Gamma radiation
Electromagnetic radiation emitted by an atomic nucleus as a result of a nuclear transformation.
(NCRP 111)
Gamma radiation
Also gamma rays; short wavelength electromagnetic radiation of nuclear origin, similar to x rays but of higher energy (100 keV to 9 Mev).
(BEIR V)
Gamma radiation
A ray of energy in contrast to beta and alpha particles' radiation. The properties are similar to those of X rays and other electromagnetic waves. Gamma radiation is highly penetrating but relatively low in ionizing potential.
(ENV RAD)
Gamma radiation
Electromagnetic radiation emitted in the process of nuclear transition or particle annihilation.
(ANSI N1.1-1976)
Gamma radiography system
All components necessary to male radiographic exposures, including the exposure device, source assembly, control, and other components associated with positioning the source such as source guide tubes, exposure head, and collimators, if used.
(ANSI N432-1980)
Gamma ray
Electromagnetic radiation frequently accompanying alpha and beta emissions as radioactive materials decay.
(NCRP 118)
Gamma ray
Short-wavelength electromagnetic radiation of nuclear origin (range of energy, 10 keV to 9 MeV).
(BEIR IV)
Gamma ray
Short-wavelength electromagnetic radiation of nuclear origin (range of energy, 10 keV to 9 MeV).
(BEIR III)
Gamma ray
Electromagnetic radiation emitted in the process of nuclear transition or radioactive decay.
(NCRP 51)
Gamma ray
Short wavelength electromagnetic radiation of nuclear origin (range of energy from 10 KeV to 9 MeV) emitted from the nucleus.
(BEIR I)
Gamma ray
Short-wavelength electromagnetic radiation of nuclear origin (range of energy, 10 keV to 9 MeV).
(RHH)
Gamma rays
Short-wavelength electromagnetic radiation of nuclear origin (approximate range of energy 10 keV to 9 MeV).
(NCRP 98)
Gamma rays
Electromagnetic radiation emitted in the process of nuclear transition.
(NCRP 105)
Gamma rays
High-energy, short-wavelength electromagnetic radiation. Gamma radiation frequently accompanies alpha and beta emissions and always accompanies fission. Gamma rays are very penetrating and are best stopped or shielded by dense materials, such as lead or depleted uranium. Gamma rays are essentially similar to x-rays, but are usually more energetic, and are nuclear in origin.
(NCRP 65)
Gamma rays
High-energy, short-wavelength electromagnetic radiation. Gamma radiation frequently accompanies alpha and beta emissions and always accompanies fission. Gamma rays are very penetrating and are best stopped or shielded by dense materials, such as lead or depleted uranium. Gamma rays are essentially similar to x-rays, but are usually more energetic, and are nuclear in origin.
(USAEC-1974)
Gamma rays
Electromagnetic radiation of short wave length and correspondingly high frequency, emitted by nuclei in the course of radioactive decay.
(NBS 73)
Gamma rays
Electromagnetic radiation of short wave length and correspondingly high frequency, emitted by nuclei in the course of radioactive decay.
(NBS 66)
Gamma rays
See X-rays.
(NBS 55)
Gamma rays
Electromagnetic radiation of short wave length and correspondingly high frequency, emitted by nuclei in the course of radioactive decay.
(NBS 54)
Gamma rays (g)
Electromagnetic radiation like x rays, emitted by the disintegrating radioactive nucleus. In general, gamma rays are more penetrating than x rays.
(NCRP 48)
Gamma, prompt
Gamma radiation emitted at the time of fission of a nucleus.
(RHH)
Gamma-ray
Short wavelength electromagnetic radiation of nuclear origin ( range of energy, 10 keV to 9 MeV) emitted from the nucleus, usually higher energy than x rays.
(HPJ 60)
Gamma-ray beam therapy
Therapeutic irradiation with collimated gamma rays.
(NCRP 49)
Gamma-ray transmission
The fraction or percentage of gamma rays that penetrate a material without being absorbed or scattered.
(ANSI N15.35-1983)
Gammaridae
Family of amphipod Crustacea common in marine habitat and in all freshwaters of the world.
(NCRP 109)
Gas
An aeriform fluid which is in the gaseous state at ordinary temperature and pressure.
(ANSI Z88.2-1980)
Gas
An aeriform fluid which is in the gaseous state at ordinary temperature and pressure.
(ANSI Z88.2-1969)
Gas amplification
As applied to gas ionization radiation detecting instruments, the ratio of the charge collected to the charge produced by the initial ionizing event.
(RHH)
Gas centrifuge process
A method of isotopic separation in which heavy gaseous atoms or molecules are separated from light ones by centrifugal force. (See isotope separation.)
(USAEC-1974)
Gas chromatograph
An analytical instrument used for quantitative analysis of extremely small quantities of organic compounds whose operation is based upon the absorption and partitioning of a gaseous phase within a column of granular material.
(ERDA 76-21)
Gas Exchange (Respiratory)
Process by which inhaled air supplies molecules of oxygen to the body and exhaled air removes molecules of carbon dioxide to the outside air.
(NCRP 125)
Gas flow ionization chamber
Ionization chamber in which gas flows continuously.
(IEC 50-394-1993)
Gas mask
See respirator.
(ANSI Z88.2-1980)
Gas mask
See respirator.
(ANSI Z88.2-1969)
Gas multiplication
Process whereby in a sufficiently intense electric field the ion pairs produced in a gas by incident radiation generate additional ion pairs.
(IEC 50-394-1993)
Gas multiplication factor
Factor by which the initial number of ion pairs is multiplied as a result of the gas multiplication process, under stated conditions.
(IEC 50-394-1993)
Gas radioactivity meter
Radiation meter for the continuous measurement in a gas of the radioactive emission in a given time interval.
(IEC 50-394-1993)
Gas residence time
The calculated time that a contaminant or test agent theoretically remains in contact with an adsorbent, based on active volume of adsorbent and air or gas velocity through the adsorber bed.
(ERDA 76-21)
Gas-cooled reactor
A nuclear reactor in which a gas is the coolant.
(USAEC-1974)
Gas-flow detector
Radiation detector in which an appropriate gaseous medium is maintained by means of a low rate of flow of a suitable gas.
(IEC 50-394-1993)
Gas-flow neutron fluence rate measuring assembly
Assembly designed to measure the neutron fluence rate in a nuclear reactor and which consists of a target of fissile material and a detector, the fission products created in the target being carried by an inert gas flow to the detector situated outside the reactor.
(IEC 50-394-1993)
Gas-Phase Boundary Zone
Distance above a reactive or absorbing surface within which transfer of gas or vapor from an air stream to the surface is occurring. (Distance depends on the diffusion coefficient of the gas or vapor, Temperature difference between the stream and surface and turbulent mixing in the gas stream.)
(NCRP 125)
Gaseous diffusion (plant)
A method of isotopic separation based on the fact that gas atoms or molecules with different masses will diffuse through a porous barrier (or membrane) at different rates. The method is used by the AEC to separate uranium-235 from uranium-238; it requires large gaseous-diffusion plants and enormous amounts of electric power. (See cascade, isotope separation, uranium hexafluoride.)
(USAEC-1974)
Gases
Normally formless fluids which occupy the space of enclosure and which can be changed to a liquid or solid state only by the combined effect of increased pressure and decreased temperature. Gases diffuse.
(ANSI Z9.2-1971)
Gastrointestinal absorption factor (f1)
The fraction of ingested activity which is absorbed into the blood.
(ICRP 20)
Gastrointestinal tract model
Model used to stylize the behavior of radionuclides in the gastrointestinal tract of man.
(NCRP 84)
Gauging
The measurement of the thickness, density or quantity of material by the amount of radiation it absorbs. This is the most common use of radioactive isotopes in industry. Also spelled gaging.
(USAEC-1974)
Gauss
A unit of magnetic induction. The earth's magnetic field is approximately 0.5 gauss.
(NCRP 105)
Gaussian curve
A profile of distribution or a curve similar to that observed for the normal distribution.
(AM-1993)
Gaussian model
A pollutant diffusion model based on an assumption of stationary, homogeneous turbulent flow. The distribution of material in the plume or puff is assumed to be Gaussian in shape.
(NCRP 123I)
Gaussian model
A pollutant diffusion model based on an assumption of stationary, homogeneous turbulent flow. The distribution of material in the plume or puff is assumed to be gaussian shaped.
(NCRP 76)
Gaussian plume model
Commonly used mathematical model to predict atmospheric diffusion of particulates and gases. Based on assumptions of statistically 'normal' or Gaussian plume dispersion, modified by empirical dispersion coefficients.
(NUREG/CR 3332)
Geiger region
In an ionization radiation detector, the operating voltage interval in which the charge collected per ionizing event is essentially independent of the number of primary ions produced in the initial ionizing event.
(RHH)
Geiger threshold
The lowest voltage applied to a counter tube for which the number of pulses produced in the counter tube is essentially the same, regardless of a limited voltage increase.
(RHH)
Geiger-Mueller (GM) counter
Highly sensitive, gas-filled radiation-detecting device, which is capable of detecting individual nuclear particles.
(NCRP 105)
Geiger-Mueller (GM) counter
A radiation detection and measuring instrument. It consists of a gas-filled (Geiger-Mueller) tube containing electrodes, between which there is an electrical voltage but no current flowing. When ionizing radiation passes through the tube, a short intense pulse of current passes from the negative electrode to the positive electrode and is measured or counted. The number of pulses per second measures the intensity of radiation. It is also often known as a Geiger counter; it was named for Hans Geiger and W. Mueller who invented it in the 1920's.
(NCRP 65)
Geiger-Mueller (GM) counter
A radiation detection and measuring instrument. It consists of a gas-filled (Geiger-Mueller) tube containing electrodes, between which there is an electrical voltage but no current flowing. When ionizing radiation passes through the tube, a short intense pulse of current passes from the negative electrode to the positive electrode and is measured or counted. The number of pulses per second measures the intensity of radiation. It is also often known as a Geiger counter; it was named for Hans Geiger and W. Mueller who invented it in the 1920's.
(USAEC-1974)
Geiger-Mueller region
The range of applied voltage in a gas filled counter tube in which the charge collected per ionizing event is constant and independent of the charge liberated by that event.
(ANSI N1.1-1976)
Geiger-Muller counter (G-M counter)
A chamber equipped with suitable electrodes and operated at a voltage and gas pressure that will permit ionization by collision and in which the total ionization per event is independent of the amount of ionization produced by the absorption of radiation.
(NBS 51)
Geiger-Muller counter tube
Counter tube operating in the Geiger-Muller mode.
(IEC 50-394-1993)
Geiger-Muller region
Range of applied voltage of a counter tube in which the gas multiplication factor is much greater than one, the pulse amplitude being substantially independent of the total number of ion pairs initially produced in the sensitive volume as a result of an ionizing event.
(IEC 50-394-1993)
Geiger-Muller threshold
Under specified conditions, minimum applied voltage for a counter tube to operate in the Geiger-Muller region.
(IEC 50-394-1993)
Geiger-Muller tube
A radiation sensing instrument which relies on an avalanche process initiated by the production of electron-ion pairs.
(AM-1993)
Gene
Fundamental unit of inheritance which determines and controls hereditarily transmissible characteristics. Genes are arranged linearly at definite loci on chromosomes.
(RHH)
General employee
An individual who is either a DOE or DOE contractor employee; an employee of a subcontractor to a DOE contractor; or an individual who performs work for or in conjunction with DOE or utilizes DOE facilities.
(10CFR835.2-1998)
General employee
An individual who is either a DOE or DOE contractor employee; an employee of a subcontractor to a DOE contractor; or a visitor who performs work for or in conjunction with DOE or utilizes DOE facilities.
(10CFR835.2-1993)
General license
An export or import license effective without the filing of a specific application with the Commission or the issuance of licensing documents to a particular person.
(10CFR110.2)
General public
In the contest of this report, the general mass of the populace not regarded as radiation workers.
(NCRP 59)
General public
In the contest of this report, the general mass of the populace not regarded as radiation workers.
(NCRP 51)
Generally applicable environmental radiation standards
Standards issued by the Environmental Protection Agency (EPA) under the authority of the Atomic Energy Act of 1954, as amended, that impose limits on radiation exposures or levels, or concentrations or quantities of radioactive material, in the general environment outside the boundaries of locations under the control of persons possessing or using radioactive material.
(10CFR20.1003)
Generation
A loosely defined set of passageways in the lung characterized by roughly equal anatomical dimensions and depth into the lung.
(ENV RAD)
Generation time
Mean time required for neutrons arising from fission to produce other fissions.
(IEC 50-393-1993)
Generation time
The average time taken for a cell to complete one interdivision cycle.
(ICRU 30)
Generation time
The mean time required for neutrons arising from fission to produce other fissions.
(ANSI N1.1-1976)
Genetic effects of radiation
Radiation effects that can be transferred from parent to offspring. Any radiation-caused changes in the genetic material of sex cells.
(USAEC-1974)
Genetically significant dose (GSD)
The GSD is "that dose which, if received by every member of the population, would be expected to produce the same genetic injury to the population as do the actual doses received by the individuals irradiated" (UNSCEAR, 1972). Thus, the GSD is the dose equivalent to the gonads weighted for the age and sex distribution in those members of the irradiated population expected to have offspring. The GSD is expressed in sieverts (or rem).
(NCRP 93)
Genetically significant dose (GSD)
The gonad dose from medical exposure which, if received by every member of the population, would be expected to produce the same total genetic effect on the population as the sum of the individual doses actually received. The GSD can be expressed algebraically as:
Di = Average gonad dose to persons age i who received x-ray examinations
Ni = Number of persons in population of age i who receive x-ray examinations
Pi = Expected future number of children for person of age i
Ni = number of persons in population of age i.
In 1964 the GSD was computed to be 55 millirads per person per year, for the United States. An estimated 55% of the population were receiving x-rays at that time. Thus, the average dose to those receiving medical radiation could be computed to be approximately 80 millirads.
(BEIR I)
Genetics
The branch of biology dealing with the phenomena of heredity and variation.
(RHH)
Geniculate bodies
An eminence produced by the underlying lateral geniculate nucleus, a group of nerve cell bodies; it is related to the central visual pathway.
(ICRP 49)
Genome
The genetic complement of a living organism or a single cell.
(NCRP 109)
Genotype
The fundamental hereditary (genetic) constitution of an organism.
(RHH)
Geologic repository
A system which is intended to be used for, or may be used for, the disposal of radioactive wastes in excavated geologic media. A geologic repository includes:
(1) The geologic repository operations area, and
(2) the portion of the geologic setting that provides isolation of the radioactive waste.
(10CFR60.2)
Geologic repository operations area
A high-level radioactive waste facility that is part of a geologic repository, including both surface and subsurface areas, where waste handling activities are conducted.
(10CFR60.2)
Geologic setting
The geologic, hydrologic, and geochemical systems of the region in which a geologic repository operations area is or may be located.
(10CFR60.2)
Geomagnetic equator
The terrestrial great circle everywhere 90° from the geomagnetic poles. These poles are the intersections of the earth's surface with the axis of a dipole approximating the source of the actual magnetic field of the earth.
(NCRP 94)
Geomagnetic equator
The terrestrial great circle everywhere 90° from the geomagnetic poles. These poles are the intersections of the earth's surface with the axis of a dipole approximating the source of the actual magnetic field of the earth.
(NCRP 45)
Geomagnetic latitude
Angular distance from the geomagnetic equator measured northward or southward through 90°.
(NCRP 45)
Geometric
Refers to a size parameter on a logarithmic size scale, where a given ratio of two sizes appears as the same linear distance.
(AM-1993)
Geometric attenuation
Reduction of a radiation intensity due to the effect of the distance between the point of interest and the source, e.g. the inverse-square law for a point source, and excluding the effect of any matter present.
(IEC 50-393-1993)
Geometric buckling
For a bare reactor Bēg is the first eigenvalue of the equation :
where r is the radius vector, with the condition that the neutron fluence rate f(r) should be zero at the extrapolated boundary of the assembly.
(IEC 50-393-1993)
Geometric mean
The geometric mean of a set of positive numbers is the exponential of the arithmetic mean of their logarithms. The geometric mean of a log normal distribution is the exponential mean of the associated normal distribution.
(BEIR V)
Geometric Mean Diameter
Median diameter of a lognormal distribution of particle diameters.
(NCRP 125)
Geometric Standard Deviation
For a log normal distribution it is the exponential of the standard deviation of the associated normal distribution (always-1).
(NCRP 125)
Geometric standard deviation
A measure of dispersion in a lognormal distribution (always > 1).
(AM-1993)
Geometric standard deviation
The geometric standard deviation of a log normal distribution is the exponential of the standard deviation of the associated normal distribution.
(BEIR V)
Geometric standard deviation
The measure of dispersion for a log-normal distribution, the ratio of the 84.13 percentile to the 50 percentile.
(TID-26608)
Geometric unsharpness
Unsharpness of the recorded image due to the combined optical effect of finite size of the radiation source and geometric separation of the anatomic area of interest from the image receptor and the collimator.
(NCRP 102)
Geometrical distortion
The departure of the shape of an image from an agreed conventional representation of the object producing it.
(NCRP 66)
Geometrical edges of the beam
The lines joining the center of the front face of the source to the innermost diaphragm edges (usually the edges farthest from the source).
(NCRP 69)
Geometry
The spatial configuration, pattern or relationship of components in an experiment or apparatus. In reactor technology, the term refers to the shape and size of fuel elements, moderator and reflector and their location with respect to each other. In nuclear physics, it refers to the arrangement of source and detecting equipment. In counting and scanning, the term commonly indicates the percentage of the radiation leaving a sample which reaches the sensitive volume of a counter. (See lattice.)
(USAEC-1974)
Geometry
Relative arrangement of source and measuring system.
(NBS 54)
Geometry (good, bad)
A term used colloquially to signify the arrangement in space of the various components in an experiment, as in, for example, plane geometry, or 2 pi geometry. In beam-attenuation measurements, good geometry means that a material whose cross section is to be measured is interposed between source and detector so that scattering as well as absorption in the material reduces the detection rate. With bad-geometry, there may be scattering of the beam into the detector volume as well as away from it.
(ANSI N1.1-1976)
Geometry factor
The fraction of the total solid angle about the source of radiation that is subtended by the face of the sensitive volume of a detector.
(RHH)
Geometry, good
In nuclear physics measurements, an arrangement of source and detecting equipment such that the use of finite source size and finite detector aperture introduces little error.
(RHH)
Geometry, poor
In a nuclear experiment, an arrangement in which the angular aperture between the source and detector is large, introducing into the measurement a comparative large uncertainty for which correction may be necessary.
(RHH)
Geosynchronous orbit (Geo)
An orbit in which a satellite travels at the same speed above the equator as the earth's rotation and therefore appears stationary.
(NCRP 98)
Geotropism
The degree of instrument reading change as a function of the physical orientation of the meter.
(NCRP 112)
Geotropism
A change in instrument reading with a change in instrument orientation as a result of gravitational effects.
(ANSI N42.17C-1989)
Geotropism
A change in instrument reading with a change in instrument orientation as a result of gravitational effects.
(ANSI N42.17A-1989)
Geotropism
A change in instrument response with a change in instrument orientation as a result of gravitational effects.
(ANSI N323-1978)
Germ cells
The cells of an organism whose function is reproduction.
(RHH)
Germanium
Symbol Ge. Element with atomic number 32. It is a semiconductor and used as the sensitive element in some g
-ray detectors.
(HPJ 60)
Given dose (applied dose)
The use of this term is not recommended because it can lead to ambiguities. Its frequent mention in the literature, however, warrants it inclusion here. Its use has most generally been as a step in the calculation of treatment time. It is always located on the central ray of the beam. For x rays generated at potentials of 400 kV or less, it is at the surface of the irradiated body. For higher energy photon beams, it is below the surface, at the depth of the peak absorbed dose (q.v.). If bolus or a tissue compensator is used, the "given dose" may be in the bolus or in the air gap which is being compensated. It should not be confused with tumor dose or dose at the isocenter, if one exists.
(ICRU 24)
Global fallout
Radioactive material which has been widely dispersed over the Earth by natural environmental processes arising from the detonation of nuclear weapons or devices, nuclear accidents, or debris from aerospace devices.
(10CFR834.2)
Glory hole
A beam hole.
(USAEC-1974)
Glove box
A sealed enclosure in which all handling of items inside the box is carried out through long rubber or neoprene gloves sealed to ports in the walls of the enclosure. The operator places his hands and forearms in the gloves from the room side of the box so that he is physically separated from the glove box environment but is able to manipulate items inside the box with relative freedom while viewing the operation through a window.
(ERDA 76-21)
Glove box
A sealed box in which workers, using gloves attached to and passing through openings in the box, can handle radioactive materials safely from the outside.
(USAEC-1974)
Gneiss
A coarse-grained, high-grade, metamorphic rock that has a distinct banding due to segregation of light and dark minerals.
(ENV RAD)
Goblet Cells
Epithelial cells that are distended with mucin so as to have a goblet shape (mucin is capable of being discharged upon the epithelial surface).
(NCRP 125)
Goblet cells
Columnar epithelial cells in extrathoracic and bronchial airways with cytoplasm distended with stored mucus.
(ICRP 66)
Goggle
A device, with contour shaped eye cups with glass or plastic lenses, worn over the eyes and held in place by a headband or other suitable means for the protection of the eyes and eye sockets.
(ANSI Z88.2-1980)
Goiter
Enlargement of part or all of the thyroid.
(NCRP 80)
Gonad
An ovary or testis.
(NCRP 48)
Gonad
A gamete-producing organ in animals; testis or ovary.
(RHH)
Governing body
Organization or authority responsible for the teaching establishment.
(ICRP 36)
Government agency
Any Federal, State or local government organization designated in the plant's emergency response plan.
(ANSI/ANS-3.8.1-1987)
Government Agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government;
(10CFR70.4)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR50.2)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR40.4)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR30.4)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR20.1003)
Government Agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the government.
(10CFR171.5)
Government Agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America, which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR74.4)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR170.3)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR61.2)
Government agency
Any executive department, commission, independent establishment, corporation, wholly or partly owned by the United States of America which is an instrumentality of the United States, or any board, bureau, division, service, office, officer, authority, administration, or other establishment in the executive branch of the Government.
(10CFR20.3)
Grab sample
A sample indicative of the concentration of radon or progeny at one point in time.
(ENV RAD)
Grab sample
A randomly taken, single sample removed from a stream over a short interval of time.
(ANSI N13.1-1969)
Grab samples
Samples of limited volume taken at random or at preselected frequencies.
(NCRP 118)
Gradient-transport theory
A theory of pollutant transport which assumes that the pollutant flux is proportional to the local concentration gradient in the direction of the mean fluid flow and from this derives a diffusion equation based on mass continuity.
(NCRP 76)
Gram atomic weight
Mass, in grams, numerically equal to atomic weight of an element.
(BEIR III)
Gram atomic weight
A mass in grams numerically equal to the atomic weight of an element.
(BEIR I)
Gram atomic weight
Mass, in grams, numerically equal to atomic weight of an element.
(RHH)
Gram molecular weight (gram-mole)
Mass in grams numerically equal to the molecular weight of a substance.
(BEIR I)
Gram molecular weight (synonym, mole)
Mass, in grams, numerically equal to molecular weight of a substance.
(BEIR III)
Gram molecular weight (synonym, mole)
Mass, in grams, numerically equal to molecular weight of a substance.
(RHH)
Gram-rad
Unit of integral dose equal to 100 ergs.
(BEIR III)
Gram-rad
Unit of integral dose equal to 100 ergs.
(BEIR I)
Gram-rad
Unit of integral dose equal to 100 ergs.
(RHH)
Gram-roentgen
An obsolete unit of integral absorbed dose equal to about 84 ergs.
(ANSI N1.1-1976)
Granular Activated Carbon (GAC)
A unique material made of wood, coal or other carbon base that has been carbonized (to charcoal) and activated to develop a vast internal pore structure and adsorption capacity.
(ENV RAD)
Granulocyte
A cell with granule-containing cytoplasm, especially a leukocyte (white blood cell) containing neutrophil, basophil, or eosinophil granules in cytoplasm.
(HPJ 60)
Graphite
A very pure form of carbon used as a moderator in nuclear reactors.
(USAEC-1974)
Graphite
A form of carbon in which the atoms are hexagonally arranged in planes. Commonly used for moderators because it can be made in compact, fairly strong blocks, easily machined to close tolerances, and because the prolonged baking at high temperature used in its manufacture helps eliminate impurities that might absorb neutrons.
(RHH)
Graphite Moderated Reactor (GMR)
A nuclear reactor where graphite is used as a moderator, primarily gas cooled reactors.
(NCRP 81)
Graticule
A transparent disk with a calibrated scale placed in the focal plane of an optical system, e.g., a microscope, used for the measurement of particles or other objects.
(AM-1993)
Grave's disease
A disease state in which the thyroid gland enlarges and may produce excessive amounts of thyroid hormone. Currently considered to represent an autoimmune disease which is caused by the formation of abnormal immunoglobulin stimulators of the thyroid gland.
(NCRP 80)
Gravitation
Force of attraction existing between all material bodies in the universe. The magnitude of the force between any two bodies is proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between them.
(RHH)
Gravitational deposition parameter
Ratio of particle settling distance during transport in the sampling inlet region to the diameter of the inlet.
(AM-1993)
Gravitational settling velocity
Particle motion in a gravitational field after an equilibrium between gravity and aerodynamic drag forces has been reached.
(AM-1993)
Gray
The SI unit of absorbed dose. One gray is equal to an absorbed dose of 1 Joule/kilogram. It is also equal to 100 rads.
(10CFR34.3)
Gray
The SI unit of absorbed dose. 1 Gy = 1 J kg-1, where J = joule. (See units).
(BEIR V)
Gray
The SI unit of absorbed dose. 1 Gy = 1 J kg-1, where J = joule. (See units).
(BEIR IV)
Gray
The SI unit of absorbed dose. 1 Gy = 1 J kg-1, where J = joule. (See units).
(NCRP 83)
Gray
Proposed unit of absorbed dose of radiation = 1 J/kg = 100 rads.
(BEIR III)
Gray (Gy)
The SI unit of absorbed dose. One gray is equal to an absorbed dose of 1 Joule/ kilogram (100 rads).
(10CFR20.1004)
Gray (Gy)
SI unit of absorbed dose, kerma and specific energy imparted (1 Gy = 1 J kg-1 = 100 rad).
(NCRP 125)
Gray (Gy)
The special name for the SI unit of absorbed dose. 1 Gy = 1 J kg-1.
(ICRP 68)
Gray (Gy)
The unit of absorbed dose. 1 Gy = 1 Joule per kg.
(NCRP 118)
Gray (Gy)
SI unit of absorbed dose, kerma and specific energy imparted. 1 Gy = 1 J kg-1.
(IEC 50-393-1993)
Gray (Gy)
The special name for the SI unit of absorbed dose or kerma. 1 Gy = 1 J kg-1 = 100 rad.
(NCRP 114)
Gray (Gy)
The unit of absorbed dose in the SI: 1 Gy = 1 J kg-1 = 100 rad.
(HPJ 60)
Gray (Gy)
The SI unit of absorbed dose. 1 gray = 1 J/kg = 100 rad.
(NCRP 111)
Gray (Gy)
The special name for the SI unit of absorbed dose, kerma, and specific energy imparted. 1 Gy = 1 J kg-1.
(NCRP 107)
Gray (Gy)
The special name for the SI unit of absorbed dose, kerma, and specific energy imparted equal to one joule per kilogram. The previous unit of absorbed dose, rad, is currently being replaced by the gray. One gray equals 100 rad.
(NCRP 102)
Gray (Gy)
The special name for the SI unit of absorbed dose, kerma and specific energy imparted. 1 Gy = 1 J kg-1 = 100 rad.
(NCRP 101)
Gray (Gy)
The new international system unit (SI unit) of absorbed dose of radiation, 1 Gy = 1 J kg-1 = 100 rad.
(NCRP 98)
Gray (Gy)
The special name for the SI unit of absorbed dose. 1 Gy = 1 Joule kg-1 = 100 rad.
(FGR 11)
Gray (Gy)
The unit of absorbed dose in the SI: 1 Gy = 1 J kg-1 = 100 rad.
(NCRP 87)
Gray (Gy)
The unit of absorbed dose in the SI: 1 Gy = 1 J kg-1 = 100 rad.
(NCRP 84)
Gray (Gy)
The special name for the SI unit of absorbed dose. 1 gray = 1 J/kg.
(NCRP 69)
Gray (Gy)
The unit of absorbed dose in the SI: 1 Gy = 1 J kg-1 = 100 rad.
(ICRP 30)
Gray (reactor technology)
Of a body or medium, absorbing a significant part of, but not all, the radiation of some specified energy incident on it.
(ANSI N1.1-1976)
Green salt
Uranium tetrafluoride.
(USAEC-1974)
Grenz rays
Very soft x rays of 15 keV or less.
(ANSI N1.1-1976)
Grenz rays
X-rays produced at voltages of 5 to 20 kVp, intended primarily for surface therapy.
(RHH)
Grid ionization chamber
Pulse ionization chamber, generally used to measure the energy of alpha particles or fission fragments.
(IEC 50-394-1993)
Grid model
A pollutant transport model that is a finite-difference approximation to the equation of motion, continuity, diffusion, and species conservation and removal. Grid models are severely restricted in their applicability to a large class of pollutant problems.
(NCRP 76)
Gross Tumor Volume (GTV)
The gross palpable or visible/demonstrable extent and location of malignant growth.
(ICRU 50)
Ground fault
An accidental electrical grounding of an electrical conductor.
(ANSI N537-1976)
Ground state
The state of a nucleus, atom or molecule at its lowest (normal) energy level.
(USAEC-1974)
Ground state
The state of a nucleus, atom or molecule at its lowest energy. All other states are "excited".
(RHH)
Ground water
Subsurface water that occurs in soils and geologic formations that are fully saturated.
(10CFR834.2)
