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Discharge characteristics of a plasma generator for SITEX (Surface Ionization with Transverse Extraction) and VITEX (Volume Ionization with Transverse Extraction) ion sources

Description: Surface Ionization with Transverse Extraction (SITEX) and Volume Ionization with Transverse Extraction (VITEX) ion sources are being developed to produce intense beams of light negative ions for neutral particle beam applications. The salient feature of these ion sources is their ability to form intense negative-ion beams. With the objective of improving the performance of these sources, an experimental study of their plasma properties has been conducted. The effects of various electrodes in the plasma generator were investigated. Low electron and ion temperatures (below 1 eV) and positive plasma potential up to +6 V have been measured. The measured distributions of plasma density and potential reveal the existence of multichamber characteristics in the source plasma. The significant discharge characteristics and the plasma properties associated with the performance of SITEX and VITEX ion sources are discussed.
Date: January 1, 1986
Creator: Tsai, C.C.; Dagenhart, W.K.; Stirling, W.L.; Barber, G.C.; Haselton, H.H.; Ryan, P.M. et al.
Partner: UNT Libraries Government Documents Department

Extracted current densities from surface conversion sources of negative ions

Description: The condition for extracting a maximum negative ion current density is found when the product of the radius of the negative ion conversion electrode, the cross-section for negative and positive ion recombination, and the density of positive ions in the ion source equals one. The optimum output is obtained at the highest positive ion density and the smallest electrode radius.
Date: February 10, 1982
Creator: Fink, J.H.
Partner: UNT Libraries Government Documents Department

Considerations involved in the design of negative-ion-based neutral beam systems

Description: We consider the requirements and constraints for negative-ion-based neutral beam injection systems, and show how these are reflected in design considerations. We will attempt to develop a set of guidelines for users and developers to use to see how well (in a qualitative sense, at least) a particular neutral beam system fits a particular proposed need.
Date: November 1, 1983
Creator: Cooper, W.S.
Partner: UNT Libraries Government Documents Department

Pressure limits of negative ion sources based upon gas efficiency and extracted ion-current density

Description: The nature of the electrical discharge has an obvious impact upon the gas efficiency of an ion source and on the current density whch can be drawn from it. However external factors, such as the conductance of the grids and the background pressure along the beamline, also have an effect. Simple approximations based upon these factors show that there is a lower limit to the pressure of an ion source, which can deliver an ion beam of given current density at a specific gas efficiency. Estimates of ion stripping losses in a double gridded structure show that for all practical purposes, there is an upper limit as well.
Date: March 10, 1982
Creator: Fink, J.
Partner: UNT Libraries Government Documents Department

Neutral-beam development plan, FY 1982-1987

Description: The following chapters are included: (1) status of BNL negative ion source development, (2) source development program plan, (3) status of beam transport and acceleration, (4) accelerator development program plan, (5) neutralizer concepts, (6) neutralization program plan, (7) neutral beam systems, (8) test facilities, (9) program milestones and time schedules, (10) organization and Grumman participation, and (11) funding tables. (MOW)
Date: September 1, 1981
Partner: UNT Libraries Government Documents Department

Determination of species yield of ion sources used for intense neutral-beam injection

Description: For efficient plasma heating, ion sources of neutral-beam injectors should be capable of producing ion beams with an atomic fraction of 90% or higher. Diagnostic techniques for quantitatively determining source species yield have been developed and evaluated. These include magnetic momentum analysis of the unneutralized ions passing through the neutralizer, energy analysis of the neutral beam by electrostatic separation of ions emanating from a stripping cell, and quantity vs implantation-depth analysis of hydrogen implanted into a crystal by SIMS technique. The operational features and advantages and disadvantages of each technique will be discussed. If the effects of beamlet optics, energy straggling in the accelerator, and neutralizer gas scattering are taken into account, the results of the measurements using the three techniques are shown to be mutually consistent within experimental error.
Date: January 1, 1982
Creator: Tsai, C.C.; Barnett, C.F.; Haselton, H.H.; Langley, R.A. & Stirling, W.L.
Partner: UNT Libraries Government Documents Department

Electrode design and performance of the ORNL positive ion sources

Description: The neutral beam development group at ORNL has designed, constructed, and shipped four 50-kV, 100-A sources to PPPL to be used for neutral beam heating of the confined plasma on the PDX tokamak. These sources have higher current capability than scaled-down sources, and they are required to run for 0.5 s as opposed to the 0.3-s requirement for PLT and ISX-B sources. Due to an innovative electrode design, these higher power sources met these requirements and achieved a higher transmission efficiency - 76% of the total input power on target vs 60% for the original ISX-B and modified PLT sources or 40% for the original PLT sources. As a consequence, a power of 2 MW of neutrals to the torus target was achieved; this is a record for measured neutral power and exceeds that of any other power source expected to be used on such advanced tokamaks as TFTR and D-III. A theoretical consideration of the relevant Poisson-Vlasov equations for ions extracted from a plasma was used to optimize the ion optics. Using the same electrode design with a tetraode accelerating structure and a new, indirectly heated cathode, repeatable long pulse, high energy conditions of 70 kV, 7 A, 8 s and 90 kV, 9 A, 5 s were achieved. Grid deformation calculations and Monte Carlo beam line gas deposition algorithms will be discussed. A direct-magnetic-electron-blocking, direct-recovery device is described, and theoretical considerations of it are discussed.
Date: January 1, 1980
Creator: Whealton, J.H.; Gardner, W.L. & Haselton, H.H.
Partner: UNT Libraries Government Documents Department

Negative-ion generator

Description: This negative ion generator comprises a magnetically insulated transmission line having at least one hole in the cathode to permit negative ions to escape the transmission line, and a device for removing electrons from the negative ion flow.
Date: February 11, 1982
Creator: Stinnett, R.W.
Partner: UNT Libraries Government Documents Department

24-MW neutral-beam injector of 400-keV H/sup 0/

Description: The negative and positive ion systems have both common goals and common problems. In fact, we have identified five items that must be developed before any large, neutral-beam injector, operating continuously or almost so, can be engineered. The five items are: (1) a continuous or almost continuous ion source, with 1A designating a source of positive ions and 1B a direct extraction source of negatives, (2) a recirculating metal-vapor cell, (3) a computer code with which to calculate beam trajectories in three dimensions, (4) a resistive coating to bleed stray charges from the surface of high-voltage vacuum insulators, and (5) an arc suppression technique for large systems. These items are discussed and it is shown how their development is prerequisite to the design of a 24-MW, 400-keV neutral hydrogen injector such as might be required for a fusion power reactor.
Date: November 1, 1979
Creator: Fink, J.H.; Hamilton, G.W. & Erickson, J.L.
Partner: UNT Libraries Government Documents Department

Characteristics of a long-pulse (30-s), high-power (4-MW) ion source for neutral beam injection

Description: A quasi-steady-state ion source has been developed for neutral beam injection applications. It is of the duoPIGatron type designed for delivering 50 A of hydrogen ions at 80 keV for 30-s-long pulses. Ion beams of 40 A at 75 keV were extracted for pulse lengths up to 30 s, maintaining excellent optical quality in the beam for the entire pulse duration. The design features and operational characteristics of the ion source are elaborated.
Date: January 1, 1983
Creator: Menon, M.M.; Barber, G.C.; Combs, S.K.; Dagenhart, W.K.; Gardner, W.L.; Haselton, H.H. et al.
Partner: UNT Libraries Government Documents Department

Experimental database and design concept for a 1-MW, 200-keV neutral-beam line based on a SITEX negative ion source

Description: Scaling studies for a SITEX negative ion source to produce 200-keV, 10-A, long pulse D/sup -/ beams are under way at Oak Ridge National Laboratory (ORNL). Designs have been restricted to the use of established techniques and reasonably well-demonstrated scaling. The results show that the 1-A SITEX source can be directly scaled to produce 200-keV, 10-A long pulse ion beams with a source power efficiency of less than or equal to 5 kW of total plasma generator power per ampere of D/sup -/ beam generated. Extracted electron-to-D/sup -/ ratios should be less than or equal to 0.06, with all extracted electrons recovered at less than or equal to 10% of the first gap potential energy difference. The close-coupled accelerating structure will be 5 cm long and have five electrodes with 21 slits each, with a 50-kV/cm field in each gap.
Date: January 1, 1983
Creator: Dagenhart, W.K.; Gardner, W.L.; Stirling, W.L. & Whealton, J.H.
Partner: UNT Libraries Government Documents Department

Neutral-particle-beam production and injection

Description: This paper is divided into two sections: the first is a discussion of the interactions of neutral beams with confined plasmas, the second is concerned with the production and diagnosis of the neutral beams. In general we are dealing with atoms, molecules, and ions of the isotopes of hydrogen, but some heavier elements (for example, oxygen) will be mentioned. The emphasis will be on single-particle collisions; selected atomic processes on surfaces will be included.
Date: July 1, 1982
Creator: Post, D. & Pyle, R.
Partner: UNT Libraries Government Documents Department

Plasma neutralizers for H/sup -/ or D/sup -/ beams

Description: Plasma neutralizers can produce higher conversion efficiencies than are obtainable with gas neutralizers for the production of high-energy neutral beams from negative hydrogen ions. Little attention has been paid to experimental neutralizer studies because of the more critical problems connected with the development of negative-ion sources. With the prospect of accelerating ampere dc beams from extrapolatable ion sources some time next year, we are re-examining plasma neutralizers. Some basic considerations, two introductory experiments, and a next-step experiment are described.
Date: October 1, 1980
Creator: Berkner, K.H.; Pyle, R.V.; Savas, S.E. & Stalder, K.R.
Partner: UNT Libraries Government Documents Department

Volume production of negative ions in the reflex-type ion source

Description: The production of negative hydrogen ions is investigated in the reflex-type negative ion source. The extracted negative hydrogen currents of 9.7 mA (100 mA/cm/sup 2/) for H/sup -/ and of 4.1 mA(42 mA/cm/sup 2/) for D/sup -/ are obtained continuously. The impurity is less than 1%. An isotope effect of negative ion production is observed.
Date: June 1, 1982
Creator: Jimbo, K.
Partner: UNT Libraries Government Documents Department

High energy negative deuterium beams using double charge-exchange or surface production

Description: Experimental and theoretical research on production of negative ion beams is described. Results from a double charge-exchange experiment include 10 ms pulses of 100 ma of D/sup -/ accelerated to 60 kV. Equilibrium fractions of D/sup -/ in several metal vapors are presented. Mechanisms and measurements of D/sup -/ on surfaces are described, and a scheme is shown for producing high current, high energy beams originating on surfaces.
Date: November 29, 1977
Creator: Hooper, E.B. Jr.; Anderson, O.A.; Orzechowski, T. & Poulsen, P.
Partner: UNT Libraries Government Documents Department

Technology of neutral-beam injection based on positive-ion sources

Description: Advances made in each of the following areas are summarized: (1) long pulse plasma sources, (2) the arc discharge, (3) the atomic species, (4) impurities, (5) accelerator development, (6) beam line components, and (7) the role of positive-ion-based injection systems for reactor-size devices. (MOW)
Date: January 1, 1983
Creator: Menon, M.M.
Partner: UNT Libraries Government Documents Department

Improvement of gas efficiency of negative ion sources

Description: A modification of the currently operating Calutron, magnetron, and modified duoPIGatron negative ion source is proposed. The modification should improve gas efficiency by more than an order of magnitude in the Calutron, by a factor of 5 in the magnetron, and by a factor of 2 in the duoPIGatron.
Date: August 1, 1981
Creator: Whealton, J.H.
Partner: UNT Libraries Government Documents Department

BNL Neutral-Beam Development Group. Progress report FY 1981

Description: The Brookhaven High Energy Neutral Beam Development Group is developing injector systems, particularly for the next generation of fusion mirror and tokamak experiments. These injectors are based on the acceleration and neutralization of negative deuterium ions, to utilize their high neutralization efficiency which is nearly independent of energy above 50 keV/nucleon.
Date: January 15, 1982
Creator: Prelec, K. & Sluyters, T.
Partner: UNT Libraries Government Documents Department

Progress in the development of steady state negative ion sources for fusion applications

Description: During the past few years or so, the development of steady state sources of negative hydrogen or deuterium ions has made a substantial progress. There are several approaches under investigation, some operating with long pulses and some in a true steady state, and delivering H/sup -/ or D/sup -/ beam currents of several hundred mA up to 1 A. The improvement in the gas efficiency from a few percent for pulsed sources to the range of 5% to 15% and possibly even higher for the new sources, is another advance that was not anticipated only 4 to 5 years ago. A higher gas efficiency has come as the result of using independent plasma generation and geometrical focusing of surface produced negative ions. The power efficiency has not been changed so much, but, in a high energy system, savings of a few kW/A are less important than the reduction of the gas load. It can be expected that within five or so years a small (<1 MW) long pulse or steady state neutral beam system based on negative ions could be put into operation.
Date: January 1, 1982
Creator: Prelec, K.
Partner: UNT Libraries Government Documents Department

National negative-ion-based neutral-beam development plan

Description: The plan covers facilities required, program milestones, and decision points. It includes identification of applications, experiments, theoretical research areas, development of specific technologies and reactor development and demonstration facilities required to bring about the successful application of negative-ion-based neutral beams. Particular emphasis is placed on those activities leading to use on existing plasma confinement experiments or their upgrades.
Date: August 1, 1983
Creator: Cooper, W.S. & Pyle, R.V. (eds.)
Partner: UNT Libraries Government Documents Department

Neutralization of a fast negative-ion beam

Description: Neutralization of a fast negative-ion beam, primarily H/sup -/, is discussed in terms of competing one- and two-electron detachment processes in a variety of media: gas (vapor), plasma, liquid sheet, solid foil.
Date: January 1, 1986
Creator: Schlachter, A.S.; Mowat, J.R.; Stearns, J.W.; Gohil, P. & Pyle, R.V.
Partner: UNT Libraries Government Documents Department

Neutral beam production using negative ions

Description: Techniques for producing intense negative ion beams are discussed. These beams are required for intense neutral beam development at energies greater than 150 keV. Handling, acceleration, and stripping of negative ion beams are described.
Date: June 14, 1978
Creator: Hooper, E.B. Jr.
Partner: UNT Libraries Government Documents Department