DHS 157.03(113)(113) “Dosimeter” means a recording device used to measure exposure to ionizing radiation. DHS 157.03(114)(114) “Dosimetry processor” means an individual or an organization that processes and evaluates individual monitoring devices to determine the radiation dose delivered to the monitoring devices. DHS 157.03(115)(115) “Doubly encapsulated sealed source” means a sealed source in which the radioactive material is sealed within an inner capsule and that capsule is sealed within an outer capsule. DHS 157.03(116)(116) “Effective dose equivalent” or “EDE” means the sum of the products of the dose equivalent to each organ or tissue and the weighting factor applicable to each of the body organs or tissues that are irradiated (HE = å wTHT). DHS 157.03 NoteNote: Effective dose equivalent (HE) equals the sum of the weighting factor (wT) times the dose equivalent to each organ or tissue (HT).
DHS 157.03(117)(117) “Electron microscope” means a microscope utilizing electrons to provide high magnification examination of materials. DHS 157.03(118)(118) “Elemental area” means the smallest area within a tomogram for which the x-ray attenuation properties of a body are depicted. DHS 157.03(119)(119) “Embryo or fetus” means the developing human organism from conception until the time of birth. DHS 157.03(120)(120) “Emergency” means an event requiring prompt action to mitigate a threat to the health and safety of workers and the public or a threat of damage to the environment. DHS 157.03(121)(121) “Energy compensation source” or “ECS” means a small sealed source, with an activity not exceeding 3.7 MBq (100 microcuries), used within a well logging tool, or other tool components, to provide a reference standard to maintain the well logging tool’s calibration when in use. DHS 157.03(122)(122) “Enriched uranium” means uranium containing more uranium-235 than the naturally occurring distribution of uranium isotopes. DHS 157.03(123)(123) “Entrance air kerma rate” means the air kerma free in air per unit time at the point where the center of the useful beam enters the patient. DHS 157.03(124)(124) “Entrance or access point” means any location through which an individual could gain access to radiation areas or to licensed or registered radioactive materials. This includes entry or exit portals of sufficient size to permit human entry, irrespective of their intended use. DHS 157.03(124g)(124g) “Escorted access” means the continuous direct visual surveillance by an approved individual over an individual in the security zone who is not approved for unescorted access. DHS 157.03(124m)(124m) “Exclusive use” means the sole use by a single consignor of a conveyance for which all initial, intermediate, and final loading and unloading are carried out in accordance with the direction of the consignor or consignee. The consignor and the carrier must ensure that any loading or unloading is performed by personnel having radiological training and resources appropriate for the safe handling of the consignment. The consignor shall issue specific instructions, in writing, for maintenance of exclusive use shipment controls, and include them with the shipping paper information provided to the carrier by the consignor. DHS 157.03(125)(125) “Explosive material” means any chemical compound, mixture or device that produces a substantial instantaneous release of gas and heat spontaneously or by contact with sparks or flame. DHS 157.03(126)(126) “Exposure” means the quotient of dQ divided by dm where “dQ” is the absolute value of the total charge of the ions of one sign produced in air when all the electrons liberated by photons in a volume element of air having mass “dm” are completely stopped in air. The SI unit of exposure is the coulomb per kilogram. The standard unit of exposure is the roentgen. DHS 157.03(127)(127) “Exposure head” means a device that locates the gamma radiography sealed source in the selected working position. DHS 157.03(128)(128) “Exposure rate” means the exposure per unit of time, such as roentgen per minute and milliroentgen per hour. DHS 157.03(129)(129) “External beam radiation therapy” means therapeutic irradiation in which the source of radiation is at a distance from the body. DHS 157.03(130)(130) “External dose” means that portion of the dose equivalent received from any source of radiation outside the body. DHS 157.03(131)(131) “External sinking fund” means an account, segregated from licensee assets and outside the licensee’s administrative control, into which monies are periodically deposited that are sufficient to pay decommissioning costs expected at the time licensee operations are terminated. DHS 157.03(132)(132) “Extremity” means hand, elbow, arm below the elbow, foot, knee and leg below the knee. DHS 157.03(133)(133) “Extremity bone densitometer” means a device that tests the mineral content of the bone of the fore arm, hand or foot. DHS 157.03(135)(135) “Field emission equipment” means equipment that uses an x-ray tube in which electron emission from the cathode is due solely to the action of an electric field. DHS 157.03(136)(136) “Field station” means a facility where radioactive sources may be stored or used and from which equipment is dispatched to temporary job sites. DHS 157.03(137)(137) “Film badge” means a dosimeter containing radiation sensitive photographic film for measuring radiation dose plus various filters that characterize the type of radiation encountered. When developed, the darkness of the film is directly proportional to the amount of radiation received. DHS 157.03(138)(138) “Filter” means material placed in the useful beam to preferentially absorb selected radiation energies.