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Prospects for physics at e/sup +/e/sup -/ linear colliders (open access)

Prospects for physics at e/sup +/e/sup -/ linear colliders

The present thinking on high-energy e/sup /plus//e/sup /minus// linear colliders is reviewed, stressing those points that have consequences for detector design and physics analyses. Detector requirements are discussed. Experimental aspects of the physics that can be done at these colliders are discussed: first the general physics environment, then a standard process, W/sup /plus// W/sup /minus// detection, and finally four examples of the discovery potential of these colliders /emdash/ heavy quarks, heavy leptons, standard Higgs bosons, and charged Higgs bosons. The conclusions of this study will be stated. 23 refs., 40 figs.
Date: March 1, 1988
Creator: Feldman, G. J.
System: The UNT Digital Library
Di-leptons at the Bevalac (open access)

Di-leptons at the Bevalac

Recent results on the production of di-leptons measured by the Di-Lepton-Spectrometer (DLS) collaboration are discussed. Results are reported from observations made on p /plus/ Be collisions with proton beams from 1.0 to 4.9 GeV and on Ca collisions with calcium beams of 1.0 to 2.0 GeV/A. The shape of the distributions are similar to that at higher energies. The low mass cross section appears to be explained by ..pi..-..pi.. annihilation, but detailed calculations are needed to substantiate that hypothesis. (LEN)
Date: March 1, 1988
Creator: Matis, H.S.
System: The UNT Digital Library
Measurements of the dependence of damage thresholds on laser wavelength, pulse duration and film thickness (open access)

Measurements of the dependence of damage thresholds on laser wavelength, pulse duration and film thickness

Results of three experiments will be described. We used 351-nm and 355-nm pulses with durations of 0.6, 1, 5 and 9 ns measure thresholds for a variety of anti-reflectance and high reflectance coatings. The functional form t/sup m/, with t the pulse duration, was used to scale fluence thresholds measured at 0.6 ns to those measured at 9.0 ns. Values of the coefficient m ranged from 0.10 to 0.51. The average value was 0.30. In the second experiment, we measured thresholds at 1064 nm, 527 nm and 355 nm for single-frequency high reflectance ZrO/sub 2//SiO/sub 2/ coatings. Coatings for all three frequencies were deposited simultaneously by use of masks in the coating chamber. Thresholds varied from 2 to 4 J/cm/sup 2/ at 355 nm to 7 to 10 J/cm/sup 2/ at 1064 nm. The third experiment measured thresholds at 355 nm for antireflection coatings made with layer thicknesses varying from greater than one wavelength to less than a quarterwavelength. A significant variation of threshold with coating thickness was not observed, but the median thresholds increased slightly as coating thickness increased.
Date: March 1, 1984
Creator: Rainer, F.; Vercimak, C.L.; Milam, D.; Carniglia, C.K. & Tuttle Hart, T.
System: The UNT Digital Library
Irradiation experiment for lithium ceramics (open access)

Irradiation experiment for lithium ceramics

Solid breeder materials are required in D-T fusion reactor blankets to convert fusion neutrons to tritium and thermal energy while providing some neutron shielding for the magnets. Lithium compounds such as Li/sub 2/O, LiAlO/sub 2/, Li/sub 4/SiO/sub 4/ and Li/sub 2/ZrO/sub 3/ have been proposed as solid breeder materials. Tritium is necessary to maintain the fuel supply for the D-T fusion reaction. No high burnup irradiation performance data is available for these materials in a neutron environment prototypic of the fusion blanket. The FUBR Experiment in EBR-II has been designed and built to evaluate the irradiation performance of these materials.
Date: March 1, 1982
Creator: Hollenberg, G.W.
System: The UNT Digital Library
Shear alfven resonances in Tokapole II (open access)

Shear alfven resonances in Tokapole II

It has been suggested that efficient heating can occur by coupling energy through the shear Alfven resonance that is predicted to occur at particular locations within inhomogeneous plasmas. This heating mechanism should be applicable to tokamaks; however, the existence of the resonances in tokamaks has not yet been established experimentally. We present here direct observations of localized enhancement in the driven wave magnetic field which are compatible with theoretical predictions for the shear Alfven resonance in tokamak geometry. These resonance studies at low absorbed power will be followed by higher power heating (approx. 1 MW) presently being developed.
Date: March 1, 1982
Creator: Witherspoon, F.D.; Prager, S.C. & Sprott, J.C.
System: The UNT Digital Library
Field characterization and personal dosimetry at a high energy ion accelerator (open access)

Field characterization and personal dosimetry at a high energy ion accelerator

The response of a variety of dosimeters was evaluated in the radiation field outside the shielding of the Lawrence Berkeley Laboratory Bevalac Biomedical Facility. The primary beam was 580 MeV/center dot/A neon ions, incident upon a 30.5-cm polyethylene cube. The field was characterized by a neutron spectrometer consisting of Bonner spheres and other detectors and by estimates of charged particle fluences in NTA film and in the Berklet spectrometer. The responses of American Acrylics CR-39 track-etch plastic detectors and AECL (Canada) type BD-100 Bubble Detectors were compared to those of NTA film, Andersson-Braun remmeter and recombination-chamber results as well as to reference dose equivalents based upon the unfolded neutron spectrum. Evaluations of these dosimeters are discussed. 7 refs., 4 figs.
Date: March 1, 1988
Creator: Greenhouse, N. A.; Busick, D. D.; de Castro, T. M.; Elwyn, A. J.; Hankins, D. E.; Ipe, N. E et al.
System: The UNT Digital Library
Nuclear mass formula with a neutron skin degree of freedom and finite-range model for the surface energy (open access)

Nuclear mass formula with a neutron skin degree of freedom and finite-range model for the surface energy

We study the possibility of extending the model used by Moeller and Nix in 1980 to calculate nuclear masses and fission barriers for nuclei throughout the periodic system, to describe compressibility effects and the existence of a neutron skin. 9 references. (WHK)
Date: March 1, 1984
Creator: Moeller, P. & Myers, W.D.
System: The UNT Digital Library
Detection of charged particles in thick hydrogenated amorphous silicon layers (open access)

Detection of charged particles in thick hydrogenated amorphous silicon layers

We show our results in detecting particles of various linear energy transfer, including minimum ionizing electrons from a Sr-90 source with 5 to 12 micron thick n-i-p and p-i-n diodes. We measured W ( average energy to produce one electron-hole pair) using 17keV filtered xray pulses with a result W = 6.0 /+-/ 0.2eV. This is consistent with the expected value for a semiconductor with band gap of 1.7 to 1.9eV. With heavily ionizing particles such as 6 MeV alphas and 1 to 2 MeV protons, there was some loss of signal due to recombination in the particle track. The minimum ionizing electrons showed no sign of recombination. Applications to pixel and strip detectors for physics experiments and medical imaging will be discussed. 7 refs., 8 figs.
Date: March 1, 1988
Creator: Fujieda, I.; Cho, G.; Kaplan, S. N.; Perez-Mendez, V.; Qureshi, S.; Ward, W. et al.
System: The UNT Digital Library
Semiclassical methods in chemical dynamics (open access)

Semiclassical methods in chemical dynamics

A general semiclassical (multidimensional WKB-type) approximation to quantum mechanics is reviewed. The principal feature of the approach is that it is able to incorporate the exact classical mechanics of the system and also the quantum principle of superposition. Applications to inelastic and reactive scattering, and to statistical mechanics and reaction rates are discussed. 13 refs.
Date: March 1, 1985
Creator: Miller, W. H.
System: The UNT Digital Library
Capture reactions of /sup 40/Ca and /sup 48/Ca with targets of /sup 197/Au and /sup 208/Pb (open access)

Capture reactions of /sup 40/Ca and /sup 48/Ca with targets of /sup 197/Au and /sup 208/Pb

The reactions of /sup 40/Ca and /sup 48/Ca with targets of /sup 197/Au and /sup 208/Pb have been measured in the region from below the interaction barrier to about twice the barrier energy. The fission-like fragments were detected in a pair of position-sensitive, multi-wire proportional counters and were identified from measurements of position and time using two-body kinematics. In the region above the barrier the cross sections for capture are less than those given by the touching condition, indicating that an /open quotes/extra push/close quotes/ is required to induce capture. The observations for /sup 40/Ca and /sup 48/Ca show different fissilities for the onset of the extra push and indicate that charge equilibration may be an important factor governing capture reactions. Below the barrier the cross sections show an enhancement relative to the prediction for a one dimensional barrier. The enhancements are larger for /sup 40/Ca than for /sup 48/Ca (for both targets) and this is in qualitative agreement with predictions based on the coupling of the relative motion to low-lying collective states. Both above and below the barrier, we find that the change in the light partner, from /sup 48/Ca to /sup 40/Ca, has a larger effect on the …
Date: March 1, 1988
Creator: Stokstad, R.; Chan, Y.; Chavez, E.; Di Gregorio, D.; di Tada, M.; Gazes, S. et al.
System: The UNT Digital Library
An outdoor test facility for the large-scale production of microalgae (open access)

An outdoor test facility for the large-scale production of microalgae

The goal of the US Department of EnergySolar Energy Research Institute's Aquatic Species Program is to develop the technology base to produce liquid fuels from microalgae. This technology is being initially developed for the desert Southwest. As part of this program an outdoor test facility has been designed and constructed in Roswell, New Mexico. The site has a large existing infrastructure, a suitable climate, and abundant saline groundwater. This facility will be used to evaluate productivity of microalgae strains and conduct large-scale experiments to increase biomass productivity while decreasing production costs. Six 3-m/sup 2/ fiberglass raceways were constructed. Several microalgae strains were screened for growth, one of which had a short-term productivity rate of greater than 50 g dry wt m/sup /minus/2/ d/sup /minus/1/. Two large-scale, 0.1-ha raceways have also been built. These are being used to evaluate the performance trade-offs between low-cost earthen liners and higher cost plastic liners. A series of hydraulic measurements is also being carried out to evaluate future improved pond designs. Future plans include a 0.5-ha pond, which will be built in approximately 2 years to test a scaled-up system. This unique facility will be available to other researchers and industry for studies on microalgae …
Date: March 1, 1988
Creator: Johnson, D.A.; Weissman, J. & Goebel, R.
System: The UNT Digital Library
Electron-positron physics at 1 TeV (open access)

Electron-positron physics at 1 TeV

We discuss the motivation for TeV e/sup +/ e/sup )minus/) linear colliders, some aspects of their design, and the experimental consequences that follow from the design. After a brief discussion of the general physics environment, we consider the discovery potential of these colliders by examining three sample processes: the detection of new heavy leptons, standard Higgs bosons, and charged Higgs bosons. 13 refs., 22 figs., 5 tabs.
Date: March 1, 1988
Creator: Feldman, G. J.
System: The UNT Digital Library
Cycle 7 outage experience. [Fast Flux Test Facility (FFTF)] (open access)

Cycle 7 outage experience. [Fast Flux Test Facility (FFTF)]

The scheduled 58-day refueling outage in preparation for the seventh operating cycle of the Fast Flux Test Facility (FFTF) was successfully completed three days ahead of schedule. The planning and execution of the outage was greatly aided by Project/2 automated scheduling capabilities. For example, the use of ''maintenance windows'' and resource loading capabilities was particularly effective. The value of the planning process was demonstrated by the smooth transition into the outage phase after an early shutdown and set the stage for our best outage to date.
Date: March 1, 1986
Creator: Gadeken, A.D.
System: The UNT Digital Library
Introduction to human factors (open access)

Introduction to human factors

Some background is given on the field of human factors. The nature of problems with current human/computer interfaces is discussed, some costs are identified, ideal attributes of graceful system interfaces are outlined, and some reasons are indicated why it's not easy to fix the problems. (LEW)
Date: March 1, 1988
Creator: Winters, J. M.
System: The UNT Digital Library
Comparison of aerosol behavior during sodium fires in CSTF with the HAA-3B code. [LMFBR] (open access)

Comparison of aerosol behavior during sodium fires in CSTF with the HAA-3B code. [LMFBR]

Four large-scale tests using sodium fire aerosol sources have been carried out in the Containment System Test Facility (CSTF). Two of the tests employed pool fires and two used spray fires as the aerosol source. Because the CSTF containment vessel is approximately half-scale (20.3 m in height) of a typical reactor building, the CSTF results have provided a large-scale proof test of the HAA-3B Code. For the two pool fire tests, the measured and predicted airborne concentrations were in good agreement when the aerosol source term was based on post-test measurements of aerosol formation, accounting for water vapor uptake.
Date: March 1, 1980
Creator: Postma, A.K. & Owen, R.K.
System: The UNT Digital Library
Breakdown phenomena in high power klystrons (open access)

Breakdown phenomena in high power klystrons

In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. …
Date: March 1, 1988
Creator: Vlieks, A. E.; Allen, M. A.; Callin, R. S.; Fowkes, W. R.; Hoyt, E. W.; Lebacqz, J. V. et al.
System: The UNT Digital Library
Comparing the Floating Point Systems, Inc. AP-190L to representative scientific computers: some benchmark results (open access)

Comparing the Floating Point Systems, Inc. AP-190L to representative scientific computers: some benchmark results

Results are presented of comparative timing tests made by running a typical FORTRAN physics simulation code on the following machines: DEC PDP-10 with KI processor; DEC PDP-10, KI processor, and FPS AP-190L; CDC 7600; and CRAY-1. Factors such as DMA overhead, code size for the AP-190L, and the relative utilization of floating point functional units for the different machines are discussed. 1 table.
Date: March 27, 1980
Creator: Brengle, T.A. & Maron, N.
System: The UNT Digital Library
Fifteenth LAMPF users group meeting (open access)

Fifteenth LAMPF users group meeting

The Fifteenth LAMPF Users Group Meeting was held November 2-3, 1981 at the Clinton P. Anderson Meson Physical Facility. The program of papers scheduled to be presented was amended to include a Report from Washington by Clarence R. Richardson, US Department of Energy. The general meeting ended with a round-table working group discussion concerning the Planning for a Kaon Factory. Individual items from the meeting were prepared separately for the data base.
Date: March 1, 1982
Creator: Cochran, D.R.F. (comp.)
System: The UNT Digital Library
State-of-the-art review of phase equilibria (open access)

State-of-the-art review of phase equilibria

High-pressure phase-equilibrium calculations using an equation of state are more sensitive to the mixing rules than to details in the effect of density or temperature on pressure. Attention must be given to the problem of how to extend equations of state to mixtures. One possible technique is provided by perturbation theory; another by superposition of chemical equilibria. At low or moderate pressures, vapor-phase corrections are often important. When specific intermolecular forces produce formation of molecular aggregates, strong deviations from ideal-gas behavior can be significant even at pressures well below 1 bar. When vapor-liquid equilibrium data are reduced using conventional expressions for the excess Gibbs energy, the resulting binary parameters tend to be partially correlated, it difficult, but no impossible, to calculate ternary liquid-liquid equilibria using binary parameters only. New models for calculating properties of liquid-phase mixtures mist allow for changes in free volume to give consideration to the effect of mixing on changes in rotational and vibrational degrees of freedom. Liquid-phase volumetric effects are also important in describing the solubilities of gases in solvent mixtures. Therefore, future liquid-phase models should incorporate a liquid-phase equation of state, either of the van der Waals type or, perhaps, as given by the direct-correlation …
Date: March 1, 1980
Creator: Prausnitz, J.M.
System: The UNT Digital Library
Sensitivity of the eastern United States to acid precipitation impacts on surface waters (open access)

Sensitivity of the eastern United States to acid precipitation impacts on surface waters

Efforts to identify areas of the United States where soils and freshwaters might be sensitive to acidification have proceeded from analyses of large scale geologic maps. These are useful in a general way but a finer scale analysis has been needed. We have carried out such an analysis for the eastern United States based primarily on geologic maps of scales 1:250,000 to 1:500,000. This report is a synopsis of and excerpted from that effort. Other workers have prepared maps on a similar scale of the soils to a depth of 25 cm, and we anticipate that both sets of maps will be merged into a combined analysis of sensitivity. Other factors important in controlling acidification of soils and freshwaters include hydrologic charcteristics of the terrain, such as: soil porosity or permeability; water residence time in soil; temporal variation in precipitation rate, chemistry and volume; regional temperature patterns; and topography.
Date: March 1, 1980
Creator: Hendrey, G. R.; Galloway, J. N.; Norton, S. A. & Schofield, C. L.
System: The UNT Digital Library
Doublet III neutral beam injector test tank cryopanel design (open access)

Doublet III neutral beam injector test tank cryopanel design

A simple condensing cryopanel has been designed for the Doublet III neutral beam test tank with a 320,000 liters per second pumping capacity for hydrogen. This maintains a vacuum in the test tank which simulates the Doublet III vessel, 1.3 x 10/sup -3/ Pa (approx.10/sup -5/ torr). The hydrogen gas load comes from the beam striking the test tank calorimeter and amounts to about 7.2 torr liters per second. The cryopanel is cylindrical shaped with a liquid helium (LHe) surface that pumps through liquid nitrogen (LN) cooled aluminum chevrons located in squirrel-cage fashion around the inside surface of the cylinder. The LHe cooled surface is a smooth cylinder 2.09m in diameter by .69m long with LHe flowing in a approx. 1mm annular space between concentric cylinders. The chevrons which are not blackened are cooled from each end with LN flowing in ring manifolds that serve as the primary cryopanel structure. The LHe is force fed at 55.2 kPa remaining in the liquid phase through the panel. External heat exchanger capability permits use of helium at 3.8 to 4.2/sup 0/K. Normal operating flow rate is 1.4 g/sec for a heat load expected to be 12.2 W total.
Date: March 1, 1980
Creator: Doll, D.W.; Kamperschroer, J.H. & Arend, P.V.
System: The UNT Digital Library
Failure of sheathed thermocouples due to thermal cycling (open access)

Failure of sheathed thermocouples due to thermal cycling

Open circuit failures (up to 100%) in small-diameter thermocouples used in electrically heated nuclear fuel rod simulator prototypes during thermal cycling tests were investigated to determine the cause(s) of the failures. The experiments conducted to determine the relative effects of differential thermal expansion, wire size, grain size, and manufacturing technology are described. It was concluded that the large grain size and embrittlement which result from certain common manufacturing annealing and drawing procedures were a major contributing factor in the breakage of the thermocouple wires.
Date: March 1, 1982
Creator: Anderson, R.L. & Ludwig, R.L.
System: The UNT Digital Library
Arming and firing system for DISTANT RUNNER (open access)

Arming and firing system for DISTANT RUNNER

Sandia A and F systems Division 1132 provided arming and firing support for the DISTANT RUNNER Test Program at White Sands Missile Range. This report describes the field support and the firing system that was used.
Date: March 1, 1982
Creator: Skenandore, L. H. & Johnson, J. P.
System: The UNT Digital Library
Fast-timing methods for semiconductor detectors (open access)

Fast-timing methods for semiconductor detectors

The basic parameters are discussed which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter.
Date: March 1, 1982
Creator: Spieler, H.
System: The UNT Digital Library