The cern requirement is for a microwave amplifier which will provide pulsed. Pdf circuit analysis of kaband extended interaction klystron. In this tube there are two microwave cavity resonators, the catcher and the buncher. Derive an expression for the efficiency of the klystron amplifier. 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. 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. For a lower price and with a reduced warranty a rebuild of our tube, product number l582290, is also available. Diode drive cavity idler cavities output cavity collector f 2996 mhz gain 55 db efficiency. The feedback path provides energy of the proper delay and phase relationship to sustain oscillations. It is common that references to such systems are as klystron systems, rather than synthesis systems, but the distinction, synthesis, encompasses all possible methods, including travellingwave tubes, hard.
Diploma sem v two cavity klystron amplifier microwave and radar lecture vidyalankar duration. The two cavity klystron in figure 27 may be used either as an oscillator or an amplifier. The configuration shown in the figure is correct for oscillator operation. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation.
The helix travelingwave tube twt, the coupledcavity twt, the forwardwave am plifier fwa, and the backwardwave amplifier and oscillator bwa and bwo are also 0type tubes, but they have nonresonant periodic structures for electron inter actions. Each klystron type, operating as a television visual rf amplifier, will deliver 5. These electrons move at a uniform speed towards the anode until they are attracted by it. The simplest klystron tube is the two cavity klystron. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. Special thanks to richard hall k5gzr for donating this device. Stability analysis of cband 500kw klystron with multicell.
As the first kpa to utilize multi stage depressed collector msdc technology, the gen iv offers by far the best combination of high power, high. Since all intermediate cavities in a multicavity klystron operate in the same manner, a. The microwave energy modulates the velocities of electrons in the beam, which then enters a drift space. A lowvoltage, multibeam radio frequency source that operates at a voltage less than or equal to approximately 2040 kv and that generates at least 600 kw at a pulse width of approximately 530 ms. Circuit analysis of kaband extended interaction klystron. Due to the number of the resonant cavities, klystrons are divided up into two cavity klystrons, multi cavity klystrons, and repeller klystrons. Question bank department of electronics and communication. Mwe unit 3 topic 36 two cavity klystron amplifier duration. In finding a solution to this design problem, several factors were taken into account. Circuit analysis of kaband extended interaction klystron conference paper pdf available in journal korean physical society 445. Formulate the expression for optimum drift space distance l optimum in a two cavity klystron. These will set up a field in the third cavity, which produces more concentrated bunches and. It is known by this name due to its reflex action of electron beam.
A multi cavity klystron amplifier according to claim 1 wherein said output cavity comprises an electroconductive cylinder, electroconductive end plates connected to the opposite ends of said cylinder and provided with axial openings for passing said electron beam, drift tubes secured to the inner sides of said end plates, tuning means electrically connected to one side wall of said cylinder. Sandalov msu, moscow, russia abstract the necessity to create the rf sources operating in twofrequency mode is supported by the proposals concerning the suppression of the emittance growth generated inside the rf. Multicavity klystron amplifiers nippon electric co. Cpis gen iv klystron power amplifier kpa is the overwhelming choice among directtohome service providers for uplink service, and is also very popular for other broadcasting applications. Jul 31, 2018 the two cavity klystron utilizes an electron source heater, an anode, and a cathode like a conventional vacuum tube. Oct 01, 2014 0type tube is the twocavity klystron, and it is followed by the reflex klystron.
Up to a certain output power level, therefore, a four cavity klystron may be represented by a two cavity model the input cavity of which comprises a linear amplifier having the gain and frequency characteristics of the first. 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. They are velocitymodulated tubes that are used in radars as amplifiers or. The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. For use as an amplifier, a klystron receives microwave energy at an input cavity through which the electron beam passes. Explain the principle of operation of a reflex klystron oscillator and derive an expression for the bunching parameter. When switch on the circuit, the electrons starts emitting from the cathode. Figure ii4 illustrates a multicavity power klystron amplifier. Classification of the klystrons, mode of operation of the twocavity, multicavity and. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. The gain of klystron amplifiers can be very high more than 60 db, with output power up to tens of megawatts.
Klystron multi cavity klystron, reflex klystron, working. Tuning measurement of multicavity klystrons in diode mode. The gain of both waves can be determined from the prototype of the periodic structure shown in fig. What is a klystron amplifier, types, differences and their. Klystron, thermionic electron tube that generates or amplifies microwaves by controlling the speed of a stream of electrons. Klystron tube article about klystron tube by the free. A network is arranged in the hub of multi cavities to let the flow of electrons. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons.
Caryotakis, performance of a 150mw sband klystron, aip conf. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. New techniques for computing the largesignal behaviour of multicavity klystron amplifiers have shown how significant increases in their efficiency can be. Multicavity klystron efficiency and bandwith additional cavities are used to increase gain, bunches are formed by the first n1 cavities power is extracted by the n th cavity perveance electron gun is a spacecharge limited diode with given by k. With the signal applied in the first cavity, we get weak bunches in the second cavity.
Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Solid state amplifiers are being increasingly used instead of electronic vacuum tubes to feed accelerating cavities with radio frequency power in the 100 kw range. Since the cavity is approximately a 1inch cube, it is apparent that removing the heat is a formidable prob lem. The electron beam first passes through a cavity to which the input signal is applied. The multi cell cavity can provide the higher power and the wider bandwidth, however there is a possibility to generate the self. Ds58220411a l5822 linear accelerator klystron amplifier. Understandformulate the expression for optimum drift space distance l optimum in a two 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. For example, in a 20kilowatt, 10ghz klystron amplifier, approximately 1 kilowatt of heat is generated by the circulating rf currents in the output cavity. Remembera reflex klystron operates at 8 ghz with dc beam voltage 300 v, repeller space1mm for 1 mode. Sketch output power and frequency of klystron versus repeller voltage for reflex klystron. A klystron is used either as an amplifier in the microwave region or as an oscillator. Mwe unit 3 topic 66 multi cavity klystron amplifier. Since all intermediate cavities in a multicavity klystron operate in the same manner, a representative three cavity klystron will be discussed.
In addition to the intermediate cavities, there are several physical differences between the basic and. Figure 1 shows a segment of the klystron resonator system in which a twogap resonator in the drift tube 3 is located between two main bunching onegap resonators 1, 2 of the klystron. Output cavity oscillates not necessarily at an integer multiple of the. But klystrons have limited bandwidth less than 2% because of their use of resonant cavities. The two cavity klystron in figure 27a and b may be used either as an oscillator or an amplifier. An electronic oscillator can be made from a klystron tube, by providing a.
The entire drifttube assembly, the three cavities, and the collector plate of the three cavity klystron are operated at ground potential for. A two cavity klystron amplifier has the following parameters. Vidyalankar group of educational institutes 947 views 8. The klystron power amplifier is the transmitting tube in most highpower synthesis systems.
It also utilizes a collector element at the end of the electron stream. Microwave engineering cavity klystron tutorialspoint. Mode ac uplink formats reply downlink format side lobe suppression. A three cavity klystron is illustrated in figure 28. These types of cavity klystron amplifiers include various cavities used for controlling the electric field in the region of the axis of the klystron tube. The following figure depicts an example of multi cavity klystron amplifier. A 500 kw lband klystron with broad bandwidth for subharmonic. The rf source includes an electron gun having a cathode configured to generate a plurality of beamlets. On the other hand, klystrons are narrowband devices, compared with travellingwave tubes. In a multicavity klystron amplifier of the class comprising an electron gun for. Comparison has been made with the results in normal triode operation and has shown a good agreement. Oct 03, 2016 mwe unit 3 topic 36 two cavity klystron amplifier duration. There are two cavities known as buncher and catcher cavity.
Amplification of such two cavity klystron is low and hence multi cavity klystrons are used. Other articles where two cavity klystron is discussed. The same method has been applied to tuning measurement of a diode pulsed klystron, e3712. Introduction to the twocavity klystron amplifier technical. F input signal to the buncher cavity with the help of loop coupling. 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. Power is obtained from the combination of hundreds of transistor amplifier modules. Other articles where twocavity klystron is discussed.
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