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  • 1
    Electronic Resource
    Electronic Resource
    Negative ion production in multicusp sources (2002)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1746-1751 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The study of negative ion production in the multicusp negative ion sources (MS) was done by the directed deposition of well-defined amount of cesium into MS, by the cesium recovery from the polluted layers in the MS and by the plasma grid masking. The data obtained evidences the surface-plasma mechanism of negative ion production in the MS. It is shown that a dynamic cesium-tungsten coverage on a plasma grid surface provides the enhanced H− production in the MS. The Cs+W coverage is produced on the hot plasma grid surface due to coadsorption of cesium and of tungsten, evaporated from filaments. The permanent flux of cesium to plasma grid coverage is produced by the thick Cs+W reservoir with a high (75%) percentage of cesium on the cold anode surface. A relatively high cesium seed with a rate of about 20 mg/1 h/30 shots operation is necessary to support the increased H− production in the regular MS. Electrode processing by an additional discharge recovers the cesium from the aged coverage and enhances the H− production without an additional cesium seed. Recovery processing permits the use of deposited cesium more efficiently and to minimize cesium addition during the MS long-term operation. An essential decrease of cesium escape to accelerator and an improvement of injector high voltage operation is produced by introducing the shutter mask at plasma grid surface. The shutter mask experiment displayed, that 〉60% of H− beam current was born on the hot shutter mask surface. The source operation with a high negative shutter mask biasing and an increased hydrogen pressure resulted in a 35% higher H− yield, than of regular MS. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1461875
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  • 2
    Electronic Resource
    Electronic Resource
    Negative hydrogen ion production in multicusp volume source with a pulsed discharge (abstract)a) : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 993-993 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The pulsed operation of a negative ion volume source has been investigated, both with a magnetic filter present and without it, under conditions of full-scale acceleration of the extracted negative hydrogen ion beam. We report the observation of three afterglow negative ion peaks. As the negative ion current during the discharge pulse, each of the afterglow peaks can be optimized by varying the pressure, the plasma electrode bias and the extraction voltage. Under optimum conditions, the negative ion current during the discharge pulse exceeds the afterglow peaks. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146794
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  • 3
    Electronic Resource
    Electronic Resource
    Multiampere negative ion source development at Novosibirsk (invited) : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1108-1113 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Results on multiampere negative ion (NI) sources with a surface-plasma mechanism of negative ion production are presented. Several types of surface-plasma sources (SPS)—Honeycomb semiplanotrons and hollow-cathode Penning source—are reviewed. The data on SPS H−(D−) production with average NI current density in the beam up to 0.1 A/cm2 is presented. The properties of high-current glow hydrogen–cesium discharge that produces a large-area, thin layer of plasma and provides the necessary components for intense negative ion emission and collecting (low work function coverage, electric and magnetic field distribution across the plasma, current composition to NI emitter) are analyzed. Data on efficiency and contribution of different channels of surface-plasma NI production are presented. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146652
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  • 4
    Electronic Resource
    Electronic Resource
    Hydrogen negative ion source with LaB6 inserts : The 8th international conference on ion sources (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 1079-1081 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The compact negative ion source having a semiplanotron discharge geometry and the two independently heated LaB6 cathode inserts was developed and studied. The hot LaB6 cathode insert supports discharge ignition and operation at low hydrogen pressure, while the cold one provides the glow discharge concentration in its vicinity. The stable production of H− beams with the current density in the emission hole in the range of about 0.1 A/cm2 was obtained in the pure hydrogen discharge. Negative ion yield at the different parts of the composite source cathode was measured. It was maximal in the glow region. An enhanced H− yield was recorded due to discharge concentration near the LaB6 inserts. LaB6 with a decreased work function does not produce a sizable income of surface-produced negative ions to the beam, extracted from the pure hydrogen discharge. The use of LaB6 inserts as a reliable source of electrons to form the discharge simplifies the surface-plasma source use. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150390
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  • 5
    Electronic Resource
    Electronic Resource
    Study of pulsed discharge operation of volume H− ion source : Proceedings of the 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1207-1209 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The pulsed operation of a negative ion volume source has been investigated, both with and without a magnetic filter present, under conditions of full-scale acceleration of the extracted negative hydrogen ion beam. This investigation is relevant to the temporal filter concept, which was recently proposed. The observation of three afterglow negative ion peaks is reported. As the negative ion current during the discharge pulse, each of the afterglow peaks can be optimized by varying the pressure, the plasma electrode bias, and the extraction voltage. Under optimum conditions, the negative ion current during the discharge pulse exceeds the afterglow peaks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145059
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  • 6
    Electronic Resource
    Electronic Resource
    Negative hydrogen ion production in the hollow cathode Penning surface-plasma source (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 417-425 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A small hollow cathode Penning surface-plasma source (SPS) was developed and studied. The H− yield was proportional to the emission apertures area and increased over a wide range of discharge current. The H− yield, with an intensity of up to 0.95 A and an emission current density of up to 3.6 A/cm2, was obtained in a pulsed mode. With the discharge current of 20 A and a pulse duration of 60 s, an H− yield with current of 0.1 A was obtained. The H− emission current density had approximately the same value for various diameters (0.5–7 mm) and thicknesses (0.3–4.0 mm) of cylindrical emission holes, if the thickness of hole walls did not exceed the hole diameter. The H− yield extracted through the thick conical emission holes had a value 25% higher than that for a thin cylindrical hole with the same permeable diameter. Dependencies of the H− yield versus magnetic field and hydrogen feed were different from that of the standard Penning SPS. The optimal cesium coverage of the electrodes was stable for both high-current, long-pulse and low-current, dc source operation. Noticeable H− production was realized with a low-discharge voltage of 15 V. The heavy negative ions fraction was less than 1% of total negative ion yield for long-pulse operation. The yield of D− ions from deuterium discharge had a value 15% lower than that of H− ions from the hydrogen discharge. Most of the extracted H− ions are produced by conversion of fast and superthermal (E(approximately-greater-than)1 eV) atoms on the cesiated surfaces of the emission hole cones or they are due to the resonant charge exchange of anode-produced H− ions in the volume adjacent to the emission apertures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145149
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  • 7
    Electronic Resource
    Electronic Resource
    Recovery of cesium in the hydrogen negative ion sources : The 8th international conference on ion sources (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 741-743 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Cesium recovery from the polluted layers in the 1/3 scale hydrogen negative ion source for LHD-NBI system has tested. It was found that the cesium recovery can be produced by additional discharges as from the cesium layer, aged by tungsten and residual gas, so as from the cesium layers, polluted by an occasional water leak. The highest cesium recovery to negative ion production was produced by a xenon arc, while glow discharge and arcing in hydrogen were less effective. The mechanism of recovery is the ejection of cesium from the underlying enriched layer by the arc and its transport to the surface. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150280
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  • 8
    Electronic Resource
    Electronic Resource
    Surface-plasma sources with an intense cathode and anode productions of negative ions : Proceedings of the 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1179-1181 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Two types of the surface-plasma sources of negative hydrogen ions developed at Budker Institute of Nuclear Physics are discussed. The source characteristics and the mechanism of negative ion production are presented. It is shown that several channels of plasma particle surface conversion and desorption are responsible for an intense negative ion production in these sources. The results of a detailed study of the quasistationary honeycomb and its comparison with the data for hollow-cathode Penning sources are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145050
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  • 9
    Electronic Resource
    Electronic Resource
    Compact hollow cathode Penning surface-plasma sources for steady-state negative ion production : Proceedings of the 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1204-1206 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact steady-state negative ion source using a hollow cathode Penning discharge is described. Water-cooled gas-discharge electrodes and permanent Sm-Co magnets were used. Steady-state source operation with a H− beam current intensity of up to 50 mA and discharge power of up to 0.8 kW was achieved. The H− current density in the emission holes was about 50 mA/cm2. The gas efficiency was 3%. The H− yield was proportional to the area of the emission apertures and to the discharge current. About 10 mA of H− beam was accelerated and transported with the source having a smaller emission hole area of 0.3 cm2 in the tests at the Ecole Polytechnique accelerator facility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145058
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  • 10
    Electronic Resource
    Electronic Resource
    Cesiated hollow cathodes in the multicusp ion source : Papers from the Ninth International Conference on Ion Sources (2002)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 940-942 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A cesiated hydrogen hollow cathode (CHC) was tested for plasma injection in the multicusp negative ion source (MS). The CHC arc with hydrogen feed and cesium seeding through the CHC volume was explored. One cathode unit (40 mm length, 19 mm in diameter, emission opening area 1–3 mm2) with no special cooling provided the MS discharge operation with direct current up to 30 A, and up to 60 A in the long-pulse mode. High efficiency of negative ion production in the MS discharge, driven by a CHC plasma injection was recorded. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1428786
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