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Encyclopedia > Krytron

The Krytron is a cold-cathode gas filled tube intended for use as a very high-speed switch and was one of the earliest developments of the EG&G Corporation. Gas filled tubes are arrangements of electrodes in a gas within an insulating, temperature-resistant envelope. ... EG&G is a defense contractor and provider of management and technical services. ...

Contents

Description

Unlike most other gas switch tubes, the krytron uses arc discharge to handle very high voltages and currents (several kV and several kA peak), rather than the usual low-current glow discharge. The krytron is a development of the triggered spark gaps and thyratrons originally developed for radar transmitters during World War II. Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, similar to the instant spark, resulting from a current flowing through normally nonconductive media such as air. ... now. ... A spark plug. ... A thyratron is a type of gas filled tube used as a high energy electrical switch. ... 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. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

KN2 "Krytron" switch tube, made by EG&G--approx 25 mm tall

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Operation

Diagram of a Krytron.

There are four electrodes in a krytron. Two are conventional anode and cathode. One is a keep-alive electrode, arranged to be close to the cathode. The keep-alive has a low positive voltage applied, which causes a small area of gas to ionize near the cathode. High voltage is applied to the anode, but primary conduction does not occur until a positive pulse is applied to the trigger electrode ("Grid" in the image above). Once started, arc conduction carries a considerable current. In place of or in addition to the keep-alive electrode some krytrons may contain a very tiny amount of radioactive material (usually nickel-63) which emits beta particles (high-speed electrons) to make ionization easier. The amount of radiation in a krytron is very small and not harmful. Image File history File links Krytron. ... An electrode is an electrical conductor used to make contact with a metallic part of a circuit (e. ... Diagram of a zinc anode in a galvanic cell. ... Diagram of a copper cathode in a Daniells cell. ... General Name, symbol, number nickel, Ni, 28 Chemical series transition metals Group, period, block 10, 4, d Appearance lustrous, metallic and silvery with a gold tinge Standard atomic weight 58. ... Alpha radiation consists of helium nuclei and is readily stopped by a sheet of paper. ... e- redirects here. ... Ionization is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. ...


Performance

This design, dating from the late 1940s, is still capable of pulse-power performance which even the most advanced semiconductors (even IGBT transistors) cannot match easily. The vacuum-filled version is called a Sprytron and is designed for use in environments where high levels of ionizing radiation are present (because the radiation might cause the gas-filled krytron to trigger inadvertently.) A power IGBT The Insulated (or sometimes called Isolated) Gate Bipolar Transistor combines the simple gate drive characteristics of the MOSFET with the high current and low saturation voltage capability of bipolar transistors by combining an isolated gate FET for the control input, and a bipolar power transistor as a... Radiation hazard symbol. ...


Applications

Krytrons and their variations are still manufactured by Perkin-Elmer Components, and used in a variety of industrial and military devices. They are best known for their use in igniting the exploding-bridgewire detonators and slapper detonators in nuclear weapons, their original application, either directly or by triggering the higher-power spark gap switches. They are also used to trigger large flashlamps in photocopiers, lasers and scientific apparatus, as well as firing ignitors for industrial explosives. The exploding-bridgewire detonator (EBW, also known as exploding wire detonator) was invented by Luis Alvarez and Lawrence Johnston for the Fat Man-type bombs of the Manhattan Project, during their work in Los Alamos National Laboratory. ... A slapper detonator is a relatively recent kind of a detonator developed in Lawrence Livermore National Laboratory. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 kilometers (11 mi) above the hypocenter A nuclear weapon derives its destructive force from nuclear reactions of fusion or fission. ... A spark plug. ... U-shaped Xenon Flash Lamp A xenon flash lamp is a gas discharge lamp designed to produce extremely intense, incoherent, full-spectrum white light for very short durations. ... A small, much-used Xerox copier in a high school library. ... Experiment with a laser (US Military) In physics, a laser is a device that emits light through a specific mechanism for which the term laser is an acronym: Light Amplification by Stimulated Emission of Radiation. ... This article is concerned solely with chemical explosives. ...


Export restrictions

Because of the potential for use as nuclear triggers, the export of krytrons is tightly regulated. A number of cases involving the smuggling or attempted smuggling of krytrons have been reported, as countries seeking to develop nuclear weapons have attempted to procure supplies of krytrons for igniting their weapons. This article does not cite any references or sources. ...


Krytron in popular culture

A Krytron was the "MacGuffin" in Roman Polanski's 1988 film Frantic. A MacGuffin (sometimes McGuffin or Maguffin) is a plot device that motivates the characters and/or advances the story, but has little other relevance to the story. ... This is a trivia section. ...


References

  • EG&G Electronic Components Catalog, 1994.

External links


  Results from FactBites:
 
Krytron - All About All (429 words)
The krytron is a development of the triggered spark gaps and thyratrons originally developed for radar transmitters during World War II.
Because of the potential for use as nuclear triggers, the export of krytrons is tightly regulated.
A number of cases involving the smuggling or attempted smuggling of krytrons have been reported, as countries seeking to develop nuclear weapons have attempted to procure supplies of krytrons for igniting their weapons.
  More results at FactBites »

 
 

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