A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. In fact, according to kek injector operating statistics during 10 years in 2000s, the failures in focusing solenoids were the most frequent reasons to exchange klystron assemblies among the other. 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. Due to the large number of klystron units, even a low failure rate of each component could increase the load of maintenance work and limit availability of the facility. The main difference between two cavity reflex klystron amplifier. The reflector voltage may be varied slightly from the optimum value, which results in some loss of output power, but also in a variation in frequency. Avalanche diode construction, working and its applications. Moreover it uses repeller inplace of catcher cavity. 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. A klystron is basically a vacuum tube with input and output structures replaced with resonant cavities known as buncher cavity and catcher cavity. The reflex klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. A small hole in the broad wall of the waveguide is provided, through which output coupling pin of klystron tube enters into the waveguide. Slacpub16466 increasing klystron efficiency using com.
For drfs, the reliability of klystron itself is estimated to be fairly high because of its relativelylow output power 800 kw per klystron. Comsol conference 2016 munich multiphysics design of a ghz klystron the analysis follows a multiphysics model approach, in order to prevent alterations of the electromagnetic em behavior, while exposing the device to these multiple physics factors. Toni on download multisim blue 14 free schematic capture, simulation, pcb design, and bom toni on simple circuit stereo audio amplifier with ic lm386 toni on circuit power audio amplifier stereo ic tda2822 2x 1 w. Mode 1 is obtained when the repeller voltage produces an electron transit time of 34 cycle. This page on klystron vs magnetron describes difference between klystron and magnetron. Their prototype was completed and demonstrated successfully on august. Reflex klystron free download as powerpoint presentation. Klystron types presentday klystrons fall into three categories. An avalanche diode is a one kind of diode that is designed to experience an avalanche breakdown at a particular reverse bias voltage. The multiphysics design of a ghz klystron buncher cavity is described in this paper.
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. Reflex klystron vacuum tube manufactured goods free. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. A klystron is a vacuum tube that can be used either as a generator or as an amplifier of power, at microwave frequencies klystron types there are two basic configurations of klystron tubes 1. These electrons move at a uniform speed towards the anode until they are attracted by it. The first papers on the theory of the reflex klystron were published by the soviet physicists ia. The microwaves flow into the waveguide, which transports them to the. When switch on the circuit, the electrons starts emitting from the cathode. The klystron was the first significantly powerful source of radio waves in the microwave range. Lowpower klystrons are used as oscillators in terrestrial microwave relay. Slow wave structures are also otype but have nonresonant periodic structures for electron interactions. Performance evaluation of klystron beam focusingsystem. The essential elements of klystron are electron beams and cavity resonators.
Performance of an sband klystron at an output power of 200 mw. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. Alberto leggieri1, davide passi 1, franco di paolo, giovanni saggio1. Lowpower klystrons are used as oscillators in terrestrial microwave relay communications links, while highpower klystrons are. The modulator is the dc power supply for the klystron. An electron can be accelerated or decelerated by an electrostatic field. Yes, they had a bellows that was externally adjusted to cause the separation between grids that coupled to a resonant chamber as reflex. The electronic tuning range of the reflex klystron is usually referred to as the variation in frequency between half power pointsthe points in the oscillating mode where the power output is half the maximum output in the mode. How reflex klystron works electrical engineering stack exchange. The multiphysics design of a ghz klystron buncher cavity is described in this. Twystron is a hybrid amplifier which uses a combination of klystron and slow wave structures. Figure 22 shows an electron moving in an electrostatic field. It covers basics of klystron and magnetron and mention difference between them.
The bunching cavities regulate the speed of the electrons so that they arrive in bunches at the output cavity. Klystron and microwave department capabilities and xband. In this video, i have explained reflex klystron with following points 1. The direction of travel shown by the heavy arrow is against the. The 5045 klystron design has remained largely unchanged over the last couple decades. Department of electronics and communication engineering ec 2405 optical and microwave lab manual vii sem ece 1 prepared by m. Slacpub16466 increasing klystron efficiency using com and. Their work was preceded by the description of velocity modulation by a. I was an aetm3c in the navy and also remember those local oscillators. The electron gun emits the electron beam, which passes through the gap in the anode cavity. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into.
The voltage should always be switched on before providing the input to the reflex klystron as the whole function of the reflex klystron would be destroyed if the supply is provided after the input. Thermal excitation allows free electrons reaching the vacuum level and escape the material. Comsol conference 2015 grenoble multiphysics design of a klystron buncher the analysis follows a multiphysics model approach, in order to prevent alterations of the electromagnetic em behavior, while exposing the device to these multiple physics factors. The klystron beam focusing system is one of the key components in the whole system. Performance evaluation of klystron beam focusingsystem with. Reflex klystron used as a lowpower microwave oscillator 2. Klystron vs magnetrondifference between klystron,magnetron. My apologies for the long answer but this is a complicated bit of technology and needs an appreciation of the physics behind it.
Photon absorption by the electron, electron transport to. In klystron strong electrostatic fields are required for its operation efficiently. Klystron for high gradient accelerator research, in aip conf. A reflex klystron is an obsolete type in which the electron beam was reflected back along its path by a high potential electrode, used as an oscillator. A collector is present at the end to collect the electrons. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. Klystron multi cavity klystron, reflex klystron, working.
Modern semiconductor technology has effectively replaced the reflex klystron in most applications. Klystron an ultrahighfrequency electronic vacuum device in which a steady stream. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. This hole is exactly located in the center of broad wall. Download ebook pdf radio transmitters tube power rf. Explain the operation principle of the cavity klystron with neat sketch.
Zhou stanford linear accelerator ce nter, menlo park, ca 94025, u. Product description a small hole in the broad wall of the waveguide is provided, through which output coupling pin of klystron tube enters into the waveguide. Introduction to the twocavity klystron amplifier technical articles. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical engineers russell and sigurd varian, which is used as an amplifier for high radio frequencies, from uhf up into the microwave range. Reflex klystrons were developed in 1940 by the soviet engineers n. The new design improves the klystron efficiency from 45% to 55% by adding 4 cavities to the drift section figure 4. Design study on the high power klystron for komac hyeokjung kwon1, kangok lee1, hansung kim2, minjoon park2, moonsung chun2, kiehyung chung2, seungjeong noh3 1 korea accelerator and plasma research association, chonan 330825, korea 2dept. The klystron was the first embodiment of the velocity modulation principle. This article discusses about a brief information about the construction and working of an avalanche diode. Klystron article about klystron by the free dictionary. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation.
The principle of velocityvariation, first used in heil oscillators, was also used in other microwave amplifying and oscillating tubes. The klystron is a device for amplifying microwave frequency signals that achieve high levels of power gain by applying vacuum tube principles. Klystron works on the principle of velocity modulation of electrons. Theory and practice at the stanford linear accelerator center. Electron beams are produced from a source and the cavity klystrons are employed to amplify the signals. Microwave engineering reflex klystron tutorialspoint. Although the design is robust, the bac principles discussed above have been applied to achieve an even more efficient design. Classification of the klystrons, mode of operation of the twocavity, multicavity and.
Sep 27, 2017 in this video, i have explained reflex klystron with following points 1. It was invented by the brothers russell and sigurd varian at stanford university. The application for klystron with integral cavities is usually credited in the early 1939 to hahn and metcalf and to russell and sigurd varian, two brothers that. Reflex klystron working, oscillator and applegate diagram. Klystron, thermionic electron tube that generates or amplifies microwaves by controlling the speed of a stream of electrons. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Reflex klystron working free download as powerpoint presentation. The bunches of electrons excite microwaves in the output cavity of the klystron. The name klystron comes from the greek verb klyzo referring to the action of waves breaking against a shore, and the suffix. The paramount o type tube is the two cavity klystron followed by the reflex klystron.
The whole set up is as shown in the following figure. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. Reflex klystron oscillator pdf source of an electronbeam and the radiofrequency por tion of the klystron is independent of the electron source. F input signal to the buncher cavity with the help of loop coupling. 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. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. This hole is exactly located in the center of broad wall because the. Pre 1939 the transit time in triodes and tethrodes and pentodes was a limiting factor to produce high frequency amplifiers up t.
Microwave engineering cavity klystron tutorialspoint. To understand the operation of a reflex klystron i think you need to start with a basic understanding of a tuned circuit made up from a capacitor c and inductor l. Mar 24, 2016 working of reflex klystron oscillator. Design study of rf section and cavities for cepc 650 mhz klystron. A klystron is a high frequency device which could be used as an amplifier or an oscillator. Since all intermediate cavities in a multicavity klystron operate in the. Reflex klystron vacuum tube manufactured goods free 30. The reflex klystron operates in a different mode for each additional cycle that the electrons remain in the repeller field.
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