Final Technical Report on STTR Project DE-FG02-04ER86191 Hydrogen Cryostat for Muon Beam Cooling (open access)

Final Technical Report on STTR Project DE-FG02-04ER86191 Hydrogen Cryostat for Muon Beam Cooling

The project was to develop cryostat designs that could be used for muon beam cooling channels where hydrogen would circulate through refrigerators and the beam-cooling channel to simultaneously refrigerate 1) high-temperature-superconductor (HTS) magnet coils, 2) cold copper RF cavities, and 3) the hydrogen that is heated by the muon beam. In an application where a large amount of hydrogen is naturally present because it is the optimum ionization cooling material, it was reasonable to explore its use with HTS magnets and cold, but not superconducting, RF cavities. In this project we developed computer programs for simulations and analysis and conducted experimental programs to examine the parameters and technological limitations of the materials and designs of Helical Cooling Channel (HCC) components (magnet conductor, RF cavities, absorber windows, heat transport, energy absorber, and refrigerant).The project showed that although a hydrogen cryostat is not the optimum solution for muon ionization cooling channels, the studies of the cooling channel components that define the cryostat requirements led to fundamental advances. In particular, two new lines of promising development were opened up, regarding very high field HTS magnets and the HS concept, that have led to new proposals and funded projects.
Date: May 7, 2008
Creator: Johnson, Rolland P.
Object Type: Report
System: The UNT Digital Library
Computation of Three Dimensional Tokamak and Spherical Torus Equilibria (open access)

Computation of Three Dimensional Tokamak and Spherical Torus Equilibria

A nominally axisymmetric plasma con�guration, such as a tokamak or a spherical torus, is highly sensitive to non-axisymmetric magnetic perturbations due to currents outside of the plasma. The high sensitivity means that the primary interest is in the response of the plasma to very small perturbations, | →(over) β/→(over)Β | ≈ 10–2 to 10–4, which can be calculated using the theory of perturbed equilibria. The Ideal Perturbed Equilibrium Code (IPEC) is described and applied to the study of the plasma response in a spherical torus to such external perturbations.
Date: May 7, 2007
Creator: Jong-kyu Park, Allen H. Boozer, and Alan H. Glasser
Object Type: Report
System: The UNT Digital Library
River water temperature survey (open access)

River water temperature survey

Data acquired from the temperature survey of the Columbia River, April 2, 1945, is presented.
Date: May 7, 1945
Creator: Jordan, W. E.
Object Type: Report
System: The UNT Digital Library
Hybrid Chirped Pulse Amplification (open access)

Hybrid Chirped Pulse Amplification

We present a novel chirped pulse amplification method which combines optical parametric amplification and laser amplification. We have demonstrated this hybrid CPA concept with a combination of beta-barium borate and Ti:sapphire. High-efficiency, multi-terawatt compatible amplification is achieved without gain narrowing and without electro-optic modulators using a simple commercial pump laser.
Date: May 7, 2002
Creator: Jovanovic, I & Barty, C P J
Object Type: Article
System: The UNT Digital Library
VVER-1000 weapons-grade MOX computational benchmark analysis (open access)

VVER-1000 weapons-grade MOX computational benchmark analysis

Calculations of computational benchmark problems for the disposition of weapons-grade plutonium fuel in VVER-1000 reactors have been performed under the Joint US/Russian Fissile Material Disposition Program. The benchmarks cover pin cell, single fuel assembly, and multi-assembly structures with several different fuel types, moderator densities, and boron content for operational and off-normal conditions. Fuel depletion is performed to a burnup of 60 MWd/kgHM. The results of the analysis of the benchmarks with US and Russian code systems have been compared and indicated good agreement among the different methods and data.
Date: May 7, 2000
Creator: Kalugin, M. A.; Lazarenko, A. P.; Kalahnikov, A. G. & Gehin, J. C.
Object Type: Article
System: The UNT Digital Library
Microwave versus conventional sintering of silicon carbide tiles (open access)

Microwave versus conventional sintering of silicon carbide tiles

Silicon carbide is being evaluated as an armor material because of its lightweight, high-hardness, and excellent armor efficiency. However, one of the problems associated with silicon carbide is the high cost associated with achieving fully dense tiles. Full density requires either hot pressing and sintering or reaction bonding. Past efforts have shown that hot pressed tiles have a higher armor efficiency than those produced by reaction bonded sintering. An earlier stuy showed that the acoustic properties of fully-dense silicon carbide tiles were enhanced through the use of post-sintered microwave heat treatments. One of the least expensive forming techniques is to isostatically press-and-sinter. In this study, the authors have used microwave energy to densify silicon carbide green bodies. Microwave sintering has been demonstrated to be a very quick way to sinter ceramics such as alumina to exceptionally high densities. Previous work has shown that microwave post treatment of fully-dense reaction bonded silicon carbide tiles significantly improves the acoustic properties of the tiles. These properties include Poisson`s ratio, Young`s modulus, shear modulus, and bulk modulus.
Date: May 7, 1997
Creator: Kass, M. D.; Caughman, J. B. O.; Forrester, S. C. & Akerman, A.
Object Type: Report
System: The UNT Digital Library
Redesign of the H-Bridge Switch Plate of the SNS High Voltage Converter Modulator (open access)

Redesign of the H-Bridge Switch Plate of the SNS High Voltage Converter Modulator

The 1-MW High Voltage Converter Modulators [1] have operated in excess of 250,000 hours at the Spallation Neutron Source. Increased demands on the accelerator performance require increased modulator reliability. An effort is underway at SLAC National Accelerator Laboratory to redesign the modulator H-bridge switch plate with the goals of increasing reliability and performance [2]. The major difference between the SLAC design and the existing design is the use of press-pack IGBTs. Compared to other packaging options, these IGBTs have been shown to have increased performance in pulsed-power applications, have increased cooling capability, and do not fragment and disassemble during a fault event. An overview of the SLAC switch plate redesign is presented. Design steps including electrical modeling of the modulator and H-bridge, development of an integrated IGBT clamping mechanism, and fault tests are discussed. Experimental results will be presented comparing electrical performance of the SLAC switch plate to the existing switchplate under normal and fault conditions.
Date: May 7, 2009
Creator: Kemp, M. A.; Burkhart, C.; Nguyen, M. N. & Anderson, D. E.
Object Type: Article
System: The UNT Digital Library
3D unstructured mesh ALE hydrodynamics with the upwind discontinuous galerkin method (open access)

3D unstructured mesh ALE hydrodynamics with the upwind discontinuous galerkin method

The authors describe a numerical scheme to solve 3D Arbitrary Lagrangian-Eulerian (ALE) hydrodynamics on an unstructured mesh using a discontinuous Galerkin method (DGM) and an explicit Runge-Kutta time discretization. Upwinding is achieved through Roe's linearized Riemann solver with the Harten-Hyman entropy fix. For stabilization, a 3D quadratic programming generalization of van Leer's 1D minmod slope limiter is used along with a Lapidus type artificial viscosity. This DGM scheme has been tested on a variety of hydrodynamic test problems and appears to be robust making it the basis for the integrated 3D inertial confinement fusion modeling code (ICF3D). For efficient code development, they use C++ object oriented programming to easily separate the complexities of an unstructured mesh from the basic physics modules. ICF3D is fully parallelized using domain decomposition and the MPI message passing library. It is fully portable. It runs on uniprocessor workstations and massively parallel platforms with distributed and shared memory.
Date: May 7, 1999
Creator: Kershaw, D S; Milovich, J L; Prasad, M K; Shaw, M J & Shestakov, A I
Object Type: Article
System: The UNT Digital Library
Alcator C-Mod Experiments in Support of the ITER Baseline 15 MA Scenario (open access)

Alcator C-Mod Experiments in Support of the ITER Baseline 15 MA Scenario

Experiments on Alcator C-Mod have addressed several issues for the ITER 15 MA baseline scenario from 2009-2012. Rampup studies show ICRF can save significant V-s, and that an H-mode in the ramp can be utilized to save 50% more. ICRF modifications to li(1) are minimal, although the Te profile is peaked relative to ohmic in the plasma center, and alter sawtooth onset times. Rampdown studies show H-modes can be routinely sustained, avoiding an OH coil over-current associated with the H-L transition, that fast rampdowns are preferred, the density drops with Ip, and that the H-L transition occurs at Ploss/Pthr,LH ~ 1.0-1.3 at n/nGr ~ 0.85. Flattop plasmas targeting ITER baseline parameters have been sustained for 20 Ï„E or 8-13 Ï„CR, but only reach H98 ~ 0.6 at n/nGr = 0.85, rising to 0.9 at n/nGr = 0.65.
Date: May 7, 2013
Creator: Kessel, C.
Object Type: Report
System: The UNT Digital Library
100-300 Area program meeting of May 7, 1946 (open access)

100-300 Area program meeting of May 7, 1946

None
Date: May 7, 1946
Creator: Kidder, C. P.
Object Type: Report
System: The UNT Digital Library
Imaging back scattered and near back scattered light in ignition scale plasmas (open access)

Imaging back scattered and near back scattered light in ignition scale plasmas

Diagnostics have been developed and fielded at the Nova laser facility that image scattered light in the vicinity of the final laser focusing lens. The absolute calibration of optical components exposed to the target debris have been achieved by a combination of routine in situ calibration and maintenance. The scattering observed from plasmas relevant to ignition experiments indicates that light scattered just outside the lens can be larger than that collected by the lens, and is a significant factor in the energy balance when the f number is high.
Date: May 7, 1996
Creator: Kirkwood, R. K.; Back, C. A.; Glenzer, S. H. & Moody, J. D.
Object Type: Article
System: The UNT Digital Library
Quantitative Characterization of Inertial Confinement Fusion Capsules Using Phase Contrast Enhanced X-Ray Imaging (open access)

Quantitative Characterization of Inertial Confinement Fusion Capsules Using Phase Contrast Enhanced X-Ray Imaging

Current designs for inertial confinement fusion capsules for the National Ignition Facility (NIF) consist of a solid deuterium-tritium (D-T) fuel layer inside of a copper doped beryllium capsule. Phase contrast enhanced x-ray imaging is shown to render the D-T layer visible inside the Be(Cu) capsule. Phase contrast imaging is experimentally demonstrated for several surrogate capsules and validates computational models. Polyimide and low density divinyl benzene foam capsules were imaged at the Advanced Photon Source synchrotron. The surrogates demonstrate that phase contrast enhanced imaging provides a method to characterize surfaces when absorption imaging cannot be used. Our computational models demonstrate that a rough surface can be accurately reproduced in phase contrast enhanced x-ray images.
Date: May 7, 2004
Creator: Kozioziemski, B. J.; Koch, J. A.; Barty, A.; Martz, H. E.; Lee, W. & Fezzaa, K.
Object Type: Article
System: The UNT Digital Library
Time Evolution of Beam in the Recycler Ring (open access)

Time Evolution of Beam in the Recycler Ring

We study the time evolution of the beam current in the Fermilab Recycler Ring due to abrupt physical processes (single coulomb scattering, nuclear scattering) that cause sudden loss of beam, and diffusive processes (multiple coulomb scattering, lattice dependence, etc.) which cause emittance growth. This emittance growth combined with finite aperture of the beam pipe will lead to eventual loss of most beam. We develop a fitting technique to the time evolution of beam current to estimate emittance growth. Finally we compare the directly measured growth with the fitted value.
Date: May 7, 2003
Creator: Krish Gounder, John Marriner and Shekhar Mishra
Object Type: Article
System: The UNT Digital Library
Comparisons of cloud cover estimates and cloud fraction profiles from ARM's cloud-detecting instruments and GOES-8 data (open access)

Comparisons of cloud cover estimates and cloud fraction profiles from ARM's cloud-detecting instruments and GOES-8 data

The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward- and downward-looking remote-sensing instruments to measure the horizontal and vertical distributions of clouds across its Southern Great Plains (SGP) site. No single instrument is capable of completely determining these distributions over the scales of interest to ARM's Single Column Modeling (SCM) and Instantaneous Radiative Flux (IRF) groups; these groups embody the primary strategies through which ARM expects to achieve its objectives of developing and testing cloud formation parameterizations (USDOE, 1996). Collectively, however, the data from ARM's cloud-detecting instruments offer the potential for such a three-dimensional characterization. Data intercomparisons, like the ones illustrated in this paper, are steps in this direction. Examples of some initial comparisons, involving satellite, millimeter cloud radar, whole sky imager and ceilometer data, are provided herein. that many of the lessons learned can later be adapted to cloud data at the Boundary and Extended Facilities. Principally, we are concerned about: (1) the accuracy of various estimates of cloud properties at a single point, or within a thin vertical column, above the CF over time, and (2) the accuracy of various estimates of cloud properties over the Cloud and Radiation Testbed (CART) site, which can then be reduced …
Date: May 7, 1999
Creator: Krueger, S K & Rodriguez, D
Object Type: Article
System: The UNT Digital Library
Molecular Line Emission from Massive Protostellar Disks: Predictions for ALMA and the EVLA (open access)

Molecular Line Emission from Massive Protostellar Disks: Predictions for ALMA and the EVLA

We compute the molecular line emission of massive protostellar disks by solving the equation of radiative transfer through the cores and disks produced by the recent radiation-hydrodynamic simulations of Krumholz, Klein, & McKee. We find that in several representative lines the disks show brightness temperatures of hundreds of Kelvin over velocity channels {approx} 10 km s{sup -1} wide, extending over regions hundreds of AU in size. We process the computed intensities to model the performance of next-generation radio and submillimeter telescopes. Our calculations show that observations using facilities such as the EVLA and ALMA should be able to detect massive protostellar disks and measure their rotation curves, at least in the nearest massive star-forming regions. They should also detect significant sub-structure and non-axisymmetry in the disks, and in some cases may be able to detect star-disk velocity offsets of a few km s{sup -1}, both of which are the result of strong gravitational instability in massive disks. We use our simulations to explore the strengths and weaknesses of different observational techniques, and we also discuss how observations of massive protostellar disks may be used to distinguish between alternative models of massive star formation.
Date: May 7, 2007
Creator: Krumholz, M R; Klein, R I & McKee, C F
Object Type: Article
System: The UNT Digital Library
Mobile Ice Nucleus Spectrometer (open access)

Mobile Ice Nucleus Spectrometer

This first year report presents results from a computational fluid dynamics (CFD) study to assess the flow and temperature profiles within the mobile ice nucleus spectrometer.
Date: May 7, 2012
Creator: Kulkarni, Gourihar R. & Kok, G. L.
Object Type: Report
System: The UNT Digital Library
GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATION OF THE DWPF CHEMICAL PROCESSING CELL WITH MATRIX SIMULANTS AND SUPERNATE (open access)

GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATION OF THE DWPF CHEMICAL PROCESSING CELL WITH MATRIX SIMULANTS AND SUPERNATE

Savannah River Remediation (SRR) is evaluating changes to its current DWPF flowsheet to improve processing cycle times. This will enable the facility to support higher canister production while maximizing waste loading. Higher throughput is needed in the CPC since the installation of the bubblers into the melter has increased melt rate. Due to the significant maintenance required for the DWPF gas chromatographs (GC) and the potential for production of flammable quantities of hydrogen, reducing or eliminating the amount of formic acid used in the CPC is being developed. Earlier work at Savannah River National Laboratory has shown that replacing formic acid with an 80:20 molar blend of glycolic and formic acids has the potential to remove mercury in the SRAT without any significant catalytic hydrogen generation. This report summarizes the research completed to determine the feasibility of processing without formic acid. In earlier development of the glycolic-formic acid flowsheet, one run (GF8) was completed without formic acid. It is of particular interest that mercury was successfully removed in GF8, no formic acid at 125% stoichiometry. Glycolic acid did not show the ability to reduce mercury to elemental mercury in initial screening studies, which is why previous testing focused on using …
Date: May 7, 2012
Creator: Lambert, D.; Stone, M.; Newell, J. & Best, D.
Object Type: Report
System: The UNT Digital Library
Fourier mode analysis of slab-geometry transport iterations in spatially periodic media (open access)

Fourier mode analysis of slab-geometry transport iterations in spatially periodic media

We describe a Fourier analysis of the diffusion-synthetic acceleration (DSA) and transport-synthetic acceleration (TSA) iteration schemes for a spatially periodic, but otherwise arbitrarily heterogeneous, medium. Both DSA and TSA converge more slowly in a heterogeneous medium than in a homogeneous medium composed of the volume-averaged scattering ratio. In the limit of a homogeneous medium, our heterogeneous analysis contains eigenvalues of multiplicity two at ''resonant'' wave numbers. In the presence of material heterogeneities, error modes corresponding to these resonant wave numbers are ''excited'' more than other error modes. For DSA and TSA, the iteration spectral radius may occur at these resonant wave numbers, in which case the material heterogeneities most strongly affect iterative performance.
Date: May 7, 1999
Creator: Larsen, E W & Zika, M R
Object Type: Article
System: The UNT Digital Library
Proceedings of the 1986 summer workshop on antiproton beams in the 2-10 GeV/c range (open access)

Proceedings of the 1986 summer workshop on antiproton beams in the 2-10 GeV/c range

The possibilities for building a facility for the formation spectroscopy of ''charmonium'' and the study of ''exotics'' at the AGS with high intensity antiproton beams of good resolution and enhanced purity are explored. The performance potential of a number of long beams and the AGS booster are evaluated and costs are estimated. Fluxes of several 10/sup 7/ antiprotons per pulse with purities of 5% to 99% are possible with conventional long beams. A similar total antiproton flux would be available with the Booster with no beam contamination. This could effectively be enhanced by two orders of magnitude by reducing the momentum spread in order to scan very narrow (less than 1 MeV) resonances. The maximum momentum attainable with the present Booster magnet design is 5.6 GeV/c which only reaches the Chi/sub 0/ (3415) charmonium state. Modifications are possible which would raise the maximum momentum to 6.3 GeV/c to include all states up to and including eta'/sub c/ (3590) in its range. The performance potential for this physics at the AGS is found to compare favorably with that at other laboratories with more antiprotons delivered annually, running in the post-Booster era, than at FNAL or Super-Lear with ACOL under typical scheduling …
Date: May 7, 1987
Creator: Lazarus, D. (ed.)
Object Type: Article
System: The UNT Digital Library
STELLOPT Modeling of the 3D Diagnostic Response in ITER (open access)

STELLOPT Modeling of the 3D Diagnostic Response in ITER

The ITER three dimensional diagnostic response to an n=3 resonant magnetic perturbation is modeled using the STELLOPT code. The in-vessel coils apply a resonant magnetic perturbation (RMP) fi eld which generates a 4 cm edge displacement from axisymmetry as modeled by the VMEC 3D equilibrium code. Forward modeling of flux loop and magnetic probe response with the DIAGNO code indicates up to 20 % changes in measured plasma signals. Simulated LIDAR measurements of electron temperature indicate 2 cm shifts on the low field side of the plasma. This suggests that the ITER diagnostic will be able to diagnose the 3D structure of the equilibria.
Date: May 7, 2013
Creator: Lazerson, Samuel A
Object Type: Report
System: The UNT Digital Library
Measurements of CKM angles beta/phi_1 and alpha/phi_2 at the Babar and Belle experiments. (open access)

Measurements of CKM angles beta/phi_1 and alpha/phi_2 at the Babar and Belle experiments.

We report measurements of the CKM angles {beta}/{phi}{sub 1} and {alpha}/{phi}{sub 2} done by the BABAR and Belle experiments. Both experiments have collected large data samples, corresponding to a total of more than 1 billion of B{bar B} pairs, at the e{sup +}e{sup -} asymmetric-energy colliders PEP-II (SLAC) and KEK-B (KEK), respectively.
Date: May 7, 2009
Creator: Lazzaro, A.
Object Type: Article
System: The UNT Digital Library
Time-dependent ionization balance model for non-LTE plasma (open access)

Time-dependent ionization balance model for non-LTE plasma

We have developed a detailed configuration-accounting kinetic model for calculating time-dependent ionization-balance and ion-level populations in non-local thermal-equilibrium (non-LTE) plasmas. We use these population estimates in computing spectral line intensities, line ratios, and synthetic spectra, and in fitting these calculated values to experimental measurements. The model is also used to design laboratory x-ray laser experiments. For this purpose, it is self-consistently coupled to the hydrodynamics code LASNEX. 20 refs., 14 figs.
Date: May 7, 1986
Creator: Lee, Y. T.; Zimmerman, G. B.; Bailey, D. S.; Dickson, D. & Kim, D.
Object Type: Article
System: The UNT Digital Library
Design of the extraction system and beamline of the superconducting ECR ion source VENUS (open access)

Design of the extraction system and beamline of the superconducting ECR ion source VENUS

A new, very high magnetic field superconducting ECR ion source, VENUS, is under construction at the LBNL 88-Inch Cyclotron [1,2]. The paper describes the VENUS extraction system and discusses the ion beam formation in the strong axial magnetic field (3 T) of the ECR ion source. Emittance values as expected from theory, which assumes a uniform plasma density across the plasma outlet hole, are compared with actual measurements from the AECR-U ion source. Results indicate that highly charged heavier ions are concentrated on the source axis. They are extracted from an ''effective'' plasma outlet hole, whose smaller radius must be included in ion optics simulations.
Date: May 7, 2001
Creator: Leitner, Matthaeus A.; Wutte, Daniela C. & Lyneis, Claude M.
Object Type: Article
System: The UNT Digital Library
Mixing and CP violation in the D0 and B0(s) systems (open access)

Mixing and CP violation in the D0 and B0(s) systems

Recent developments for mixing and CP violation in the D0 and Bs systems are reviewed, including (i) the recently emerging evidence for D0-D0bar mixing and the interpretations of the measurements; (ii) the theoretical status of the calculations of Delta(Gamma_D) and Delta(m_D); (iii) some implications of the measurement of Bs mixing for new physics.
Date: May 7, 2007
Creator: Ligeti, Zoltan & Ligeti, Zoltan
Object Type: Article
System: The UNT Digital Library