Functional and schematic diagram of a twocavity klystron. The following figure depicts an example of multi cavity klystron amplifier. Klystron twocavity klystron amplifier electronics desk. The direct and comb loop feedback around the rf cavities in pepii is critical in reducing longitudinal instabilities driven by the cavity impedance. Introduction a klystron is a vacuum tube that can be used either as a generator or as an amplifier or as an oscillator, at microwave frequencies. Diagram of a twocavity klystron, used as an amplifier and. Twocavity klystron amplifier 62801 circuit and wiring. Obtain electronic efficiency from twocavity klystron. Electromagnetic analysis of reentrant klystron cavity. Klystron amplifier vacuum tube electrical engineering. The catcher grids are placed along the beam at a point where the bunches are fully formed.
Connectlosb 41pu wvguino the output of the 8562 klystron, klystron. Klystron amplifiers include twocavity power klystrons and multicavity power klystrons. In this tube there are two microwave cavity resonators, the catcher and the buncher. Thus basically klystron amplifiers possess less power than their counterparts magnetron and travelling wave tube. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. These include the two cavity amplifier or oscilator, the reflex klystron, and the multicavity high power amplifier. Amplification of such two cavity klystron is low and hence multi cavity klystrons are used. Cpi also offers a series of compact kpas with the same feature sets as the gen iv, but utilizing traditional klystron technology. 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. Ppt slac klystron lectures powerpoint presentation. The function of the catcher grids is to absorb energy from the electron beam. As a result, the effective smallsignal gain of the klystron at 85% saturation reduces the impedance control by factors of 5 to 20 as compared to a linear power amplifier. The vacuum tube consists of a cathode, which is heated by a filament.
As shown electron beam is generated by electron gun which passes through the space. Lowlevel rf control of a klystron for medical linear. Two cavity klystron amplifiers working, amplification. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the. Ppt slac klystron lectures powerpoint presentation free to download id. Microwave engineering ece questions and answers this is the electronics and communication engineering questions and answers section on microwave communication with explanation for various interview, competitive examination and entrance test.
Klystrons are a special type of vacuum tubes that find applications as amplifiers and oscillators at microwave frequencies. Can a two cavity klystron amplifier be used an oscillator. Amplification of such twocavity klystron is low and hence multicavity klystrons are used. Perhaps we can digress a moment to discuss the cavity used in the buncher and the catcher. These electrons move at a uniform speed towards the anode until they are attracted by it. A preferred embodiment of a high power multi cavity klystron amplifier 1 embodying the invention and shown in fig. All amplifiers are available as single units or in redundant or combined systems. The klystron amplifier comprises an input cavity a plurality of intermediate cavities and an output cavity which are arranged along the path of an electron beam for focusing it, and an output waveguide coupled to the output cavity through a coupling opening. This is the multiple choice questions in chapter 11. An electron beam is formed in an electron gun and passed through the gaps associated with the two cavities fig. Other articles where two cavity klystron is discussed.
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. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. Diagram of a twocavity klystron, used as an amplifier and rf signal source at microwave frequencies, and also as an oscillator. It is economically competitive with the older thyratronpfn technology, and when the greatly reduced maintenance and sizeweight characteristics of clw modulator systems are taken into account, the clw system is seen to be more costeffective than older technologies.
F input signal to the buncher cavity with the help of loop coupling. Introduction a klystron is a vacuum tube that can be used either as a generator or as an. Multicavity klystron amplifiers nippon electric co. What is the purpose of slow wave structures in twt. So lets see 2 cavity klystron amplifier first two cavity klystron amplifier 2 cavity klystron amplifier. With the signal applied in the first cavity, we get weak bunches in the second cavity. Draw the equivalent circuit diagram of a reflex klystron. Download scientific diagram schematic diagram of a twocavity klystron amplifier. Reflex klystron is a lowpower, lowefficiency microwave oscillator another tube based on velocity modulation, and used to generate microwave energy, it contain cathod. At a very high temperature, the cathode emits electrons. These will set up a field in the third cavity, which produces more concentrated bunches and. Derive the equation for power output and efficiency of two cavities and four cavity klystron amplifiers. Other articles where twocavity klystron is discussed. The klystron has six cavities, with each cavity having a series of.
There are few intermediate cavities used between buncher cavity and catcher cavity. Microwave tubes and circuits from the book electronic communication systems by george kennedy. The cavities in the klystron are usually adjusted by an inductive tuning slug. Thus the device used for amplifying microwave signals is known as two cavity klystron in the year 1937, american engineers russell and sigurd varian developed klystrons. The following figure depicts an example of multicavity klystron amplifier. In the llrf control system of an sband klystron, a pulse modulator generated 140kv95a at a fixed microperveance value of 1. Download scientific diagram schematic diagram of a two cavity klystron amplifier. Figure 2 shows the waveguide harmonic damper design employing coaxial probe antennas. Klystron 1 vacuum tube radio technology free 30day. The kaband eik amplifier provides up to 800 watts of kaband power. A klystron is a microwave vacuum tube using cavity resonators to produce velocity modulation of the electron beam and produce amplification. What is meant by frequency pushing and frequency pulling 6. Klystron tube article about klystron tube by the free.
Figure 28 shows a simplified sche matic of a triode amplifier with resonant circuits at both the input and the output. Review of highpower microwave source research this. When switch on the circuit, the electrons starts emitting from the cathode. The casing and central member are maintained at ground potential, which maintains the space charge. On each side of the cavity hole is a grid that the electrons pass through. Klystrons are used as amplifiers at microwave and radio frequencies to produce both lowpower reference signals for superheterodyne radar receivers and to produce highpower carrier. As for ec, the development issues for the klystron relate mainly to the cooling of the structure. Microwave communication questions and answers pdf free download for ece mcqs objective type interview questions lab viva manual gate cat syllabus microwave communication questions and answers. In klystron amplifiers, which are physi cally long, it is difficult to keep the electron beam properly formed during its travel through the rf section. Draw the electronic admittance diagram of reflex klystron. The adobe flash plugin is needed to view this content. Microwave engineering ece questions and answers page 2. A klystron amplifier in which the drift tube is in the form of a casing and a central member disposed coaxially about the same centerline to form a coaxial space between the central member and the casing which runs parallel to the centerline, and through which the klystrons electron beam flows. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron.
A klystron is a specialized linearbeam vacuum tube evacuated electron tube. 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. A linear array of five probe antennas is used on a narrow wall of the rectangular waveguide for damping klystron harmonics. In this video, i have explained two cavity klystron amplifier with following points 1. Microwave engineering cavity klystron tutorialspoint. The rf source is a klystron amplifier see section 17. The location is determined by the transit time of the bunches at the. Klystron multi cavity klystron, reflex klystron, working. Bb4c6c from alamys library of millions of high resolution stock photos, illustrations and vectors. Akash patil 090240111016 outline introduction two cavity klystron operation performance characteristics application. Explain in detail about 2cavity klystron amplifier. The simplest klystron tube is the twocavity klystron. Mwe unit 3 topic 36 two cavity klystron amplifier duration.
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