Triode Design Research Articles

Advancements in ion diode and triode design

Selfconsistent laminar flow models, which enable to predict the optimal cathode and anode geometry in simple diodes, must be modified to account for the anode aperture and the effect of other electrodes. An equation for charge coupled to arbitrary laminar flows is here first presented and its numerical solutions are obtained with a new method, based on mesh transformations. It is found that a close match to theoretical flows requires an increase of the simple diode voltage v0 by an amount vδ, which, for a typical case designed for zero exit angle condition, are v0 = 0.7465 and vδ = 0.0294 in adimensional units. States "in" and "out" for the anode lens are also shown, where "out" is a new and nonlinear solution for the beam expansion in a drift tube.

Moderately converging ion and electron flows in two-dimensional diodes

Flow of particles in diodes is solved selfconsistently assuming an approximated system of flow lines, that can be easily represented by an analytic transformation in a complex plane, with assumed uniformity in the third spatial direction. Beam current compression is tunable by an angle parameter α(0); transformed coordinate lines are circular arcs, exactly matching to the curved cathode usually considered by rectilinear converging flows. The curvature of flow lines allows to partly balance the transverse effect of space charge. A self-contained discussion of the whole theory is reported, ranging from analytical solution for selfconsistent potential to electrode drawing to precise numerical simulation, which serves as a verification and as an illustration of typical electrode shapes. Motion and Poisson equation are written in a curved flow line system and their approximate consistency is shown to imply an ordinary differential equation for the beam edge potential. Transformations of this equation and their series solutions are given and discussed, showing that beam edge potential has a maximum, so supporting both diode (with α(0) =/~ π∕3) and triode design. Numerical simulations confirm the consistency of these solution. Geometrical details of diode design are discussed: the condition of a zero divergence beam, with the necessary anode lens effect included, is written and solved, as a function of beam compression; accurate relations for diode parameters and perveance are given. Weakly relativistic effects including self-magnetic field are finally discussed as a refinement.

Design of a Triodelike Electron Gun for Millimeter-Wave Gyrodevices

A computational study has been made on the design of a 150-kV triodelike switchable electron gun. A smooth magnetic cusp arrangement was used to produce an axis-encircling beam. Numerical optimization of this arrangement led to a gun design that produced beam parameters of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$I_{b} \sim \hbox{6}\ \hbox{A}$</tex></formula> , <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\alpha = \hbox{1.2}$</tex></formula> , and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$d\alpha \sim \hbox{15}\%$</tex></formula> . It has also been shown that this triode design can produce beam suppression at <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\sim$</tex></formula> 2 kV while not interfering with the beam parameters under operation conditions.

Thin diamond films for integrated circuits

We propose a technology for the synthesis of thin diamond films, which allows integrated emission elements of the vacuum triode type to be created on a substrate surface. The process includes three main stages: (i) deposition of a thin diamond film onto a silicon substrate; (ii) lithographic procedure with an aluminum mask; and (iii) post-growth in a regime ensuring required emission properties. An emission triode design is presented that can be realized using the proposed technology.

Modeling and fabricating micro-cavity integrated vacuum tubes

The authors discuss the modeling and fabricating miniature, vacuum, field-emission diodes and triodes for use in electronics in hazardous environments. They are micrometer-sized devices that are fabricated on a semiconductor wafer using integrated-circuit fabrication techniques and that use field emission rather than thermionic emission to generate charge carriers. Compared to existing semiconductor devices, they should be faster and much more tolerant of high temperatures and radiation. The device design uses the sacrificial layer technique to produce the device on a silicon wafer. All of the processing is completely compatible with existing integrated-circuit technology, making possible eventual integration of these devices and existing integrated-circuit components. To model these devices, the authors have used a static field modeling code to analyze the effect of device design variations on the field at the field-emission tip. Using these field results, they have calculated the tube's plate resistance, transconductance, gain, and current versus voltage characteristics. They have completed construction of a diode and are currently testing and interpreting the results. In addition, they have nearly completed a triode design.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Calculation of Characteristics and the Design of Triodes

The primary object of the paper is to present a simple method of designing triode vacuum tubes. It comprises three parts; the first part deals with the calculation of characteristics and constants of the triode from the electrode structures, special considerations being taken for applying the formulas already established for tubes of complicated structures. In the second part the derivation of various working conditions of a triode from its static characteristic is treated, in which the writer worked out a graphical representation of d-c and a-c components of the anode working current at various working voltages. The resulting dynamic characteristic diagram is applicable to any type of triodes in evaluating the working voltages, currents and powers, whether the tube be used as an amplifier, oscillator, or modulator. The third part presents the designing procedure for a typical case in which the use of the triode is indicated and its power output is given. First the working points are determined on the dynamic characteristic diagram so as to give the required working condition; then all the quantities arising in the operation are known in their relative amounts. The type of the tube is selected between the high-impedance type and the low-impedance one, which necessitates technical and economical considerations. Then all the quantities are known in numerical values and characteristics of the tube are determined. The electrode structures are calculated to give the required characteristics.