were lower than the initial screening criteria for concentrations to produce dose rates at existing or proposed limits. Radionuclide concentrations measured …
Date: July 1, 2003
Creator: Antonio, Ernest J.; Poston, Ted M.; Tiller, Brett L. & Patton, Gene W.
System: The UNT Digital Library
Magnets for the national spallation neutron source accumulator ring (open access)

Magnets for the national spallation neutron source accumulator ring

The National Spallation Neutron Source Accumulator Ring will require large aperture dipole magnets, strong focusing quadrupole magnets, and smaller low field dipole, quadrupole, and sextupole correcting magnets. All of the magnets will provide a fixed magnetic field throughout the accumulator`s fill/storage/extraction cycle. Similar fixed field magnets will also be provided for the beam transport systems. Because of the high intensity in the accumulator, the magnets must be designed with high tolerances for optimum field quality and for the high radiation environment which may be present at the injection/extraction areas, near the collimators, and near the target area. Field specifications and field plots are presented as well as planned fabrication methods and procedures, cooling system design, support, and installation.
Date: July 1, 1997
Creator: Tuozzolo, J.; Brodowski, J. & Danby, G.
System: The UNT Digital Library
Ultrafast observation of shocked states in a precompressed material (open access)

Ultrafast observation of shocked states in a precompressed material

None
Date: July 8, 2010
Creator: Armstrong, M R; Crowhurst, J C; Bastea, S & Zaug, J M
System: The UNT Digital Library
Electromagnetic field effects on cells of the immune system: The role of calcium signalling (open access)

Electromagnetic field effects on cells of the immune system: The role of calcium signalling

During the past decade considerable evidence has accumulated demonstrating the exposures of cells of the immune system to relatively weak extremely-low-frequency (ELF) electromagnetic fields (< 300 Hz) can elicit cellular changes which might be relevant to in-vivo immune activity. However, knowledge about the underlying biological mechanisms by which weak fields induce cellular changes is still very limited. It is generally believed that the cell membrane and Ca{sup 2+} regulated activity is involved in bioactive ELF field-coupling to living systems. This article begins with a short review of the current state of knowledge concerning the effects of nonthermal levels of ELF electromagnetic fields on the biochemistry and activity of immune cells, and then closely examines new results which suggest a role for Ca{sup 2+} in the induction of these cellular field effects. Based on these findings it is proposed that membrane-mediated Ca{sup 2+} signalling processes are involved in the mediation of field effects on the immune system. 64 refs., 2 tabs.
Date: July 1, 1991
Creator: Walleczek, J.
System: The UNT Digital Library
Polarization for Background Reduction in EDXRF - The Technique That Would Not Work (open access)

Polarization for Background Reduction in EDXRF - The Technique That Would Not Work

As with all electromagnet radiation, polarization of x-rays is a general phenomenon. Such polarization has been known since the classic experiments of Barkla in 1906. The general implementation of polarization to x-ray analysis had to await the fixed geometry of energy-dispersive systems. The means of optimizing these systems is shown in this review paper. Improved detection limits are the result.
Date: July 24, 2002
Creator: Ryon, R W
System: The UNT Digital Library
Novel QCD Phenomena (open access)

Novel QCD Phenomena

I discuss a number of novel topics in QCD, including the use of the AdS/CFT correspondence between Anti-de Sitter space and conformal gauge theories to obtain an analytically tractable approximation to QCD in the regime where the QCD coupling is large and constant. In particular, there is an exact correspondence between the fifth-dimension coordinate z of AdS space and a specific impact variable {zeta} which measures the separation of the quark constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and allow the computation of exclusive scattering amplitudes. I also discuss a number of novel phenomenological features of QCD. Initial- and final-state interactions from gluon-exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam Tung relation in Drell-Yan reactions, and nuclear shadowing and non-universal antishadowing--leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. I also discuss tests of hidden color in nuclear wavefunctions, the use of diffraction to materialize …
Date: July 6, 2007
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Neutral beam injector research and development work in the USA (open access)

Neutral beam injector research and development work in the USA

We describe neutral beam injector research and development at the Brookhaven National Laboratory, Lawrence Berkeley and Lawrence Livermore Laboratories, and Oak Ridge National Laboratory. All neutral beam systems for present and near-term applications are based on the acceleration and neutralization of positive ions. The research and development is carried out at LBL/LLL and ORNL. Present emphasis at LBL/LLL is on 80 to 120 kV systems for the mirror program and for the TFTR and D III tokamaks. Present emphasis at ORNL is on 40 to 80 kV systems for the PLT, ISX, and PDX, and 80 to 200 kV systems for LPTT and TNS tokamaks. Injectors for the future experiments and reactors may operate at energies of 200 keV or higher, especially for mirror machine applications, where positive-ion-based efficiencies will be very low, assuming no energy recovery. Research on negative-ion-based systems with potentially high efficiencies is carried out at BNL and at LBL/LLL and ORNL. The first demonstration of a high-power neutral beam based on negative ions is planned for 1980.
Date: July 1, 1978
Creator: Pyle, R.V.; Baker, W.R. & Barr, W.L.
System: The UNT Digital Library
Controlling the Actuation Rate of Low Density Shape Memory Polymer Foams in Water (open access)

Controlling the Actuation Rate of Low Density Shape Memory Polymer Foams in Water

None
Date: July 6, 2012
Creator: Singhal, P.; Boyle, T.; Infanger, S.; Letts, S.; Small, W.; Maitland, D. J. et al.
System: The UNT Digital Library
Development and Performance of Bechtel Nevada's Nine-Frame Camera System (open access)

Development and Performance of Bechtel Nevada's Nine-Frame Camera System

Bechtel Nevada, Los Alamos Operations, has developed a high-speed, nine-frame camera system that records a sequence from a changing or dynamic scene. The system incorporates an electrostatic image tube with custom gating and deflection electrodes. The framing tube is shuttered with high-speed gating electronics, yielding frame rates of up to 5MHz. Dynamic scenes are lens-coupled to the camera, which contains a single photocathode gated on and off to control each exposure time. Deflection plates and drive electronics move the frames to different locations on the framing tube output. A single charge-coupled device (CCD) camera then records the phosphor image of all nine frames. This paper discusses setup techniques to optimize system performance. It examines two alternate philosophies for system configuration and respective performance results. We also present performance metrics for system evaluation, experimental results, and applications to four-frame cameras.
Date: July 1, 2002
Creator: Baker, S. A.; Griffith, M. J. & Tybo, J. L.
System: The UNT Digital Library
Dispersion of waves in porous cylinders with patchy saturation Part I. Formulaton and torsional waves (open access)

Dispersion of waves in porous cylinders with patchy saturation Part I. Formulaton and torsional waves

Laboratory experiments on wave propagation through saturated and partially saturated porous media have often been conducted on porous cylinders that were initially fully saturated and then allowed to dry while continuing to acquire data on the wave behavior. Since it is known that drying typically progresses from outside to inside, a sensible physical model of this process is concentric cylinders having different saturation levels--the simplest example being a fully dry outer cylindrical shell together with a fully wet inner cylinder. We use this model to formulate the equations for wave dispersion in porous cylinders for patchy saturation (i.e. drainage) conditions. In addition to multiple modes of propagation obtained numerically from these dispersion relations, we find two distinct analytical expressions for torsional wave modes. We solve the dispersion relation for torsional waves for two examples: Massillon sandstone and Sierra White granite. The drainage analysis appears to give improved agreement with the data for both these materials.
Date: July 28, 2004
Creator: Berryman, J G & Pride, S R
System: The UNT Digital Library
New experimental capabilities and theoretical insights of high pressure compression waves (open access)

New experimental capabilities and theoretical insights of high pressure compression waves

Currently there are three platforms that offer quasi-isentropic compression or ramp-wave compression (RWC): light-gas gun, magnetic flux (Z-pinch), and laser. We focus here on the light-gas gun technique and on some current theoretical insights from experimental data. A gradient impedance through the length of the impactor provides the pressure pulse upon impactor to the subject material. Applications and results are given concerning high-pressure strength and liquid to solid, phase transition of water plus its associated phase fraction history. We also introduce the Korteweg-deVries-Burgers equation as a means to understand the evolution these RWC waves that propagate through the thickness of the subject material. This equation has the necessary competition between non-linear, dispersion, and dissipation processes, which is shown through observed structures that are manifested in the experimental particle velocity histories. Such methodology points towards a possible quantifiable dissipation, through which RWC experiments may be analyzed.
Date: July 20, 2007
Creator: Orlikowski, D.; Nguyen, J.; Patterson, J. R.; Minich, R.; Martin, L. P. & Holmes, N.
System: The UNT Digital Library
ESTIMATING IMPURITIES IN SURPLUS PLUTONIUM FOR DISPOSITION (open access)

ESTIMATING IMPURITIES IN SURPLUS PLUTONIUM FOR DISPOSITION

The United States holds at least 61.5 metric tons (MT) of plutonium that is permanently excess to use in nuclear weapons programs, including 47.2 MT of weapons-grade plutonium. Surplus inventories will be stored safely by the Department of Energy (DOE) and then transferred to facilities that will prepare the plutonium for permanent disposition. The Savannah River National Laboratory (SRNL) operates a Feed Characterization program for the Office of Fissile Materials Disposition of the National Nuclear Security Administration and the DOE Office of Environmental Management. Many of the items that require disposition are only partially characterized, and SRNL uses a variety of techniques to predict the isotopic and chemical properties that are important for processing through the Mixed Oxide Fuel Fabrication Facility and alternative disposition paths. Recent advances in laboratory tools, including Prompt Gamma Analysis and Peroxide Fusion treatment, provide data on the existing inventories that will enable disposition without additional, costly sampling and destructive analysis.
Date: July 17, 2013
Creator: Allender, J. & Moore, E.
System: The UNT Digital Library