A cathode-ray switch tube with 11 channels of electron multiplication

An 11-channel switch tube with 5 stages of electron multiplication has been developed. In some applications the switch tube will replace the camera-oscilloscope system for recording the rise times of electrical signals. This tube will be used to convert wide-band information from a single channel into eleven channels of lower bandwidth information which can be transmitted over standard telephone cables for telemetering operations. Venetian-blind dynodes are used for the multiplier structure. Each channel is defined by a pair of louvers on the dynode disk. U-shaped shields, which just straddle the louver edge of the preceding dynode, are used to minimize crosstalk. The channel width is 0.120 inch or a total length of 1.32 in for the 11 channels. The collector system provides a method for equalizing the gain of all the channels. The switch tube is 3 in in diameter and 24 in in length. Operating at a 4-kv beam potential with 2-µa beam current, the tube provides 20 ma of output current, with less than 5 per cent crosstalk to adjacent channels. The electron optics and the performance of the tube are described.     

A new type of cathode-ray tube with a crossed-field gun

This paper introduces a new type of cathode-ray tube with a crossed-field electron gun which produces an electron beam in a region where a nonuniform magnetic field and an electric field cross perpendicularly. The new configuration gives increased freedom in the design of crossed-field guns. As a result, a long, directly heated cathode can be readily applied to a gun structure which makes high perveance and instant operation possible with much improved cathode heating efficiency. The new gun provides ion trap action by virtue of a magnetic field which separates ions from electrons due to the difference in their masses. A new type of cathode-ray tube using this gun not only demonstrates these features but also requires relatively low operational voltages for beam acceleration and control electrodes. The paper includes an analysis of electron motion in a crossed field with a nonuniform magnetic field. It also shows practical configuration of electrodes and current characteristics of the gun.     

A high-sensibility cathode-ray tube for millimicrosecond transients

A high-sensibility cathode-ray tube has been developed for the photographic recording of transients in the millimicrosecond region. The new cathode-ray tube uses a traveling-wave deflection system with magnetic focusing and attains a spot diameter of 0.001 inch. The first models have a sensibility of 0.026 volt/trace width and a writing speed of 10¹¹trace widths/second. Improved production models are expected to have sensibilities of less than 0.02 volt/trace width. In this particular application, sensibility in volts per trace width and writing speed in trace widths per second are the significant performance characteristics. Analysis of the dependency of these on several important parameters in the general cathode-ray tube design shows that the use of a much smaller spot and display than is conventional results in large gains in sensibility. Analysis also indicates that maximum sensibility is achieved with the deflection plates located in the lens region. Magnetic focusing is used to permit this optimum deflection plate location. To allow the choice of long plates with short effective transit time, a traveling-wave deflection system is employed. Postdeflection acceleration is introduced to obtain high writing speeds.     

Diocotron instability of the electron beam in the drift tube of a gyrotron

A cold fluid model is used to investigate instabilities associated with a velocity shear due to the self fields of a relativistic electron beam inside the beam tunnel of a gyrotron. General statements concerning the stability of an electron beam like the frequency and the growth rate are possible. The growth is expressed as a length that can be compared with the geometry in the gun-tube-resonator system.     

A high luminance high-resolution cathode-ray tube for special purposes

For those applications where light sources of high radiance or displays of high resolution are necessary, miniature cathode-ray tubes have been developed with monocrystalline luminescent screens. These newly developed screens consist of cerium-doped yttrium-aluminum garnet (YAG), epitaxially grown on commercially available YAG substrates; they have an excellent heat conductivity and are optically clear. The construction of the tube and its performance in two modes of operation are described. When the tube is operated with a continuous undeflected beam, the luminance of the spot is limited by thermal quenching of the phosphor material. Under these circumstances, the maximum luminance of 1.9 × 10⁸cd/m²(0.55 × 10⁸FTL or 4 × 10⁵W/m²sr) is reached at a power of 70 mW in a 3.5-µA 20-kV beam, focussed to a spot of 9 µm diameter. Equipped with appropriate deflection coils and scanned with an interlaced field of 575 active lines and 25-Hz repetition frequency, the tube can handle up to 20 W of beam power in a 12 × 16 mm²image area. In this mode, the luminance is limited by the design of the electron gun and the desired resolution. At 20 kV and 100 µA (i.e., at 7500 cd/m²) the tube has a half-intensity linewidth of 60 µm, which is equivalent to 500-TV limiting response lines in the same 12 × 16 mm²area.     

电子注偏心对共焦波导回旋行波管的影响

利用线性和非线性理论研究了电子注偏心对0.22 THz回旋行波管注波互作用的影响。基于色散方程研究了电子注偏心对线性增益、绝对不稳定性的起振电流和返波振荡的起振条件的影响。引入自洽非线性理论,分析了电子注偏心对输出功率和注波互作用效率的作用。同时,在考虑速度离散的情况下,研究了电子注质量对共焦波导注波互作用的影响。结果表明,电子注偏心会导致效率的降低。     

Frequency mixing in a relativistic electron beam

A theoretical analysis and an experimental study of millimeter wave generation by a fast wave interaction between a bunched electron beam and a transverse wave are reported in this paper. The technique appears to be practical for the generation of wavelengths as short as 1 to 2 mm. The experimental apparatus reported here converts power at a frequency of 9.17 Gc to power at a frequency of 39.71 Gc with an output power of 2 to 3 mw.     

Modeling a subterahertz traveling-wave tube with a slow-wave structure of the double grating type and a sheet electron beam

A traveling-wave tube of the millimeter range belonging to the short-wavelength region with a sheet electron beam and a slow-wave structure of the double grating type is studied. Its dispersion characteristics and coupling impedances for various spatial harmonics are calculated. The issues of design of the electron-optical system are discussed. The focusing of a sheet electron beam with a high current density by a uniform magnetic field is modeled.     

The problem of the formation of a cylindrical electron beam

Various forms of a solution to the problem of the formation of a cylindrical electron beam and the possibility of extending the approaches employed earlier to the more complicated cases of the formation of electron and electron-ion streams are discussed.     

Linear beam tube theory

This paper presents the basic theories underlying the principles of operation of linear beam tubes. These theories are more general than the previous ones because they can be applied equally well to all types of tubes using linear electron beams. The tube types will differ only in the rf circuits that are being used. Emphasis of the theories is placed on the fundamental equations involved rather than the analytic solutions of these equations. The concept of electromagnetic and hydrodynamic power flow is emphasized in the treatments. The purpose is to leave the details of the solution to the electronic computer that is now being adapted to this type of problem. To this end, the equations are only developed in such a way as to facilitate programming in the computer. To illustrate the use of the theory, the special cases of the traveling-wave tube in which a waveguide mode is continuously interacting with the beam, and the klystron tube in which the interaction takes place in a limited space, will be developed in more detail. To further avoid mathematical complexities, electron motion, limited to the longitudinal direction, will be emphasized, and only the small-signal case will be treated. However, sufficient fundamental ideas will be presented so that the extension to the cases involving transverse electron motions and the large signal operation can be easily accomplished.     

Studies of a magnetically compressed electron beam

An experimental investigation of the problem of magnetically compressing a perveance0.54 times 10^{-6}A/V^3/2beam is reported. The feasibility of magnetic compression is demonstrated by passing this beam, compressed in area by a factor of 1000, through a drift tube 0.014 inch in diameter and 1 inch long with 95 percent transmission. The success of the magnetic-compression technique rests on the hitherto unsuspected ability of the beam to damp out undulations and to lose its thermal structure within a relatively short distance. A semiempirical theory from which the field required to maintain the compressed beam can be calculated is also presented.     

The annealing of phosphorus-ion-implanted cadmium telluride by a pulsed electron beam

A pulsed electron beam of 10 µs FWHM has been successfully applied to anneal phosphorus-implanted CdTe. The sheet resistance drops to 6.3 × 10²Ω/ from nearly infinite for the As-implanted wafers as the irradiation intensity exceeds 9.2 J/cm². A p-type carrier concentration as high as 3 × 10¹⁸cm^-3has been reached as measured by the van der Pauw and Hall techniques.     

Eccentricity of the electron beam in a gyrotron cavity

Dependence of the coupling of the electron beam and RF field in a gyrotron cavity on eccentricity of the electron beam is studied.     

适用于Ka波段圆形电子注行波管的半圆形卷绕微带线慢波结构

提出了一种基于开槽介质基底的卷绕微带线慢波结构.由于金属曲折微带线印制在介质基底的半圆形槽中,这种卷绕微带线慢波结构非常适合圆形电子注行波管,从而使得采用这种新型慢波结构的行波管可以利用传统的周期永磁磁场进行聚焦.文章对提出的卷绕微带线慢波结构的色散特性,耦合阻抗,传输特性及注-波互作用进行了分析.和传统的平面微带线慢波结构相比,提出的卷绕微带线慢波结构具有更低的相速、更弱的色散和更高的耦合阻抗,从而使得其适合于低电压、宽频带、小型化的毫米波行波管.将同步电压及直流电流分别设置为6 550 V及0.1 A的情况下,基于该卷绕微带线慢波结构的Ka波段行波管在35 GHz处能够输出42.32 W的功率,对应增益为26.26 dB,且均匀聚焦磁场只需0.4 T.     

The Ubitron, a high-power traveling-wave tube based on a periodic beam interaction in unloaded waveguide

The Ubitron is a high-power traveling-wave tube which makes use of the interaction between a magnetically undulated periodic electron beam and the TE01mode in unloaded waveguide. The electron-wave interaction exhibits the same type of first-order axial beam bunching characteristic of the conventional slow-wave traveling-wave tube; hence, it can be used in place of conventional O-type interaction in extended interaction klystrons and electron accelerators, as well as traveling-wave tubes. Experimental results are presented for the simplest physical embodiment of the Ubitron, which consists of an undulated pencil beam in a rectangular waveguide. Two of the unique features of this tube are very broad interaction bandwidth which results from the absence of a dispersive slow-wave circuit, and variable interaction phase velocity--hence, variable saturation power level. Among the physical embodiments of the Ubitron are a number of higher-order mode waveguide and beam configurations. These include plane, coaxial, and circular waveguides, all supporting the TE01mode, interacting with magnetically undulated sheet, hollow and cylindrical beams, respectively. The advantage of these configurations, which have not yet been tested experimentally, is that they provide a very large interaction area for beam placement. This property, plus the fact that the peak interacting field is far from the waveguide walls, makes the Ubitron an interesting prospect for high-power millimeter wave amplification.     

Prebunched beam traveling-wave tube studies

A traveling-wave tube with a prebunched beam is found to have a considerably higher efficiency than the same tube without prebunching. For the particular tube tested the efficiency is increased from 20 to over 35 per cent at a gain of 8. Computer calculations using a discrete disk model give similar results. The beam is bunched tightly in energy at the position of highest efficiency, indicating that very high efficiency could be obtained with a depressed collector. Both current and velocity modulation are required for prebunching, and are obtained by means of a current grid followed by an inductively tuned velocity modulation cavity. The requirements of the current grid are not great so that operation should be possible at frequencies well above the normal operating region of a microwave triode. The operation of the tube is sensitive to the output match, and it appears to be difficult to obtain a good match with the beam on.