Carbon and carbon-coated electrodes for multistage depressed collectors for electron-beam devices—A technology review

Curren, A. N.

doi:10.1109/t-ed.1986.22842

Cited by 28 publications

(15 citation statements)

References 5 publications

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“…The low porosity, low vapor pressure, low secondary electron emission characteristics, and high temperature capabilities of pyrolytic graphite make this material very attractive for demanding vacuum electronics applications [55]. The anisotropies of the thermal conductivity and thermal expansion play a particularly useful role in fabricating unique electron device components.…”

Section: A Manufacture Structure and Properties Of Pyrolytic Graphitementioning

confidence: 99%

“…Pyrolytic graphite has a number of desirable properties for application in multistage depressed collectors [55], [57]. Compared to oxygen-free-high-conductivity (OFHC) copper, it has a much higher thermal emissivity and elevated temperature capability.…”

Section: B Pyrolytic Graphite Collector Electrodesmentioning

confidence: 99%

“…These lower frequency results led to a successful effort to develop a 20-GHz frequency-range TWT employing ion-textured pyrolytic graphite depressed collectors [60]. Multistage depressed collectors employing pyrolytic graphite have been utilized in selected high-power TWT's manufactured for broadcasting satellites [55], [61].…”

Section: B Pyrolytic Graphite Collector Electrodesmentioning

confidence: 99%

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Applications of advanced materials technologies to vacuum electronic devices

Calame

Abe

1999

Proc. IEEE

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Section: A Manufacture Structure and Properties Of Pyrolytic Graphitementioning

confidence: 99%

Section: B Pyrolytic Graphite Collector Electrodesmentioning

confidence: 99%

Section: B Pyrolytic Graphite Collector Electrodesmentioning

confidence: 99%

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Applications of advanced materials technologies to vacuum electronic devices

Calame

Abe

1999

Proc. IEEE

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“…Aside from early efforts in surface texture development to control SEE [17,18], the use of advanced characterization and new processing techniques to develop microarchitected surfaces and experimentally determine the reduction in SEE yield is relatively recent [19][20][21]. There are now numerous examples of successful designs that are seen to lower the secondary electron yield [19,[22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo raytracing method for calculating secondary electron emission from micro-architected surfaces

Alvarado

Chang

Nadvornick

et al. 2019

Applied Surface Science

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Secondary electron emission (SEE) from inner linings of plasma chambers in electric thrusters for space propulsion can have a disruptive effect on device performance and efficiency. SEE is typically calculated using elastic and inelastic electron scattering theory by way of Monte Carlo simulations of independent electron trajectories. However, in practice the method can only be applied for ideally smooth surfaces and thin films, not representative of real material surfaces. Recently, micro-architected surfaces with nanometric features have been proposed to mitigate SEE and ion-induced erosion in plasma-exposed thruster linings. In this paper, we propose an approach for calculating secondary electron yields from surfaces with arbitrarily-complex geometries using an extension of the ray tracing Monte Carlo (RTMC) technique. We study nanofoam structures with varying porosities as representative micro-architected surfaces, and use RTMC to generate primary electron trajectories and track secondary electrons until their escape from the outer surface. Actual surfaces are represented as a discrete finite element meshes obtained from X-ray tomography images of tungsten nanofoams. At the local level, primary rays impinging into surface elements produce daughter rays of secondary electrons whose number, energies and angular characteristics are set by pre-calculated tables of SEE yields and energies from ideally-flat surfaces. We find that these micro-architected geometries can reduce SEE by up to 50% with respect to flat surfaces depending on porosity and primary electron energy.

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“…A steep gradient in applied magnetic field near the voltage gap before the depressed collector-electrode, together with space charge, impart transverse deflection to beam electrons and provide trapping of electrons against leaving the collector [2]. While the known best practices in designing of depressed collectors [3][4][5][6][7][8][9][10] are used, the aforementioned key features set this collector aside from its predecessors, and are the core of the proposed collector novelty.…”

Section: Introductionmentioning

confidence: 99%

Partially–grounded depressed beam collector for the O-MBK and beyond

Jiang¹,

Teryaev²,

Shchelkunov³

et al. 2017

AIP Conference Proceedings

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Abstract. To address RF source inefficiency, we present a design of an L-band multi-beam klystron with a new type of depressed collector. It comprises a grounded element, a magnetic lens, and an electrode held at negative potential. This collector allows recovery of a larger portion of energy in the spent electron beams than could a conventional depressed collector, and will increase the tube efficiency towards 80 % in a single stage.

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Carbon and carbon-coated electrodes for multistage depressed collectors for electron-beam devices—A technology review

Cited by 28 publications

References 5 publications

Applications of advanced materials technologies to vacuum electronic devices

Applications of advanced materials technologies to vacuum electronic devices

Monte Carlo raytracing method for calculating secondary electron emission from micro-architected surfaces

Partially–grounded depressed beam collector for the O-MBK and beyond

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