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  • 1
    Electronic Resource
    Electronic Resource
    High current, low pressure plasma cathode electron gun (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 388-398 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A plasma-cathode electron gun based on a moderate pressure (〉5 mTorr) cold-cathode discharge and a high perveance, multiaperture accelerator was previously developed at Hughes Research Laboratories and produced electron beam currents of up to 1 kA at voltages of over 200 kV for pulse lengths of 100 μs. This gun was limited in pulse repetition frequency and duty by the gas-puff system that provided adequate gas pressure in the hollow cathode to operate the glow discharge while keeping the pressure in the beam transport region sufficiently low. We describe a new plasma cathode electron gun (PCE gun) that eliminates this problem by replacing the glow-discharge plasma generator in the electron gun by a low-pressure thermionic discharge in a magnetic multipole confinement chamber. Proper design of the plasma generator and electrical circuit provides high electron-current densities to the accelerator structure at very low gas pressure (〈10−4 Torr). The static gas pressure permits the pulse repetition frequency to be very high (〉1.5 kHz demonstrated) with electron beam currents up to 200 A at voltages up to 120 kV demonstrated. The design and performance of the PCE gun, along with several models used to predict and scale the performance, are discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150212
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    Paper (German National Licenses)
    Fulltext
  • 2
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    High current, low pressure plasma cathode electron gun (2000)
    American Institute of Physics
    Details
    Publication Date: 2000-02-01
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Published by American Institute of Physics
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    PAPER CURRENT
  • 3
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    Hollow cathode theory and experiment. I. Plasma characterization using fast miniature scanning probes (2005)
    American Institute of Physics
    Details
    Publication Date: 2005-12-01
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics
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    PAPER CURRENT
  • 4
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    Hollow Cathode and Keeper-region Plasma Measurements Using Ultra-fast Miniature Scanning Probes (2004)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: In order to support the development of comprehensive performance and life models for future deep space missions that will utilize ion thrusters, we have undertaken a study of the plasma structure in hollow cathodes using an new pneumatic scanning probe diagnostic. This device is designed to insert a miniature probe directly into the hollow cathode orifice from either the upstream insert region in the interior of the hollow cathode, or from the downstream keeper-plasma region at the exit of the hollow cathode, to provide complete axial profiles of the discharge plasma parameters. Previous attempts to diagnose this region with probes was Limited by the melting of small probes in the intense discharge near the orifice, or caused significant perturbation of the plasma by probes large enough to survive. Our new probe is extremely compact, and when configured as a single Langmuir probe, the ceramic tube insulator is only 0.5mm in diameter and the current collecting conductor has a total area of 0.002 cm2. A series of current-voltage characteristics are obtained by applying a rapid sawtooth voltage waveform to the probe as it is scanned by the pneumatic actuator into and out of the plasma region, The bellow-sealed pneumatic drive scans the probe 4 cm in the cathode insert region and 10 cm in the anode/keeper plasmas region at average speeds of about 1 mm/msec, and the residence time at the end of the insertion stroke in the densest part of the plasma near the orifice is measured to be only 10 msec. Since the voltage sweep time is fast compared to the motion of the probe, axial profiles of the plasma density, temperature and potential with reasonable spatial resolution are obtained. Measurements of the internal cathode pressures and the axial plasma-parameter profiles for a hollow cathode operating at discharge currents of up to 35 A in xenon will be presented.
    Keywords: Electronics and Electrical Engineering
    Type: 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Fort Lauderdale, Florida, July 11-14, 2004; Jul 11, 2004 - Jul 14, 2004; Fort Lauderdale, FL; United States
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    NASA TECHNICAL REPORTS
  • 5
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    Local Neutral Density and Plasma Parameter Measurements in a Hollow Cathode Plume (2006)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: In order to understand the cathode and keeper wear observed during the Extended Life Test (ELT) of the DS1 flight spare NSTAR thruster and provide benchmarking data for a 2D cathode/cathode-plume model, a basic understanding of the plasma and neutral gas parameters in the cathode orifice and keeper region of the cathode plume must be obtained. The JPL cathode facility is instrumented with an array of Langmuir probe diagnostics along with an optical diagnostic to measure line intensity of xenon neutrals. In order to make direct comparisons with the present model, a flat plate anode arrangement was installed for these tests. Neutral density is deduced from the scanning probe data of the plasma parameters and the measured xenon line intensity in the optical regime. The Langmuir probes are scanned both axially, out to 7.0 cm downstream of the keeper, and radially to obtain 2D profile of the plasma parameters. The optical fiber is housed in a collimating stainless steel tube, and is scanned to view across the cathode plume along cuts in front of the keeper with a resolution of 1.5 mm. The radial intensities are unfolded using the Abel inversion technique that produces radial profiles of local neutral density. In this paper, detailed measurements of the plasma parameters and the local neutral densities will be presented in the cathode/keeper plume region for a 1.5 cm diameter NEXIS cathode at 25A of discharge current at several different strengths of applied magnetic field.
    Keywords: Spacecraft Propulsion and Power
    Type: 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit; Jul 09, 2006 - Jul 12, 2006; Sacramento, CA; United States
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    NASA TECHNICAL REPORTS
  • 6
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    Hollow cathode and keeper-region plasma measurements (2005)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The successful performance of the NSTAR ion thruster in Deep Space 1 mission, coupled with the recently completed 30,032 hour life test of the flight spare thruster, has accelerated with the implementation of electric propulsion in NASA missions.
    Keywords: Spacecraft Propulsion and Power
    Type: AIAA Paper 2005-3667 , 41st AIAA Joint Propulsion Conference; Jul 10, 2005 - Jul 13, 2005; Tuscon, AZ; United States
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    NASA TECHNICAL REPORTS
  • 7
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    High current hollow cathodes for high power ion and hall thrusters (2005)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Deep space missions continue to demand higher power ion thrusters and Hall thrusters capable of providing higher thrust and longer life.
    Keywords: Spacecraft Propulsion and Power
    Type: 2005 AIAA Joint Propulsion Conference; Jul 10, 2005 - Jul 13, 2005; Tucson, AZ; United States
    Format: text
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    NASA TECHNICAL REPORTS
  • 8
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    Hollow cathode and thruster discharge chamber plasma measurements (2005)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Due to the successful performance of the NSTAR ion thruster in Deep Space 1 mission, coupled with the recently completed 30,352 hour extended life test (ELT) of the NSTAR flight spare thruster, ion thrusters have become a viable option for future NASA missions. In this paper, detailed measurements of the plasma parameters internal and external to the cathode will presented for the NSTAR cathode up to 13.1A of discharge current and for the NEXIS cathode up to 30A of discharge current.
    Keywords: Spacecraft Propulsion and Power
    Type: 29th International Electric Propulsion Conference; Oct 31, 2005 - Nov 04, 2005; Princeton, NJ; United States
    Format: text
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    NASA TECHNICAL REPORTS
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