• gamma ray: radiation emitted in the radioactive decay of some nuclei; similar to light and x-rays.
• generation: a division of the airway in the lung from the trachea. Each division of a lung airway usually produces two smaller airways, and another generation.
• grab-sample: type of sampling method which collects a small sample of air in a scintillation cell over a short time span. The sample is analyzed for radioactive decay to determine the concentrations of radon or radon decay products.
• gray: S.I. unit of physical dose; the unit of deposition of energy in material due to the passage of ionizing radiation; 1 Gray = 1 Joule per kg.
• half-life (biologic): time required for the body to eliminate half of a dose of any substance.
• half-life (effective): time required for elimination of 50% of a radioactive element by the combination of biological elimination processes and the element's rate of decay.
• half-life (radioactive):the time required for the radioactive nuclei present to decrease by a factor of two by radioactive decay.
• ICRP: International Commission on Radiobiological Protection.
• ionizing radiation: radiation with the ability to interact with and remove electrons from the atoms of material, ionizing the atom.
• isotopes: nuclides having equal numbers of protons, but different numbers of neutrons and therefore mass numbers although similar characteristics.
• Jacobi-Eisfeld model: dosimetric model for radon daughters based on the Weibel "A" model of the lung.
• James-Birchall model: dosimetric model for radon daughters based on both the Weibel and Yeh-Schum models of the lung.
• kerma (Kinetic Energy Released in Material): unit of quantity representing the kinetic energy transferred by uncharged particles to the charged particles per unit mass of the irradiated medium.