X-ray

:In the NATO phonetic alphabet, X-ray represents the letter X.

History

Among the important early researchers in X-rays were Professor Ivan Pului, Sir William Crookes, Johann Wilhelm Hittorf, Eugen Goldstein, Heinrich Hertz, Philipp Lenard, Hermann von Helmholtz, Nikola Tesla, Thomas Edison, Charles Glover Barkla, Max von Laue, and Wilhelm Conrad Röntgen.

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Ivan Pului - William Crookes - Johann Wilhelm Hittorf - Eugen Goldstein - Heinrich Hertz - Philipp Lenard - Hermann von Helmholtz - Nikola Tesla - Thomas Edison - Charles Glover Barkla - Max von Laue - Wilhelm Conrad Röntgen

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Physicist Johann Hittorf (1824 - 1914) observed tubes with energy rays extending from a negative electrode. These rays produced a fluorescence when they hit the glass walls of the tubes. In 1876 the effect was named "cathode rays" by Eugen Goldstein. Later, English physicist William Crookes investigated the effects of energy discharges on rare gases, and constructed what is called the Crookes tube. It is a glass vacuum cylinder, containing electrodes for discharges of a high voltage electric current. He found, when he placed unexposed photographic plates near the tube, that some of them were flawed by shadows, though he did not investigate this effect.

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Tubes - 1876 - Cathode rays - Eugen Goldstein - William Crookes

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In April 1887, Nikola Tesla began to investigate X-rays using high voltages and vacuum tubes of his own design, as well as Crookes tubes. From his technical publications, it is indicated that he invented and developed a special single-electrode X-ray tube, which differed from other X-ray tubes in having no target electrode. He stated these facts in his 1897 X-ray lecture before the New York Academy of Sciences.

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April - 1887 - Nikola Tesla - 1897 - New York Academy of Sciences

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The principle behind Tesla's device is nowadays called the Bremsstrahlung process, in which a high-energy secondary X-ray emission is produced when charged particles (such as electrons) pass through matter. By 1892, Tesla performed several such experiments, but he did not categorize the emissions as what were later called X-rays, instead generalizing the phenomenon as radiant energy. He did not publicly declare his findings nor did he make them widely known. His subsequent X-ray experimentation by vacuum high field emissions led him to alert the scientific community to the biological hazards associated with X-ray exposure.

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Bremsstrahlung - 1892 - Radiant energy

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In 1892, Heinrich Hertz began experimenting and demonstrated that cathode rays could penetrate very thin metal foil (such as aluminium). Philipp Lenard, a student of Heinrich Hertz, further researched this effect. He developed a version of the cathode tube and studied the penetration by X-rays of various materials. Philipp Lenard, though, did not realize that he was producing X-rays. Hermann von Helmholtz formulated mathematical equations for X-rays. He postulated a dispersion theory before Röntgen made his discovery and announcement. It was formed on the basis of the electromagnetic theory of light (Wiedmann's Annalen, Vol. XLVIII). However, he did not work with actual X-rays.

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Heinrich Hertz - Aluminium - Philipp Lenard - Hermann von Helmholtz

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On November 8 1895, Wilhelm Röntgen, a German scientist, began observing and further documenting X-rays while experimenting with vacuum tubes. Röntgen, on December 28, 1895, wrote a preliminary report "On a new kind of ray: A preliminary communication". He submitted it to the Würzburg's Physical-Medical Society journal. This was the first formal and public recognition of the categorization of X-rays. Röntgen referred to the radiation as "X", to indicate that it was an unknown type of radiation. The name stuck, although (over Röntgen's great objections), many of his colleagues suggested calling them Röntgen rays. They are still referred to as such in many languages, where available see the list of titles for versions of this article in other languages. Röntgen received the first Nobel Prize in Physics for his discovery.

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November 8 - 1895 - Wilhelm Röntgen - German - December 28 - Würzburg - Nobel Prize in Physics

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Wilhelm Conrad Röntgen was working on a primitive cathode ray generator that was projected through a glass vacuum tube. All of a sudden he noticed a faint green light against the wall. The odd thing he had noticed, was that the light from the cathode ray generator was traveling through a bunch of the materials in its way (paper,wood, and books). He than started to put carious objects in from of the generator, as he was doing this he noticed the outline of his bones form his hand being displayed on the wall. He then studied this phenomenon in seclusion.

Related Topics:
Wilhelm Conrad Röntgen - Cathode - Seclusion

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In 1895, Thomas Edison investigated materials' ability to fluoresce when exposed to X-rays, and found that calcium tungstate was the most effective substance. Around March 1896, the fluoroscope he developed became the standard for medical X-ray examinations. Nevertheless, Edison dropped X-ray research around 1903 after the death of Clarence Madison Dally, one of his glassblowers. Dally had a habit of testing X-ray tubes on his hands, and acquired a cancer in them so tenacious that both arms were amputated in a futile attempt to save his lifehttp://www.ratical.org/radiation/KillingOurOwn/KOO6.html. In 1906, physicist Charles Barkla discovered that X-rays could be scattered by gases, and that each element had a characteristic X-ray. He won the 1917 Nobel Prize in Physics for this discovery.

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1895 - Thomas Edison - March - 1896 - 1903 - Clarence Madison Dally - Cancer - Amputated - 1906 - Charles Barkla - 1917 - Nobel Prize in Physics

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The use of X-rays for medical purposes (to develop into the field of radiation therapy) was pioneered by Major John Hall-Edwards in Birmingham, England. In 1908, he had to have his left arm amputated owing to the spread of X-ray dermatitishttp://www.birmingham.gov.uk/xray. In the 1950s X-rays were first harnessed to produce an X-ray microscope.

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Radiation therapy - John Hall-Edwards - Birmingham - England - 1908 - X-ray dermatitis - 1950s - X-ray microscope

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In the 1980s an X-ray laser device was proposed as part of the Reagan administration's Strategic Defense Initiative, but the first and only test of the device (a sort of laser "blaster", or death ray, powered by a thermonuclear explosion) gave inconclusive results. For technical and political reasons, the overall project (including the X-ray laser) was de-funded (though was later revived by the second Bush administration as National Missile Defense using different technologies).

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1980s - Reagan - Strategic Defense Initiative - Death ray - Bush - National Missile Defense

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In the 1990s the Chandra X-Ray Observatory was launched, allowing the exploration of the very violent processes in the universe which produce X-Rays. Unlike visible light, which is a relatively stable view of the universe, the X-ray universe is unstable, it features stars being torn apart by black holes, galactic collisions, and novas, neutron stars that build up layers of plasma that then explode into space.

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