X-rays


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to X-rays: Gamma rays, MRI, ultraviolet

X-rays

X-rays, or roentgen rays, are electromagnetic waves in which periodically variable electric and magnetic fields are perpendicular to each other and to the direction of propagation. Thus they are identical in nature with visible light and all the other types of radiation that constitute the electromagnetic spectrum. In general, x-rays are generated as the result of energy transitions of atomic electrons caused by the bombardment of a material of high atomic weight by high-energy electrons. See Electromagnetic radiation

Following W. R. Röntgen's discovery of “a new kind of ray” in 1895, other scientists found the essential experimental conditions to prove that x-rays can be polarized, diffracted by crystals, refracted in prisms and in crystals, reflected by mirrors, and diffracted by ruled gratings. See X-ray optics

The range of x-rays in the electromagnetic spectrum, as excited in x-ray tubes by the bombardment of anode targets by cathode electrons under a high accelerating potential, overlaps the ultraviolet range on the order of 100 nanometers on the long-wavelength side, and the shortest-wavelength limit moves downward as voltages increase. An accelerating potential of 109 volts, now readily generated, produces a wavelength of 10-15 m (10-6 nm). An average wavelength used in research is 0.1 nm, or about 1/6000 the wavelength of yellow light. See X-ray tube

In diffraction, refraction, polarization, and interference phenomena, x-rays, together with all other related radiations, appear to act as waves. In other phenomena—such as the appearance of sharp spectral lines, a definite short-wavelength limit of the continuous “white” spectrum, the shift in wavelength of x-rays scattered by electrons in atoms (Compton effect), and the photoelectric effect—the energy seems to be propagated and transferred in quanta, called photons. See Compton effect, Electron diffraction, Neutron diffraction, Photoemission, Quantum mechanics

Important uses have been found for x-rays in many fields of scientific endeavor, for example, roentgen spectrometry and roentgen diffractometry. Extensive tables of the wavelengths of x-ray emission lines in series (K, L, M, and so on) and so-called absorption edges, characteristic of the chemical elements, afford the necessary information for chemical analyses, exactly as in the case of optical emission spectra and for derivation of theories of atomic structure to account for the origin of spectra. See X-ray crystallography, X-ray diffraction, X-ray powder methods

X-rays

High-energy electromagnetic radiation lying between gamma rays and ultraviolet radiation in the electromagnetic spectrum. The XUV region bridges the gap between the X-ray and ultraviolet bands. X-rays, unlike light and radio waves, are usually considered in terms of photon energy, h ν, where ν is the frequency of the radiation and h is the Planck constant. X-ray energies range from about 100 electronvolts (eV) up to about 100 000 eV, corresponding to a wavelength range of about 12 nanometers (nm) to about 0.012 nm. Low-energy X-rays are sometimes called soft X-rays to distinguish them from high-energy or hard X-rays. In astronomy, thermal X-rays are produced from very high temperature gas (˜106–108 K), with nonthermal X-rays arising from the interaction of high-energy electrons with a magnetic field (synchrotron emission) or with low-energy photons (inverse Compton emission – see Compton scattering). See also nonthermal emission; thermal emission.

x-rays

[′eks ‚rāz]
(physics)
A penetrating electromagnetic radiation, usually generated by accelerating electrons to high velocity and suddenly stopping them by collision with a solid body, or by inner-shell transitions of atoms with atomic number greater than 10; their wavelengths range from about 10-5 angstrom to 103 angstroms, the average wavelength used in research being about 1 angstrom. Also known as roentgen rays; x-radiation.
References in periodicals archive ?
In three out of five comparisons, CNN's performance in diagnosing diseases on X-rays from hospitals outside of its own network was significantly lower than on X-rays from the original health system.
The team's analysis, presented in a paper published on Monday, July 2, in Nature Astronomy, shows that these "hard" X-rays vary with the binary orbital period and show a similar pattern of energy output as the gamma rays observed by Fermi.
The study, titled "Non-thermal X-rays from colliding wind shock acceleration in the massive binary Eta Carinae," was published July 2 in the journal(https://www.nature.com/articles/s41550-018-0505-1) Nature Astronomy.
Different x-ray tubes from various manufacturers will vary slightly from these values, of course, but based on these numbers, what does this mean for the geometric magnification of an x-ray system where the detector is 300mm from the focal spot of both tube types?
Thus, we demonstrate a reliable and accurate method using x-rays to ascertain social spider colony sizes which does not require opening of retreats, and minimizes disturbance that can trigger dispersal from retreats when colonies are counted manually.
King said in a People interview that he 'didn't have any pain' and was doing a routine chest x-ray when doctors noticed a 'little cloud.'
Lisse's team used the Chandra X-ray telescope, once in 2014 and three times in 2015, to look for X-rays.
A spokesman for Worcestershire Acute Hospitals NHS Trust said: "We apologise for any distress this has caused and can confirm that the backlog concerns a secondary review of x-rays with the majority of these x-rays having been reviewed by the requesting clinician, mostly on the same day.
Results: For confirmed NEC group, the detection rate of portal venous gas (PVG) and dilatation of intestine by abdominal ultrasound was obviously higher than by plain X-rays (P<0.05).
Results: From 1st Jan 2015 to 1st June 2015 1200 chest X-rays were performed at Peshawar Institute Of Medical Sciences using Toshiba 100mAs/150kv latest computed radiography system.
The fantastic four--Wilhelm Conrad Roentgen (1845-1923), Nikola Tesla (1856-1943), Pupin (1854-1935.) and Maria Sklodowska-Curie (1867-1934), who had worked independently of each other, did not know that their work on the nature of X-rays would set the foundation of the new branch of medicine--radiology and contribute to its evolution, without which the modern medicine cannot even be imagined [1-27].
They said one should go for X-rays after consulting a seasoned doctor for preventing its harmful effects.