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Use of molybdenum ion source electrodes at RTNS-II (open access)

Use of molybdenum ion source electrodes at RTNS-II

Reports are reported for an ongoing effort to optimize D+ beam production by the MATS-III ion source used at RTNS-II. The three seven-aperture electrodes, originally consisting of water-cooled copper, have now been tested using uncooled molybdenum and with water cooling on the second (decel) electrode only. Details of the change, the results of the testing, and the benefits in operation, performance and cost are given.
Date: September 29, 1986
Creator: Massoletti, D.J.; Harter, G.A. & Heikkinen, D.W.
System: The UNT Digital Library
Structure functions: Their status and implications (open access)

Structure functions: Their status and implications

I discuss the current status of structure functions. Attention is given to the uncertainties in them and the implications of these uncertainties for experimental predictions. I indicate which experiments are capable of removing these uncertainties. 17 refs., 17 figs., 1 tab.
Date: September 29, 1988
Creator: Hinchliffe, I.
System: The UNT Digital Library
Top quark and light Higgs scalar mass bounds in no-scale supergravity (open access)

Top quark and light Higgs scalar mass bounds in no-scale supergravity

No-scale supergravity theories with the minimal low-energy particle content are shown to become untenable for a top quark mass m/sub T/ much less than 40 GeV. For m/sub T/ < 55 GeV, a stringent upper bound operates on the mass of the lowest-lying Higgs scalar. Further, the Higgs pseudoscalar is constrained to be nearly a quarter as massive as the gluino.
Date: August 29, 1986
Creator: Roy, P.
System: The UNT Digital Library
Oxide cathode lifetime improvements at RTNS-II (open access)

Oxide cathode lifetime improvements at RTNS-II

Results are reported for an ongoing effort to optimize D/sup +/ beam production by the MATS-III ion source used at the RTNS-II. The oxide cathode assembly originally designed for lower power operation has been modified and redesigned for higher electron current yield, longer life and serviceability. A factor of 2.5 has been gained in cathode lifetime due to these changes. The details of the changes and results and benefits in operation and performance are given. In addition, the technique used for manufacture of the filament is described.
Date: September 29, 1986
Creator: Massoletti, D.J.
System: The UNT Digital Library
Overview of radioactive waste management (open access)

Overview of radioactive waste management

The question of what to do with radioactive wastes is discussed. The need to resolve this issue promptly is pointed out. Two significant events which have occurred during the Carter administration are discussed. An Interagency Review Group (IRG) on waste management was formed to formulate recommendations leading to the establishment of a National policy for managing radioactive wastes. The technical findings in the IRG report are listed. The author points out some issues not addressed by the report. President Carter issued a national policy statement on Radioactive Waste Management in February 1980. The most significant elements of this statement are summarized. The cancellation of the Waste Isolation Pilot Plant is currently meeting opposition in Congress. This and other items in the National Policy Statement are discussed.
Date: May 29, 1980
Creator: Ritter, G.L.
System: The UNT Digital Library
Applications of small computers for systems control on the Tandem Mirror Experiment-Upgrade (open access)

Applications of small computers for systems control on the Tandem Mirror Experiment-Upgrade

Desktop computers operating into a CAMAC-based interface are used to control and monitor the operation of the various subsystems on the Tandem Mirror Experiment-Upgrade (TMX-U) at Lawrence Livermore National Laboratory (LLNL). These systems include: shot sequencer/master timing, neutral beam control (four consoles), magnet power system control, ion-cyclotron resonant heating (ICRH) control, thermocouple monitoring, getter system control, gas fueling system control, and electron-cyclotron resonant heating (ECRH) monitoring. Two additional computers are used to control the TMX-U neutral beam test stand and provide computer-aided repair/test and development of CAMAC modules. These machines are usually programmed in BASIC, but some codes have been interpreted into assembly language to increase speed. Details of the computer interfaces and system complexity are described as well as the evolution of the systems to their present states.
Date: November 29, 1983
Creator: Bork, R. G.; Kane, R. J. & Moore, T. L.
System: The UNT Digital Library
Control of beam dynamics in high energy induction linacs (open access)

Control of beam dynamics in high energy induction linacs

The Advent of laser-ion-guiding in the Advanced test Accelerator along with the development of accelerator cavities optimized with respect to beam breakup coupling impedence now make it possible to consider a new class of high current, high emergy linear induction accelerators. The control of the beam breakup and other instabilities by laser guiding and by various magnetic focusing schemes will be discussed along with the scaling laws for the design of such machines to minimize the growth of the beam breakup instability. Many linacs, particularly induction linacs are limited in performance by the beam breakup (BBU) instability. The instability is found in two forms. In the first form the accelerating cavities communicate with one another through interaction with the beam and through propagation of cavity fields through the accelerator structure. In the second form which is the more virulent of the two, the cavities couple to each other only through their interactions with the beam. It is this second form of PPU that will be discussed in this paper.
Date: July 29, 1986
Creator: Caporaso, G.J.
System: The UNT Digital Library
Does the photino decay (open access)

Does the photino decay

The stability of the lightest superpartner is a crucial aspect of many experimental searches for supersymmetry and of supersymmetric dark matter candidates. It is shown that R parity may occur in operators of dimension four or less as an accidental consequence of an exact Z/sub N/ symmetry. In this case the lightest superpartner can decay via higher dimension operators. The lifetime depends on the scale of the new physics responsible for the non-renormalizable operators; it could be anywhere in the region 10/sup -20/ seconds to 10/sup +20/ seconds. Explicit examples are given. 12 refs.
Date: August 29, 1986
Creator: Hall, L.J.
System: The UNT Digital Library
Localized corrosion of steels in geothermal steam/brine mixtures (open access)

Localized corrosion of steels in geothermal steam/brine mixtures

Coupons of eight different carbon and chrome-moly alloy steels were exposed to high temperature, high salinity wellhead brine flow at a geothermal well in the Salton Sea Geothermal Field for periods of up to six months. The corrosion rate and corrosion attack morphology of each coupon was determined. Exposure time was a test variable and ranged from one month to six months. Test results indicate that carbon steels generally suffer high corrosion rates and are susceptible to severe localized attack which shows a mesa-canyon pattern. Chrome-moly alloy steels corrode at much lower rates and show an attack pattern of small shallow pits. With time, these pits grow mostly in the lateral direction. These results suggest that chrome-moly alloy steels offer significant improvement over carbon steels and that the disk-shaped pits are not likely to lead to rapid perforation.
Date: May 29, 1980
Creator: McCright, R. D.; Frey, W. F. & Tardiff, G. E.
System: The UNT Digital Library
TMX tandem-mirror experiments and thermal-barrier theoretical studies (open access)

TMX tandem-mirror experiments and thermal-barrier theoretical studies

This paper describes recent analysis of energy confinement in the Tandem Mirror Experiment (TMX). TMX data also indicates that warm plasma limits the amplitude of the anisotropy driven Alfven ion cyclotron (AIC) mode. Theoretical calculations show strong AIC stabilization with off-normal beam injection as planned in TMX-U and MFTF-B. This paper reports results of theoretical analysis of hot electrons in thermal barriers including electron heating calculations by Monte Carlo and Fokker-Planck codes and analysis of hot electron MHD and microinstability. Initial results from the TMX-U experiment are presented which show the presence of sloshing ions.
Date: July 29, 1982
Creator: Simonen, T. C.; Baldwin, D. E. & Allen, S. L.
System: The UNT Digital Library
Application of heavy-light methods to B meson physics (open access)

Application of heavy-light methods to B meson physics

The heavy-light method is applied to the study of the B meson spectrum, the pseudoscalar decay constant f{sub B}, the mixing (B) parameter, and exclusive semileptonic B meson decays. Preliminary results are discussed for f{sub B} and the B parameter at {beta} = 5.7 and {kappa} = 0.165 on a 12{sup 3} {times} 24 lattice and at {beta} = 5.9 and {kappa} = 0.158 on a 16{sup 3} {times} 32 lattice. 9 refs., 2 figs., 2 tabs.
Date: December 29, 1989
Creator: Eichten, E.; Hockney, G. & Thacker, H.B.
System: The UNT Digital Library
TMX tandem-mirror experiments and thermal-barrier theoretical studies (open access)

TMX tandem-mirror experiments and thermal-barrier theoretical studies

This paper describes recent analysis of energy confinement in the Tandem Mirror Experiment (TMX). TMX data also indicates that warm plasma limits the amplitude of the anisotropy driven Alfven ion cyclotron (AIC) mode. Theoretical calculations show strong AIC stabilization with off-normal beam injection as planned in TMX-U and MFTF-B. This paper reports results of theoretical analysis of hot electrons in thermal barriers including electron heating calculations by Monte Carlo and Fokker-Planck codes and analysis of hot electron MHD and microinstability. Initial results from the TMX-U experiment are presented which show the presence of sloshing ions.
Date: July 29, 1982
Creator: Simonen, T. C.; Baldwin, D. E. & Allen, S. L.
System: The UNT Digital Library
Reservoir response to tidal and barometric effects (open access)

Reservoir response to tidal and barometric effects

Solid earth tidal strain and surface loading due to fluctuations in barometric pressure have the effect, although extremely minute, of dilating or contracting the effective pore volume in a porous reservoir. If a well intersects the formation, the change in pore pressure can be measured with sensitive quartz pressure gauges. Mathematical models of the relevant fluid dynamics of the well-reservoir system have been generated and tested against conventional well pumping results or core data at the Salton Sea Geothermal Field (SSGF), California and at the Raft River, Geothermal Field (RRGF), Idaho. Porosity-total compressibility product evaluation based on tidal strain response compares favorably with results based on conventional pumping techniques. Analysis of reservoir response to barometric loading using Auto Regressive Integrated Moving Average (ARIMA) stochastic modeling appears also to have potential use for the evaluation of reservoir parameters.
Date: May 29, 1980
Creator: Hanson, J.M.
System: The UNT Digital Library
Ion microstability in tandem mirrors (open access)

Ion microstability in tandem mirrors

The formalism describing ion-cyclotron modes in mirror traps will be developed. Emphasis will be placed on the effects of finite axial boundaries on the normal modes of the system. Wave properties are a composite picture of: positive energy waves (plasma oscillation, shear Alfven and drift waves), negative energy waves (ion Bernstein waves in a loss-cone media), positive dissipation (electron Landau damping, outgoing waves), and negative dissipation (ion cyclotron damping in a loss-cone and anisotropic temperature medium). Stability boundaries in this bounded media is affected by scale lengths along the magnetic field; first, because they determine the widths of the resonances, and second, because they restrict the parallel structure of the modes.
Date: August 29, 1983
Creator: Pearlstein, L.D.
System: The UNT Digital Library
Mirror research: status and prospects (open access)

Mirror research: status and prospects

The tandem mirror program has evolved considerably in the last decade. Of significance is the viable reactor concept embodied in the MARS design. An aggressive experimental program culminating in the operation of MFTF-B in late 1986, will provide a firm basis for refining the MARS design as necessary for constructing a reactor prototype in the 1990s.
Date: November 29, 1983
Creator: Baldwin, D.E.
System: The UNT Digital Library
LMFBR fuel component costs (open access)

LMFBR fuel component costs

A significant portion of the cost of fabricating LMFBR fuels is in the non-fuel components such as fuel pin cladding, fuel assembly ducts and end fittings. The contribution of these to fuel fabrication costs, based on FFTF experience and extrapolated to large LMFBR fuel loadings, is discussed. The extrapolation considers the expected effects of LMFBR development programs in progress on non-fuel component costs.
Date: October 29, 1981
Creator: Epperson, E.M.; Borisch, R.R. & Rice, L.H.
System: The UNT Digital Library
Progress toward identification of gluonic states (open access)

Progress toward identification of gluonic states

Progress in the last two years toward identification of gluonic states is reviewed. Discovery of additional pseudoscalars tends to confirm the glueball interpretation of iota(1460). A variety of evidence indicates new physics in the J = 1 channel in the E mass region. 65 refs., 1 tab.
Date: May 29, 1987
Creator: Chanowitz, Michael S.
System: The UNT Digital Library
[Newspaper article: AIDS, The State of the Science] (open access)

[Newspaper article: AIDS, The State of the Science]

A special report from the Dallas Morning News defining, describing, and providing the history of AIDS.
Date: June 29, 1987
Creator: The Dallas Morning News
System: The UNT Digital Library
Use of the (t,p) reaction for in-beam spectroscopy studies (open access)

Use of the (t,p) reaction for in-beam spectroscopy studies

Triton induced reactions, such as the (t,p) reaction, can be used for in-beam gamma-ray and conversion-electron studies of nuclei that are somewhat neutron rich. We have developed systems for both conversion-electron and gamma-ray spectroscopy in coincidence with the outgoing energetic proton to identify the (t,p) reaction channel. Data from the /sup 142/Nd(t,p..gamma..) reaction illustrate several of the characteristics of this reaction for studying nuclear structure. Preliminary results from the study of /sup 96/Zr by conversion-electron spectroscopy, and /sup 240/U by gamma-ray spectroscopy, are reported. 4 refs., 4 figs.
Date: May 29, 1986
Creator: Henry, E.A.
System: The UNT Digital Library
Tools and methods for implementing the control systems on the Mirror Fusion Test Facility (open access)

Tools and methods for implementing the control systems on the Mirror Fusion Test Facility

Installation of the major hardware subsystems for MFTF is nearing completion. These subsystems include the Fusion Chamber System, the eighty KV Neutral Beam System, the Superconducting Magnet System, and the Personnel Safety System. The Local Controls group has undertaken a uniform aproach to implementing the control systems for all of these hardware subsystems. This approach has two major aspects: (1) to provide a stand-alone computer control system with a remote, portable terminal so that computer control can be provided at the site of the hardware for initial testing, (2) to provide hardware simulators so that the complicated MFTF computer control system can be tested independent of the hardware. The software and hardware tools which were developed to carry out this plan will be described. Our experiences with bringing up subsystems containing up to 900 separate channels of control and status will also be described.
Date: September 29, 1981
Creator: Minor, E. G. & Labiak, W. G.
System: The UNT Digital Library
Debugging in a multi-processor environment (open access)

Debugging in a multi-processor environment

The Supervisory Control and Diagnostic System (SCDS) for the Mirror Fusion Test Facility (MFTF) consists of nine 32-bit minicomputers arranged in a tightly coupled distributed computer system utilizing a share memory as the data exchange medium. Debugging of more than one program in the multi-processor environment is a difficult process. This paper describes what new tools were developed and how the testing of software is performed in the SCDS for the MFTF project.
Date: September 29, 1981
Creator: Spann, J.M.
System: The UNT Digital Library
Layered granule chute flow near the angle of repose (open access)

Layered granule chute flow near the angle of repose

A natural, two-layered gravity flow of sand can be obtained on chutes inclined at angles slightly above the angle of repose of the sand. The top-surface layer is free-flowing, is thin, and moves rapidly at supercritical velocity. The velocity depends mainly on the character of the sand and the chute inclination angle. The bottom layer is thick and moves more slowly, with the flow controlled by adjustable weirs at the chute exit. The velocity profile in the thick bottom layer is curved; as much as an order of magnitude higher velocity occurs in the upper portion of the layer than occurs along the bottom wall of the chute. This study has applications to the cascade inertial fusion concept.
Date: March 29, 1985
Creator: Pitts, J.H. & Walton, O.R.
System: The UNT Digital Library
Three-dimensional equilibrium in quadrupole symmetric tandem mirrors in the paraxial limit (reduced MHD) (open access)

Three-dimensional equilibrium in quadrupole symmetric tandem mirrors in the paraxial limit (reduced MHD)

Equilibrium in quadrupole symmetric mirrors is fully three dimensional; however, because axial scale lengths are long compared with radial scale lengths (equivalently weak curvature) it is possible to reduce the complexity of the equations by expanding in the appropriate smallness parameter. Such a procedure leads to set of reduced MHD equations. The general theory will be presented, numerical results discussed, modifications due to finite Larmor radius will be added, and an analytic solution for sharp boundary pressure models will be developed.
Date: August 29, 1983
Creator: Pearlstein, L.D.
System: The UNT Digital Library
The LLNL CR-39 personnel neutron dosimeter (open access)

The LLNL CR-39 personnel neutron dosimeter

We developed a personnel neutron dosimetry system based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This CR-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. 3 refs., 4 figs.
Date: September 29, 1987
Creator: Hankins, D.E.; Homann, S. & Westermark, J.
System: The UNT Digital Library