Development of High Current-Density Cathodes With Scandia-Doped Tungsten Powders

Wang, Yiman; Wang, Jinshu; Liu, Wei; Zhang, Ke; Li, Ji

doi:10.1109/ted.2007.894602

Cited by 110 publications

(52 citation statements)

References 20 publications

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“…The results were excellent and seem to verify the Chinese claims. Close-spaced diode tests went up to 20 A/cm 2 , also with good results.…”

Section: Discussionmentioning

confidence: 89%

“…To this end, we obtained scandate cathodes from The Beijing Institute of Technology (BJUT) and tested them in closespaced diode format and in open-structure pierce gun testers. These latter devices were designed for loadings up to 100 A/cm 2 , and in fact, were tested to over 50 A/cm 2 during the course of the project. The results were excellent and seem to verify the Chinese claims.…”

Section: Discussionmentioning

confidence: 99%

“…The scandium oxide doped porous matrix is subsequently impregnated in the molten phase with 4:1:1 barium calcium aluminates to form the cathode. Important for the operation of the cathode the impregnant and scandium oxide particles are removed from the cathode surface by using water to a depth of several microns 2 . In operation nano particles of scandium oxide migrate to the surface by an as yet undetermined process along with the free barium.…”

Section: Sol-gel Processesmentioning

confidence: 99%

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Acquisition of Equipment for Research in Nanobiomedical Technologies

Adesida¹,

Cunningham²,

Ahmad³

et al. 2008

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“…The results were excellent and seem to verify the Chinese claims. Close-spaced diode tests went up to 20 A/cm 2 , also with good results.…”

Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Sol-gel Processesmentioning

confidence: 99%

See 1 more Smart Citation

Acquisition of Equipment for Research in Nanobiomedical Technologies

Adesida¹,

Cunningham²,

Ahmad³

et al. 2008

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“…This beam requires a cathode loading of about 30 A/cm 2 and cathode emission area of 100 µm×600 µm, when the beam compression of three-fold is chosen along the beam height. A rectangular emitting geometry with the height of 100 µm and the width of 600 µm is adapted as a planar emission surface of a scandate-doped dispenser (SDD) cathode of which diameter is 2.0 mm [15].…”

Section: Design Approachmentioning

confidence: 99%

Design of Sheet-Beam Electron Gun with Planar Cathode for Terahertz Devices

Srivastava

Wang

et al. 2009

J Infrared Milli Terahz Waves

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The design of a sheet-beam electron gun with planar cathode was made with the help of a three-dimensional electrostatic field solver that was capable of forming a sheet-beam of 19 mA at 12 kV. It uses one-dimensional three-fold beam cross-sectional area compression meets the specific requirement of a beam to be formed of height 30 µm and width 600 µm at the beam-waist position with over 100 A/cm 2 uniform current density and 0.068 π-mm-mrad emittance, typically, for 0.5 THz devices. A novel beam focusing electrode (BFE) provided with extended-corner rectangular-aperture geometry alleviating the commonly encountered sheet-beam formation problem with a gun that uses a conventional BFE, as well as it reduced beam emittance more than 50%. The practicability of the design was tested by the highvoltage, the thermal and structural analyses. Work has been initiated to test the performance of special high current scandate cathode using anode-aperture mapping.

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“…There are many remarkable advantages of scandate cathode compared with the ''M'' type cathode, i.e., the working temperature of scandate cathode can be reduced by 100-150°C, which is highly significant in vacuum electronic devices. It was found in previous work that the raw powder properties, for example morphology and particle size, greatly affected the emission property of the cathode [2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of scandia-doped tungsten powders prepared by a spray-drying method

2011

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Scandium oxide-doped tungsten powders were prepared by a new method of spray drying combined with two-step hydrogen reduction. The particle size of doped tungsten, powder morphology, and distribution of doped scandium oxide were characterized by scanning electron microscopy, X-ray diffraction, and laser diffraction particle size analysis. Experimental results indicated that the predecessor powders prepared by spray drying were spherical in shape. Two compounds, WO 3 and Sc 2 W 3 O 12 , in the raw powder calcined at 600°C were transformed into metallic tungsten and scandia after reduction at 850°C by hydrogen for 1 h. The scandia-doped tungsten powders obtained had an average size of 950 nm and scandium oxide was distributed evenly throughout the tungsten powder. The mechanism of reduction of the doped tungsten oxide is discussed in this paper.

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Development of High Current-Density Cathodes With Scandia-Doped Tungsten Powders

Cited by 110 publications

References 20 publications

Acquisition of Equipment for Research in Nanobiomedical Technologies

Acquisition of Equipment for Research in Nanobiomedical Technologies

Design of Sheet-Beam Electron Gun with Planar Cathode for Terahertz Devices

Preparation and characterization of scandia-doped tungsten powders prepared by a spray-drying method

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