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Encyclopedia > Klystron tube

A klystron is a specialized vacuum tube (evacuated electron tube) called a linear-beam tube. The pseudo-Greek word klystron comes from the stem form κλυσ- (klys) of a Greek verb referring to the action of waves breaking against a shore, and the end of the word electron. In electronics, a vacuum tube (U.S. and Canadian English) or (thermionic) valve (outside North America) is a device generally used to amplify, or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ...


The Varian brothers (Russel and Sigurd) of Stanford University are generally considered to be the inventors of the klystron. Their prototype was completed in August 1937. Upon publication in 1939, news of the klystron immediately influenced the work of US and UK researchers working on radar equipment. (The Varians went on to found Varian Associates to commercialize the technology.) Stanford redirects here. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to detect, determine the distance of, and map, objects such...

Contents


Explanation

Klystrons are used as an oscillator or amplifier at microwave and radio frequencies to produce both low power reference signals for superheterodyne radar receivers and to produce high-power carrier waves for communications and the driving force for linear accelerators. It has the advantage (over the magnetron) of coherently amplifying a reference signal and so its output may be precisely controlled in amplitude, frequency and phase. Many klystrons have a waveguide for coupling microwave energy into and out of the device, although it is also quite common for lower power and lower frequency klystrons to use coaxial couplings instead. In some cases a coupling probe is used to couple the microwave energy from a klystron into a separate external waveguide. Microwave image of 3C353 galaxy at 8. ... The Super Heterodyne receiver (or to give it its full name, The Supersonic Heterodyne Receiver) was invented by Edwin Armstrong in 1918. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to detect, determine the distance of, and map, objects such... A Linear particle accelerator is an electrical device for the acceleration of subatomic particles. ... A cavity magnetron is a high-powered vacuum tube that generates coherent microwaves. ... Coherence is from Latin cohaerere = stick together, to be connected with). ... Amplitude is a nonnegative scalar measure of a waves magnitude of oscillation, that is, magnitude of the maximum disturbance in the medium during one wave cycle. ... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... Look up Phase in Wiktionary, the free dictionary Phase may refer to: Phase (matter), a physically distinctive form of a substance, such as the solid, liquid, and gaseous states of ordinary matter Phase (waves), the time position (or angle in the complex plane) within a cycle of a periodic waveform... A waveguide is a structure which guides waves, such as electromagnetic waves, light, or sound waves. ...


Two-cavity klystron amplifier

In the two-chamber klystron, an electron beam from the cathode of an electron gun is injected into a resonant cavity. The electron beam is constrained by an axial magnetic field and is accelerated through a connecting passage (called a drift tube) to a second resonant chamber containing a positively charged anode. While passing through the connecting chamber the electron beam is velocity modulated (periodically bunched) by the weaker RF signal. The negative electrons are attracted to the positive anode contained in the second resonant chamber. As the bunched electrons enter the second chamber they induce standing waves at the same frequency as the input signal. The signal induced in the second chamber is much stronger than that in the first. Image File history File links Klystron. ... A charged particle beam is a group of electrically charged particles that have approximately the same kinetic energy and move in approximately the same direction. ... Diagram of a copper cathode in a Daniells cell. ... Electron gun from a cathode ray tube An electron gun is a component that produces an electron stream that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology, and in other instruments, eg. ... The Tacoma Narrows Bridge (shown twisting) in Washington collapsed spectacularly, under moderate wind, in part because of resonance. ... Diagram of a zinc anode in a Daniells cell. ... A standing wave, also known as a stationary wave, is a wave that remains in a constant position. ...


Two-cavity klystron oscillator

The two-cavity amplifier klystron is readily turned into an oscillator klystron by providing a feedback loop between the input and output cavities. Two-cavity oscillator klystrons have the advantage of being among the lowest-noise microwave sources available, and for that reason have often been used in the illuminator systems of missile targeting radars. The two-cavity oscillator klystron normally generates more power than the reflex klystron—typically watts of output rather than milliwatts. Since there is no reflector, only one high-voltage supply is required; however, to cause the tube to oscilate, the voltage must be adjusted to a particular value. This is because the electron beam must produce the bunched electrons in the second cavity in order to generate output power. Voltage must be adjusted by varying the velocity of the electron beam to a suitable level due to the fixed physical separation between the two cavities. Often several 'modes' of oscillation can be observed in a given klystron. Feedback is (generally) information about actions. ... Microwave image of 3C353 galaxy at 8. ... A missile (CE pronunciation: ; AmE: ) is, in general, a projectile—that is, something thrown or otherwise propelled. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to detect, determine the distance of, and map, objects such... The watt (symbol: W) is the SI derived unit of power. ... The velocity of an object is simply its speed in a particular direction. ...


Reflex klystron

In the reflex klystron, the electron beam passes through a single resonant cavity. The electrons are fired into one end of the tube by an electron gun. After passing through the resonant cavity they are reflected by a negatively charged reflector electrode for another pass through the cavity, where they are then collected. The electron beam is velocity modulated when it first passes through the cavity. The formation of electron bunches takes place in the drift space between the reflector and the cavity. The voltage on the reflector must be adjusted so that the bunching is at a maximum as the electron beam re-enters the resonant cavity, thus ensuring a maximum of energy is transferred from the electron beam to the RF oscillations in the cavity. The reflector voltage may be varied slightly from the optimum value, which results in some loss of output power, but also in a variation in frequency. This effect is used to good advantage for automatic frequency control in receivers, and in frequency modulation for transmitters. The level of modulation applied for transmission is small enough that the power output essentially remains constant. At regions far from the optimum voltage, no oscillations are obtained at all. Image File history File links Reflex. ... Electron gun from a cathode ray tube An electron gun is a component that produces an electron stream that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology, and in other instruments, eg. ... Josephson junction array chip developed by NIST as a standard volt. ... Rough plot of Earths atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including radio waves. ... Frequency modulation (FM) is a form of modulation which represents information as variations in the instantaneous frequency of a carrier wave. ...


There are often several regions of reflector voltage where the reflex klystron will oscillate; these are referred to as modes. The electronic tuning range of the reflex klystron is usually referred to as the variation in frequency between half power points—the points in the oscillating mode where the power output is half the maximum output in the mode.


Modern semiconductor technology has effectively replaced the reflex klystron in most applications. A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ...


Multicavity klystron

In the multicavity klystron, multiple toroidal cavities surround a cylindrical acceleration tube.


To achieve high efficiency the electron would have to be modulated by a saw-tooth signal, so that very small bunches enter the second cavity when the voltage peaks. The saw-tooth is synthesized by a fourier series. The harmonics needed for this series are usually generated from the beam itself, but wider bandwidth, efficiency and stability may be achieved by generating them before the klystron.


Tuning a klystron

Some klystrons have cavities that are tunable. Tuning a klyston is delicate buisness that if not done properly can cause damage to equipment and or personnel. Klystrons can cost between as much as a house or a luxury car. By adjusting the graduated knobs found on the body of the klystron, metal grids inside the klyston cavities change the resonant frequency that the cavities resonates at dilivering peak Transmitter power output(TPO) for the desired frequency. Be carefull not to exceed the limits of the graduations because the grid can fall off the corkscrew that the grid rides on inside the cavity. This will permanantly damage the klystron if not send a massive wave of reflected power back into your upstream equipment causing further damage. Manufacturers will send a card calibrated unique to that klystron's performance charecteristics that lists the graduations that are to be set for any given frequency. No two klystrons are alike and every card is different. Even when comparing the like part/model number klystrons. Do not lose that calibration card or it may never run right again, unless you can get a copy from the manufacturer. Klystrons have serial numbers on each of them that distinguishes them uniquely in which manufacturers may hopefully have the performance charecteristics in a database. Other precautions when tuning a klystron include using nonferrous tools. If ferrous (Magnetically reactive) tools come to close within the intense magnetic fields that contain the electron beam(even when turned off these fields are present) the tool can get sucked in by the intense magnetic force smashing fingers, hurting the technician, or damaging the klystron. Special tools made of Beryllium[1] are designed specifically for tuning klystrons. It would be a wise idea to wash your hands after using these tools because Beryllium is mildly toxic as well as a carcinogen when injested. Precautions should be taken when transporting these devices in aircraft as the instense magnetic field can interfere with magnetic navigation equipment. Special overpacks are designed help limit this field and transport the klystron safely. Transmitter power output (TPO) is the actual amount of power (in watts) of RF energy that a transmitter produces at its output. ... FerrLink titleMedia:Example. ... In pathology, a carcinogen is any substance or agent that promotes cancer. ...


Optical klystron

In an optical klystron the cavities are replaced with undulators. Very high voltages are needed. But the gun, the drift tube and the collector are still used. An undulator is a device from high-energy physics and usually part of a larger installation, a synchrotron. ...


Floating drift tube klystron

The floating drift tube klystron has a single cylindrical chamber containing an electrically isolated central tube. Electrically, this is similar to the two cavity oscillator klystron with a lot of feedback between the two cavities. Electrons exiting the source cavity are velocity modulated by the electric field as they travel through the drift tube and emerge at the destination chamber in bunches, delivering power to the oscillation in the cavity. This type of oscillator klystron has the advantage over the two-cavity klystron on which it is based of only needing one tuning element to effect changes in frequency. The drift tube is electrically insulated from the cavity walls, and DC bias is applied separately. The DC bias on the drift tube may be adjusted to alter the transit time through it, thus allowing some electronic tuning of the oscillating frequency. The amount of tuning in this manner is not large and is normally used for frequency modulation when transmitting. Download high resolution version (458x800, 70 KB)Klystron found at the Canberra Deep Space Communications Complex (i took this picture) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Download high resolution version (458x800, 70 KB)Klystron found at the Canberra Deep Space Communications Complex (i took this picture) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... 70m telescope at the Canberra Deep Space Communications Complex Tidbinbilla Locality Map The Canberra Deep Space Communications Complex (CDSCC) is located in Australia at Tidbinbilla in a valley of the Murrumbidgee River, about half an hours drive out of Canberra in the Australian Capital Territory, accessible from either the northern...


Collector

The used electron beam is sent through an electron spectrometer. Electrons with different energies are then retarded by different DC fields, so they all hit their collectors with low energy. This process provides several advantages: unused energy flows back to the power supply; unwanted X-rays and secondary electrons are minimized; and the system runs at a lower temperature, minimizing the need for cooling. For the klystron article: Bend the electron with electric or magnetic fields. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...


Applications

These amplifiers are used to produce UHF, SHF, and EHF signals where such high amplitude (power) is required that solid-state devices are inadequate. Klystrons can be found at work in radar, satellite and wideband high-power communication (very common in television broadcasting and EHF satellite terminals), and high-energy physics (particle accelerators and experimental reactors). This article is about the radio frequency. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... Extremely high frequency is the highest radio frequency band. ... Amplitude is a nonnegative scalar measure of a waves magnitude of oscillation, that is, magnitude of the maximum disturbance in the medium during one wave cycle. ... In physics, the solid state is one of the three phases of matter (solid, liquid, and gas). ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to detect, determine the distance of, and map, objects such... This article or section is missing references or citation of sources. ... A satellite is any object that orbits another object (which is known as its primary). ... Particle physics is a branch of physics that studies the elementary constituents of matter and radiation, and the interactions between them. ... A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A particle accelerator is a device that uses electric and/or magnetic fields to propel electrically charged particles to high speeds. ...


A misleadingly similarly named tube, the krytron, has been used in nuclear weapons, used as switches to detonate explosives at high speeds to start the fission process. They have also been used in Photocopiers. Krytron is one of the earliest developments of the EG&G Corporation. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the hypocenter. ...


Klystron tube trivia

  • A klystron tube is used by Dan Aykroyd's character in the 1988 comedy film, My Stepmother Is an Alien. In this case, the equipment overloads after coming in contact with the metal buttons of a jacket, causing a reaction that sends a powerful signal to a distant world. That signal gains the attention of aliens who come to Earth to investigate. Later, the original malfunction is intentionally reproduced and an alien creature is destroyed by contact with the electrified tube.

Dan Aykroyd (left) with John Belushi in The Blues Brothers Daniel Edward Aykroyd (born July 1, 1952) is an Academy Award-nominated Canadian comedian, actor, screenwriter and musician. ... My Stepmother is an Alien is a 1988 comedy science fiction movie directed by Richard Benjamin. ...

See also

A crossed-field amplifier (CFA) is a specialized vacuum tube, frequently used as a microwave amplifier in very-high-power transmitters. ... wave f[o[Image:Light-wave. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Gyrotrons are high powered electron tubes which emit a millimeter wave beam by bunching electrons with cyclotron motion in a strong magnetic field. ... The inductive output tube or IOT is a variety of vacuum tube which evolved in the 1980s to meet increasing efficiency requirements for high-power RF amplifiers. ... A Linear particle accelerator is an electrical device for the acceleration of subatomic particles. ... A cavity magnetron is a high-powered vacuum tube that generates coherent microwaves. ... A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A particle accelerator is a device that uses electric and/or magnetic fields to propel electrically charged particles to high speeds. ... It has been suggested that this article or section be merged with Traveling wave tube amplifier. ... A waveguide is a structure which guides waves, such as electromagnetic waves, light, or sound waves. ...

External links


  Results from FactBites:
 
Klystron tube - Wikipedia, the free encyclopedia (1297 words)
Klystrons are used as an oscillator or amplifier at microwave and radio frequencies to produce both low power reference signals for superheterodyne radar receivers and to produce high-power carrier waves for communications and the driving force for linear accelerators.
Many klystrons have a waveguide for coupling microwave energy into and out of the device, although it is also quite common for lower power and lower frequency klystrons to use coaxial couplings instead.
Klystrons can be found at work in radar, satellite and wideband high-power communication (very common in television broadcasting and EHF satellite terminals), and high-energy physics (particle accelerators and experimental reactors).
  More results at FactBites »

 
 

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