The circuit and collector designs for a highaverage power sband multiple beam klystron are presented. It was used as a local oscillator in some radar receivers and a modulator in microwave transmitters the 1950s and 1960s, but is now obsolete, replaced by semiconductor microwave devices. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. Other articles where two cavity klystron is discussed. Klystron multi cavity klystron, reflex klystron, working. Klystron, including the reflex and multicavity klystron. An eightcavity klystron has a large number of control elements, making it practically impossible to perform the tuning empirically. The multicell cavity can provide the higher power and the wider bandwidth, however there is a possibility to generate the self. The same method has been applied to tuning measurement of a. Comparison has been made with the results in normal triode operation and has shown a good agreement. Multi cavity klystron used as lowpower microwave amplifier efficient microwave tubes usually operate on the. Klystron power sources had then been investigated even at birmingham before the successful work on magnetron.
The electrons are originally accelerated to high velocity by a potential of several hundred volts and enter a narrow gap that forms part of a cavity resonator system see figure, where they are acted upon by a radiofrequency field, which causes a bunchingup effect. The traveling wave tube amplifier twta together with the klystron are. Cavity test has demonstrated the use of high power rf vector modulators to control multiple rf cavities driven by a single high power klystron to accelerate a nonrelativistic beam. Since all intermediate cavities in a multicavity klystron operate in the same manner, a. Pdf experimental study of complex dynamics in a delayed. Caryotakis, performance of a 150mw sband klystron, aip conf. The outstanding performance features of multibeam klystrons enabled the application of concepts of low power integrated circuits to high power complex microwave devices cmd. Stability analysis of a cband 500kw klystron with a. This year marks the 60th anniversary of the birth of the klystron at stanford university. The velocities of electrons emitted from the cathode are modulated to produce a densitymodulated electron beam. The heater boils off electrons when heated and the electrons are ejected from the cathode and accelerate towards the anode due to the high dc potential. The catcher grids are placed along the beam at a point where the bunches are fully formed.
Klystron switching power supplies for the international. Our klystron design with electrostatic focusing is light, inexpensive and amenable to volume production. It is given the name reflex klystron because of its reflex action of electron beam. Molecular and cell biology methods for fungi pdf free. Klystron works on the principle of velocity modulation of electrons. Highpower fourcavity sband multiplebeam klystron design. Multicavity klystron article about multicavity klystron. There are two cavities known as buncher and catcher cavity. A multicavity klystron is used in uhf tv transmitters, radar transmitter and satellite. Kotov fsue srpc istok, 141190, fryazino, russia abstract.
The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. Klystron, thermionic electron tube that generates or amplifies microwaves by controlling the speed of a stream of electrons. Figure 17 shows the arrangement of a multicavity klystron. A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form. High power microwave systems based on power combining and pulse compression of conventional klystrons have characteristics of high peak power, good stability and longterm operation with high repetition frequency.
Stability analysis of cband 500kw klystron with multi. A klystron in which there is at least one cavity between the input and output cavities, each of which remodulates the beam so that electrons are more. The basic electrode arrangement of a reflex klystron is given below. The klystron will be powered by the recently completed 41. Experimental study of complex dynamics in a delayedfeedback multiplecavity klystron selfoscillator article pdf available in technical physics 487. Ppt slac klystron lectures powerpoint presentation. Select multiple pdf files and merge them in seconds. Keywords klystron cavityr sh q 0, slaters perturbation technique, cylindrical reentrant cavity, perturbed frequency shift. Klystrons chapter microwave and rf vacuum electronic. Normally, multibeam klystrons are focused with powerful magnetic fields, but this type of focusing is complex, expensive and adds considerable weight and size to the device.
The initial set of scan parameters was obtained by benchmarking the e3762 klystron, and we are able to obtain optimized design parameters for a cavity system with better efficiency by adopting a multicell output cavity. Electrically, the operation of the planar triode is much more complicated at microwave frequencies than at low fre. Multiplebeam klystrons and their use in complex microwave devices e. Comsol conference 2015 grenoble multiphysics design of a klystron buncher.
With the signal applied in the first cavity, we get weak bunches in the second cavity. Amplification of such twocavity klystron is low and hence multicavity klystrons are used. Functional and schematic diagram of a twocavity klystron. The location is determined by the transit time of the bunches at the. In one case, a multicavity experimental klystron efficiency of 74 percent has been a result of such optimum bunching. The following figure depicts an example of multi cavity klystron amplifier. Microwave electronics because of the presence of the electron beam, this amplifier periodic structure can propagate both a growing wave and a decaying wave in the direction of electron flow. I am reading two cavity klystrons but not able to understand at all. The sixcavity test demonstrated acceleration of beam. Microwave engineering cavity klystron tutorialspoint. Wellknown technologies such as klystrons are being reinvented with.
Tuning measurement of multicavity klystrons in diode mode. Operation is similar to that of a klystronexcept that coupled cavity twts are designed with attenuation between the slowwave structure instead of a drift tube. Would you like to make it the primary and merge this question into it. The reflex klystron also known as a sutton tube after one of its inventors, robert sutton was a low power klystron tube with a single cavity, which functioned as an oscillator. Multiplebeam klystrons and their use in complex microwave. Firstly, as we know that klystrons are used as amplifiers for microwave frequency and conventional vaccum tubes cant be used due to interelectrode capacitance and lead inductance effect,but though microwave signals can be amplified by klystrons is there any limitation to.
Vaughan, an experimental clusteredcavity klystron, proceedings technical digest of the international electron devices meeting, washington dc, december 1987. The reflex klystron is an oscillator with a built in feedback mechanism. A reflex klystron consists of an electron gun, a cavity with a pair of grids and a repeller plate as shown in the above diagram. Microwave tubes perform the same functions of generation and amplification in the microwave portion of the frequency spectrum that vacuum tubes perform at lower frequencies. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. An alternative way of combining high power with low perveance is to use a sheet electron beam 7, 83, 84. The gain of both waves can be determined from the prototype of the periodic structure shown in fig. Klystron amplification, power output, and efficiency can be greatly improved by the addition of intermediate cavities between the input and output cavities of the basic klystron. We know that, since the tizard mission in the second half of 1940, both britain and us for their microwave radar programs relied. Klystron is a vacuum tube used for the amplification and generation of.
Alberto leggieri1, davide passi 1, franco di paolo, giovanni saggio1. Other articles where twocavity klystron is discussed. Presentation1 klystron electrical components force. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Ms purva sharma, assistant professor, biyani girls college explained about two cavity klystron. It is physically shorter than a klystron because of the absence of a multicavity. The main difference between two cavity reflex klystron amplifier. The power electronics include a 500 kv multiplier power supply, a 10 kv grid modulator, a multiconcentric high voltage cable and an advanced, reentrant interface between the cable and the klystron figure 1. The brothers russell and sigurd varian of stanford university are the. The function of the catcher grids is to absorb energy from the electron beam. The qvalue at the output port is matched to this group velocity so that the.
Philips also devised some multireflex structures, see. The klystron was the first embodiment of the velocity modulation principle. However, the multicell output cavity is prone to selfoscillations due to the prolonged several half rf periods beamfield. Difference between two cavity klystron and reflex klystron. Status and future strategy for advanced high power. It also utilizes a collector element at the end of the electron stream. These will set up a field in the third cavity, which produces more concentrated bunches and. Installation of 6 cavities in the existing hins beamline has been completed and beam measurements have. This section will explain the basic operation of the most widely used microwave tubes, including klystrons, travelingwave tubes, backwardwave oscillators, magnetrons, and crossedfield amplifiers. Ultrawideband clusteredcavity klystron springerlink. The two cavity klystron utilizes an electron source heater, an anode, and a cathode like a conventional vacuum tube. High power microwave system based on power combining. The cavity is integrated with a carbon nanotube cold cathode in order to reduce thermal expansion and cooled by an opportune airflow that regulates the temperature distribution to compensate the resonant frequency shift. It is different from the two or multi cavity klystron because it uses a single cavity for modulation or demodulation.
Design of reentrant cavity with multibeam channel analytical methods can be used for the estimation of parameters of the cavity having simple shapes but for the more complex shapes experimentation or computer simulation are the only resorts. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. Amplification of such two cavity klystron is low and hence multi cavity klystrons are used. The l3403 klystron is a fourcavity, modulating anode, pulsed klystron amplifier which can be mechanically tuned to amply any frequency within the range from 400 to 450 mhz. Two cavity klystron amplifiers working, amplification and applegate diagram by engineering funda duration. The following figure depicts an example of multicavity klystron amplifier. For the rf source of ilc, so called multibeam klystronmbk which was developed.
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