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in subjects: "Impurities"

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Boron reclamation

A process to recover high purity /sup 10/B enriched crystalline boron powder from a polymeric matrix was developed on a laboratory basis and ultimately scaled up to production capacity. The process is based on controlled pyrolysis of boron-filled scrap followed by an acid leach and dry sieving operation to return the powder to the required purity and particle size specifications. Typically, the recovery rate of the crystalline powder is in excess of 98.5 percent, and some of the remaining boron… more

Date: July 1, 1980

Creator: Smith, R. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Murakami density limit in tokamaks and reversed-field pinches

A theoretical upper limit for the density in an ohmically heated tokamak discharge follows from the requirement that the ohmic heating power deposited in the central current-carrying channel exceed the impurity radiative cooling in this critical region. A compact summary of our results gives this limit n/sub M/ for the central density as n/sub M/ = (Z/sub e//(Z/sub e/-1)/sup 1/2/n/sub eo/ (B/sub T//1T)(1m/R) where n/sub eo/ depends strongly on the impurity species and is remarkably independent … more

Date: March 1, 1984

Creator: Perkins, F.W. & Hulse, R.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Direct spectroscopic observation of charge-exchange recombination of medium-Z elements in the PLT tokamak

We report the first observation of line emission resulting directly from charge-exchange recombination of medium-Z elements (Al, Sc) injected into a PLT discharge. Transitions due to the radiative cascade immediately following charge-exchange of He-like Al and Sc were observed by a VUV spectrograph and two air monochromators. In two cases, AlXI 3209 A and ScXIX 112.1 A, the observed transition had not previously been experimentally identified. Spatial scans provided information on the profile o… more

Date: March 1, 1984

Creator: Skinner, C. H.; Suckewer, S.; Cohen, S. A.; Schilling, G.; Wilson, R. & Stratton, B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Study of impurities in the Tandem Mirror Experiment using extreme-ultraviolet spectroscopy

Impurities in the Tandem Mirror Experiment (TMX) have been studied using extreme ultraviolet spectroscopy. Three time-resolving absolutely-calibrated normal-incidence monochromators, one on each section of TMX, were used to study the impurity emissions in the wavelength range of 300 A to 1600 A. The instruments on the east end cell and central cell were each capable of obtaining spatially-resolved profiles from 22 chords of the plasma simultaneously while the instrument on the west end cell mon… more

Date: May 12, 1982

Creator: Strand, O. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Summary of HTGR (high-temperature gas-cooled reactor) benchmark data from the high temperature lattice test reactor

The High Temperature Lattice Test Reactor (HTLTR) was a unique critical facility specifically built and operated to measure variations in neutronic characteristics of high temperature gas cooled reactor (HTGR) lattices at temperatures up to 1000{degree}C. The Los Alamos National Laboratory commissioned Pacific Northwest Laboratory (PNL) to prepare this summary reference report on the HTLTR benchmark data and its associated documentation. In the initial stages of the program, the principle of th… more

Date: October 1, 1989

Creator: Newman, D.F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Low-cost solar array project. Task I. Silicon material. Investigation of the hydrogenation of SiCl/sub 4/

Reaction kinetic measurements on the hydrochlorination of SiCl/sub 4/ and m.g. silicon metal were last reported as a function of reaction temperature, reactor pressure, H/sub 2//SiCl/sub 4/ ratio and silicon metal particle size distribution, 3 SiCl/sub 4/ + 2 H/sub 2/ + Si reversible 4 SiHCl/sub 3/. The effect of impurities in the m.g. silicon metal on the rate of this reaction has been investigated in this quarter. The m.g. silicon was replaced with high purity, electronic grade silicon metal … more

Date: October 7, 1980

Creator: Mui, J. Y. P. & Seyferth, D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Development and evaluation of die and container materials. Final report

Specific compositions of high purity silicon aluminum oxynitride (Sialon) and silicon beryllium oxynitride (Sibeon) solid solutions are shown to be promising refractory materials for handling and manipulating solar grade silicon into silicon ribbon. Well controlled processing schedules were developed for fabricating high purity Sialon and Sibeon materials. Essentially the impurity content of the hot pressed ceramics was due only to impurities from the original starting powders. A ceramic shapin… more

Date: May 1, 1979

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Size effects and interstitial impurities in Nb/sub 3/Zr superconductors. Superconducting solenoids with metal insulation. [Oxygen and carbon]

No Description Available.

Date: September 11, 1962

Creator: Betterton, Jr, J O; Kneip, Jr, G D; Easton, D S & Scarbrough, J O

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of erosion and transport of carbon impurity in the TFTR inner bumper limiter region

Carbon sputtering and transport on the TFTR inner graphite bumper limiter is investigated with the impurity transport code REDEP. Analysis is carried out for a series of ohmic discharges in TFTR. Predictions for Z{sub eff} in the core plasma agree well with in-situ experimental measurements. Run-away self-sputtering of carbon is predicted at low densities and high edge plasma temperatures when the limiter surface was purged of deuterium. Surface erosion and deposition is analyzed. In general, r… more

Date: January 1, 1992

Creator: Hua, T. Q. & Brooks, J. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electron-beam fusion welding of beryllium

Ingot-sheet beryllium (Be) having three different chemistries and three different thicknesses was fusion-welded by the electron-beam process. Several different preheats were used to obtain 100% penetration and crack-free welds. Cracking susceptability was found to be related to aluminum (Al) content; the higher Al-content material was most susceptable. However, adequate preheat allowed full penetration and crack-free welds to be made in all materials tested. The effect of a post-weld heat treat… more

Date: January 1, 1978

Creator: Campbell, R. P.; Dixon, R. D. & Liby, A. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Effect of the self-pumped limiter concept on the tritium fuel cycle

The self-pumped limiter concept for impurity control of the plasma of a fusion reactor has a major impact on the design of the tritium systems. To achieve a sustained burn, conventional limiters and divertors remove large quantities of unburnt tritium and deuterium from the plasma which must be then recycled using a plasma processing system. The self-pumped limiter which does not remove the hydrogen species, does not require any plasma processing equipment. The blanket system and the coolant pr… more

Date: January 1, 1988

Creator: Finn, P.A.; Sze, D.K. & Hassanein, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Depth distributions of low energy deuterium implantations in (110) tungsten: a theoretical model

The depth distributions of 80 eV D/sup +/ implants in (110) W have recently been measured by field desorption microscopy. Prominent structure, consisting of seven major and several minor peaks, is observed in the measured distributions. This contrasts with conventional implantation theory which predicts two peaks, one for the channeled D/sup +/ and one for the nonchanneled D/sup +/. The observed structure is explained in the present report by a model which ascribes the various peaks to D/sup +/… more

Date: March 1, 1978

Creator: Brice, D.K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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SM-1A PROJECT--TECHNICAL MANUAL: CHEMISTRY

A manual is given of the equipment and procedures used in the Army Reactor (SM-1A) to control the water purity and makeup. In addition to a description of the primary purification control system, a discussion is presented of the water chemistry control procedures for the auxiliary systems (e.g., the spent-fuel pit, the shield tank, and the waste disposal system). (T.F.H.)

Date: September 29, 1960

Creator: Chupak, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Liquid metal corrosion considerations in alloy development

Liquid metal corrosion can be an important consideration in developing alloys for fusion and fast breeder reactors and other applications. Because of the many different forms of liquid metal corrosion (dissolution, alloying, carbon transfer, etc.), alloy optimization based on corrosion resistance depends on a number of factors such as the application temperatures, the particular liquid metal, and the level and nature of impurities in the liquid and solid metals. The present paper reviews the va… more

Date: January 1, 1984

Creator: Tortorelli, P. F. & DeVan, J. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Nuclear spin polarization of solid deuterium-tritium

It appears that parallel alignment of deuteron and triton magnetic moments increases the cross section of the nuclear reaction T(d,n) He/sup 4/ by 50%, thereby promising a laser driver of perhaps half the original energy. Both ''brute-force'' and dynamic nuclear polarization are considered, and the many potential problems of the latter are considered. High nuclear polarization by the dynamic technique requires a small nucleus-to-unpaired electron ratio, a long longitudinal nuclear relaxation ti… more

Date: January 1, 1985

Creator: Souers, P. C.; Fearon, E. M.; Mapoles, E. R.; Gaines, J. R.; Sater, J. D. & Fedders, P. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Experimental observations and model calculations of impurity radiation in a plasma gun compact torus experiment

Several types of radiation measurements were performed on the Beta II compact forms experiment. Among these are time integrated spectra ranging in wavelength from the vuv to the uv, time resolved bolometer measurements of radiation from the x-ray to the infrared, and time and wavelength resolved measurements of certain spectral lines. It is difficult to relate any one of these measurements to plasma parameters of interest such as temperature, density, or impurity content. In this report we comp… more

Date: August 10, 1982

Creator: Goldenbaum, G. C.; Granneman, E. H. A.; Hartman, C. W.; Prono, D. S.; Taska, J. & Turner, W. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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New method to determine the chemical composition and structure of non-elemental acceptor and donor centers in ultra-pure germanium

A new approach towards the understanding of hitherto unknown, non-elemental acceptors and donors which can limit the purity of ultra-pure germanium has been explored for a specific pair of shallow centers, designated A/sub 2/ and D. Using photoelectric spectroscopy, we have demonstrated that an isotope shift in the ground-state binding energy occurs when the germanium crystals are grown in pure deuterium instead of in the usual pure hydrogen atmosphere. This isotope shift is the most direct pro… more

Date: October 1, 1977

Creator: Haller, E.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Radially resolved emission spectroscopy on ZT-40M

Measurements of line integrated emission profiles of D/sub ..beta../, OIII, OV, OVI, and CV line radiation have been performed in the ZT-40M device at Los Alamos National Laboratory. The behavior of these emission profiles will be presented for several operating currents, fill pressures, and current risetimes. The basic oxygen radial structures are seen to resemble an onion skin at any particular time, with OIII farthest out in radius and OVI nearest the axis, as one would expect in the absence… more

Date: May 1, 1982

Creator: Watt, R.G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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ICRF (Ion Cyclotron Range of Frequencies) edge modeling studies

Theoretical models have been developed, and are currently being refined, to explain the edge plasma-antenna interaction that occurs during ICRF heating. The periodic structure of a Faraday shielded antenna is found to result in strong ponderomotive force in the vicinity of the antenna. A fluid model, which incorporates the ponderomotive force, shows an increase in transport to the Faraday shield. A kinetic model shows that the strong antenna near fields act to increase the energy of deuterons w… more

Date: January 1, 1989

Creator: Lehrman, I.S. (Grumman Aerospace Corp., Princeton, NJ (USA). Corporate Research Center) & Colestock, P.L. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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In-situ impurity measurements in PDX Edge plasma

The surface analysis station of PDX combines several surface analysis techniques (AES, XPS, SIMS) for in-situ measurement of impurity fluxes in the edge-plasma. The major impurities deposited on a sample surface during nondiverted PDX discharges are oxygen, titanium (limiter material) and chlorine. The impurity fluxes measured at different radial positions decreased by a factor of ten from the plasma edge to the wall. The sample surface collecting the impurity ions is located behind a circular … more

Date: July 1, 1980

Creator: Staib, P.; Dylla, H.F. & Rossnagel, S.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Critical current studies on fine filamentary NbTi accelerator wires

The magnets for the Superconductig Super Collider, a high energy proton colliding beam accelerator, require a superconductor with very high current density (>2400 A/mm/sup 2/ at 5 T) and very small filaments (approx. 2..mu..m in diameter). Previous work has shown that by controlling the formation of Cu/sub 4/Ti compound particles on the filament surfaces it is possible to make fine filamentary NbTi wire with high critical current density. The performance of multi-filamentary wire is characteriz… more

Date: January 1, 1985

Creator: Garber, M.; Suenaga, M.; Sampson, W.B. & Sabatini, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Tokamak startup with electron cyclotron heating

Experiments are described in which the startup voltage in a tokamak is reduced by approx. 60% by the use of a modest amount of electron cyclotron resonance heating power for preionization. A 50% reduction in volt-second requirement and impurity reflux are also observed.

Date: April 1, 1980

Creator: Holly, D. J.; Prager, S. C.; Shepard, D. A. & Sprott, J. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Continuous Czochralski growth: silicon sheet growth development of the large area silicon sheets task of the Low Cost Silicon Solar Array Project. Ninth quarterly progress report, October 1-December 31, 1979

During this reporting period, four more 100 kg continuous runs were completed to satisfy the six required by the project extension. One of the four (2*) was performed using a new standard CG2000 RC grower, using accessory equipment and process techniques developed under this project. The sixth and final 100 kg continuous run was performed with purified carbon parts and resulted in the best results to date. Run No. 62 resulted in 103.0 kg being pulled from 104.5 kg total charge weight (98.6% pul… more

Date: January 1, 1979

Creator: Lane, R.L. & Roberts, E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Control of alpha particle transport by spatially inhomogeneous ion cyclotron resonance heating

Control of the radial alpha particle transport by using Ion Cyclotron Range of Frequency waves is investigated in a large-aspect-ratio tokamak geometry. It is shown that spatially inhomogeneous ICRF-wave energy with properly selected frequencies and wave numbers can induce fast convective transport of alpha particles at the speed of order {upsilon}{sub alpha} {approximately} (P{sub RF}/n{sub {alpha}}{epsilon}{sub 0}) {rho}{sub p}, where P{sub RF} is the ICRF-wave power density, n{sub {alpha}} i… more

Date: February 1, 1990

Creator: Chang, C. S.; Imre, K.; Weitzner, H. (New York Univ., NY (USA). Courant Inst. of Mathematical Sciences) & Colestock, P. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

Item Type: Report

Partner: UNT Libraries Government Documents Department