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Bumps and poles in the S-matrix: A systematic study of 0 sup ++ and 2 sup ++ mesons plus a molecule approach to the E(1420) in the K K. pi. system (open access)

Bumps and poles in the S-matrix: A systematic study of 0 sup ++ and 2 sup ++ mesons plus a molecule approach to the E(1420) in the K K. pi. system

The goal of Hadron Spectroscopy is to find the spectrum of states formed by color singlet arrangements of quarks and gluons. Ideally these spectral states are associated with poles of the scattering matrix of hadrons which are the decay channels of the states. For example the {rho} meson is the lowest q{bar q} s-wave, spin one color singlet state and decays into {pi}{sup +}{pi}{sup -}. Since the {rho}decays in a relative p-wave, one finds the {rho} pole in the I = 1 p-wave {pi}{pi} phase shifts. There are forces between quarks and gluons which do not manifest themselves as true resonances and thus cannot be described by a Breit-Wigner pole. I will give some examples that are not Breit-Wigner poles of the scattering matrix but are important bumps in meson production. 22 refs., 10 figs.
Date: November 16, 1989
Creator: Longacre, R. S.
System: The UNT Digital Library
Magnetic shielding tests for MFTF-B neutral beamlines (open access)

Magnetic shielding tests for MFTF-B neutral beamlines

A test program to determine the effectiveness of various magnetic shielding designs for MFTF-B beamlines was established at Lawrence Livermore National Laboratory (LLNL). The proposed one-tenth-scale shielding-design models were tested in a uniform field produced by a Helmholtz coil pair. A similar technique was used for the MFTF source-injector assemblies, and the model test results were confirmed during the Technology Demonstration in 1982. The results of these tests on shielding designs for MFTF-B had an impact on the beamline design for MFTF-B. The iron-core magnet and finger assembly originally proposed were replaced by a simple, air-core, race-track-coil, bending magnet. Only the source injector needs to be magnetically shielded from the fields of approximately 400 gauss.
Date: November 16, 1983
Creator: Kerns, J.; Fabyan, J.; Wood, R. & Koger, P.
System: The UNT Digital Library
Three wavelength optical alignment of the Nova laser (open access)

Three wavelength optical alignment of the Nova laser

The Nova laser, presently under construction at Lawrence Livermore National Laboratory, will be capable of delivering more than 100 kJ of focused energy to an Inertial Confinement Fusion (ICF) target. Operation at the fundamental wavelength of the laser (1.05 ..mu..m) and at the second and third harmonic will be possible. This paper will discuss the optical alignment systems and techniques being implemented to align the laser output to the target at these wavelengths prior to each target irradiation. When experiments require conversion of the laser light to wavelengths of 0.53 ..mu..m and 0.35 ..mu..m prior to target irradiation, this will be accomplished in harmonic conversion crystals located at the beam entrances to the target chamber. The harmonic alignment system will be capable of introducing colinear alignment beams of all three wavelengths into the laser chains at the final spatial filter. The alignment beam at 1.05 ..mu..m will be about three cm in diameter and intense enough to align the conversion crystals. Beams at 0.53 ..mu..m and 0.35 ..mu..m will be expanded by the spatial filter to full aperture (74 cm) and used to illuminate the target and other alignment aids at the target chamber focus. This harmonic illumination system will …
Date: November 16, 1983
Creator: Swift, C. D.; Bliss, E. S.; Jones, W. A. & Seppala, L. G.
System: The UNT Digital Library
Projections of transport scaling laws for small toroidal reactors (open access)

Projections of transport scaling laws for small toroidal reactors

Transport in present day Spheromaks is dominated by impurity radiation. Fortunately, this is largely from oxygen and carbon, not metal vapor from the walls of the vessel on plasma guns and it is expected this loss can be eliminated by improved technique. The formation and gross MHD stability properties of these plasmas are quite well understood and so the reactor predictions depend on estimates of the energy loss rates from the plasma. In the absence of significant experimental data one is driven to consider other related devices. Tokamaks show classical ion transport, scaling with 1/B/sup 2/, but anomalous electron transport which is very insensitive to magnetic field, the well known Alcator scaling. The scaling of the Spheromak to a reactor size still produces favorable Q values with these pessimistic results. The reactor is small, with power output in the 10 to 50 MW range, but this could be deployed as a multiple unit power station, with good reliability due to the duplication, or as a small power unit for a ship or remote site. It also makes an attractive test reactor for the near term.
Date: November 16, 1981
Creator: McNamara, B.
System: The UNT Digital Library
Inertial-confinement-fusion targets (open access)

Inertial-confinement-fusion targets

Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques have been devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.
Date: November 16, 1981
Creator: Hendricks, C.D.
System: The UNT Digital Library
Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation (open access)

Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation

The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-based method with 3D open boundary conditions and longitudinal periodic boundary conditions. This code was completely rewritten in the late 1990s based on a message passing parallel programming paradigm using Fortran 90 and MPI following an object-oriented software design. This improved the code's scalability on large parallel computer systems and also gave the code better software maintainability and extensibility [2]. In the following years, under the SciDAC-1 accelerator project, the code was extended to include more accelerating and focusing elements such as DTL, CCL, superconducting linac, solenoid, dipole, multipoles, and others. Besides the original split-operator based integrator, a direct integration of Lorentz equations of motion using a leap-frog algorithm was also added to the IMPACT code to handle arbitrary external nonlinear fields. This integrator can read in 3D electromagnetic …
Date: November 16, 2006
Creator: Qiang, J. & Ryne, R.D.
System: The UNT Digital Library
Lepton Flavour Violation And Baryon Number Non-Conservation in tau to Lambda + h (open access)

Lepton Flavour Violation And Baryon Number Non-Conservation in tau to Lambda + h

We have searched for the violation of baryon number B and lepton number L in the (B - L)-conserving modes {tau}{sup -} {yields} {bar {Lambda}}{pi}{sup -} and {tau}{sup -} {yields} {bar {Lambda}}K{sup -} as well as the (B - L)-violating modes {tau}{sup -} {yields} {Lambda}{pi}{sup -} and {tau}{sup -} {yields} {Lambda}K{sup -} using 237 fb{sup -1} of data collected with the BaBar detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings. We do not observe any signal and we determine preliminary upper limits on the branching fractions {Beta}({tau}{sup -} {yields} {bar {Lambda}}{pi}{sup -}) < 5.9 x 10{sup -8}, {Beta}({tau}{sup -}{yields} {Lambda}{pi}{sup -}) < 5.8 x 10{sup -6}, {Beta}({tau}{sup -} {yields} {bar {Lambda}}K{sup -}) < 7.2 x 10{sup -8}, and {Beta}({tau}{sup -} {yields} {Lambda}K{sup -}) < 15 x 10{sup -8} at 90% confidence level.
Date: November 16, 2007
Creator: Lafferty, G.D.
System: The UNT Digital Library
Commissioning Results of the LCLS Injector (open access)

Commissioning Results of the LCLS Injector

The Linac Coherent Light Source (LCLS) is a SASE xray Free-Electron Laser (FEL) project presently under construction at SLAC. The injector section, from drive-laser and RF photocathode gun through first bunch compressor chicane, was installed in fall 2006. Initial system commissioning with an electron beam has recently been completed. The second phase of construction, including second bunch compressor and full linac, is planned for 2008. In this paper, we report experimental results and experience gained during the first phase of machine commissioning. This includes the cathode, drive laser, RF photocathode gun, linac booster section, S-band and X-band RF systems, first bunch compressor, and the various beam diagnostics.
Date: November 16, 2007
Creator: Dowell, D. H.; Akre, R.; Ding, Y.; Emma, P.; Frisch, J.; Gilevich, S. et al.
System: The UNT Digital Library
Evaluation of the Gas Production Potential of Marine HydrateDeposits in the Ulleung Basin of the Korean East Sea (open access)

Evaluation of the Gas Production Potential of Marine HydrateDeposits in the Ulleung Basin of the Korean East Sea

Although significant hydrate deposits are known to exist in the Ulleung Basin of the Korean East Sea, their survey and evaluation as a possible energy resource has not yet been completed. However, it is possible to develop preliminary estimates of their production potential based on the limited data that are currently available. These include the elevation and thickness of the Hydrate-Bearing Layer (HBL), the water depth, and the water temperature at the sea floor. Based on this information, we developed estimates of the local geothermal gradient that bracket its true value. Reasonable estimates of the initial pressure distribution in the HBL can be obtained because it follows closely the hydrostatic. Other critical information needs include the hydrate saturation, and the intrinsic permeabilities of the system formations. These are treated as variables, and sensitivity analysis provides an estimate of their effect on production. Based on the geology of similar deposits, it is unlikely that Ulleung Basin accumulations belong to Class 1 (involving a HBL underlain by a mobile gas zone). If Class 4 (disperse, low saturation accumulations) deposits are involved, they are not likely to have production potential. The most likely scenarios include Class 2 (HBL underlain by a zone of …
Date: November 16, 2007
Creator: Moridis, George J.; Reagan, Matthew T.; Kim, Se-Joon; Seol,Yongkoo & Zhang, Keni
System: The UNT Digital Library
Radiative Penguin Decays at the B Factories (open access)

Radiative Penguin Decays at the B Factories

In this article, I review the most recent results in radiative penguin decays from the B factories Belle and BABAR. Most notably, I will talk about the recent new observations in the decays B {yields} ({rho}/{omega}) {gamma}, a new analysis technique in b {yields} s{gamma}, and first measurements of radiative penguin decays in the B{sup 0}{sub s} meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.
Date: November 16, 2007
Creator: Koneke, Karsten
System: The UNT Digital Library
Extracting longitudinal shower developmentinformation from crystal calorimetry plus tracking (open access)

Extracting longitudinal shower developmentinformation from crystal calorimetry plus tracking

We propose a novel approach to derive longitudinal shower development information from a longitudinally unsegmented calorimeter such as the BaBar electromagnetic calorimeter by utilizing tracking information in conjunction with that of calorimetry. We show that using this information as part of an electron identification algorithm results in a significant reduction in the pion misidentification probability for low momentum particles. We also demonstrate how this information provides general charged particle separation at low momentum, particularly between pions and muons.
Date: November 16, 2007
Creator: Brown, D.N.; Ilic, J. & Mohanty, G.B.
System: The UNT Digital Library
A Simplistic View of Hadron Calorimetry (open access)

A Simplistic View of Hadron Calorimetry

All too often we rely on Monte Carlo simulations withoutworrying too much about basic physics. It is possible to start with avery simple calorimeter (a big cylinder) and learn the functional form ofpi e by aninduction argument. Monte Carlo simulations provide sanitychecks and constants. A power-law functional form describes test beamresults surprisingly well. The prediction that calorimeters responddifferently to protons and pions of the same energy was unexpected. Theeffect was later demonstrated by the CMS forward calorimeter group, usingthe most noncompensating calorimeter ever built. Calorimeter resolutionis dominated by fluctuations in piz production and the energy deposit byneutrons. The DREAM collaboration has recently used a dual readoutcalorimeter to eliminate the first of these. Ultimate resolution dependson measuring neutrons on an event-by-event basis as well.
Date: November 16, 2006
Creator: Groom, Donald E.
System: The UNT Digital Library
CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES (open access)

CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES

Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species followed by the polyvinyl acetate (PVAc) glue. The fiberboard material induced corrosion to a much lesser extent than the PVAc glue and RTV, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water as expected. A corrosion rate of 0.05 mm/year measured for coupons exposed to the most aggressive conditions was recommended as a conservative estimate for use in package performance calculations.
Date: November 16, 2007
Creator: Subramanian, K & Kerry Dunn, K
System: The UNT Digital Library
Symmetry reduction of (delta)-plutonium: an electronic-structure effect (open access)

Symmetry reduction of (delta)-plutonium: an electronic-structure effect

Using first-principles density-functional theory calculations, we show that the anomalously large anisotropy of {sigma}-plutonium is a consequence of greatly varying bond-strengths between the 12 nearest neighbors. Employing the calculated bond strengths, we expand the tenants of classical crystallography by incorporating anisotropy of chemical bonds, which yields a structure with the monoclinic space group Cm for {delta}-plutonium rather than face-centered cubic Fm{bar 3}m. The reduced space group for {delta}-plutonium enlightens why the ground state of the metal is monoclinic, why distortions of the metal are viable, and has considerable implications for the behavior of the material as it ages. These results illustrate how an expansion of classical crystallography that accounts for anisotropic electronic structure can explain complicated materials in a novel way.
Date: November 16, 2005
Creator: Moore, K; Soderlind, P; Schwartz, A & Laughlin, D
System: The UNT Digital Library
Relativistic Dark Matter at the Galactic Center (open access)

Relativistic Dark Matter at the Galactic Center

In a large region of the supersymmetry parameter space, the annihilation cross section for neutralino dark matter is strongly dependent on the relative velocity of the incoming particles. We explore the consequences of this velocity dependence in the context of indirect detection of dark matter from the galactic center. We find that the increase in the annihilation cross section at high velocities leads to a flattening of the halo density profile near the galactic center and an enhancement of the annihilation signal.
Date: November 16, 2007
Creator: Amin, Mustafa A.; /Stanford U., Phys. Dept. /KIPAC, Menlo Park & Wizansky, Tommer
System: The UNT Digital Library
A Possible Connection Between Dark Energy And the Hierarchy (open access)

A Possible Connection Between Dark Energy And the Hierarchy

Recently it was suggested that the dark energy maybe related to the well-known hierarchy between the Planck scale ({approx} 10{sup 19} GeV) and the TeV scale. The same brane-world setup to address this hierarchy problem may also in principle address the smallness problem of dark energy. Specifically, the Planck-SM hierarchy ratio was viewed as a quantum gravity-related, dimensionless fine structure constant where various physical energy scales in the system are associated with the Planck mass through different powers of the 'gravity fine structure constant'. In this paper we provide a toy model based on the Randall-Sundrum geometry where SUSY-breaking is induced by the coupling between a SUSY-breaking Higgs field on the brane and the KK gravitinos. We show that the associated Casimir energy density indeed conforms with the dark energy scale.
Date: November 16, 2007
Creator: Chen, Pisin; /SLAC /KIPAC, Menlo Park; Gu, Je-An & /NCTS, Hsinchu
System: The UNT Digital Library
CURRENT PROGRESS AND FUTURE PLANS FOR THE DOE OFFICE OF ENVIRONMENTAL MANAGEMENT INTERNATIONAL PROGRAM (open access)

CURRENT PROGRESS AND FUTURE PLANS FOR THE DOE OFFICE OF ENVIRONMENTAL MANAGEMENT INTERNATIONAL PROGRAM

The U.S. Department of Energy's (DOE) Office of Environmental Management (EM) has collaborated with various international institutes for many years on radioactive waste management challenges of mutual concern. Currently, DOE-EM is performing collaborative work with researchers at the Khlopin Radium Institute and the SIA Radon Institute in Russia and the Ukraine's International Radioecology Laboratory to explore issues related to high-level waste and to investigate experience and technologies that could support DOE-EM site cleanup needs. Specific initiatives include: (1) Application of the Cold Crucible Induction Heated Melter to DOE Wastes--SIA Radon and Savannah River National Laboratory; (2) Improved Solubility and Retention of Troublesome Components in SRS and Hanford Waste Glasses--Khlopin Radium Institute, Pacific Northwest National Laboratory and Savannah River National Laboratory; and (3) Long-term Impacts from Radiation/Contamination within the Chernobyl Exclusion Zone--International Radioecology Laboratory and Savannah River National Laboratory. This paper provides an overview of the status of the current International Program task activities. The paper will also provide insight into the future direction for the program. Specific ties to the current DOE-EM technology development multi-year planning effort will be highlighted as well as opportunities for future international collaborations.
Date: November 16, 2007
Creator: Marra, J; Kurt D Gerdes, K; David Peeler, D; John Harbour, J & Kevin Fox, K
System: The UNT Digital Library
Simulation of beams or plasmas crossing at relaticisticvelocity (open access)

Simulation of beams or plasmas crossing at relaticisticvelocity

None
Date: November 16, 2007
Creator: Vay, J. L.
System: The UNT Digital Library
Thinking Inside the Box (open access)

Thinking Inside the Box

In early 2007, SLAC was faced with a shortage of both electrical power and cooling in the main computer building, at the same time that the BaBar collaboration needed a new cluster of 250 batch machines installed. A number of different options were explored for the expansion. Provision of additional electrical power to the building was estimated to take one to two years, and cost several million dollars; additional cooling was even worse. Space in a Silicon Valley co-location facilities was reasonable on a one-year timescale, but broke even in costs by the end of three years, and were more expensive after that. There were also unresolved questions about the affects of additional latency from an offsite compute cluster to the onsite disk servers. The option of converting existing experimental hall space into computer space was estimated at one year, with uncertain availability. An option to aggressively replace several existing clusters with more power-efficient equipment was studied closely, but was disruptive to continued operations, expensive, and didn't provide any additional headroom. Finally, the installation of a Sun Project Blackbox (PBB) unit was selected as providing the capacity on a timescale of six months for a reasonable cost with minimal disruption …
Date: November 16, 2007
Creator: Boeheim, Charles T.
System: The UNT Digital Library
Exploration of GaTe for Gamma Detectors (open access)

Exploration of GaTe for Gamma Detectors

The layered III-VI semiconductor Gallium Telluride has potential for room temperature gamma ray spectroscopy applications due to its band gap of 1.67 eV, and average atomic number of 45:31 (Ga) and 52 (Te). The physical properties of GaTe are highly anisotropic due to covalent bonding within the layer and van der Waals bonding between layers. This work reports the results of surface and bulk processing, surface characterization, and electrical characterization of diodes formed on both the laminar and non-laminar GaTe surfaces. Alpha detection measurements were also performed.
Date: November 16, 2007
Creator: Conway, A. M.; Reinhardt, C. E.; Nikolic, R. J.; Nelson, A. J.; Wang, T. F.; Wu, K. J. et al.
System: The UNT Digital Library
Review of the microscopic cross sections for the americium isotopes in the resolved resonance region. [0. 5 eV to 10 keV] (open access)

Review of the microscopic cross sections for the americium isotopes in the resolved resonance region. [0. 5 eV to 10 keV]

The differential cross section measurements for /sup 241/Am, /sup 242m/Am and /sup 243/Am are reviewed in the energy range from 0.5 eV to 10 keV. Parameters extracted from resonance analysis, such as the neutron strength function, the average level spacing, the average capture and fission widths, are compared for the various measurements. The average capture and fission cross sections from 100 eV to 10 keV are directly compared. The status of the data set is discussed with suggestions for further measurements. 24 references.
Date: November 16, 1978
Creator: Browne, J. C.
System: The UNT Digital Library
The theory of temporal compression of intense pulses in a metal vapor (open access)

The theory of temporal compression of intense pulses in a metal vapor

We examine compression of near-resonant pulses in metal vapor in the nonlinear regime. Our calculations examine nonlinear effects on compression of optimally-chirped pulses of various fluences. In addition, we compare model predictions with experimental results for compression of 4 nsec Nd:YAG pumped dye pulses.
Date: November 16, 1990
Creator: Shaw, M.J. & Crane, J.K.
System: The UNT Digital Library
Laser pulse compression in strontium and calcium vapor (open access)

Laser pulse compression in strontium and calcium vapor

Application of vapor pulse compression for increasing the intensity of a large copper vapor laser pumped dye laser for x-ray generation is limited by collisional absorption and nonlinear pulse breakup. We discuss measurements of these effects. 7 refs., 1 fig., 11 tabs.
Date: November 16, 1990
Creator: Crane, J. K.; Cooke, J. D.; Shaw, M. J.; Presta, R. W.; Christensen, J. J.; Johnson, M. A. et al.
System: The UNT Digital Library
Third geopressured-geothermal energy conference.Vol 2 (open access)

Third geopressured-geothermal energy conference.Vol 2

Twenty papers were included covering the Edna Delcambre Test Well, legal studies, environmental studies, economic studies, and resource utilization. Separate abstracts were prepared for each paper. (MHR)
Date: November 16, 1977
Creator: Meriwether, J.
System: The UNT Digital Library