File:Cockcroft-Walton 3MV Kaiser Wilhelm Institute 1937 top view.png

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Cockcroft-Walton_3MV_Kaiser_Wilhelm_Institute_1937_top_view.png(523 × 417 pixels, file size: 144 KB, MIME type: image/png)

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English: 3 megavolt Cockcroft-Walton particle accelerator at Kaiser Wilhelm Institute of Physics in Berlin in 1937. The source claims it was the world's most powerful accelerator at the time. It consisted of two 4 stage Cockcroft-Walton voltage multiplier stacks of opposite polarity, with the high potential appearing at the top of the stacks applied to electrodes at opposite ends of an evacuated accelerator tube (not visible). Subatomic particles are accelerated to high speeds in the tube by the high potential. The black vertical segments on each stack are capacitors which store the charge, while the diagonal "rungs" between the columns are vacuum tube rectifiers called kenotrons, which only allow charge to pass in one direction. An alternating voltage of several hundred kilovolts is applied between the bottom of the columns, which act as a "charge pump" forcing charge into the top electrode. All exposed parts at high potential must have smooth gently curving surfaces to prevent corona discharge which causes leakage of current into the air. The output voltage of this machine was close to the limit for open-air electrostatic generators; even modern Cockcroft-Walton machines cannot produce more than about 5 megavolts.

Alterations to image: cloned in a small amount of wall behind lefthand column to replace overlap of adjacent picture on page.
Date
Source Retrieved April 12, 2015 from "World's biggest atom smasher uses 3,000,000 volts" in Popular Science Monthly, Popular Science Publishing Co., New York, Vol. 131, No. 4, October 1937, p. 53 on Google Books
Author Unknown authorUnknown author
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This 1937 issue of Popular Science magazine would have the copyright renewed in 1965. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. Search of the Renewals for Periodicals for 1964, 1965, and 1966 show no renewal entries for Popular Science. Therefore the copyright was not renewed and it is in the public domain.

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This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.

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current18:17, 5 May 2021Thumbnail for version as of 18:17, 5 May 2021523 × 417 (144 KB)Materialscientist (talk | contribs)tidied
22:14, 13 April 2015Thumbnail for version as of 22:14, 13 April 2015523 × 417 (159 KB)Chetvorno (talk | contribs)User created page with UploadWizard

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