Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A large negative-ion source immersed in the vacuum vessel on the NBI test stand at the NIFS : Proceedings of the 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1192-1194 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: To develop the powerful negative-ion-based neutral beam injection system for the large helical device, a 1/3 scaled H− source has been tested, which is immersed in the vacuum vessel. Intrinsic features of the vacuum-immersed large H− source are described. Plasma density of higher than about 1012 e/cm3 is produced. During the beam extraction, it was found that a beam-induced thin plasma exists in the vacuum vessel. In order to get a long pulse beam, this plasma was shielded and then the beam conditioning was completed up to the total beam energy of 70 keV for 100 ms, with the arc power up to about 50 kW. It is confirmed that H− current scaling as well as the plasma parameters would be similar to the scaling which is achieved by the previous 1/3 source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145054
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    High-energy and high-current hydrogen negative-ion beam production with an external-filter-type large negative-ion source : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1021-1023 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A large hydrogen negative-ion source with an external magnetic filter has been developed for a neutral beam injection (NBI) system in the Large Helical Device (LHD), and a high-energy and high-current H− ion beam has been produced. The ion source is operated at a high arc efficiency of 0.1 A/kW at an operational gas pressure of less than 3.5 mTorr, and produces 47 keV–16.2 A of a H− ion beam from a grid area of 25 cm×50 cm. With two-stage acceleration, 13.6 A of a H− ion beam has been successfully accelerated to 125 keV. Multibeamlet focusing by the aperture displacement technique has been achieved 11.2 m downstream with a gross divergence angle of 9 mrad. The alternate beamlet deflection by the magnetic field at the extraction grid, which results in beam broadening in the deflection direction, was well compensated also by the aperture displacement technique. These results satisfy the specification of the negative-ion-based LHD–NBI system. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146744
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Energetic negative ion source for fusion at NIFS (invited) (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1114-1119 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Large high current hydrogen negative ion sources have been developed for the negative ion based neutral beam injector of the Large Helical Device (LHD) at NIFS. The prototype of the negative ion source is required to deliver a negative ion beam of 45 A at the beam energy of 125 keV. The optimization of 1/3 scale ion sources which are multicusp ion source with a rod and an external magnetic filter, respectively, has been investigated for the operation parameter of the plasma source. A total H− current of 16 A is extracted at an operating pressure of 0.9–0.45 Pa with Cs seeding operation. Negative hydrogen ion current is proportional to the input arc power and a beam current density of 45 mA/cm2 is attained. The beam extraction and acceleration characteristics are studied for a single-stage and a two-stage acceleration electrode. A beam divergence angle of 5 mrad is obtained. The results of research and development of a hydrogen negative ion source at NIFS will be reviewed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146854
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Development of an intense negative hydrogen ion source with an external magnetic filter (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 2541-2546 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An intense negative hydrogen ion source has been developed, which has a strong external magnetic filter field in the wide area of 35 cm×62 cm produced by a pair of permanent magnet rows located at 35.4 cm separation. The filter strength is 70 G in the center and the line-integrated filter strength is 850 G cm, which keeps the low electron temperature in the extraction region. Strong cusp magnetic field, 1.8 kG on the chamber surface, is generated for improvement of the plasma confinement. These resulted in the high arc efficiency at the low operational gas pressure. 16.2 A of H− ion current with the energy of 47 keV was obtained at the arc efficiency of 0.1 A/kW at the gas pressure of 3.8 mTorr in the cesium-mode operation. The magnetic field in the extraction gap is also strong, 450 G, for the electron suppression. The ratio of the extraction current to the negative ion current was less than 2.2 at the gas pressure of 3 mTorr. The two-stage acceleration was tested, and 13.6 A of H− ion beam was accelerated to 125 keV. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145655
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Acceleration experiments for an intense H− ion beam (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 5412-5418 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Intense H− beams have been extracted from a large multicusp plasma source operated with cesium seeding. The H− beams were accelerated up to 100 keV by a single-stage or a two-stage electrode system. Spatial profiles of the beams are measured calorimetrically and the beam divergence angle is obtained from half of the e-folding width. A minimum beam divergence angle of 5 mrads is achieved at a H− current density of 30 mA/cm2 with a beam energy of 100 keV. The ratio of acceleration current to H− current increases abruptly when a H− current saturates in the space charge limited region. This enhancement is mainly due to secondary electrons caused by the intersection of H− beams with an extraction grid. When the operating gas pressure decreases, the ratio of the acceleration current to the H− current decreases. This is related to a stripping loss of H− ions in the electrodes. A beam divergence angle reaches a minimum when a ratio of Vacc to Vext is set at an optimum value of 1.6 in the single-stage acceleration. This ratio is almost the same as that in the double-stage acceleration, where the optimum ratio of Eaccl/Eext is 1.5. In the optimum Eaccl/Eext ratio the divergence angle is not affected by Vacc2. The divergence angle can be reduced by changing Vacc2 even if the ratio of Eaccl/Eext is not optimized. The beam steering effect by permanent magnets buried in an extraction grid is observed in nine beamlets experiments. A simple calculation of a single particle trajectory gives a good approximation of the beam deflection angle. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146424
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Multibeamlet focusing of intense negative ion beams by an aperture displacement technique (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 5236-5243 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Multibeamlet focusing of an intense negative-ion beam has been performed using beamlet steering by aperture displacement. The apertures of the grounded grid were displaced as all 270 beamlets (18×15) in an area of 25 cm×26 cm are steered to a common point (a focal point) in both the two-stage and the single-stage accelerators. The multibeamlets were successfully focused and the e-folding half width of 10 cm was achieved 11.2 m downstream from the ion source in both accelerators. The corresponding gross divergence angle is 9 mrad. The negative-ion beamlets are deflected by the electron deflection magnetic field at the extraction grid and the deflection direction reverses line by line, resulting in the beam splitting in the deflection direction. This beamlet deflection was well compensated also using beamlet steering by the aperture displacement of the grounded grid. The beam acceleration properties related to the beam divergence and the H− ion current were nearly the same for both the two-stage and the single-stage accelerators, and were dependent on the ratio of the extraction to the acceleration electric fields. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146091
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    High current H− ion production in cesium seeded large ion sources : Proceedings of the 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1195-1197 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The characteristics of a large negative-ion source with external filter is investigated for the neutral-beam injection system in a large helical device. The magnetic cusp field is set up at almost the same strength as that in our well optimized 1/3 ion source with rod-type magnetic filter. An H− ion current of 5.2 A is extracted from the ion source with Cs seeding. The H− current corresponds to 19.7 mA/cm2, and the value is comparable to the current density obtained using the 1/3 scaled ion source with a rod-type magnetic filter at the same extraction voltage. In low operating pressure, the ion source with the external filter has a better performance on the extraction of H− ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145055
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A 100 keV operation of a large vacuum-immersed H− ion source : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1029-1031 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A large vacuum-immersed H− ion source has been operated on the negative-ion-based neutral beam teststand. The achieved level of the beam and the pulse duration in beam conditioning were limited by a high-voltage breakdown in the vacuum vessel. A baffle plate at grounded potential for shielding completely from the charged particles was successful. A beam with an energy of up to 102 keV and the H− ion current of 0.55 A were achieved for 0.29 s without the breakdown. The ion current of ∼1.5 A was accelerated in cesium-seeded operation. The corresponding ion current density was ∼7 mA/cm2. A magnetic filter (as Type I LV magnetic filter) on the plasma electrode was applied. The electron beam component which was extracted from the plasma source together with H− ions was found to be very reduced. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146747
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Beam extraction from a large vacuum-immersed negative-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. 1198-1200 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A large vacuum-immersed negative-ion source has been investigated for the development of the neutral beam injection system in a large helical device. The structure of the vacuum-immersed source is compact and light because it is free from atmospheric pressure. Therefore, this is very advantageous for a large-scaled ion source. Moreover, since the grids of the accelerator are supported by post insulators, enhanced pumping of gaps between grids is expected, leading to a reduction of stripping loss of negative ions. The gas pressure distribution between grids was calculated and the stripping loss of H− ions was estimated and the effectiveness of the vacuum-immersed source structure was confirmed. The gas temperature effect of the gas pressure distribution is also considered by using a Monte Carlo code.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145056
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Large current negative hydrogen ion beam production (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 1 (1994), S. 2813-2815 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Large current negative hydrogen ions are extracted from a multicusp ion source with an extraction area of 25×44 cm2. By seeding a small amount of cesium vapor into a source chamber, the H− current is enhanced to several times larger than that in a pure hydrogen discharge, accompanied by a reduction of the electron current and the filling gas pressure. A H− current up to 16 A is obtained with a beam energy of 40 keV from 560 extraction holes of 9 mm in diameter each, where the current density is 45 mA/cm2. The H− current increases linearly with the input arc power.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.870519
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...