The multipulse Thomson scattering diagnostic on the DIII-D tokamak (open access)

The multipulse Thomson scattering diagnostic on the DIII-D tokamak

This paper describes the design and operation of a 40-spatial channel Thomson scattering system that uses multiple 20 Hz Nd:YAG lasers to measure the electron temperature and density profiles periodically throughout an entire plasma discharge. Interference filter polychromators disperse the scattered light which is detected by silicon avalanche photodiodes. The measurable temperature range from 10 eV to 20 keV and the minimum detectable density is about 2 {times} 10{sup 18} m{sup {minus}3}. Laser control and data acquisition are performed in real-time by a VME-based microcomputer. Data analysis is performed by a MicroVAX 3400. Unique features of this system include burst mode'' operation, where multiple lasers are fired in rapid succession (< 10 KHz), real-time analysis capability, and laser beam quality and alignment monitoring during plasma operation. Results of component testing, calibration, and plasma operation are presented. 8 refs. 6 figs.
Date: September 1, 1991
Creator: Carlstrom, T. N.; Campbell, G. L.; DeBoo, J. C.; Evanko, R. G.; Evans, J.; Greenfield, C. M. et al.
System: The UNT Digital Library
Prospects of physics at CDF with the SVX (open access)

Prospects of physics at CDF with the SVX

During next physics run CDF will strongly enhance its heavy flavor tagging capabilities with the installation of a silicon vertex detector (SVX), that will allow precise measurements of secondary decay vertices in the plane transverse to the beam (impact parameter resolution {approx equal} 12 {mu}m). We expect this detector to have a significant impact on b-physics (c{tau}{sub B} {approx equal} 350 {mu}m) and top search. In the following we will discuss CDF prospects for top search and for CP violation asymmetry measurements in the B-sector. 16 refs., 5 figs., 1 tabs.
Date: September 1, 1991
Creator: Dell'Agnello, S.
System: The UNT Digital Library
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
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
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
Detectors for radiation dosimetry (open access)

Detectors for radiation dosimetry

For our purposes in this review, we note the following points: (1) for charged particle detection, these counters can be filled with any noble gas-quenching gas mixture that produces satisfactory electrical signals; (2) neutron counters, in which the neutrons are detected by their interaction with the specific filling of the chamber to yield an ionizing particle, require special gas mixtures containing /sup 3/He or BF/sub 3/, an alternative approach is to coat the inner surface of the cathode with a boron or lithium compound; (3) proportional counters are used if there is any need to discriminate between different types of radiation incident on the chamber by the magnitude of the ionizing energy retained within the sensitive volume of the counter; (4) proportional counters can operate at higher speeds than Geiger counters, typically up to 10/sup 7/ cts/sec versus less than 10/sup 5//sec for the Geiger counters; and (5) Geiger counters produce very large uniform pulses which can be scaled by very simple electronics, hence, they are often used in survey meters and other portable monitoring instruments.
Date: September 1, 1979
Creator: Perez-Mendez, V.
System: The UNT Digital Library
Dilepton (e sup + e sup minus ) production recent pp and pd studies with DLS at Berkeley (open access)

Dilepton (e sup + e sup minus ) production recent pp and pd studies with DLS at Berkeley

The use of dileptons as probes of hot, dense hadronic matter is described. Preliminary results on dileptons produced in p-p and p-d interactions at the Bevalac are presented along with potential ramifications for existing model calculations of dileptons at these energies. Future directions of the dilepton program at Berkeley are outlined. 14 refs., 3 figs.
Date: September 1, 1991
Creator: Schroeder, L. S.
System: The UNT Digital Library
Techniques for preventing damage to high power laser components (open access)

Techniques for preventing damage to high power laser components

Techniques for preventing damage to components of the LASL Shiva high power laser system were briefly presented. Optical element damage in the disk amplifier from the combined fluence of the primary laser beam and the Xenon flash lamps that pump the cavity was discussed. Assembly and cleaning techniques were described which have improved optical element life by minimizing particulate and optically absorbing film contamination on assembled amplifier structures. A Class-100 vertical flaw clean room used for assembly and inspection of laser components was also described. The life of a disk amplifier was extended from less than 50 shots to 500 shots through application of these assembly and cleaning techniques. (RME)
Date: September 1, 1977
Creator: Stowers, Irving F.; Patton, Howard G.; Jones, Walter A. & Wentworth, Donald E.
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
Polarization spectroscopy of tokamak plasmas (open access)

Polarization spectroscopy of tokamak plasmas

Measurements of polarization of spectral lines emitted by tokamak plasmas provide information about the plasma internal magnetic field and the current density profile. The methods of polarization spectroscopy, as applied to the tokamak diagnostic, are reviewed with emphasis on the polarimetry of motional Stark effect in hydrogenic neutral beam emissions. 25 refs., 7 figs.
Date: September 1, 1991
Creator: Wroblewski, D.
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
A prototype on-line work procedure system for radioisotope thermoelectric generator production (open access)

A prototype on-line work procedure system for radioisotope thermoelectric generator production

An on-line system to manage work procedures is being developed to support radioisotope thermoelectric generator (RTG) assembly and testing in a new production facility. This system implements production work procedures as interactive electronic documents executed at the work site with no intermediate printed form. It provides good control of the creation and application of work procedures and provides active assistance to the worker in performing them and in documenting the results. An extensive prototype of this system is being evaluated to ensure that it will have all the necessary features and that it will fit the user's needs and expectations. This effort has involved the Radioisotope Power Systems Facility (RPSF) operations organization and technology transfer between Westinghouse Hanford Company (Westinghouse Hanford) and EG G Mound Applied Technologies Inc. (Mound) at the US Department of Energy (DOE) Mound Site. 1 ref.
Date: September 1, 1991
Creator: Kiebel, G.R.
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
Ferrocyanide-containing waste tanks: Ferrocyanide chemistry and reactivity (open access)

Ferrocyanide-containing waste tanks: Ferrocyanide chemistry and reactivity

The complexing constant for hexacyano-iron complexes, both Fe(2) and Fe(3), are exceptionally large. The derived transition metal salts or double salts containing alkali metal ions are only slightly soluble. The various nickel compounds examined in this study, i.e., those predicted to have been formed in the Hanford waste scavenging program, are typical examples. In spite of their relative stability towards most reagents under ambient conditions, they are all thermodynamically unstable towards oxidation and react explosively with oxidants such as nitrate or nitrate salts when heated to temperatures in excess of 200{degree}C. 42 refs., 5 figs., 3 tabs.
Date: September 1, 1991
Creator: Scheele, R. D.; Burger, L. L.; Tingey, J. M.; Bryan, S. A.; Borsheim, G. L.; Simpson, B. C. et al.
System: The UNT Digital Library
Search for W prime and Z prime at CDF (open access)

Search for W prime and Z prime at CDF

We have searched for heavy charged and neutral vector bosons via the decays W{prime} {yields} ev, W{prime} {yields} {mu}v, Z{prime} {yields} {mu}{mu} in p{bar p} collisions at {radical}s = 1.8 TeV, using data taken with the collider Detector at Fermilab. The nonobservation of these processes leads to a lower limit (95% confidence level) of 520 GeV/c{sup 2} on the mass of the W{prime} and of 412 GeV/C{sup 2} on the mass of the Z{prime}, assuming standard model coupling to fermions. 12 refs., 6 figs., 1 tab.
Date: September 1, 1991
Creator: Fuess, T.
System: The UNT Digital Library
The Scalable Coherent Interface and related standards projects (open access)

The Scalable Coherent Interface and related standards projects

The Scalable Coherent Interface (SCI) project (IEEE P1596) found a way to avoid the limits that are inherent in bus technology. SCI provides bus-like services by transmitting packets on a collection of point-to-point unidirectional links. The SCI protocols support cache coherence in a distributed-shared-memory multiprocessor model, message passing, I/O, and local-area-network-like communication over fiber optic or wire links. VLSI circuits that operate parallel links at 1000 MByte/s and serial links at 1000 Mbit/s will be available early in 1992. Several ongoing SCI-related projects are applying the SCI technology to new areas or extending it to more difficult problems. P1596.1 defines the architecture of a bridge between SCI and VME; P1596.2 compatibly extends the cache coherence mechanism for efficient operation with kiloprocessor systems; P1596.3 defines new low-voltage (about 0.25 V) differential signals suitable for low power interfaces for CMOS or GaAs VLSI implementations of SCI; P1596.4 defines a high performance memory chip interface using these signals; P1596.5 defines data transfer formats for efficient interprocessor communication in heterogeneous multiprocessor systems. This paper reports the current status of SCI, related standards, and new projects. 16 refs.
Date: September 1, 1991
Creator: Gustavson, D.B.
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
Some initial measurements of DDT resuspension and translocation from Pacific Northwest forests (open access)

Some initial measurements of DDT resuspension and translocation from Pacific Northwest forests

None
Date: September 1, 1974
Creator: Orgill, M M; Petersen, M R & Sehmel, G A
System: The UNT Digital Library
Bootstrap and fast wave current drive for tokamak reactors (open access)

Bootstrap and fast wave current drive for tokamak reactors

Using the multi-species neoclassical treatment of Hirshman and Sigmar we study steady state bootstrap equilibria with seed currents provided by low frequency (ICRF) fast waves and with additional surface current density driven by lower hybrid waves. This study applies to reactor plasmas of arbitrary aspect ratio. IN one limit the bootstrap component can supply nearly the total equilibrium current with minimal driving power (< 20 MW). However, for larger total currents considerable driving power is required (for ITER: I{sub o} = 18 MA needs P{sub FW} = 15 MW, P{sub LH} = 75 MW). A computational survey of bootstrap fraction and current drive efficiency is presented. 11 refs., 8 figs.
Date: September 1, 1991
Creator: Ehst, D.A.
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
Polymer concrete patching materials (open access)

Polymer concrete patching materials

The increased use of deicing salts is causing rapid deterioration of portland cement concrete bridge decks. Soluble chlorides cause corrosion of the steel reinforcing rods with a corresponding increase in volume of the rods. This expansion causes stresses in the concrete which result in delaminations and surface spalling. The repair of surface spalls with portland cement concrete can only be made if traffic can be avoided for several days. A patching material which would allow traffic to resume over the repaired area in a few hours was needed. Polymer concrete (PC) was developed to repair deteriorated portland cement concrete. Polymer concrete is defined as a composite material in which the aggregate is bound together in a dense matrix with a polymer binder. The aggregate is mixed with a monomer mixture and subsequently cured in place. Polymer concrete combines the premix characteristics of portland cement concrete with high strength, long term durability properties and fast cure times. PC placed at temperatures between 35/sup 0/F and 95/sup 0/F attains strengths greater than 5000 psi in 2 hours. The high early strength of PC is suitable for use in the repair of highway structures where traffic conditions allow closing of the area for …
Date: September 1, 1977
Creator: Fontana, J.J.
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