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
Accelerators and Light Sources of Tomorrow (Part 1: From Linacs to Lasers)
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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 ...
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 ...
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 ...
X-ray named top achievement by British museum
Nov 04, 2009 |
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The X-ray was named the most important modern scientific achievement Wednesday in a poll conducted for Britain's Science Museum, beating Apollo spacecraft and DNA.
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 ...
Radiologists develop scale to help clinicians predict disease severity in infants with NEC
Oct 20, 2009 |
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Radiologists at Duke University Medical Center have developed a scale called the Duke Abdominal Assessment Scale (DAAS) to assist clinicians in determining the severity of disease and the need for surgery in infants with ...
LCLS: The World's Largest Laser Writer?
Oct 20, 2009 |
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(PhysOrg.com) -- While not the smallest lettering ever created, the tiny initials "LCLS" have been written with what may be the world's most potent pen. Etched into boron carbide, a super-hard substance used ...
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, ...
New Twist on Favorite X-ray Technique Promises Ultrafast Molecular Studies
Oct 12, 2009 |
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(PhysOrg.com) -- A team of physicists from the Stanford Synchrotron Radiation Lightsource, including graduate student David Bernstein, have made a promising discovery that a well-known synchrotron technique ...
Femtoseconds lasers help formation flying in space
Oct 02, 2009 |
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The National Physical Laboratory (NPL) has helped to establish that femtosecond comb lasers can provide accurate measurement of absolute distance in formation flying space missions.
Watching a Supernova Come and Go
Sep 18, 2009 |
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(PhysOrg.com) -- Supernovae, the explosive deaths of massive stars, disburse into space all of the chemical elements that were spawned inside the progenitor stars.
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.
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.
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, ...
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).
