File:PositronDiscovery.png
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Summary
DescriptionPositronDiscovery.png |
Photo of a positron. Removed white background, derived from another photo. English: Cloud chamber photograph of the first positron ever observed. The thick horizontal line is a lead plate. The positron entered the cloud chamber in the lower left, was slowed down by the lead plane, and curved to the upper left. The curvature of the path is caused by an applied magnetic field that acts perpendicular to the image plane. The higher energy of the entering positron resulted in lower curvature of its path. Original caption: A 63 million volt positron (Hρ = 2.1×105 gauss-cm) passing through a 6 mm lead plate and emerging as a 23 million volt positron (Hρ = 7.5×104 gauss-cm). The length of this latter path is at least ten times greater than the possible length of a proton path of this curvature. |
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Date | Photographed 2 August 1932. Published 15 March 1933. | |||
Source | Anderson, Carl D. (1933). "The Positive Electron". Physical Review 43 (6): 491–494. DOI:10.1103/PhysRev.43.491. | |||
Author | Carl D. Anderson (1905–1991) | |||
Permission (Reusing this file) |
Obtained from American Physical Society, March 5, 2008. The copyright for the periodical containing this picture, if renewed, would have had to be renewed in 1960 or 1961. I checked the Catalog of copyright entries for Periodicals in 1960 and 1961, http://onlinebooks.library.upenn.edu/cce/, but The Physical Review is not listed there. Therefore, the copyright on the entire issue of The Physical Review, including this picture, has expired. | |||
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Licensing
Public domainPublic domainfalsefalse |
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. العربية ∙ Deutsch ∙ English ∙ español ∙ français ∙ galego ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ português ∙ português do Brasil ∙ русский ∙ sicilianu ∙ slovenščina ∙ українська ∙ 简体中文 ∙ 繁體中文 ∙ +/− |
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 21:25, 13 August 2020 | 2,408 × 2,374 (2.92 MB) | wikimediacommons>Moonrivers | Uploaded own work with UploadWizard |
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Metadata
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Width | 2,408 px |
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Height | 2,374 px |
Bits per component |
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Number of components | 4 |
Horizontal resolution | 72 dpi |
Vertical resolution | 72 dpi |
Exif version | 2.21 |
Colour space | Uncalibrated |
Image width | 2,408 px |
Image height | 2,374 px |
Unique ID of original document | 5C4837C40D48AB6282C73A354AB3CD82 |
Date and time of digitising | 06:53, 14 August 2020 |
File change date and time | 07:42, 14 August 2020 |
Date metadata was last modified | 07:42, 14 August 2020 |
Software used | Adobe Photoshop CC 2015 (Windows) |