Review of issues relevant to acceptable risk criteria for nuclear waste management (open access)

Review of issues relevant to acceptable risk criteria for nuclear waste management

Development of acceptable risk criteria for nuclear waste management requires the translation of publicly determined goals and objectives into definitive issues which, in turn, require resolution. Since these issues are largely of a subjective nature, they cannot be resolved by technological methods. Development of acceptable risk criteria might best be accomplished by application of a systematic methodology for the optimal implementation of subjective values. Multi-attribute decision analysis is well suited for this purpose.
Date: February 22, 1978
Creator: Cohen, J.J.
System: The UNT Digital Library
Fusion breeder (open access)

Fusion breeder

The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outline specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs.
Date: February 22, 1982
Creator: Moir, Ralph W.
System: The UNT Digital Library
The Third Image of the Large-Separation Lensed Quasar SDSS J1029+2623 (open access)

The Third Image of the Large-Separation Lensed Quasar SDSS J1029+2623

We identify a third image in the unique quasar lens SDSS J1029+2623, the second known quasar lens produced by a massive cluster of galaxies. The spectrum of the third image shows similar emission and absorption features, but has a redder continuum than the other two images which can be explained by differential extinction or microlensing. We also identify several lensed arcs. Our observations suggest a complicated structure of the lens cluster at z {approx} 0.6. We argue that the three lensed images are produced by a naked cusp on the basis of successful mass models, the distribution of cluster member galaxies, and the shapes and locations of the lensed arcs. Lensing by a naked cusp is quite rare among galaxy-scale lenses but is predicted to be common among large-separation lensed quasars. Thus the discovery can be viewed as support for an important theoretical prediction of the standard cold dark matter model.
Date: February 22, 2008
Creator: Oguri, Masamune; Ofek, Eran O.; Inada, Naohisa; Morokuma, Tomoki; Falco, Emilio E.; Kochanek, Christopher S. et al.
System: The UNT Digital Library
Sum Frequency Generation Vibrational Spectroscopy of Pyridine Hydrogenation on Platinum Nanoparticles (open access)

Sum Frequency Generation Vibrational Spectroscopy of Pyridine Hydrogenation on Platinum Nanoparticles

Pyridine hydrogenation in the presence of a surface monolayer consisting of cubic Pt nanoparticles stabilized by tetradecyltrimethylammonium bromide (TTAB) was investigated by sum frequency generation (SFG) vibrational spectroscopy using total internal reflection (TIR) geometry. TIR-SFG spectra analysis revealed that a pyridinium cation (C{sub 5}H{sub 5}NH{sup +}) forms during pyridine hydrogenation on the Pt nanoparticle surface, and the NH group in the C{sub 5}H{sub 5}NH{sup +} cation becomes more hydrogen bound with the increase of the temperature. In addition, the surface coverage of the cation decreases with the increase of the temperature. An important contribution of this study is the in situ identification of reaction intermediates adsorbed on the Pt nanoparticle monolayer during pyridine hydrogenation.
Date: February 22, 2008
Creator: Bratlie, Kaitlin M.; Komvopoulos, Kyriakos & Somorjai, Gabor A.
System: The UNT Digital Library
Isotopic approach for determining the structural components of silicate liquids (open access)

Isotopic approach for determining the structural components of silicate liquids

None
Date: February 22, 2008
Creator: Watkins, J J; Ryerson, F J & DePaolo, D .
System: The UNT Digital Library
Study of F- Production in BaBar RPCs (open access)

Study of F- Production in BaBar RPCs

The BaBar detector has operated over 200 2nd generation Resistive Plate Chambers (RPCs) in the forward endcap since 2002. Many chambers have increased noise rates and high voltage currents. These aging symptoms are correlated with the integrated RPC current as expected, but also depend on the rate and direction of the gas flow, indicating that pollutants produced in the gas can accelerate aging of downstream RPC surfaces. HF produced by decomposition of the Freon 134a component of the BaBar RPC gas in electric discharges has been proposed as the main pollutant. This paper presents measurements of HF production and absorption rates in BaBar RPCs. Since many of the highest rate chambers in the forward endcap were converted to avalanche mode operation, a comparison of HF production in streamer and avalanche mode RPCs is made. Correlations between the HF production rate and other chamber operating conditions were also explored.
Date: February 22, 2008
Creator: Band, H.R.; /Wisconsin U., Madison; Bellini, F.; /Rome U. /INFN, Rome; Covarelli, R.; /Perugia U. /INFN, Perugia et al.
System: The UNT Digital Library
Heavy Quarkonium Spectroscopy (open access)

Heavy Quarkonium Spectroscopy

Although the Standard Model of elementary particles is well established, strong interactions are not yet fully under control. We believe QCD is the field theory capable of describing them, but we are not yet capable, in most of the cases, to make exact predictions. Systems that include heavy quark-antiquark pairs (quarkonia) are ideal and unique laboratories to probe both the high energy regimes of QCD, where an expansion in terms of the coupling constant is possible, and the low energy regimes, where non-perturbative effects dominate. In the last years this field is experiencing a rapid expansion with a wealth of new data coming in from diverse sources: data on quarkonium formation from dedicated experiments (BES at BEPC, KEDR at VEPP-4M CLEO-c at CESR), clear samples produced by high luminosity B-factories (PEP and KEKB), and very large samples produced from gluon-gluon fusion in p{bar p} annihilations at Tevatron (CDF and D0 experiments). In this review I will first summarize recent developments in the understanding of heavy quarkonium states which have a well established quark content. Next, the core of the paper will be spent to review the experimental evidences of new states that might be aggregations of more than just a …
Date: February 22, 2008
Creator: Faccini, Riccardo
System: The UNT Digital Library
Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution (open access)

Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution

Monte Carlo simulations are used to establish the potential of mean force between two globular proteins in an aqueous electrolyte solution. This potential includes nonelectrostatic contributions arising from dispersion forces first, between the globular proteins, and second, between ions in solution and between each ion and the globular protein. These latter contributions are missing from standard models. The potential of mean force, obtained from simulation, is fitted to an analytic equation. Using our analytic potential of mean force and Barker-Henderson perturbation theory, we obtain phase diagrams for lysozyme solutions that include stable and metastable fluid-fluid and solid-fluid phases when the electrolyte is 0.2 M NaSCN or NaI or NaCl. The nature of the electrolyte has a significant effect on the phase diagram.
Date: February 22, 2006
Creator: Bostrom, Mathias; Tavares, Frederico W.; Ninham, Barry W. & Prausnitz, John M.
System: The UNT Digital Library
QCD-like Theories on R_3\times S_1: a Smooth Journey from Small to Large r(S_1)with Double-Trace Deformations (open access)

QCD-like Theories on R_3\times S_1: a Smooth Journey from Small to Large r(S_1)with Double-Trace Deformations

We consider QCD-like theories with one massless fermion in various representations of the gauge group SU(N). The theories are formulated on R{sub 3} x S{sub 1}. In the decompactification limit of large r(S{sub 1}) all these theories are characterized by confinement, mass gap and spontaneous breaking of a (discrete) chiral symmetry ({chi}SB). At small r(S{sub 1}), in order to stabilize the vacua of these theories at a center-symmetric point, we suggest to perform a double trace deformation. With these deformation, the theories at hand are at weak coupling at small r(S{sub 1}) and yet exhibit basic features of the large-r(S{sub 1}) limit: confinement and {chi}SB. We calculate the string tension, mass gap, bifermion condensates and {theta} dependence. The double-trace deformation becomes dynamically irrelevant at large r(S{sub 1}). Despite the fact that at small r(S{sub 1}) confinement is Abelian, while it is expected to be non-Abelian at large r(S{sub 1}), we argue that small and large-r(S{sub 1}) physics are continuously connected. If so, one can use small-r(S{sub 1}) laboratory to extract lessons about QCD and QCD-like theories on R{sub 4}.
Date: February 22, 2008
Creator: Shifman, Mikhail; U., /Minnesota; Unsal, Mithat & /SLAC /Stanford U., Phys. Dept.
System: The UNT Digital Library
Nansecond time resolved investigations using the in situ of Dynamic Transmission Electron Microscope (DTEM) (open access)

Nansecond time resolved investigations using the in situ of Dynamic Transmission Electron Microscope (DTEM)

None
Date: February 22, 2008
Creator: LaGrange, T.; Campbell, G. H.; Reed, B. W.; Taheri, M. L.; Pesavento, J. B.; Kim, J. S. et al.
System: The UNT Digital Library
X-ray Conversion Efficiency of high-Z hohlraum wall materials for indirect drive ignition (open access)

X-ray Conversion Efficiency of high-Z hohlraum wall materials for indirect drive ignition

We measure the conversion efficiency of 351 nm laser light to soft x-rays (0.1-5 keV) for Au, U and high Z mixtures 'cocktails' used for hohlraum wall materials in indirect drive ICF. We use spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates to achieve constant and uniform laser intensities of 10{sup 14} and 10{sup 15} W/cm{sup 2} over the target surface that are relevant for the future ignition experiments on NIF. The absolute time and spectrally-resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversion efficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses is subtracted. After {approx}0.5 ns, the time resolved x-ray conversion efficiency reaches a slowly increasing plateau of 95% at 10{sup 14} W/cm{sup 2} laser intensity and of 80% at 10{sup 15} W/cm{sup 2}. The M-band flux (2-5 keV) is negligible at 10{sup 14} W/cm{sup 2} reaching {approx}1% of the total x-ray flux for all target materials. In contrast, the M-band flux is significant and depends on the target material at 10{sup 15} W/cm{sup 2} laser intensity, reaching values between 10% of …
Date: February 22, 2008
Creator: Dewald, E; Rosen, M; Glenzer, S H; Suter, L J; Girard, F; Jadaud, J P et al.
System: The UNT Digital Library
Laser Tracker Test Facility at SLAC - Progress Report (open access)

Laser Tracker Test Facility at SLAC - Progress Report

Physics experiments at SLAC require high accuracy positioning, e. g. 100 {micro}m over a distance of 150 m or 25 {micro}m in a 10 x 10 x 3 meter volume. Laser Tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. In order to improve and get a better understanding of laser tracker measurement tolerances we extended our laboratory with a rotary calibration table (Kugler GmbH) providing an accuracy of better than 0.2 arcsec. This paper gives an overview of the calibration table and its evaluation. Results of tests on two of our Laser Trackers utilizing the new rotary table as well as the SLAC interferometer bench are presented.
Date: February 22, 2008
Creator: Gassner, G. L. & Ruland, R. E.
System: The UNT Digital Library
Interaction Region Upgrades of e+ e- B-Factories (open access)

Interaction Region Upgrades of e+ e- B-Factories

Both the PEP-II and KEKB B-Factories have plans to upgrade their Interaction Regions (IRs) in order to improve luminosity performance. Last summer PEP-II added cooling to the IR beam pipe in order to increase beam currents thereby raising the luminosity. In addition, PEP-II is working on a design that modifies the permanent magnets near the Interaction Point (IP) for an even higher luminosity increase. KEKB is also planning an improvement to their IR that will decrease the detector beam pipe radius. In addition, KEK has a design to increase the luminosity of KEKB to 1 x 10{sup 35} cm{sup -2} sec{sup -1} which includes changes to the IR. PEP-II is also investigating the feasibility of a 1 x 10{sup 36} cm{sup -2} sec{sup -1} luminosity design. I summarize these various upgrades and concentrate on issues common to the different designs.
Date: February 22, 2008
Creator: Sullivan, M.
System: The UNT Digital Library
Constructing QCD one-loop amplitudes (open access)

Constructing QCD one-loop amplitudes

In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted after examining the behavior of the cut integrand as the unconstrained parameters of a specifically chosen parameterization of the cut loop momentum approach infinity. Measurements of new physics at the forthcoming experimental program at CERN's Large Hadron Collider (LHC) will require a precise understanding of processes at next-to-leading order (NLO). This places increased demands for the computation of new one-loop amplitudes. This in turn has spurred recent developments towards improved calculational techniques. Direct calculations using Feynman diagrams are in general inefficient. Developments of more efficient techniques have usually centered around unitarity techniques [1], where tree amplitudes are effectively 'glued' together to form loops. The most straightforward application of this method, in which the cut loop momentum is in D = 4, allows for the computation of 'cut-constructible' terms only, i.e. (poly)logarithmic containing terms and any related constants. QCD amplitudes contain, in addition to such terms, rational pieces which cannot be derived using such cuts. These 'missing' rational parts can be extracted using cut loop …
Date: February 22, 2008
Creator: Forde, Darren
System: The UNT Digital Library
Towards a Real-time Transient Classification Engine (open access)

Towards a Real-time Transient Classification Engine

Temporal sampling does more than add another axis to the vector of observables. Instead, under the recognition that how objects change (and move) in time speaks directly to the physics underlying astronomical phenomena, next-generation wide-field synoptic surveys are poised to revolutionize our understanding of just about anything that goes bump in the night (which is just about everything at some level). Still, even the most ambitious surveys will require targeted spectroscopic follow-up to fill in the physical details of newly discovered transients. We are now building a new system intended to ingest and classify transient phenomena in near real-time from high-throughput imaging data streams. Described herein, the Transient Classification Project at Berkeley will be making use of classification techniques operating on"features" extracted from time series and contextual (static) information. We also highlight the need for a community adoption of a standard representation of astronomical time series data (i.e.,"VOTimeseries").
Date: February 22, 2008
Creator: Nugent, Peter E.; Bloom, Josh; Starr, Dan; Butler, Nat; Nugent, Peter; Rischard, M. et al.
System: The UNT Digital Library
DSP: A detailed spectroscopy postprocessor for H-, He-, and Li-like ions (open access)

DSP: A detailed spectroscopy postprocessor for H-, He-, and Li-like ions

A detailed plasma spectroscopy postprocessor for H-, He-, and Li-like ions with 6 {le} Z {le} 26 has been constructed. The structure of the code and the physics contained within it will be described and a sample application given. 15 refs., 5 figs.
Date: February 22, 1991
Creator: Keane, C.J.; Lee, R.S. (Lawrence Livermore National Lab., CA (USA)) & Grandy, J.P. (Massachusetts Inst. of Tech., Cambridge, MA (USA))
System: The UNT Digital Library
Modeling the Longitudinal Wall Impedance Instability in Heavy Ion Beams Using an R-Z PIC Code (open access)

Modeling the Longitudinal Wall Impedance Instability in Heavy Ion Beams Using an R-Z PIC Code

The effects of the longitudinal wall impedance instability in a heavy ion beam are of great interest for heavy ion fusion drivers. We are studying this instability using the R-Z thread of the WARP PIC code. We describe the code and our model of the impedance due to the accelerating modules of the induction LINAC as a resistive wall. We present computer simulations which illustrate this instability. 2 refs., 2 figs., 1 tab.
Date: February 22, 1991
Creator: Callahan, D. A.; Langdon, A. B.; Friedman, A.; Grote, D. P. & Haber, I.
System: The UNT Digital Library
Subsystem response determination for the US NRC Seismic Safety Margins Research Program (open access)

Subsystem response determination for the US NRC Seismic Safety Margins Research Program

The initial portion of the task described deals with a definition of the state-of-the-art of seismic qualification methods for subsystems. Too facilitate treatment of this broad class of subsystems, three classifications have been identified: multiply supported subsystems (e.g., piping systems); mechanical components (e.g., valves, pumps, control rod drives, hydraulic systems, etc.); and electrical components (e.g., electrical control panels). Descriptions of the available analysis and/or testing techniques for the above classifications are sought. The results of this assessment will be applied to the development of structural subsystem transfer functions.
Date: February 22, 1979
Creator: Johnson, J. J.
System: The UNT Digital Library
Cryogenic structural materials for superconducting magnets (open access)

Cryogenic structural materials for superconducting magnets

This paper reviews research in the United States and Japan on structural materials for high-field superconducting magnets. Superconducting magnets are used for magnetic fusion energy devices and for accelerators that are used in particle-physics research. The cryogenic structural materials that we review are used for magnet cases and support structures. We expect increased materials requirements in the future.
Date: February 22, 1985
Creator: Dalder, E.N.C. & Morris, J.W. Jr.
System: The UNT Digital Library
Status of the LLL tandem-shaped charge designs (open access)

Status of the LLL tandem-shaped charge designs

Lawrence Livermore Laboratory has been engaged in the design of tandem or multistage shaped charges for several years. Analytical and experimental work that focuses on how several aspects of tandem designs affect the jet characteristics is described. The work demonstrates the effectiveness of analytical methodology to specify liner geometries to achieve jets with controlled velocity gradients and high overall efficiency. It also shows that jet clippers and other ancillary components, along with controlled liner thickness, help make clean breaks between the jet and the slug and facilitate insertion of a second jet. Second-stage initiation and interjet time delays are discussed.
Date: February 22, 1979
Creator: Godfrey, C.S. & Jandrisevits, R.A.
System: The UNT Digital Library
Organosiloxane polymer concrete for geothermal environments (open access)

Organosiloxane polymer concrete for geothermal environments

The feasibility of using the products of free-radical copolymerization of modified organosiloxane in the formation of a thermally stable and chemically resistant polymer concrete for use in geothermal environments has been demonstrated. Specimens have been produced using mixtures of organosiloxane containing pendant vinyl groups and styrene or different silicon fluids as a comonomer in conjunction with a free-radical initiator and several aggregate materials. The use of these monomers in conjunction with materials such as SiO/sub 2/ and portland cement to form polymer concrete results in composites with high compressive strength (80 to 100 MPa) and thermal and hydrolytic stability. The results from studies to determine the effect of variables such as sand-particle size, type of cement, and sand-cement ratio are discussed.
Date: February 22, 1979
Creator: Zeldin, A.; Kukacka, L. E.; Fontana, J. & Carciello, N.
System: The UNT Digital Library
Overview of WARP, a particle code for Heavy Ion Fusion (open access)

Overview of WARP, a particle code for Heavy Ion Fusion

The beams in a Heavy Ion beam driven inertial Fusion (HIF) accelerator must be focused onto small spots at the fusion target, and so preservation of beam quality is crucial. The nonlinear self-fields of these space-charge-dominated beams can lead to emittance growth; thus a self-consistent field description is necessary. We have developed a multi-dimensional discrete-particle simulation code, WARP, and are using it to study the behavior of HIF beams. The code`s 3d package combines features of an accelerator code and a particle-in-cell plasma simulation, and can efficiently track beams through many lattice elements and around bends. We have used the code to understand the physics of aggressive drift-compression in the MBE-4 experiment at Lawrence Berkeley Laboratory (LBL). We have applied it to LBL`s planned ILSE experiments, to various ``recirculator`` configurations, and to the study of equilibria and equilibration processes. Applications of the 3d package to ESQ injectors, and of the r, z package to longitudinal stability in driver beams, are discussed in related papers.
Date: February 22, 1993
Creator: Friedman, A.; Grote, D. P.; Callahan, D. A.; Langdon, A. B. & Haber, I.
System: The UNT Digital Library
PIC space-charge emission with finite {Delta}t and {Delta}z (open access)

PIC space-charge emission with finite {Delta}t and {Delta}z

A new algorithm for space charge emission has been developed to provide the correct (to a few percent) Child-Langmuir steady-state current limits as the number of mesh points in the voltage gap drops to O(10). Further, the transient behavior of such flows compares well with idealized, analytic cases, lending confidence as we extend these algorithms into full RZ geometry with curved emitting surfaces to investigate transient characteristics of realistic injector designs.
Date: February 22, 1993
Creator: Hewett, D. W. & Chen, Yu-Jiuan
System: The UNT Digital Library
Developing models for simulation of pinched-beam dynamics in heavy ion fusion. Revision 1 (open access)

Developing models for simulation of pinched-beam dynamics in heavy ion fusion. Revision 1

For heavy-ion fusion energy applications, Mark and Yu have derived hydrodynamic models for numerical simulation of energetic pinched-beams including self-pinches and external-current pinches. These pinched-beams are applicable to beam propagation in fusion chambers and to the US High Temperature Experiment. The closure of the Mark-Yu model is obtained with adiabatic assumptions mathematically analogous to those of Chew, Goldberger, and Low for MHD. Features of this hydrodynamic beam model are compared with a kinetic treatment.
Date: February 22, 1984
Creator: Boyd, J. K.; Mark, J. W. K.; Sharp, W. M. & Yu, S. S.
System: The UNT Digital Library