X radiation
Ionizing radiation consisting of photons other than gamma radiation, originating in the extranuclear part of the atom, comprising bremsstrahlung and characteristic radiation.
(IEC 50-393-1993)
X ray
Penetrating electromagnetic radiation whose wavelength is shorter than that of visible light; usually produced by bombarding a metallic target with fast electrons in a high vacuum; in nuclear reactions, it is customary to refer to photons originating in the nucleus as gamma rays, and those originating in the extranuclear part of the atom as x-rays; sometimes called Roentgen rays, after their discoverer, W.C. Roentgen.
(BEIR III)
X ray
A penetrating form of electromagnetic radiation emitted either when the inner orbital electrons of an excited atom return to their normal state or when a metal target is bombarded with high-speed electrons. X rays are always nonnuclear in origin.
(NCRP 65)
X ray
Penetrating electromagnetic radiation whose wavelength is shorter than that of visible light; usually produced by bombarding a metallic target with fast electrons in a high vacuum; in nuclear reactions, it is customary to refer to photons originating in the nucleus as gamma rays, and those originating in the extranuclear part of the atom as x-rays; sometimes called Roentgen rays, after their discoverer, W.C. Roentgen.
(RHH)
X ray apparatus
Device designed to produce x rays. Distinguished from an x-ray source that produces unwanted x rays.
(ICRP 36)
X ray fluorescence thickness meter
Thickness meter including a source of ionizing radiation and intended to determine material thickness by measurement of X ray fluorescence excited in the material itself or in the
(IEC 50-394-1993)
X rays
Penetrating electromagnetic radiations having wavelengths shorter than visible light. The are usually produced by bombarding a metallic target with fast electrons in a high vacuum. In nuclear reaction it is customary to refer to photons originating in the nucleus as g rays, and those originating in the extranuclear part of the atom as x rays. These rays are sometimes called "roentgen rays," after their discoverer, W.C. Roentgen.
(HPJ 60)
X rays
Penetrating electromagnetic radiations whose wave lengths are shorter than those of visible light. They are usually produced by bombarding a metallic target with fast electrons in a high vacuum. In nuclear reactions, it is customary to refer to photons originating in the nucleus as gamma rays, and those originating in the extranuclear part of the atom as X rays. These rays are sometimes called roentgen rays, after their discoverer, W.C. Roentgen.
(BEIR I)
XET (t)
Fractional rate of extrinsic clearance of material from the ET region at time T after an acute intake.
(ICRP 66)
X-ray
Electromagnetic radiation of energy usually above 1 keV. X rays are produced by impingement of charged particles (usually electrons) on materials. (See bremsstrahlung and characteristic x ray(s).)
(NCRP 51)
X-ray
A penetrating form of electromagnetic radiation emitted either when the inner orbital electrons of an excited atom return to their normal state (these are characteristic X rays), or when a metal target is bombarded with high speed electrons (these are bremsstrahlung). X rays are always nonnuclear in origin. (See excited state.)
(USAEC-1974)
X-ray accessory apparatus
Any portion of an x-ray installation which is external to the radiation source housing and into which an x-ray beam is directed for making x-ray measurements or other uses.
(ANSI N43.2-1977)
X-ray apparatus
Any source of X-rays, its power supply and controls, coming within the scope of this Handbook.
(NBS 55)
X-ray converter
Material in which electron energy is converted to x-ray energy, e.g., a thick target of high-Z material. In this report, the term is usually applied to a target in which the electron power is converted with a high degree of efficiency into x-ray power.
(NCRP 51)
X-ray film characteristic curve
A graph of film density versus the logarithm of the x-ray exposure.
(NCRP 68)
X-ray film characteristic curve
A graph of film density versus the logarithm of the x-ray exposure.
(NCRP 66)
X-ray film latitude
The range of exposures which will produce film densities in a certain range (usually for medical radiography 0.25-2). Film latitude and contrast are inversely related.
(NCRP 66)
X-ray generator
That portion of an x-ray system which provides the accelerating voltage and current for the x-ray tube.
(ANSI N43.2-1977)
X-ray generator
A type of electron accelerator in which the electron beam is used mainly for the production of x rays.
(NCRP 51)
X-ray installation
One or more x-ray systems, the surrounding room or controlled area, and the installation enclosure.
(ANSI N43.2-1977)
X-ray monitor
A device for indicating the X-radiation level from an accelerator for purposes of control or comparison. Frequently the X-ray monitor consists of an ionization chamber and a current-measuring device to indicate continuously the average ionization current in the chamber gas produced by the action of the X-rays.
(NBS 55)
X-ray system
Apparatus for generating and using ionizing radiation, including all x-ray accessory apparatus.
(ANSI N43.2-1977)
X-ray target
The structure subjected to bombardment by accelerated electrons in an accelerator for the production of X-rays.
(NBS 55)
X-ray tube assembly
A tube housing with the tube installed. It may include high voltage and filament transformers and other appropriate elements when they are contained within the tube housing.
(ANSI N537-1976)
X-ray tube housing
See radiation source housing.
(ANSI N43.2-1977)
X-rays
Electromagnetic radiations having wavelengths shorter than 10-6 cm. The X-radiation resulting from the interaction of external electrons with the nuclear and electronic fields of target atoms is produced by a process called bremsstrahlung. It is customary to refer to electromagnetic radiations originating in atomic nuclei as gamma rays.
(NBS 55)
Xenon effect
Phenomenon that takes place in thermal reactors, due to a build up of xenon, which is a very important nuclear poison.
(IEC 50-393-1993)
Xenon effect
The decrease in the reactivity of a thermal reactor or chain-reacting system after a long period of power operation due to the presence of large numbers of xenon-135 atoms generated in the fission products. (Also called xenon poisoning.)
(ANSI N1.1-1976)
Xenon instability
Oscillations in the power level in localized parts of a large reactor, due to the dependence of the xenon poisoning on the thermal neutron flux density. (Also called xenon oscillation.)
(ANSI N1.1-1976)
Xenon override
(1) That part of excess reactivity provided in a reactor to enable it to achieve criticality in the presence of increased xenon poison, which builds up following reactor shutdown. Xenon override is described as "full" when the reactivity available is sufficient to overcome the maximum xenon poison which can be achieved in the reactor following shutdown after full-power operation.
(2) The act of reactor operation, using the excess reactivity provided, under the above circumstances
(ANSI N1.1-1976)
Xeroradiography
The production of an image on a xerographic plate (e.g., electrically charges selenium) by the action of x rays transmitted through the patient. (Xeromammography: Mammography carried out by the xerographic process.)
(NCRP 102)
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