Preparation of impregnated barium scandate cathode and its application

Jiang, Dingjian; Hong, Sikong; Zhou, Chenfeng; Wang, De’an; Liu, Xueque

doi:10.1109/ivesc.2004.1414199

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…Given the spatial distribution of Ba-containing material deposited on the anode, a crude estimate of the mass deposited on the anode can be made. Approximating the deposited volume as a uniform, 100% dense, 5 µm thick layer of pure BaO (the densest species potentially present, ρ = 5.72 g/cm 3 ) within the primary deposition region (2 mm diameter) yields an estimate of~0.05 mg of deposited mass. This is likely an overestimate of the amount of deposited material as it ignores porosity in the deposited layer, assumes the deposited material is the most dense of likely species, and neglects potential thinning of the deposited layer towards the edges of primary deposition region.…”

Section: Implications Of Anode Depositsmentioning

confidence: 99%

“…Thermionic cathodes are electron sources used in a wide range of vacuum electron devices (VEDs) critical to both military and civilian applications. Examples include devices based on RF amplifying traveling wave tubes-satellite communication systems and military/civilian RADAR applications [1]), miniature thermionic diodes [2], and more [3,4]. To meet increasing demand, high-power cathodes are being sought for THz or mm-wave devices [5] operating beyond the crowded kHz, MHz, and GHz frequency ranges.…”

Section: Introductionmentioning

confidence: 99%

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Desorption from Hot Scandate Cathodes: Effects on Vacuum Device Interior Surfaces after Long-Term Operation

2020

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Scandate cathodes have exhibited superior emission properties compared to current state-of-the-art “M-type” thermionic cathodes. However, their integration into vacuum devices is limited in part by a lack of knowledge regarding their functional lifespan and behavior during operation. Here, we consider thermal desorption from scandate cathodes by examining the distribution of material deposited on interior surfaces of a sealed vacuum device after ~26,000 h of cathode operation. XPS, EDS, and TEM analyses indicate that on the order of 1 wt.% of the initial impregnate is desorbed during a cathode’s lifetime, Ca does not desorb uniformly with time, and little to no Sc desorbs from the cathode surfaces (or does so at an undetectable rate). Findings from this first-ever study of a scandate cathode after extremely long-time operation yield insight into the utility of scandate cathodes as components in vacuum devices and suggest possible effects on device performance due to deposition of desorption products on interior device surfaces.

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Section: Implications Of Anode Depositsmentioning

confidence: 99%