Change the meter switch of klystron power supply to beam voltage position,and rotate the beam voltage knob clockwise up to 300 v deflections in meter. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. Microwave engineering cavity klystron tutorialspoint. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. Performance evaluation of klystron beam focusingsystem with. The bunching cavities regulate the speed of the electrons so that they arrive in bunches at the output cavity. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. Hence, by changing the volume of resonator, mechanical tuning range ofklystron is possible. 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. Klystrons are the most efficient of linear beam microwave tubes. Reflex klystron free download as powerpoint presentation. In the a transmitter setup, a klystron produces 3 cm. We are a trusted manufacturer, exporter, trader and supplier of klystron mount.
Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. How reflex klystron works electrical engineering stack exchange. Reflex klystron used as a lowpower microwave oscillator 2. The simplest klystron tube is the twocavity klystron. When the beam of electrons reflect back to the grid due to the repeller voltage in reflector plate,how the grid decelerates the returning electrons and how they release their energy to the grid. Spontaneou s emission and gain are theo retically studied as functio n of electron energy and wavelength. Performance evaluation of klystron beam focusingsystem. Six ips were arranged vertically at 25cm distant from a typical klystron, determined by a tld measurement. Reflex klystron working free download as powerpoint presentation. All these components are enclosed in a glass envelope. Some clas sical techniques such as using a low perveance, harmonic bunching 5 and a multibeam klystron 6 have been used in commercial klystrons. Klystron for high gradient accelerator research, in aip conf. 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.
Lowpower klystrons are used as oscillators in terrestrial microwave relay. Reflex klystron vacuum tube manufactured goods free. Series attempts to cover the basic principles underlying the operation of klystrons and planar grid tubes as oscillators and amplifiers. Multi cavity klystron two cavity klystronused as lowpower. Cw klystron amplifier is to acquire various experiences in the domestic design and parts fabrication of the mw grade klystron amplifier, which are essential in proper and efficient operation of high power rf system. Modulation is accomplished by varying the velocity of the beam, which. Reflex klystron vacuum tube manufactured goods free 30. The frequency is primarily determined by the dimension of resonant cavity.
The essential elements of klystron are electron beams and cavity resonators. This page on klystron vs magnetron describes difference between klystron and magnetron. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. The expected lifetime of a tetrode in uhf service is usually shorter than a klystron ofthesamepowerlevel. Klystron vs magnetrondifference between klystron,magnetron. The electron gun emits the electron beam, which passes through the gap in the anode cavity. The passthrough effect, therefore, contributes to the overall operating efficiency of the transmitter. In this tube there are two microwave cavity resonators, the catcher and the buncher. Switching was accomplished by applying a pulse to the repeller of the passive klystron. The klystron power supply also provides all the other d.
The microwaves flow into the waveguide, which transports them to the accelerator. 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. A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form. Several effects limiting the gain enhancement are calculate d. Of the resulting frequency spectrum only a narrow band, which. Klystrons with mw output power have been developed at cpi, slac, thales, and so on. Oct 01, 2014 338 microwave linearbeam tubes 0 type chap. If you need an oscillator, a reflex tube will work fine, but it is old school technology. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. Typicallifetimesof8,000to15,000hourshavebeenreported. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. 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. Klystron types presentday klystrons fall into three categories. The modulator consisted of an eplane tjunction that was terminated on the sidearm by a reflex klystron operating in the passive region.
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. For the love of physics walter lewin may 16, 2011 duration. Klystron oscillator reflex klystron traveling wave tube magnetron. Klystron usually will have two or more cavities as per gain and bandwidth requirements needed for different applications. Experiments were carried out to determine the characteristics of a reflectiontype modulator. Keep, the ammod amplitude knob and amfre knob at the mid position. When used as an amplifier, the weak microwave signal to be amplified is applied to the buncher cavity through a coaxial cable or waveguide, and the amplified signal is extracted from the catcher cavity. Voltages required for operation of reflex klystron tube such as beam, heater and reflector voltage. Multi cavity klystron used as lowpower microwave amplifier reflex klystron reflex klystron reflex klystron single reentrant cavity as a resonator. First, you need to determine what your need for a klystron is. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. Jensen abstract this report deals with a method of modulating a reflex klystron whereby the message to be transmitted is modulated on a subcarrier, which in turn modulates the klystron through its repeller. For the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes.
A klystron is characterized by high power, large size, high stability, high gain, and high operating voltages. 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 bunches of electrons excite microwaves in the output cavity of the klystron. Klystron characteristics free download as word doc. 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. Microwave engineering reflex klystron this microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a.
It was found that the switching characteristics were strongly dependent on. Design study of rf section and cavities for cepc 650 mhz klystron. Gyroklystrons not only have the bunching in the axial direction, which is. The brothers russell and sigurd varian of stanford university are the. Twystron is a hybrid amplifier which uses a combination of klystron and slow wave structures. It consists of movable short at one end of the waveguide to direct the microwave energy generated by the klystron tube. The modulator is the dc power supply for the klystron. 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. Klystron multi cavity klystron, reflex klystron, working. Klystron, thermionic electron tube that generates or amplifies microwaves by controlling the speed of a stream of electrons.
A loop coupling is used inside the cavity to get the output. The principle of velocityvariation, first used in heil oscillators, was also used in other microwave amplifying and oscillating tubes. A reflex klystron is an obsolete type in which the electron beam was reflected back along its path by a high potential electrode. Operation klystrons amplify rf impinj speedway revolution. It is extensively used for microwave experiments, this is manufactured by some of the reliable and experienced professionals following set parameters and using modern machines. There is a tuneable cavity which adjusts the position of the potential nodes and antinodes in the waveguide. Characteristics of a reflectiontype microwave modulator. A small hole located exactly at the center of the broad wall of the waveguide is used to put the coupling pin of the tube as the electric field vector of em energy is maximum at the center only. Klystron mount manufacturer, klystron mount supplier in. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical engineers russell and sigurd varian, which is used as an. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. It covers basics of klystron and magnetron and mention difference between them.
Department of electronics and communication engineering ec 2405 optical and microwave lab manual vii sem ece 1 prepared by m. Microwave engineering reflex klystron tutorialspoint. The klystron is a linearbeam device that overcomes the transittime limitations of a gridcontrolled tube by accelerating an electron stream to a high velocity before it is modulated. Note that in the spacecharge limited regime the power of the klystron rises as the 52 power of the voltage and the impedance that the. In the process, the electrons give up their kinetic energy to the cavity rf fields.
Reflex klystron article about reflex klystron by the. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. Normally we use separate components in devices such as radio transmitters and receivers but as frequencies increase the two components merge into one structure and become a. The paramount o type tube is the two cavity klystron followed by the reflex klystron. 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. The main difference between two cavity reflex klystron amplifier. A moveable detector on the waveguide can detect the waveguide potential variations using a milliameter. The electron beam emitted from the cathode is accelerated by the grid. Chin kek, 11 oho, tsukubashi, ibarakiken, 305, japan abstract we have developed a new method for a realistic and more accurate simulation of klystron using the magic code. Let a beam of electrons, which has been accelerated by a. 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. After the focusing electrodes there is a cavity resonator which encircles the glass envelope.
Reflex klystron oscillator pdf source of an electronbeam and the radiofrequency por tion of the klystron is independent of the electron source. Reflex klystron article about reflex klystron by the free. The most impressive power achieve ments at very good efficiencies continue to occur in the gyrotron area. Since all intermediate cavities in a multicavity klystron operate in the same manner, a. Slow wave structures are also otype but have nonresonant periodic structures for electron interactions. On the klystron power supply, vswr meter and cooling fan. Measurements of xrays from the rf systems of the electron. Highpower gyroklystrons for acceleration applications strathprints.
The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. The klystron beam focusing system is one of the key components in the whole system. Klystron characteristics physical quantities electrical. The optical klystron is a modificatio n of the undulato r which can be used to improve the gain in a free electro n laser. Lowpower klystrons are used as oscillators in terrestrial microwave relay communications links, while highpower klystrons are used as output tubes in uhf television. Sprehn, rettig, peebles and luhmann, of ucla, described experiments in phase locking a 280 ghz backwardwave oscillator and a 140 ghz reflex klystron to a 35 ghz reference.
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