The energy imparted by ionizing radiation per unit mass of irradiated material. The units of absorbed dose are the rad and gray (Gy).

The energy imparted by ionizing radiation per unit mass of irradiated material. The units of absorbed dose are the rad and gray (Gy).

The number of nuclear transformations occurring in a material per unit of time. (see Curie and becquerel)

The diameter in an aerodynamic particle size distribution for which the total activity above and below this size are equal. A lognormal distribution of particle sizes is assumed. The AMAD refers to the entire distribution. The AMAD is the AED for which one-half of the radioactivity in a distribution has an AED smaller than the AMAD and one-half of the radioactivity in a distribution has an AED larger than the AMAD. The AMAD (along with the associated sg) is the most useful diameter for characterizing the behavior of the aerosol in air, in sampling instruments, and the respiratory tract.

The diameter of a sphere, in µm, of unit density (1 g/cm3) that has the same terminal settling velocity in air as the particle of interest (A 1 µm AED particle has 1000 times the volume of a 0.1 µm AED particle). The AED refers to an individual particle.

To disperse as a suspension of fine solid or liquid particles in air.

Acronym for "as low as reasonably achievable." The Nuclear Regulatory Commission defines ALARA as making every reasonable effort to maintain radiation exposures as far below the dose limits as is practical -- taking into account the state of technology, the economics of improvement in relation to the state of technology, the economics of improvement in relation to the benefits to the public health and safety, and other societal and socioeconomic considerations.

A charged particle emitted from the nucleus of an atom, having a mass and charge equal in magnitude to a helium nucleus (two protons and two neutrons stripped of both electrons, thereby, retaining a +2 charge).

A radioactive metallic element produced by the radioactive decay of certain plutonium isotopes after bombardment of uranium, neptunium, and/or plutonium with high-energy neutrons.

A condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume (British variant of anemia).

The activity in µCi of a radionuclide which taken alone would irradiate a person represented by reference man, to a limit established by a regulatory agency for each year of occupational exposure.

The smallest unit of an element that is capable of entering into a chemical reaction.

The mass of a nuclide's neutral atom, usually expressed in terms of "atomic mass units." The "atomic mass unit" is one-twelfth the mass of one neutral atom of carbon-12, equivalent to 1.6604 X 10-24 gm. (Symbol: amu).

Number of protons contained in the nucleus of an atom.

The weighted average of the masses of the isotopes of an element, expressed in atomic mass units.