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Stark broadening of isolated lines from high-Z emitters in dense plasmas (open access)

Stark broadening of isolated lines from high-Z emitters in dense plasmas

The joint distribution of the electric microfield and its longitudinal derivative is required for the calculation of line profiles for the He-like ions in very dense plasmas. We used a molecular dynamics code to compute exact distributions in single- and multi-component plasmas, and then we investigated various analytical approximations to these results. We found that a simplified, two-nearest-neighbor scheme leads to surprisingly accurate distribution functions. Our results are illustrated by sample profiles for Ne/sup +8/ and Ar/sup +16/ resonance lines.
Date: September 1, 1980
Creator: Weisheit, J.C. & Pollock, E.L.
System: The UNT Digital Library
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
Automatic program timing profiles with FTN4 (open access)

Automatic program timing profiles with FTN4

Design of a scheme for producing execution timing profiles of FORTRAN programs automatically is proposed with a recommendation to implement it as an option to the compiler. An experimental implementation on the LBL 7600 is also described. 1 figure.
Date: September 1, 1980
Creator: Friedman, R.
System: The UNT Digital Library
High beta studies on ISX-B with neutral beam injection (open access)

High beta studies on ISX-B with neutral beam injection

Injection of H/sup 0/ into D/sup +/ plasmas with beam power P/sub b/ of up to 1.7 MW has produced rms betas of approx. 4%, volume-averaged betas of approx. 3%, and central betas of approx. 10% in the ISX-B tokamak. Although theoretical calculations indicate that the observed equilibria may be unstable to ballooning modes, no catastrophic loss of confinement has been observed, and beta continues to increase with injection power. In these beam-dominated high-beta discharges the electron and ion energy confinement times are still similar to those obtained with ohmic heating: ion energy confinement is neoclassical within a factor of approx. 2, and electron energy confinement follows the usual Alcator scaling. In high-power injection discharges the character of the magnetohydrodynamic (MHD) behavior changes, the particle confinement time decreases, and the inward impurity transport appears to be inhibited. These effects, however, may not be linked directly to beta.
Date: September 1980
Creator: Sheffield, J.; Bates, S.C. & Bush, C.E.
System: The UNT Digital Library
Technology for large tandem mirror experiments (open access)

Technology for large tandem mirror experiments

Construction of a large tandem mirror (MFTF-B) will soon begin at Lawrence Livermore National Laboratory (LLNL). Designed to reach break-even plasma conditions, the facility will significantly advance the physics and technology of magnetic-mirror-based fusion reactors. This paper describes the objectives and the design of the facility.
Date: September 4, 1980
Creator: Thomassen, K.I.
System: The UNT Digital Library
Performance and development of dE/dx counters (open access)

Performance and development of dE/dx counters

The performance of existing or nearly completed detectors for particle identification by using the relativistic rise of energy loss will be discussed. Detailed analysis of systematic errors leads finally to large detector systems approaching the ultimate resolution as measured in small test devices. New methods for extracting the information from the counter with the potential of better particles separation than standard dE/dx will be presented. It includes very fine sampling, delta-ray clipping, and cluster counting.
Date: September 1, 1980
Creator: Walenta, A. H.
System: The UNT Digital Library
Mirror fusion. Quarterly report, April-June 1981 (open access)

Mirror fusion. Quarterly report, April-June 1981

The information in each Quarterly is presented in the same sequence as in the Field Work Package Proposal and Authorization System (WPAS) submissions prepared for the U.S. Department of Energy; the main sections are Applied Plasma Physics, Confinement Systems, Development and Technology, and Mirror Fusion Test Facility (Planning and Projects). On occasion, we shall include information pertaining to the LLNL role as Lead Laboratory for the Open Systems Mirror Fusion Program. Each of these sections is introduced by an overall statement of the goals and purposes of the groups reporting in it. As appropriate within each section, statements of the goals of individual programs and projects are followed by articles containing summaries of significant recent activity and descriptive text.
Date: September 11, 1981
Creator: unknown
System: The UNT Digital Library
Shiva automatic pinhole alignment (open access)

Shiva automatic pinhole alignment

This paper describes a computer controlled closed loop alignment subsystem for Shiva, which represents the first use of video sensors for large laser alignment at LLNL. The techniques used on this now operational subsystem are serving as the basis for all closed loop alignment on Nova, the 200 terawatt successor to Shiva.
Date: September 5, 1980
Creator: Suski, G.J.
System: The UNT Digital Library
RODCON: a finite difference heat conduction computer code in cylindrical coordinates (open access)

RODCON: a finite difference heat conduction computer code in cylindrical coordinates

RODCON, a finite difference computer code, was developed to calculate the internal temperature distribution of the fuel rod simulator (FRS) for the Core Flow Test Loop (CFTL). RODCON solves the implicit, time-dependent forward-differencing heat transfer equation in 2-dimensional (Rtheta) cylindrical coordinates at an axial plane with user specified radial material zones and surface conditions at the FRS periphery. Symmetry of the boundary conditions of coolant bulk temperatures and film coefficients at the FRS periphery is not necessary.
Date: September 16, 1980
Creator: Conklin, J. C.
System: The UNT Digital Library
Development of superconductors for applications in high-field, high-current-density magnets for fusion research (open access)

Development of superconductors for applications in high-field, high-current-density magnets for fusion research

The development of large-bore, high-field magnets for fusion energy applications requires a system approach to both magnet and conductor design. At Lawrence Livermore National Laboratory (LLNL), the criteria used to choose superconductors include: strain tolerance, radiation tolerance, heat removal, stability, fabricability, and cost. We report on the performance of industrially produced, prototype, Ti-modified Nb/sub 3/Sn wires developed with LLNL support. Wire performance characteristics evaluated include critical current as a function of magnetic field, temperature, and applied strain. Tests were performed to determine how this performance translates to the performance of a cable-in-conduit conductor system using this wire. An alternative to Nb/sub 3/Sn superconductors is NbN, which is strain and radiation insensitive. We report preliminary efforts to produce multifilamentary NbN conductors by liquid-metal infiltration of NbN-coated, high-strength fibers. In addition, we discuss the fabrication of multifilamentary NbN conductors and their possible impact on magnet design.
Date: September 26, 1986
Creator: Summers, L. T. & Miller, J. R.
System: The UNT Digital Library
Making sense of anomalous gauge theories (open access)

Making sense of anomalous gauge theories

An anomalous gauge theory is defined here as a gauge theory in which the field equation is inconsistent and gauge invariance is lost. A conventional approach to anomalous gauge theories, that of adjusting the fermion content so the anomaly vanishes, is discussed, followed by a mathematically coherent frame for anomalies. 10 refs. (LEW)
Date: September 1, 1985
Creator: Jackiw, R.
System: The UNT Digital Library
Hybrid reactors. [Fuel cycle] (open access)

Hybrid reactors. [Fuel cycle]

The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.
Date: September 9, 1980
Creator: Moir, Ralph W.
System: The UNT Digital Library
Probing the possibility of a /sup 12/C/sup 13/C abundance gradient from observations of interstellar CH/sup +/ (open access)

Probing the possibility of a /sup 12/C/sup 13/C abundance gradient from observations of interstellar CH/sup +/

I have performed high signal-to-noise (SN /equals/ 300 to 500) observations of interstellar CH/sup /plus// at Lick Observatory and at CTIO of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a /sup 12/C/sup 13/C abundance gradient in our Galaxy.
Date: September 16, 1987
Creator: Hawkins, I.
System: The UNT Digital Library
Physical protection solutions for security problems at nuclear power plants. [PWR; BWR] (open access)

Physical protection solutions for security problems at nuclear power plants. [PWR; BWR]

Under Department of Energy sponsorship, Sandia National Laboratories has developed a broad technological base of components and integrated systems to address security concerns at facilities of importance, including nuclear reactors. The primary security concern at a light water reactor is radiological sabotage, a deliberate set of actions at a plant which could expose the public to a significant amount of radiation (on the order of 10 CFR 100 limits). (Also of importance to plant operators are acts of industrial sabotage that could prevent a plant from producing electrical power).
Date: September 1, 1980
Creator: Darby, J.L. & Jacobs, J.
System: The UNT Digital Library
Injection septum magnets for the Loma Linda medical accelerator (open access)

Injection septum magnets for the Loma Linda medical accelerator

The injection beamline runs over the last magnet before a long straight section and is then displaced downward 55.88 cm to the accelerator beamline. The displacement is magnetic and the final deflection onto the synchrotron orbit is by an electric kicker. The first component, the reverse septum magnet, bends the injection beam 25)degree) downward. This is followed by the injection septum (20)degree) bend upward) and the final injection kicker (5)degree) bend upward). The septum magnets produce a peak field of 3.4 K gauss at a current of 28,000 amperes within a 0.1 msec long pulse. The electric kicker produces a field of 7.3 KV/cm with a pulse length of 0.0011 msec. The septum magnets are similar to each other in construction with a bending radium of 72.7 cm. The curvature is required to increase the effective aperture. Each magnet has a single-turn copper coil bonded to a stainless steel plate for reinforcement. This eliminates insulating material, which could be subject to radiation damage, at the septum. The stainless steel plate is welded to the magnet laminations. The current is confined to the septum by the insulation between the laminations, which are a standard core material. The total septum thickness with …
Date: September 22, 1987
Creator: Satti, J.A.
System: The UNT Digital Library
Background field coils for the High Field Test Facility (open access)

Background field coils for the High Field Test Facility

The High Field Test Facility (HFTF), presently under construction at LLNL, is a set of superconducting coils that will be used to test 1-m-o.d. coils of prototype conductors for fusion magnets in fields up to 12 T. The facility consists of two concentric sets of coils; the outer set is a stack of Nb-Ti solenoids, and the inner set is a pair of solenoids made of cryogenically-stabilized, multifilamentary Nb/sub 3/Sn superconductor, developed for use in mirror-fusion magnets. The HFTF system is designed to be parted along the midplane to allow high-field conductors, under development for Tokamak fusion machines, to be inserted and tested. The background field coils were wound pancake-fashion, with cold-welded joints at both the inner and outer diameters. Turn-to-turn insulation was fabricated at LLNL from epoxy-fiberglass strip. The coils were assembled and tested in our 2-m-diam cryostat to verify their operation.
Date: September 22, 1980
Creator: Zbasnik, J. P.; Cornish, D. N.; Scanlan, R. M.; Jewell, A. M.; Leber, R. L.; Rosdahl, A. R. et al.
System: The UNT Digital Library
Panel discussion on laboratory accelerator programs: present and future (open access)

Panel discussion on laboratory accelerator programs: present and future

The present SLAC accelerator program is summarized briefly, and the future of electron-positron colliders is discussed. Present activities discussed include the PEP storage ring, the SPEAR storage ring, the Linear Accelerator, and the SLAC Linear Collider (SLC) project. Future prospects include a larger scale linear collider. The stability requirements on acceleration are briefly discussed. (LEW)
Date: September 1, 1986
Creator: Richter, B.
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
Open and hidden charm muoproduction. [209 GeV] (open access)

Open and hidden charm muoproduction. [209 GeV]

New results are presented on open and hidden charm and bottom production by 209-GeV muons interacting in a magnetized steel calorimeter. The upper limit on the production of T states by muons is sigma(..mu..N ..-->.. ..mu..UPSILONX)B(UPSILON ..-->.. ..mu mu..) < 22 x 10/sup -39/ cm/sup 2/ (90% confidence level). The distributions of elastically produced psi's are consistent with s-channel helicity conservation (SCHC) and disagree with psi dominance. From analysis of dimuon final states the cross section for diffractive charm muoproduction is 6.9/sub -1.4/sup +1.9/ nb. The structure function F/sub 2/(c anti c) for diffractive charmed-quark pair production is presented. 5 figures, 2 tables.
Date: September 1, 1980
Creator: Clark, A.R.; Johnson, K.J. & Kerth, L.T.
System: The UNT Digital Library
Nuclear de-excitation processes following medium energy heavy ion collisions (open access)

Nuclear de-excitation processes following medium energy heavy ion collisions

As heavy ion reaction studies have progressed from beam energies below 10 MeV/nucleon to higher energies, many non-equilibrium reaction phenomena have been observed. Among these are nucleon emission with velocities in excess of the beam velocity, incomplete momentum transfer to evaporation residue and fission-like fragments, ..gamma..-rays with energies in excess of 100 MeV, and ..pi../sup 0/ production when beam energies are below the threshold for production by the nucleon-nucleon collision mechanism. Additionally, prefission neutrons have been observed in excess of numbers expected from equilibrium models. A few of the approaches which have been applied to these phenomena are as follows: Intranuclear cascade: two body collisions are assumed to mediate the equilibration. The geometry and momentum space is followed semiclassically. The approach has many successes though it may suffer in a few applications is not following holes; TDHF considers one body processes only; in the energy regime of interest, two body processes are important so that this may not be a viable approach; Boltzmann-Uehling-Uhlenbeck or Vlasov-Uehling-Uhlenbeck (BUU/VUU) equations combine both one body and two body dynamics. The spatial and momentum evolution of the reactions are followed in a mean field. These should be the Cadillacs of the models. They are computationally …
Date: September 1, 1986
Creator: Blann, M.
System: The UNT Digital Library
Operational history of Fermilab's 1500 W refrigerator used for energy saver magnet production testing (open access)

Operational history of Fermilab's 1500 W refrigerator used for energy saver magnet production testing

The 1500 W helium refrigerator system utilizes two oil-injected screw compressors staged to feed a liquid nitrogen pre-cooled cold box. Refrigeration is provided by two Sulzer TGL-22 magnetic/gas bearing turbines. The refrigerator feeds six magnet test stands via a 10,000 L dewar and subcooler equipped distribution box. The design of the controls has permitted the system to be routinely operated 24 hours/day, seven days/week with only five operators. It has operated approximately 90% of the 4-1/2 years prior to shutting down in 1984 for a period of one year to move the compressor skid. Scheduled maintenance, failures, repairs and holidays are about equal to the 10% off time. The equipment described was used to test approximately 1200 superconducting magnets for the Fermilab accelerator ring. The seven year operating experience is presented as an equipment and technique review. Compressor hours currently exceed 42,000 and turbine hours exceed 39,000 each. Failure rates, causes, preventive maintenance, monitoring practices and equipment, and modifications are examined along with notes on some of the more successful applications of technique and equipment. 4 refs.
Date: September 1, 1985
Creator: Bianchi, A. J.; Barger, R. K.; Johnson, F. B.; McGuire, K. J.; Pinyan, K. D.; Wilson, F. W. et al.
System: The UNT Digital Library
Positron computed tomography: current state, clinical results and future trends (open access)

Positron computed tomography: current state, clinical results and future trends

An overview is presented of positron computed tomography: its advantages over single photon emission tomography, its use in metabolic studies of the heart and chemical investigation of the brain, and future trends. (ACR)
Date: September 1, 1980
Creator: Schelbert, H. R.; Phelps, M. E. & Kuhl, D. E.
System: The UNT Digital Library
Pellet fueling development at ORNL (open access)

Pellet fueling development at ORNL

Advanced plasma fueling systems for magnetic confinement devices are being developed at the Oak Ridge National Laboratory (ORNL). The general approach is that of producing and accelerating frozen hydrogenic pellets at speeds in the range of 1-2 km/s and higher. Two specific concepts are under development: (1) high-speed pneumatic acceleration; and (2) mechanical (centrifugal) acceleration. Both approaches are being pursued to meet the projected pellet size and delivery rates for major near-term plasma confinement devices, such as the Tokamak Fusion Test Reactor (TFTR), Tore Supra, the Joint European Torus (JET), JT-60, and Doublet III-D (DIII-D), as well as future applications. In addition to these confinement physics related activities, ORNL is pursuing advanced technologies to achieve pellet velocities significantly in excess of the 2-km/s range already attained with pneumatic injectors and has embarked on a development program designed to explore the feasibility of fabricating and accelerating tritium pellets. This paper describes these ongoing activities.
Date: September 1, 1986
Creator: Combs, S. K.; Milora, S. L.; Foster, C. A.; Schuresko, D. D.; Foust, C. R.; Simmons, D. W. et al.
System: The UNT Digital Library