Radiation Sensitive Vacuum Electronic Components and Devices

Eichmeier, Joseph

doi:10.1007/978-3-540-71929-8_3

Cited by 16 publications

(16 citation statements)

References 1 publication

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“…Han has performed analysis and simulations for the design of FWTWT taking space charge effects into account, i.e., the electron-electron interactions are considered, using the Pierce's theorem [7]. Pierce theorem combines the Eulerian view of the electron beam with the replacement of the delay line as propagation structure by an equivalent transmission line model consisting of distributed inductances, L and capacitances, C [16,34]. However, Park has not studied the effect of the gain of the FWTWT using Madey's theorem.…”

Section: Gain Of Fwtwt Using Madey's Theoremmentioning

confidence: 99%

The Analytical Design of a Folded Waveguide Traveling Wave Tube and Small Signal Gain Analysis Using Madey's Theorem

Malek

2009

PIER

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Abstract-We are developing an analytical model for the design of the folded waveguide traveling wave tube (FWTWT). This analytical model provides the physical view for rapid design optimization of the FWTWT. The design and analysis of the FWTWT using the spatial harmonics method of the TE 10 mode of the EM wave are presented. An X-band FWTWT is used to verify this method. The normalized dispersion and beam line equations are used to simplify the design process so that the FWTWT can be designed to operate at any desired frequency. The small signal gain of an FWTWT is calculated by using Madey's theorem. The results of this analysis are compared with the numerical single particle simulation carried out using MATLAB. The results are in excellent agreement. The Madey's theorem can be used to provide a potential indication of the gain magnitude of the FWTWT.

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Section: Gain Of Fwtwt Using Madey's Theoremmentioning

confidence: 99%

The Analytical Design of a Folded Waveguide Traveling Wave Tube and Small Signal Gain Analysis Using Madey's Theorem

Malek

2009

PIER

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“…The key indicators of thruster performance, thrust T, total efficiency η t , and specific impulse I sp , are used to determine the performance of the downscaled CFT in comparison to similar propulsion devices. Starting with the basic relations of spacecraft propulsion thrust T equating with force on a charged particle in an electric field, specific impulse I sp and power P a [2,10,16].…”

Section: Methodsmentioning

confidence: 99%

“…The magnetic field strength B is chosen such that the Larmor radius of the electrons is much smaller than the inner geometry of the discharge chamber. This effectively confines the electrons to the center of the engine that in turn helps to electrostatically confine the ions, of which the magnetic field has little effect upon as the mean free path of the ion is significantly smaller than its gyro radius and is not considered magnetized [10]. Ions that escape this confinement contribute to an overall positive charge of the chamber wall and therefore an enhancement of ion beam formation [11].…”

Section: Introductionmentioning

confidence: 99%

High Fidelity Multi-Objective Design Optimization of a Downscaled Cusped Field Thruster

Fahey

Muffatti²,

Ogawa

2017

Aerospace

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The Cusped Field Thruster (CFT) concept has demonstrated significantly improved performance over the Hall Effect Thruster and the Gridded Ion Thruster; however, little is understood about the complexities of the interactions and interdependencies of the geometrical, magnetic and ion beam properties of the thruster. This study applies an advanced design methodology combining a modified power distribution calculation and evolutionary algorithms assisted by surrogate modeling to a multi-objective design optimization for the performance optimization and characterization of the CFT. Optimization is performed for maximization of performance defined by five design parameters (i.e., anode voltage, anode current, mass flow rate, and magnet radii), simultaneously aiming to maximize three objectives; that is, thrust, efficiency and specific impulse. Statistical methods based on global sensitivity analysis are employed to assess the optimization results in conjunction with surrogate models to identify key design factors with respect to the three design objectives and additional performance measures. The research indicates that the anode current and the Outer Magnet Radius have the greatest effect on the performance parameters. An optimal value for the anode current is determined, and a trend towards maximizing anode potential and mass flow rate is observed.

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“…Table 4. Averages and standard deviations of collected literature values for outgassing rates of various common vacuum materials after different treatments (unbaked unless otherwise stated) [37][38][39][40][41][42][43][44][45][46], N/A for standard deviation indicates that only a single literature value was found for a particular material…”

Section: Net Outgassingmentioning

confidence: 99%

A Review of Outgassing and Methods for its Reduction

Grinham

Chew

2017

Appl. Sci. Converg. Technol.

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There are several contributions to the gas load of a system of which often the most important is outgassing. Adsorption occurs via two main processes, physisorption and chemisorption, and can be described using five (or six) classifying isotherms. Outgassing is the result of desorption of previously adsorbed molecules, bulk diffusion, permeation and vapourisation. Looking at the desorption rate, pumping speed and readsorption on surfaces, the net outgassing of the system can be calculated. There is significant variation in measured outgassing rates between different materials but also between published rates for the same materials, in part due to the number of different methods used to measure outgassing. This article aims to review the outgassing process, outgassing rates, measurement methods and techniques that can be used to reduce the outgassing of a system.

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Radiation Sensitive Vacuum Electronic Components and Devices

Cited by 16 publications

References 1 publication

The Analytical Design of a Folded Waveguide Traveling Wave Tube and Small Signal Gain Analysis Using Madey's Theorem

The Analytical Design of a Folded Waveguide Traveling Wave Tube and Small Signal Gain Analysis Using Madey's Theorem

High Fidelity Multi-Objective Design Optimization of a Downscaled Cusped Field Thruster

A Review of Outgassing and Methods for its Reduction

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