Reflex klystron vacuum tube manufactured goods free. Reflex klystron vacuum tube manufactured goods free 30. I was an aetm3c in the navy and also remember those local oscillators. The modulator is the dc power supply for the klystron. Klystron works on the principle of velocity modulation of electrons. Secondly, the solidstate switch protects the klystron against arc damage. It covers basics of klystron and magnetron and mention difference between them. The ranges of all these voltages are given in the specification data sheet. 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. In this tube there are two microwave cavity resonators, the catcher and the buncher. Lowpower klystrons are used as oscillators in terrestrial microwave relay communications links, while highpower klystrons are used as output tubes in uhf television. A loop coupling is used inside the cavity to get the output.
Set the variable attenuator at the maximum position a zero micrometer reading. Reflex klystron oscillator pdf source of an electronbeam and the radiofrequency por tion of the klystron is independent of the electron source. In a reflex klystron, a small modulation of the repeller voltage is more often employed to fix the emitted frequency to that of a microwave resonator by a phase locking loop technique. Important question and answers on reflex klystron with. Operation the klystron was the first embodiment of the velocity modulation principle. The simplest klystron tube is the twocavity klystron. Reflex klystron article about reflex klystron by the. Klystron vs magnetrondifference between klystron,magnetron.
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. Yes, they had a bellows that was externally adjusted to cause the separation between grids that coupled to a resonant chamber as reflex. Experimental demonstration of enhanced selfamplified. Why is pulse modulation required in reflex klystron. The expected lifetime of a tetrode in uhf service is usually shorter than a klystron ofthesamepowerlevel. The same method has been applied to tuning measurement of a diode pulsed klystron, e3712. The 5045 klystron design has remained largely unchanged over the last couple decades. 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. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. The electron beam is accelerated towards the anode cavity. 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. This is the reflex klystron oscillator, which will now be described.
Klystron oscillator reflex klystron traveling wave tube magnetron klystron. In 1986, a study contract was placed with varian for a. 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. Lowpower klystrons are used as oscillators in terrestrial microwave relay. Klystron tube 2k25 the klystron tube 2k25 is a single cavity variable frequency microwave generator of low. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. Microwave engineering reflex klystron tutorialspoint.
The klystron beam focusing system is one of the key components in the whole system. Reflex klystron free download as powerpoint presentation. Reflex klystron used as a lowpower microwave oscillator 2. Slacpub16466 increasing klystron efficiency using com. The operation of reflex klystron is understood by some assumptions. Reflex klystron working, oscillator and applegate diagram. The klystron was the first embodiment of the velocity. This paper describes a new deq circuit with feedforward compensation to stabilize the output pulse amplitude of the existing modulator for the pulse klystron. Klystrons article about klystrons by the free dictionary. 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. Previous data indicated the tube operated properly. Since all intermediate cavities in a multicavity klystron operate in the same manner, a. Microwave engineering cavity klystron tutorialspoint. Voltages required for operation of reflex klystron tube such as beam, heater and reflector voltage.
This page on klystron vs magnetron describes difference between klystron and magnetron. Multiphysics design of a ghz klystron alberto leggieri, davide passi, rocco citroni. Three power sources are required for reflex klystron operation. Since one might presume the beam is off center, the collector operation should not be as good as is possible. Performance evaluation of klystron beam focusingsystem with. The two velocity modulated tubes described in the present chapter, the klystron amplifier and the reflex oscillator, are gen erally designed for operation at.
Pulsemode klystrons have an output from several hundred watts w to 40 megawatts mw. Moreover it uses repeller inplace of catcher cavity. Comparison has been made with the results in normal triode operation and has shown a good agreement. Slacpub16466 increasing klystron efficiency using com and. Klystron types there are two basic configurations of klystron tubes 1. 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 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 and microwave department capabilities and xband. The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Difference between two cavity klystron and reflex klystron. Other articles where twocavity klystron is discussed. Correct operation of the buncher is ensured if it can use all the available power provided at the input to produce the desired axial electric field bunching field. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Klystron for high gradient accelerator research, in aip conf.
On the klystron power supply, vswr meter and cooling fan. Performance evaluation of klystron beam focusingsystem. Of the resulting frequency spectrum only a narrow band, which. In klystron strong electrostatic fields are required for its operation efficiently. The principle of operation of this device is based on velocity modulation of the electrons in a beam generated by an electron gun. At microwave frequencies, however, the transit time or angle is large compared to the period of the microwave signal, and the potential between the cathode and the. Adjust the reflector voltage to set klystron for maximum mode of. Klystron types presentday klystrons fall into three categories. In this video, i have explained reflex klystron with following points 1. Let a beam of electrons, which has been accelerated by a. Work supported by department of energy contract deac0376sf00515 abstract major changes to the next linear collider nlc design were facilitated by the experimental testing of the 75 mw xband klystron at a 3. It is given the name reflex klystron because of its reflex action of electron beam. Let us assume that a reference electron e r crosses the anode cavity but has no extra velocity and it repels back after reaching the repeller electrode, with the same velocity.
Multi cavity klystron two cavity klystronused as lowpower. A brief introduction to rf power sources 1 introduction 2 klystrons. Pure carrier wave operation and in external modulation facilities is also provided with the instrument for generalized use. This type of klystron oscillator is called a reflex klystron because of the reflex action of the electron beam.
The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. The new design improves the klystron efficiency from 45% to 55% by adding 4 cavities to the drift section figure 4. Reflex klystron article about reflex klystron by the free. 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. A range of four modes of operation are normally available. Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. Voltage variations and flatness of the flattop of the klystron beam voltage obtained were less than 0. Oct 01, 2014 340 microwave linearbeam tubes 0 type chap. Typicallifetimesof8,000to15,000hourshavebeenreported.
A klystron is a vacuum tube that can be used either as a generator or as an amplifier of power, at microwave frequencies. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. For the love of physics walter lewin may 16, 2011 duration. Klystron oscillator reflex klystron traveling wave tube magnetron. What modes are generally used in a reflex klystron. Klystron amplifiers are built for operation in narrow frequency ranges of the decimeter or centimeter wavelengths. Before outlining its history, it is useful to sketch out the operating principles of the device. The slac highpowered klystron for 2856 mhz operation, the model 5045, operates at a voltage of 350 kv with a beam current of 400 amperes, yielding a. Controls the entire 2 mw klystron transmitter is controlled and monitored figure 6 through a threelevel system, similar to other dti transmitter control system designs.
The linear collider at slac uses sband klystrons operating at 60mw peak. 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. This is indeed the principal operation of such microwave tubes as klystrons and magnetrons. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. The actual mode used 1 34 cycles through 4 34 cycles, 2 34 cycles through 6 34 cycles, etc. Klystron rf stabilization using feedforward circuit. The choice of mode is determined by the difference in power available from each mode and the band of frequencies over which the circuit can be tuned. Reflex klystron oscillator operation application of. Turn the meter switch of power supply to beam voltage position and beam voltage at 300volt with the help of beam voltage knob. 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. The main difference between two cavity reflex klystron amplifier. Anatoly krasnykh, slac, box 4349 stanford, ca 94309. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids.
Klystron multi cavity klystron, reflex klystron, working. Tuning measurement of multicavity klystrons in diode mode. Improvements and new designs for slac klystron modulators. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. The klystron power supply also provides all the other d.
How reflex klystron works electrical engineering stack exchange. It provides reflow compatibility for mobile communications, bluetooth, and wireless lan applications. Set the modswitch of klystron power supply to cw position, beam voltage control knob to. The first level, fast control and monitoring, provides fast response, hardwired fault detection, and safety shutdown. Sep 27, 2017 in this video, i have explained reflex klystron with following points 1. 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. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. All these components are enclosed in a glass envelope. A klystron is basically a vacuum tube with input and output structures replaced with resonant cavities known as buncher cavity and catcher cavity.
Connect the components and equipments as shown in the fig. Although a small deviation has been found in tuning. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. Fast current sensors in the modulator recognize the presence of an arc when the current in the switch exceeds a preset fault threshold value. It has two microwave cavity resonators the catcher and the buncher. The passthrough effect, therefore, contributes to the overall operating efficiency of the transmitter. Design study of rf section and cavities for cepc 650 mhz klystron. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. What is the operating frequency and power output of a reflex klystron. The transmitter contains two klystrons operating in parallel to generate the output power. Although the design is robust, the bac principles discussed above have been applied to achieve an even more efficient design.
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