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Electron beam charge state amplifier (EBQA)--a conceptual evaluation.

Description: A concept is presented for stripping low-energy, radioactive ions from 1+ to higher charge states. Referred to as an Electron Beam Charge State Amplifier (EBQA), this device accepts a continuous beam of singly-charged, radioactive ions and passes them through a high-density electron beam confined by a solenoidal magnetic field. Singly-charged ions may be extracted from standard Isotope-Separator-Online (ISOL) sources. An EBQA is potentially useful for increasing the charge state of ions prior to injection into post-acceleration stages at ISOL radioactive beam facilities. The stripping efficiency from q=1+ to 2+ ({eta}{sub 12}) is evaluated as a function of electron beam radius at constant current with solenoid field, injected ion energy, and ion beam emittance used as parameters. Assuming a 5 keV, 1 A electron beam, {eta}{sub 12} = 0.38 for 0.1 keV, {sup 132}Xe ions passing through an 8 Tesla solenoid, 1 m in length. Multi-pass configurations to achieve 3+ or 4+ charge states are also conceivable. The calculated efficiencies depend inversely on the initial ion beam emittances. The use of a helium-buffer-gas, ion-guide stage to improve the brightness of the 1+ beams [1] may enhance the performance of an EBQA.
Date: October 12, 1998
Creator: Dooling, J. C.
Partner: UNT Libraries Government Documents Department

Supersymmetric Higgs Pair Production at Hadron Colliders

Description: We study the pair production of neutral Higgs bosons through gluon fusion at hadron colliders in the framework of the Minimal Supersymmetric Standard Model. We present analytical expressions for the relevant amplitudes, including both quark and squark loop contributions, and allowing for mixing between the superpartners of left- and right-handed quarks. Squark loop contributions can increase the cross section for the production of two CP--even Higgs bosons by more than two orders of magnitude, if the relevant trilinear soft breaking parameter is large and the mass of the lighter squark eigenstate is not too far above its current lower bound. In the region of large tan{beta}, neutral Higgs boson pair production might even be observable in the 4b final state during the next run of the Tevatron collider.
Date: May 12, 1999
Creator: Mizukoshi, Jose
Partner: UNT Libraries Government Documents Department

Sodium carbonate salt transport system

Description: A sodium carbonate salt transport system is required to support the Molten Salt Oxidation system being constructed at Lawrence Livermore National Laboratory. We are embarking on a project to create a national test bed for evaluating mixed waste destruction technologies. This project is called the Mixed Waste Management Facility. It is currently in the second phase of design and will be operational in 1998. One of the first technologies demonstrated in this facility is Molten Salt Oxidation. Molten Salt Oxidation is a thermal process that destroys the organic constituents of mixed and hazardous wastes. Sodium carbonate salt is heated in a reactor vessel to approximately 950{degrees}C. Organic wastes, along with oxidant air, are injected under the pool of molten salt. A catalytic reaction occurs converting the organics into CO{sub 2} and water. Inorganic constituents in the salt such as metals, silica, alumina, and radionuclides remain captured in the salt. Chlorides in the waste feed are converted in the salt to sodium chloride. As these impurities build up in the salt, the salt must be recycled to remove them or else the reaction rate is reduced. Spent salt is periodically taken from the reactor and transported to a salt recycle system. In this system the molten salt is freeze-dried, dissolved in water, and filtered to remove the insoluble inorganics. The unconverted sodium carbonate is removed by fractional crystallization. This sodium carbonate is then dried and stored for future use in the reactors, eliminating a secondary waste stream. The remaining brine is disposed of as waste.
Date: September 12, 1995
Creator: Brummond, W.
Partner: UNT Libraries Government Documents Department

The place for sodars in a high-technology environment.

Description: In an era of increasingly complex technology, some of the atmospheric quantities most difficult to measure and observe are yielding their secrets to increasingly complex instruments and combinations of instruments. For example, water vapor profiles, a long-time nemesis to detailed examination, have become measurable with the use of Raman lidar; temperature profile measurements are becoming relatively routine with radio acoustic sounding systems (RASSs) or infrared Fourier transform instrumentation such as the atmospheric emitted radiance interferometer (AERI); and radar, lidar, or combinations of the two are enabling wind profile measurements to increasing altitudes. What, then, is the role of the relatively pedestrian sodar in such an era? Because the sodar's propagation speed in the atmosphere is six orders of magnitude smaller than that of its electromagnetic counterparts (3 x 10{sup 2} vs. 3 x 10{sup 8} m/s), severely limiting its rate of interrogation, and because the sodar's signal limit frequency modulation techniques, many high-technology advances associated with enormous increases in computation speed and available memory have had relatively little direct impact on acoustic remote sensing. However, the principal elements of acoustic remote sensing continue to make it a useful, even essential, tool for obtaining a better understanding of the physics of the lower atmosphere. The sodar's ''slow'' propagation speed provides relatively easy access to the region between 10 m and several hundred meters above the surface that is often inaccessible to other instruments. This is the region of the atmosphere where conditions often change radically with height, the ''matching'' region between large-scale forcing and small-scale surface heterogeneities that can have large effects on human activity. The atmosphere provides signals for sodars that are rich in content because the phase speed of sound is dependent on the atmosphere itself and is tied directly to the atmosphere's temperature and wind structure. Hence, the ...
Date: June 12, 1998
Creator: Coulter, R. L.
Partner: UNT Libraries Government Documents Department

Computation of Nonlinear One-Turn Maps from Measurement with Model-Independent Analysis

Description: It is desirable to determine the nonlinear transformation maps, especially the one-turn map, of a storage ring from measured BPM data for nonlinear analysis in order to improve the machine performance. However, the accuracy of detecting the weak signals from nonlinear effects is often limited by the available BPM resolution. With the recent development of Model-Independent Analysis methods, which can significantly reduce BPM random noise via statistical analysis, it is possible to more accurately determine the nonlinear maps from measured data by using a large number of BPMs. Computational techniques and some simulation results for PEP-II will be presented.
Date: April 12, 1999
Creator: Wang, Chunxi
Partner: UNT Libraries Government Documents Department

BEAM-BEAM COLLISIONS AND CROSSING ANGLES IN RHIC.

Description: This paper evaluates the strength of head on and parasitic beam-beam collisions in RHIC when the crossing angle is zero. A non-zero crossing angle is not required in normal operation with 120 bunches, thanks to the early separation of the two beams. The RHIC lattice is shown to easily accommodate even conservatively large crossing angles, for example in beam dynamics studies, or in future operational upgrades to as many as 360 bunches per ring. A modest loss in luminosity is incurred when gold ions collide at an angle after 10 hours of storage.
Date: April 12, 1999
Creator: PEGGS,S.
Partner: UNT Libraries Government Documents Department

Welding and Weldability of Thorium-Doped Iridium Alloys

Description: Ir-0.3%W alloys doped with thorium are currently used as post-impact containment material for radioactive fuel in thermoelectric generators that provide stable electrical power for a variety of outer planetary space exploration missions. Welding and weldability of a series of alloys was investigated using arc and laser welding processes. Some of these alloys are prone to severe hot-cracking during welding. Weldability of these alloys was characterized using Sigmajig weldability test. Hot-cracking is influenced to a great extent by the fusion zone microstructure and composition. Thorium content and welding atmosphere were found to be very critical. The weld cracking behavior in these alloys can be controlled by modifying the fusion zone microstructure. Fusion zone microstructure was found to be controlled by welding process, process parameters, and the weld pool shape.
Date: March 12, 2000
Creator: David, S.A.; Ohriner, E.K. & King, J.F.
Partner: UNT Libraries Government Documents Department

Cryogenic System for a High Temperature Superconducting Power Transmission Cable

Description: High-temperature superconducting (HTS) cable systems for power transmission are under development that will use pressurized liquid nitrogen to provide cooling of the cable and termination hardware. Southwire Company and Oak Ridge National Laboratory have been operating a prototype HTS cable system that contains many of the typical components needed for a commercial power transmission application. It is being used to conduct research in the development of components and systems for eventual commercial deployment. The cryogenic system was built by Air Products and Chemicals, Allentown, Pennsylvania, and can circulate up to 0.35 kg/s of liquid nitrogen at temperatures as low as 67 K at pressures of 1 to 10 bars. Sufficient cooling is provided for testing a 5-m-long HTS transmission cable system that includes the terminations required for room temperature electrical connections. Testing of the 5-m HTS transmission cable has been conducted at the design ac conditions of 1250 A and 7.5 kV line to ground. This paper contains a description of the essential features of the HTS cable cryogenic system and performance results obtained during operation of the system. The salient features of the operation that are important in large commercial HTS cable applications will be discussed.
Date: July 12, 1999
Creator: Demko, J.A.; Gouge, M.J.; Hughey, R.L.; Lue, J.W.; Martin, R.; Sinha, U. et al.
Partner: UNT Libraries Government Documents Department

Laser plasma diagnostics of dense plasmas

Description: The authors describe several experiments on Nova that use laser-produced plasmas to generate x-rays capable of backlighting dense, cold plasmas (p {approximately} 1--3 gm/cm{sup 3}, kT {approximately} 5--10 eV, and areal density {rho}{ell}{approximately} 0.01--0.05 g/cm{sup 2}). The x-rays used vary over a wide range of h{nu}, from 80 eV (X-ray laser) to 9 keV. This allows probing of plasmas relevant to many hydrodynamic experiments. Typical diagnostics are 100 ps pinhole framing cameras for a long pulse backlighter and a time-integrated CCD camera for a short pulse backlighter.
Date: July 12, 1995
Creator: Glendinning, S.G.; Amendt, P.; Budil, K.S.; Hammel, B.A.; Kalantar, D.H.; Key, M.H. et al.
Partner: UNT Libraries Government Documents Department

HADRON BEAM-BEAM DIFFUSION IN 2.5-D*.

Description: The standard analysis of modulational diffusion for general nonlinearities is qualitatively summarized, and compared to the particular case of a beam-beam simulation with two kicks per turn, plus tune modulation. A simulation with realistic Tevatron parameters shows amplitude growth over long timescales of order 10{sup 4} synchrotrons periods. The simulated amplitude growth is qualitatively similar to the predictions of modulational diffusion, showing large discrete steps in the evolution speed as the tune distance from the nearest 2-D weak coupling resonance is varied. However, the simulation shows a fundamental difference is that the observed amplitude growth is approximately exponential in time, and not approximately root time as predicted in the standard analysis. Possible reasons for this and other discrepancies are briefly discussed.
Date: April 12, 1999
Creator: SATOGATA,T.
Partner: UNT Libraries Government Documents Department

Decomposition mechanism in supercooled liquid alloys.

Description: The authors performed small-angle neutron scattering experiments on the bulk amorphous alloy Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} (Vit1{reg_sign}) and on further alloys, where the ZrTi and CuBe content have been changed, following the tie-line in the direction of Zr{sub 46.8}Ti{sub 8.2}Cu{sub 7.5}Ni{sub 10}Be{sub 27.5} (Vit4{reg_sign}). The SANS data of the samples, preannealed at temperatures between 330 C and 390 C, show interference peaks giving evidence for spatially correlated arrangements of inhomogeneities. The Q values of the interference peaks, Q{sub max}, decrease with increasing annealing temperature T{sub a} and, at a given annealing temperature, with composition following the tie-line from Vit1 to Vit4. They find that, in two distinguished regimes, the data follow a relation 1/L{sup 2} {proportional_to} T{sub a} as predicted by Cahn's theory (L = 2{pi}/Q{sub max} is the wavelength of the decomposition), with a crossover at the glass transition temperature T{sub g} = 350 C. The authors explain the crossover by different diffusion mechanisms below and above T{sub g}.
Date: July 12, 1999
Creator: Johnson, W. L.; Loffler, J. F. & Thiyagarajan, P.
Partner: UNT Libraries Government Documents Department

ACRV instrumentation plan for NMD HTK light gas gun tests

Description: In support of the NMD Hit-To-Kill Program for the US Army, twenty scaled tests on simulated nuclear targets are planned. The AEDC Light Gas Gun operated by Sverdrup Technology (SVT) in Tullahoma, TN will launch the scaled NMD projectile into scaled targets. The target for all the tests is a 1/4-scale version of the Attitude Controlled Re-Entry Vehicle (ACRV). The targets were designed and fabricated by Sandia National Laboratories (SNL) and Lawrence Livermore National Laboratory (LLNL). ITT Systems (ITT) is the integrating contractor for coordination of the multiple contractors involved in these tests. The targets are inert and contain no hazardous materials. The payloads have been instrumented to aid in post-test evaluation of the functional status of the postulated weapon systems. This document describes the instrumentation methods to be used on these tests.
Date: April 12, 1999
Creator: Dobie, D W
Partner: UNT Libraries Government Documents Department

A database of wavefront measurements for laser system modeling, optical component development and fabrication process qualification

Description: In the second half of the 1990`s, LLNL and others anticipate designing and beginning construction of the National Ignition Facility (NIF). The NIF will be capable of producing the worlds first laboratory scale fusion ignition and bum reaction by imploding a small target. The NIF will utilize approximately 192 simultaneous laser beams for this purpose. The laser will be capable of producing a shaped energy pulse of at least 1.8 million joules (MJ) with peak power of at least 500 trillion watts (TV). In total, the facility will require more than 7,000 large optical components. The performance of a high power laser of this kind can be seriously degraded by the presence of low amplitude, periodic modulations in the surface and transmitted wavefronts of the optics used. At high peak power, these phase modulations can convert into large intensity modulations by non-linear optical processes. This in turn can lead to loss in energy on target via many well known mechanisms. In some cases laser damage to the optics downstream of the source of the phase modulation can occur. The database described here contains wavefront phase maps of early prototype optical components for the NIF. It has only recently become possible to map the wavefront of these large aperture components with high spatial resolution. Modem large aperture static fringe and phase shifting interferometers equipped with large area solid state detectors have made this possible. In a series of measurements with these instruments, wide spatial bandwidth can be detected in the wavefront.
Date: April 12, 1995
Creator: Wolfe, C.R.; Lawson, J.K.; Aikens, D.M. & English, R.E.
Partner: UNT Libraries Government Documents Department

Evaluation of Reservoir Wettability and its Effect on Oil Recovery

Description: This project has three main goals. The first is to achieve improved understanding of the surface and interfacial properties of crude oils and their interactions with mineral surfaces. The second goal is to apply the results of surface studies to improved predictions of oil production in laboratory experiments. Finally, we aim to use the results of this research to recommend ways to improve oil recovery by waterflooding. In order to achieve these goals, the mechanisms of wetting alteration must be explained. We propose a methodology for studying those mechanisms on mineral surfaces, then applying the results to prediction and observation of wetting alteration in porous media. Improved understanding of the underlying mechanisms will show when and how wettability in the reservoir can be altered and under what circumstances that alteration would be beneficial in terms of increased production of oil. In the work reported this quarter, crude oil interactions with Berea sandstone have been used to prepare cores with mixed wettability.
Date: June 12, 1998
Creator: Buckley, Jill S.
Partner: UNT Libraries Government Documents Department

Direct and indirect measures of speech articulator motions using low power EM sensors

Description: Low power Electromagnetic (EM) Wave sensors can measure general properties of human speech articulator motions, as speech is produced. See Holzrichter, Burnett, Ng, and Lea, J.Acoust.Soc.Am. 103 (1) 622 (1998). Experiments have demonstrated extremely accurate pitch measurements (< 1 Hz per pitch cycle) and accurate onset of voiced speech. Recent measurements of pressure-induced tracheal motions enable very good spectra and amplitude estimates of a voiced excitation function. The use of the measured excitation functions and pitch synchronous processing enable the determination of each pitch cycle of an accurate transfer function and, indirectly, of the corresponding articulator motions. In addition, direct measurements have been made of EM wave reflections from articulator interfaces, including jaw, tongue, and palate, simultaneously with acoustic and glottal open/close signals. While several types of EM sensors are suitable for speech articulator measurements, the homodyne sensor has been found to provide good spatial and temporal resolution for several applications.
Date: May 12, 1999
Creator: Barnes, T; Burnett, G; Gable, T; Holzrichter, J F & Ng, L
Partner: UNT Libraries Government Documents Department

Measurement of wavefront structure from large aperture optical components by phase shifting interferometry

Description: This paper discusses the results of high spatial resolution measurement of the transmitted or reflected wavefront of optical components using phase shifting interferometry with a wavelength of 6328 {angstrom}. The optical components studied range in size from approximately 50 mm {times} 100 mm to 400 mm {times} 750 mm. Wavefront data, in the form of 3-D phase maps, have been obtained for three regimes of scale length: ``micro roughness``, ``mid-spatial scale``, and ``optical figure/curvature.`` Repetitive wavefront structure has been observed with scale lengths from 10 mm to 100 mm. The amplitude of this structure is typically {lambda}/100 to {lambda}/20. Previously unobserved structure has been detected in optical materials and on the surfaces of components. We are using this data to assist in optimizing laser system design, to qualify optical components and fabrication processes under study in our component development program.
Date: May 12, 1995
Creator: Wolfe, C.R.; Lawson, J.K.; Kellam, M.; Maney, R.T. & Demiris, A.
Partner: UNT Libraries Government Documents Department

Evaluation of superconducting wiggler designs and free-electron laser support: Final report

Description: This report consists of copies of previous progress reports, and copies of viewgraphs presented in a talk at Los Alamos. The report describes activities carried out as part of a project to evaluate the design and performance of a superconducting wiggler magnet design. It includes work on evaluating the appropriate materials for the magnet coils and poles, and stress evaluations for the design. It includes work on beam optics through the magnet, and design considerations to optimize extraction: work on the cryocooling system; weight minimization efforts; and design work on the vacuum liner for the magnet. A major concern in all of this design work is heat loads which will be dissipated in different parts of the system during operation, as well as transient events.
Date: October 12, 1990
Partner: UNT Libraries Government Documents Department

Shock wave measurements

Description: Much of our knowledge of the properties of matter at high pressures, from the static ruby pressure scale to shock compression at Gbar pressures, rests ultimately on the use of shock waves. Simple conservation relations define the initial and final states, leading to absolute measurements. I will describe some methods for measuring the equation of state of materials under shock loading for a variety of methods of shock production, and also describe the basis for other optical methods used widely in shock physics.
Date: September 12, 1995
Creator: Holmes, N.C.
Partner: UNT Libraries Government Documents Department

MEASURING GLOBAL OBSERVABLES WITH PHENIX.

Description: When the Relativistic Heavy-Ion Collider (RHIC) begins operations, it will be capable of colliding nuclei of various sizes, from protons up to Au, at center-of-mass energies of 200 to 500 GeV per nucleon pair. Some of these collisions are expected to produce a new state of matter, the quark-gluon plasma (QGP), in which quarks are no longer confined to individual hadrons and in which chiral symmetry has been restored. Numerous predictions have been made as to how a phase transition to a QGP would affect the particle spectra produced in these collisions (see, for example, a recent review by Harris and Mueller). The PHENIX physics philosophy is to detect and systematically study the QGP via a simultaneous measurement of many different probes/signatures of the plasma, as a function of the energy density achieved in the nucleus-nucleus collision. To achieve this goal, the PHENIX detector has been designed as a multi-purpose spectrometer, capable of concurrently measuring hadrons, leptons and photons, as well as global properties of the collision, e.g. energy density, as will be detailed below.
Date: June 12, 1998
Creator: BENNETT,M.J. FOR THE PHENIX COLLABORATION
Partner: UNT Libraries Government Documents Department

MIL-L-87177 and CLT:X-10 Lubricants Improve Electrical Connector Fretting Corrosion Behavior

Description: We have conducted a fretting research project using MIL-L-87177 and CLT: X-10 lubricants on Nano-miniature connectors. When they were fretted without lubricant, individual connectors first exceeded our 0.5 ohm failure criteria from 2,341 to 45,238 fretting cycles. With additional fretting, their contact resistance increased to more than 100,000 ohms. Unmodified MIL-L-87177 lubricant delayed the onset of first failure to between 430,000 and over 20,000,000 fretting cycles. MIL-L-87177 modified by addition of Teflon powder delayed first failure to beyond 5 million fretting cycles. Best results were obtained when Teflon was used and also when both the straight and modified lubricants were poured into and then out of the connector. CLT: X-10 lubricant delayed the onset of first failure to beyond 55 million cycles in one test where a failure was actually observed and to beyond 20 million cycles in another that was terminated without failure. CLT: X-10 recovered an unlubricated connector driven deeply into failure, with six failed pins recovering immediately and four more recovering during an additional 420 thousand fretting cycles. MIL-L-87177 was not able to recover a connector under similar conditions.
Date: October 12, 1999
Creator: AUKLAND,NEIL R. & HANLON,JAMES T.
Partner: UNT Libraries Government Documents Department

Production and Innovative Applications of Cryogenic Solid Pellets

Description: For over two decades Oak Ridge National Laboratory has been developing cryogenic pellet injectors for fueling hot, magnetic fusion plasmas. Cryogenic solid pellets of all three hydrogen isotopes have been produced in a size range of 1- to 10-mm diameter and accelerated to speeds from <100 to {approx}3000 m/s. The pellets have been formed discretely by cryocondensation in gun barrels and also by extrusion of cryogenic solids at mass flow rates up to {approx}0.26 g/s and production rates up to ten pellets per second. The pellets traverse the hot plasma in a fraction of a millisecond and continuously ablate, providing fresh hydrogenic fuel to the interior of the plasma. From this initial application, uses of this technology have expanded to include (1) cryogenic xenon drops or solids for use as a debris-less target in a laser plasma source of X-rays for advanced lithography systems, (2) solid argon and carbon dioxide pellets for surface cleaning or decontamination, and (3) methane pellets in a liquid hydrogen bath for use as an innovative moderator of cold neutrons. Methods of production and acceleration/transport of these cryogenic solids will be described, and examples will be given of their use in prototype systems.
Date: July 12, 1999
Creator: Baylor, L.R.; Combs, S.K.; Fisher, P.W.; Foster, C.A.; Foust, C.R.; Gouge, M.J. et al.
Partner: UNT Libraries Government Documents Department

Hazard categorization for 300 area N reactor fuel fabrication and storage facility

Description: A final hazard categorization has been prepared for the 300 Area Fuel Supply Shutdown (FSS) facility in accordance with DOE-STD-1027-92, ''Hazard Categorization and Accident Analysis Techniques for Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports'' (DOE 1992). Prior to using the hazard category methodology, hazard classifications were prepared in accordance with the requirements of the Westinghouse Hanford Company (Westinghouse Hanford) controlled manual, WHC-CM-4-46, ''Safety Analysis Manual'', Chapter 4.0, ''Hazard Classification.'' A hazard classification (Huang 1995) was previously prepared for the FSS in accordance with WHC-CM-4-46. The analysis lead to the conclusion that the FSS should be declared a Nuclear facility with a Moderate Hazard Class rating. The analysis and results contained in the hazard classification can be used to provide additional information to support other safety analysis documentation. Also, the hazard classification provides analyses of the toxicological hazards inherent with the FSS inventory: whereas, a hazard categorization prepared in accordance with DOE-STD-1027-92, considers only the radiological component of the inventory.
Date: February 12, 1997
Creator: Brehm, J.R., Fluor Daniel Hanford
Partner: UNT Libraries Government Documents Department

HTS Magnets for Advanced Magnetoplasma Space Propulsion Applications

Description: Plasma rockets are being considered for both Earth-orbit and interplanetary missions because their extremely high exhaust velocity and ability to modulate thrust allow very efficient use of propellant mass. In such rockets, a hydrogen or helium plasma is RF-heated and confined by axial magnetic fields produced by coils around the plasma chamber. HTS coils cooled by the propellant are desirable to increase the energy efficiency of the system. We describe a set of prototype high-temperature superconducting (HTS) coils that are being considered for the VASIMR ( Variable Specific Impulse Magnetoplasma Rocket) thruster proposed for testing on the Radiation Technology Demonstration (RTD) satellite. Since this satellite will be launched by the Space Shuttle, for safety reasons liquid helium will be used as propellant and coolant. The coils must be designed to operate in the space environment at field levels of 1 T. This generates a unique set of requirements. Details of the overall winding geometry and current density, as well as the challenging thermal control aspects associated with a compact, minimum weight design will be discussed.
Date: July 12, 1999
Creator: Carte, M.D.; Chang-Diaz, F.R. Squire, J.P. & Schwenterly, S.W.
Partner: UNT Libraries Government Documents Department