In the last lecture, we discussed conventional tubes and their high frequency. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. Varian reflex klystron tube va 220b etheric beam locator. It has two microwave cavity resonators the catcher and the buncher. Experiment4 study of the characteristics of the klystron tube.
The klystron is the ubiquitous source of rf power in accelerators today. The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Performance characteristics of the cebaf klystron amplifier. I was an aetm3c in the navy and also remember those local oscillators. Klystron types there are two basic configurations of klystron tubes 1. Multi cavity klystron two cavity klystronused as lowpower microwave amplifier two. Klystron multi cavity klystron, reflex klystron, working. International journal of infrared and millimeter waves 268. Reflex klystron used as a lowpower microwave oscillator 2. The main difference between two cavity reflex klystron amplifier.
Due to dc voltage in the cavity circuit, rf noise is generated. Reflex klystron is one of the most commonly used microwave low power generators. 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. 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. The general construction of the reflex klystron oscillator and a two. The brothers russell and sigurd varian of stanford university are the. This is the reflex klystron oscillator, which will now be described. 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. Following are the benefits or advantages of 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.
The conventional vacuum tubes, such as triodes, tetrodes, and pentodes, are. A klystron is a vacuum tube that can be used either as a generator or as an amplifier of power, at microwave frequencies. Klystron and microwave department capabilities and xband. This unit came from a working environment but has not been tested. Spontaneou s emission and gain are theo retically studied as functio n of electron energy and wavelength. Reflex klystron is a microwave device that works on principle of velocity modulation in addition to current modulation. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. Hannurkar raja ramanna centre for advanced technology, indore, india. The tube provides 5 kw cw output power at 1497 mhz and is permanentmagnet focused with a four. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. In wikipedia it says that, the electrons are fired into one end of the tube by an electron gun. Reflex klystron working, oscillator and applegate diagram. Several effects limiting the gain enhancement are calculate d. Reflex klystron free download as powerpoint presentation.
A klystron looks and works something like an organ pipe. Other articles where twocavity klystron is discussed. 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. A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form. The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. To study the characteristics of the reflex klystron tube and to determine the its electronic tuning range.
The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. 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. Klystron is a microwave generator compare slacs large, highpower microwave generator klystron below with this much smaller one magnetron right from a typical microwave oven. Department of electronics and communication engineering ec 2405 optical and microwave lab manual vii sem ece 1 prepared by m. Important question and answers on reflex klystron with. The schematic diagram of a reflex klystron tube is shown in fig.
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. Electromagnetic analysis of reentrant klystron cavity. The klystron beam focusing system is one of the key components in the whole system. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids.
There are three generic types of microwave tubes, with the categorization based on the character of the interaction between the microwave structures used and the. Microwave engineering reflex klystron tutorialspoint. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. It is given the name reflex klystron because of its reflex action of electron beam. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. If you need an oscillator, a reflex tube will work fine, but it is old school technology. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. Characteristics of a reflectiontype microwave modulator. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. The klystron is at heart a narrowband vacuumtube ampli. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Of the resulting frequency spectrum only a narrow band, which.
Connect the detector output to y input and sawtooth output of the klystron of power supply to xinput of scope fig. The klystron was the first embodiment of the velocity modulation principle. 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. First, you need to determine what your need for a klystron is. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. Introduction the klystrons for the ground test accelerator gta. Yes, they had a bellows that was externally adjusted to cause the separation between grids that coupled to a resonant chamber as reflex. 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. This type of klystron is mostly used for the purpose of amplification of microwave length of frequencies. The mathematically simple formalism proposed earlier for calculating electromagnetic parameters of a reentrant cavity barroso et al. Blowing into the organ pipe produces a flow of air. Slacpub16466 increasing klystron efficiency using com.
Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. Increasing klystron efficiency using com and bac tuning and application to the 5045 klystron aaron jensen, andy haase, erik jongewaard, mark kemp and jeff neilson technology and innovation directorate slac national accelerator laboratory menlo park, ca, usa, 94025 abstract. A microwave source of surprising range and endurance pdf. 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. All these products are designed, developed and manufactured at an iso 9001. 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. A klystron is a high frequency device which could be used as an amplifier or an oscillator.
Klystron production is now proceeding at tubes per month. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector. Microwave engineering cavity klystron tutorialspoint. Varian va 220b klystron tube reflex klystron tube uhv vacuum this particular item is similar to the ones used in the dr. Typical operational problems with a klystron input drive power is too low and klystron is not saturated although this is required if the tube is included in a feedback loop reduced output power, efficiency, and increased output power amplitude jitter wrong cathode filament current wrong perveance. Pre 1939 the transit time in triodes and tethrodes and pentodes was a limiting factor to produce high frequency amplifiers up t.
The klystron has produced over 1 mw at the new frcqucncy. Reflex klystron oscillator operation application of. Scribd is the worlds largest social reading and publishing site. In klystron, each cavity operates independently and there is no mutual coupling. This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency.
Two cavity klystron amplifier is not lownoise device. Abstract the design and simulation of a multibeam reentrant. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. Who tv series from england in the 70s in the tv show it was called an etheric beam locator. Various fundamental principle are used for the analysis and design purpose with the application of field measurement techniques. Difference between two cavity klystron and reflex klystron. Reflex klystron working, oscillator and applegate diagram engineering funda, microwave engineering. Reflex klystron article about reflex klystron by the. Modulation is accomplished by varying the velocity of the beam, which. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. Klystron modes measurement of klystron characteristics.
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