Russell Harrison Varian

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Russell Harrison Varian (born April 24, 1898 in Washington, DC , † July 28, 1959 in Juneau , Alaska) was an American scientist and inventor of a microwave generator and magnetometer .

Life

Russell was of Irish descent and had a younger brother, Sigurd Fergus Varian (born May 4, 1901 in Syracuse (New York) Syracuse , New York ; † October 18, 1961 in Puerto Vallarta , Mexico), who was a commercial pilot with PanAm. He studied at Stanford University and received his master's degree in 1927. William Webster Hansen , who later did research on cavity resonators , also studied here from 1925–33 . He then worked for various companies, such as Philo Farnsworth's TV company and Humble Oil and Refining Co. , on measuring instruments for oil production.

When his brother reported about his bad flying experiences at night and in fog and looked for ways of weather-independent navigation, Russell looked for methods to also be able to locate flying aircraft in bad weather and in the dark. The 1935 article by Agnessa and Oskar Heil was just as unknown to him as the secret military research with pulsed high-frequency beams, later known as radar.

He needed radio waves that could penetrate clouds and that were so short in wavelength that they could achieve the necessary resolution. The HF amplifiers used at the time had too low an upper frequency limit. On the one hand, resonant circuits with concentrated capacitances and inductances or Lecher lines in the microwave range have very high radiation losses. On the other hand, the upper frequency limit of density-controlled electron tubes is determined by the internal tube capacitances, the lead inductances of the electrodes and the electron transit time. The density-controlled electron tubes, which became smaller and smaller with the wavelength, only allowed small anode power losses. For example, the acorn tube (955 Acorn Triode) released by RCA-DeForest in March 1935 had a cut- off wavelength of 100 cm with an RF power of 0.5 W.

After Varian learned of Hansen's work on cavity resonators, the brothers traveled to Hansen on March 5, 1937. On the one hand they wanted to get his permission to use the resonator and on the other hand they wanted to discuss the Farnsworth multipactor with him, a dynamic secondary electron multiplier that they hoped would be useful as a microwave amplifier. Hansen was just testing his resonator, which his students called Rhumba , from which the name Rhumbatron later developed. On March 30, Sigurd proposed a contract to Stanford University to use the equipment at the Faculty of Physics and to consult Bill Hansen and other scientists at any time. The profit should be split equally between the university, Russell and Sigurd. Hansen took the time to test Russell's theories and formulate them mathematically. On June 5, 1937, Russel thought about a speed grouping principle that he called bunching ( Alfred Recknagel and Ernst Brüche called it phase focusing in 1938 ). They examined the idea of ​​using the transit time of the electrons as a functional principle and decided to develop a two-chamber rhumbatron oscillator for a wavelength of 10 cm, which was already oscillating stably on August 30, 1937. On October 11, 1937, they applied for their patent. They later referred to their microwave generator as a two-chamber klystron , because a double grating was used for speed modulation, which was at the same potential with two wall surfaces of a cavity resonator. The klystron in the centimeter wave range was used to set up microwave links. After the functionality had been researched in great detail, the team turned to the development of missing measurement methods for wavelength, frequency, power and impedance.

In 1948 the brothers founded the company Varian Associates for the production of klystrons, especially those with very high performance for radar technology and for television stations. For the Vanguard project , Varian developed a magnetometer in 1957 to measure the earth's magnetic field. Varian has received approximately 100 patents in the field of microwave technology. In 1995, Klystron and Radar Technology was spun off and is now called Communications & Power Industries , CPI. In 1999, Varian Associates split into three parts - Varian Inc. (part of Agilent Technologies since 2010 ), Varian Medical and Varian Semiconductor (part of Applied Materials since 2011 ).

literature

  • Dorothy Varian: The Inventor and the Pilot: Russell and Sigurd Varian ;

Web links

Individual evidence

  1. ↑ http://www.radiomuseum.org/forumdata/upload/Klystron.pdf
  2. ↑ http://journal.borderlands.com/1988/the-farnsworth-multipactor-tube/
  3. ↑ bibcode : 1938ZPhy..108..459B .
  4. ↑  ( page no longer available , search in web archives )@1@ 2Template: Toter Link / konmedia4.webmaintainer.de
  5. ↑ http://www.cpii.com/
  6. ^ "Agilent reaches deal to buy Varian for $ 1.5 billion" (press release) . In: Reuters , July 27, 2009. 
  7. ↑ Applied Materials to Buy Varian for $ 4.9 Billion. NYTimes, May 4, 2011, accessed February 20, 2014 .
personal data
SURNAME Varian, Russell Harrison
BRIEF DESCRIPTION American scientist and inventor
DATE OF BIRTH April 24, 1898
PLACE OF BIRTH Washington, DC
DATE OF DEATH July 28, 1959
Place of death Juneau