X-ray
hideX-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3 × 1016 Hz to 3 × 1019 Hz) and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays. In many languages, X-radiation is called Röntgen radiation after Wilhelm Conrad Röntgen, who is generally credited as their discoverer, and who had called them X-rays to signify an unknown type of radiation.:1-2
X-rays are primarily used for diagnostic radiography and crystallography. As a result, the term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. X-rays are a form of ionizing radiation and as such can be dangerous.
X-rays from about 0.12 to 12 keV are classified as soft X-rays, and from about 12 to 120 keV as hard X-rays, due to their penetrating abilities.
The distinction between X-rays and gamma rays has changed in recent decades. Originally, the electromagnetic radiation emitted by X-ray tubes had a longer wavelength than the radiation emitted by radioactive nuclei (gamma rays). So older literature distinguished between X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m, defined as gamma rays. However, as shorter wavelength continuous spectrum "X-ray" sources such as linear accelerators and longer wavelength "gamma ray" emitters were discovered, the wavelength bands largely overlapped. The two types of radiation are now usually defined by their origin: X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus.
For more information about X-ray, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with x rays
Gamma-ray photon race ends in dead heat; Einstein wins this round
Oct 28, 2009 |
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Racing across the universe for the last 7.3 billion years, two gamma-ray photons arrived at NASA's orbiting Fermi Gamma-ray Space Telescope within nine-tenths of a second of one another. The dead-heat finish ...
Carbon Atmosphere Discovered on Neutron Star
Nov 04, 2009 |
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(PhysOrg.com) -- Evidence for a thin veil of carbon has been found on the neutron star in the Cassiopeia A supernova remnant. This discovery, made with NASA's Chandra X-ray Observatory, resolves a ten-year ...
Astrophysicists explore a blazar
Mar 18, 2009 |
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An international team of astrophysicists using telescopes on the ground and in space have uncovered surprising changes in radiation emitted by an active galaxy. The picture that emerges from these first-ever ...
Computer scientist to 'unroll' papyrus scrolls buried by Vesuvius
Technology / Computer Sciences
May 24, 2009 |
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On Aug. 24, 79 A.D., Italy's Mount Vesuvius exploded, burying the Roman towns of Herculaneum and Pompeii under tons of super-heated ash, rock and debris in one of the most famous volcanic eruptions in history.
Massive Stars Near the Galactic Center
Aug 28, 2009 |
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The Central Molecular Zone (CMZ) of our galaxy is a giant complex of molecular gas and dust situated in the innermost 700 light-years of the Milky Way. Although the galaxy is over 100,000 light-years in size, ...
Study Reveals Small Lizard Tucks Legs and Swims Like a Snake Through Desert Sand (w/ Video)
Jul 16, 2009 |
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(PhysOrg.com) -- A study published in the July 17 issue of the journal Science details how sandfish -- small lizards with smooth scales -- move rapidly underground through desert sand. In this first thorou ...
Unusual shape of exploded star puzzles scientists
Jun 17, 2009 |
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Penn State astronomers have used NASA's Chandra X-ray Observatory to produce a new image of a ghostly exploded star with an unusual shape in a galaxy near the Milky Way. Astronomers think the object may be ...
Physicists see through the opaque with 'T-rays'
Dec 18, 2009 |
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"T-rays" may make X-rays obsolete as a means of detecting bombs on terrorists or illegal drugs on traffickers, among other uses, contends a Texas A&M physicist who is helping lay the theoretical groundwork to make the concept ...
Erratic black holes regulate their growth (w/Videos)
Mar 25, 2009 |
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(PhysOrg.com) -- New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest ...
Rare radio supernova in nearby galaxy is nearest supernova in five years
May 27, 2009 |
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(PhysOrg.com) -- The chance discovery last month of a rare radio supernova - an exploding star seen only at radio wavelengths and undetected by optical or X-ray telescopes - underscores the promise of new, ...
Superscanner sees into the unknown
Sep 10, 2009 |
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(PhysOrg.com) -- Researchers at The University of Nottingham have a new weapon in their arsenal of tools to push back the boundaries of science, engineering, veterinary medicine and archaeology.
GOES-O Releases First Solar Image
Space & Earth / Space Exploration
Aug 18, 2009 |
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GOES-14, formerly GOES-O, has achieved another significant milestone with the release of the first formal Solar Image from the Solar X-Ray Imager (SXI).
Accelerators and Light Sources of Tomorrow (Part 1: From Linacs to Lasers)
Dec 22, 2009 |
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From their humble beginnings as offshoots of the ordinary electric light bulb, particle accelerators have evolved in surprising directions. Among the most productive and promising developments have been light ...
Company Introduces Novel Nanotechnology for Revolutionizing Imaging Using T-rays
Oct 20, 2009 |
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Yissum Research Development Company of the Hebrew University of Jerusalem today announced that Professor L.D. Shvartsman and Professor B. Laikhtman, from the Racah Institute of Physics at the Hebrew University of Jerusalem, ...
NASA Approves X-ray Space Mission
Space & Earth / Space Exploration
Sep 07, 2009 |
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NASA recently confirmed that the Nuclear Spectroscopic Telescope Array, or NuSTAR, mission will launch in August 2011.
