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Alignment and orientation in ion/endash/atom collisions

Description: Recent progress in the theoretical study of alignment and orientation in atom-atom and ion-atom collisions at intermediate energies is reviewed. Recent systematic studies of the alignment and orientation of electronic charge cloud distributions of excited states resulting from such collisions clearly have provided more detailed information about the underlying collision dynamics. However, since accurate determination of these parameters is quite difficult, both theoretically and experimentally,… more
Date: January 1, 1987
Creator: Kimura, M. & Lane, N.F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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D/sup -/ production by multiple charge-transfer collisions of low-energy D ions and atoms in cesium vapor

Description: The production of D/sup -/ by multiple charge-transfer collisions of a D/sup +/ beam in a cesium-vapor target is considered for D/sup +/ energies above 300 eV. The cross sections relevant to D/sup -/ formation are obtained by a least-squares fit of three-charge-state differential equations to experimental yield curves. Implications for production of intense negative-ion beams are discussed, and speculations are made about extrapolation to lower engeries.
Date: January 22, 1978
Creator: Hooper, E. B. Jr.; Willmann, P. A. & Schlachter, A. S.
Item Type: Refine your search to only 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

Description: 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: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Efficiencies of gas neutralizers for multi-MeV beams of light negative ions

Description: Measurements are reported of the neutral and charged particle fractions produced by running beams of Li/sup -/, C/sup -/, O/sup -/, and Si/sup -/ at energies up to 7 MeV through gas cells of N/sub 2/, Ar, or CO/sub 2/. We discuss the implications of these measurements for the design of neutralizers to produce high energy light atom beams for heating or current drive in tokamaks.
Date: November 1, 1981
Creator: Grisham, L. R.; Post, D. E.; Johnson, B. M.; Jones, K. W.; Barette, J.; Kruse, T. H. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Sources of polarized ions and atoms

Description: In this presentation we discuss methods of producing large quantities of polarized atoms and ions (Stern-Gerlach separation, optical pumping, and spin-exchange) as well as experimental methods of measuring the degree of polarization of atomic systems. The usefulness of polarized atoms in probing the microscopic magnetic surface properties of materials will also be discussed. 39 refs., 5 figs., 2 tabs.
Date: January 1, 1988
Creator: Cornelius, W.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Collisionally excited few-electron systems: theoretical introduction and survey. [2-200 keV]

Description: We consider excitation, ionization, and charge transfer in collisions of protons (and antiprotons) with the single-electron targets H, He/sup +/, and Li/sup 2 +/. These collisions are first compared to other types of ion-atom collisions. A brief review of our own theoretical method is given; in particular we describe how we allow for both large charge transfer and ionization probabilities while retaining the computational efficiency that allows us to consider a variety of collision partners and… more
Date: January 1, 1982
Creator: Ford, A.L.; Reading, J.F. & Becker, R.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Performance study of the TFTR diagnostic neutral beam for active charge exchange measurements

Description: A neutral beam source will be incorporated in the Tokamak Fusion Test Reactor (TFTR) charge exchange diagnostic to provide a time modulated, spatially localized enhancement of the charge exchange efflux. Two autonomous Charge Exchange Neutral Analyzer (CENA) systems are being designed for the TFTR. One system measures the plasma ion temperature along twelve vertical line-of-sight chords spaced approximately equidistantly across the torus minor diameter. The other system is dedicated primarily t… more
Date: June 1, 1980
Creator: Medley, S. S.; Goldston, R. J. & Towner, H. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Radially resolved measurements of ''q'' on the ATC tokamak

Description: This paper describes a new technique for directly measuring the safety factor, or q, profile in a tokamak. A tightly collimated neutral beam capable of injecting approximately 100 mA of 30 keV deuterium atoms was mounted on the ATC tokamak. By proper tangential aiming of the beam a strong concentration of circulating fast ions was created at a chosen plasma minor radius. By examining the orbits of these ions with a multi-sight-line charge exchange detector, it was possible to measure the shifts… more
Date: April 1, 1978
Creator: Goldston, R.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Vacuum considerations summary

Description: The vacuum system for Heavy Ion Fusion machines can be divided according to pressure into 4 parts: (a) Ion Sources; (b) Linear Accelerators; (c) Circular Accelerators, Accumulators and Storage Rings; and (d) Reactors. Since ion sources will need rather conventional pumping arrangements and reactors will operate with greater pressures, depending on their mode of operation, only items b and c will be treated in this report. In particular, the vacuum system design will be suggested for the machine… more
Date: January 1, 1977
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Charge exchange processes involving iron ions

Description: A review and evaluation is given of the experimental data which are available for charge exchange processes involving iron ions and neutral H, H/sub 2/ and He. Appropriate scaling laws are presented, and their accuracy estimated for these systems. A bibliography is given of available data sources, as well as of useful data compilations and review articles. A procedure is recommended for providing single approximate formulae to the fusion community to describe total cross sections for electron c… more
Date: January 1, 1985
Creator: Phaneuf, R.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Cs/sup +/ + Cs/sup +/ charge-transfer and ionization cross-section measurements by a plasma-target technique

Description: A Q machine plasma target using cesium was constructed to serve as a target for a beam of Cs/sup +/ ions. The sum of charge transfer and ionization cross sections was determined by measuring the growth of the Cs/sup + +/ component of the beam as a function of the plasma radial line density. The measured cross section varies approximately linearly with energy between 50 and 110 keV. This loss cross section is 0.47 +- .11 x 10/sup -16/ cm/sup 2/ at 110 keV. These results have been compared to the… more
Date: May 1, 1982
Creator: Stalder, K.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Collision of fast highly charged ions in gas targets: ionization, recoil-ion production, and charge transfer

Description: Electron-capture, ionization, and recoil-ion-production cross sections are measured and calculated for fast highly charged projectiles in hydrogen and rare-gas targets. Recoil-ion-production cross sections are found to be large; the low energy and high charge states of the recoil ions make them useful for subsequent collision studies.
Date: July 1, 1982
Creator: Schalchter, A.S.; Berkner, K.H. & Beyer, H.F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Charge-exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment

Description: The horizontally scanning, multiangle charge-exchange analyzers on the Princeton Large Torus (PLT) and the Poloidal Divertor Experiment (PDX) were used to study the effects of MHD activity on the background ion distribution function and on the beam ion slowing-down process during high-power neutral injection. Sawtooth oscillations were observed in the fast ion flux on PLT and PDX, and measurements with neutral beams providing local neutral density enhancement indicate that ions are transported … more
Date: July 1, 1986
Creator: Goldston, R. J.; Kaita, R.; Beiersdorfer, P.; Gammel, G.; Herndon, D. L.; McCune, D. C. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Hydrogen-Transfer and Charge Transfer in Photochemical and High Energy Radiation Induced Reactions: Effects of Thiols. Final Report, February 1, 1960-January 31, 1979

Description: Absorption of ultraviolet or visible light, or high energy radiation, may lead to highly reactive free radicals. Thiols affect the reactions of these radicals in the following ways: (1) transfer of hydrogen from sulfur of the thiol to a substrate radical, converting the radical to a stable molecule, and the thiol to a reactive thiyl radical; and (2) transfer of hydrogen from a substrate radical or molecule to thiyl, regenerating thiol. The thiol is thus used repeatedly and a single molecule may… more
Date: March 1, 1980
Creator: Cohen, S. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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BNL neutral beam development group. Progress report, FY 1979

Description: The objective of the BNL Neutral Beam Program is to develop a 250 keV neutral beam system suitable for heating experiments in toroidal or mirror plasma devices. The system will be based on acceleration and neutralization of negative hydrogen ions produced in and directly extracted from a source. The objective of source studies is to develop a unit delivering 10 A of negative ion currents in pulses of 1 s duration or longer, operating with extracted current densities of at least 0.5 A/cm/sup 2/ … more
Date: January 15, 1980
Creator: Prelec, K. & Sluyters, T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Polarized negative ions

Description: This paper presents a survey of methods, commonly in use or under development, to produce beams of polarized negative ions for injection into accelerators. A short summary recalls how the hyperfine interaction is used to obtain nuclear polarization in beams of atoms. Atomic-beam sources for light ions are discussed. If the best presently known techniques are incorporated in all stages of the source, polarized H/sup -/ and D/sup -/ beams in excess of 10 ..mu..A can probably be achieved. Producti… more
Date: April 1, 1981
Creator: Haeberli, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Magnetic fusion energy annual report, July 1975--September 1976

Description: Supporting research activities continued to provide the technical basis for future mirror-confinement experiments. The industrial development of a high-current, high-field, high-current-density Nb/sub 3/Sn conductor was the main goal of the superconducting magnet program. Beam direct conversion was being developed as a means of raising the efficiency of neutral-beam production, and plasma direct conversion was shown to work as predicted. Conceptual designs were completed for various types of po… more
Date: December 2, 1976
Creator: Harrison, M.A.; McGregor, C.K. & Gottlieb, L. (eds.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Spatially resolved measurements of fully ionized low-Z impurities in the PDX tokamak

Description: Radial distributions of fully ionized oxygen and carbon in the PDX tokamak plasma are reported. These ions were detected via radiation emitted in charge-exchange recombination reactions between the impurities and hydrogen atoms from a non-perturbing neutron beam. The C/sup 6 +/ and O/sup 8 +/ ions are observed out to radii beyond the limiter, which is in contrast to expectations based on coronal equilibrium but consistent with a simple diffusive transport model. Central values of Z/sub eff/ obt… more
Date: July 1, 1982
Creator: Fonck, R. J.; Finkenthal, M.; Goldston, R. J.; Herndon, D. L.; Hulse, R. A.; Kaita, R. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Stability of space-charge neutralized beams

Description: Consideration is given to the stability of negative ion beams which are neutralized through ionization of a background gas. Two types of instabilities are examined. First, beam-plasma instabilities are analyzed with the dispersion relation showing that they are unimportant if the beam velocity is less than the electron thermal velocity. Second, results of a computer simulation on the flow of a cylindrical beam and the resulting background plasma show that when the background neutral gas density… more
Date: September 22, 1977
Creator: Turnbull, R. J. & Hooper, E. B. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Neutral-beam system based on BNL negative-hydrogen-ion sources

Description: Parameters of the conceptual design of the BNL neutral beam system were determined as follows: beam energy, 200 keV; negative ion current, 10A; neutral beam power, 1 MW; pulse length, multisecond to steady state. The completed system study, supported by successful ion source operation at the required level, will serve to evaluate and compare different approaches in the design of a negative ion based system and, eventually, lead to the design and construction of an operational system.
Date: January 1, 1982
Creator: Prelec, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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