Investigation and application of impregnated scandate cathodes

Li, Ji; Yan, Suqiu; Shao, Wensheng; Chen, Qilue; Zhu, Min

doi:10.1016/s0169-4332(03)00273-3

Cited by 25 publications

(4 citation statements)

References 3 publications

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“…Due to the high demands in reproducibility, the application of the top-layer scandate cathode is limited. To our knowledge, only the impregnated scandate cathode, in which Sc 2 O 3 was added to the barium calcium aluminate impregnant, was employed in some commercial devices [33,34].…”

Section: Top-layer Scandate Cathodementioning

confidence: 99%

A review on scandia doped tungsten matrix scandate cathode

et al. 2019

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As the cathode with the highest electron emission capability in the thermionic cathode, the scandate cathode has attracted more and more attention in recent years, especially the scandia doped tungsten matrix scandate cathode. Experimental studies show that scandia doped tungsten matrix scandate cathodes with submicron microstructures exhibit excellent emission capacity, and the pulse emission current density in the space-charge region can be over 35 A cm −2 at 850 °C b. In the direct current (DC) condition with temperature compensation, the emission current density could reach 25 A cm −2 at 850 °C b. The device lifetime is over 3700 h after operating at 950 °C b with the DC loading of 40 A cm −2. The emission mechanism of the scandate cathode including the effect of the surface structure and composition on the work function of the cathode are systematically reviewed.

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Section: Top-layer Scandate Cathodementioning

confidence: 99%

A review on scandia doped tungsten matrix scandate cathode

et al. 2019

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“…Li and his colleagues at the Beijing Vacuum Electronics Research Institute (BVERI) studied scandate cathodes with emphasis on the sacandia-doped dispenser (SDD) cathodes [6][7][8]. The CLTV tests conducted at SLAC on BVERI cathodes demonstrated current density ~ 100 A/cm 2 for 500 hours for the cathode operation temperature of 1170 o C b in a Pierce gun configuration.…”

Section: High Current Density Cathodesmentioning

confidence: 99%

MM-wave to THz vacuum electron beam devices

Baig

Gamzina

Zhao

et al. 2012

2012 Asia Pacific Microwave Conference Proceedings

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MM-wave to THz vacuum electron beam device (VED) technology has substantial potential to bridge the socalled "THz gap" for high impact applications including nonintrusive detection of contraband items/explosives, > 10 Gbit/s wireless advanced communication systems, medical imaging/ diagnostics, and all weather visibility for civil aviation safety to name a few. Recent progress on the development of MM-waveTHz coherent source technology with adequate power, bandwidth, and efficiency in a compact mobile package is briefly reviewed. Two enabling technologies: high current emission density scandate cathodes and novel micro/nano-fabrication schemes are also highlighted. In this context, the UCD efforts on the development of a 0.22 THz Sheet Beam Traveling Wave Tube Amplifier (SBTWTA) are also summarized.

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“…Consequently, scandate cathode technology has received significant attention over recent decades. Various scandate cathodes have been developed, including impregnated [24,25,26], pressed [27,28], and top-layered types [29,30,31]. Of these, scandate cathodes fabricated from starting powders of micron-scale tungsten (W) and nanoscale scandia (Sc 2 O 3 ) are reported to exhibit the most promising emission characteristics and have been widely investigated.…”

Section: Introductionmentioning

confidence: 99%

Near-Surface Material Phases and Microstructure of Scandate Cathodes

et al. 2019

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Scandate cathodes that were fabricated using the liquid-solid process and that exhibited excellent emission performance were characterized using complementary state-of-the-art electron microscopy techniques. Sub-micron BaAl2O4 particles were observed on the surfaces and edges of tungsten particles, as seen in cross-section samples extracted from the scandate cathode surface regions. Although several BaAl2O4 particles were observed to surround smaller Sc2O3 nanoparticles, no chemical mixing of the two oxides was detected, and in fact the distinct oxide phases were separately verified by chemical analysis and also by 3D elemental tomography. Nanobeam electron diffraction confirmed that the crystal structure throughout W grains is body-centered cubic, indicating that they are metallic W and did not experience noticeable changes, even near the grain surfaces, as a result of the numerous complex chemical reactions that occur during cathode impregnation and activation. 3D reconstruction further revealed that internal Sc/Sc2O3 particles tend to exhibit a degree of correlated arrangement within a given W particle, rather than being distributed uniformly throughout. Moreover, the formation of Sc/Sc2O3 particles within W grains may arise from W surface roughening that occurs during the liquid-solid synthesis process.

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Investigation and application of impregnated scandate cathodes

Cited by 25 publications

References 3 publications

A review on scandia doped tungsten matrix scandate cathode

A review on scandia doped tungsten matrix scandate cathode

MM-wave to THz vacuum electron beam devices

Near-Surface Material Phases and Microstructure of Scandate Cathodes

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