DHS 157.03DHS 157.03 Definitions. In this chapter: DHS 157.03(1)(1) “A1” means the maximum activity of special form radioactive material permitted in a Type A package. This value is either listed in Table VI and Table VIII in ch. DHS 157 Appendix O or may be derived under the procedures prescribed in ch. DHS 157 Appendix O. DHS 157.03(2)(2) “A2” means the maximum activity of radioactive material, other than special form material, LSA and SCO material, permitted in a Type A package. This value is either listed in Table VI and Table VIII in ch. DHS 157 Appendix O or may be derived under the procedures prescribed in ch. DHS 157 Appendix O. DHS 157.03(3)(3) “Absorbed dose or “D” means the energy imparted by ionizing radiation per unit of mass of irradiated material. The units of absorbed dose are the rad and the gray (Gy). DHS 157.03(4)(4) “Absorbed dose rate” means absorbed dose per unit time, for machines with timers, or dose monitor unit per unit time for accelerators. DHS 157.03(5)(5) “Accelerator” or “particle accelerator” means any machine capable of accelerating electrons, protons, deuterons or other charged particles in a vacuum and of discharging the resultant particle or other radiation into a medium at energies usually in excess of one MeV. DHS 157.03(6)(6) “Accelerator-produced radioactive material” means any material made radioactive by an accelerator. DHS 157.03(6m)(6m) “Access control” means a system for allowing only approved individuals to have unescorted access to the security zone and for ensuring that all other individuals are subject to escorted access. DHS 157.03(7)(7) “Accessible surface” means surface of equipment or of an equipment part, housing or enclosure of the radiation producing machine that may be easily or accidentally touched by persons without the use of a tool. DHS 157.03(9)(9) “Activity” means the rate of disintegration or transformation or decay of radioactive material. The units of activity are the becquerel and the curie. DHS 157.03(10)(10) “Added filtration” means any filtration which is in addition to the inherent filtration. DHS 157.03(11)(11) “Address of use” means the building or buildings that are identified on the license and where radioactive material may be received, used or stored. DHS 157.03(12)(12) “Adult” means an individual 18 or more years of age. DHS 157.03(12m)(12m) ”Aggregated” means accessible by the breach of a single physical barrier that would allow access to radioactive material in any form, including any devices that contain the radioactive material. DHS 157.03 NoteNote: An aggregated total activity equal or exceeding a category 2 to quantity of radioactive material exceeds the thresholds set forth in ch. DHS 157 Appendix U. DHS 157.03(13)(13) “Agreement state” means any state with which the U.S. nuclear regulatory commission or the U.S. atomic energy commission has entered into an effective agreement under subsection 274b of the atomic energy act of 1954, as amended. DHS 157.03(14)(14) “Air-purifying respirator” means a respirator with an air-purifying filter, cartridge, or canister that removes specific air contaminants by passing ambient air through the air-purifying element. DHS 157.03(15)(15) “Airborne radioactive material” means any radioactive material dispersed in the air in the form of dusts, fumes, particulates, mists, vapors or gases. DHS 157.03(16)(16) “Airborne radioactivity area” means a room, enclosure or area in which airborne radioactive materials, composed wholly or partly of licensed material, exist in concentrations that meet either of the following criteria: DHS 157.03(16)(b)(b) An individual present in the area without respiratory protective equipment could exceed, during the hours an individual is present in a week, an intake of 0.6% of the annual limit on intake or 12 DAC-hours. DHS 157.03(17)(17) “Air kerma” or “K” means the sum of the initial kinetic energies of all the charged ionizing particles liberated by uncharged ionizing particles per unit mass of air. Kerma is determined as the quotient of dE divided by dM, where dE is the sum of the initial kinetic energies of all the charged ionizing particles liberated by uncharged ionizing particles in air of mass dM. The SI unit of air kerma is joule per kilogram and the special name for the unit of kerma is the gray. DHS 157.03(18)(18) “Alarming ratemeter” means a radiation measurement device that may be set to alarm at a pre-set dose rate. DHS 157.03(19)(19) “Alert” means an event may occur, is in progress, or has occurred that could lead to a release of radioactive material but that the release is not expected to require a response by offsite response organizations to protect people offsite. DHS 157.03(20)(20) “Alignment helmet” means a guide placed on the head that directs radiation to a specific site during stereotactic surgery. DHS 157.03(21)(21) “Aluminum equivalent” means the thickness of type 1100 aluminum alloy affording the same attenuation, under specified conditions, as the material in question. DHS 157.03 NoteNote: The nominal chemical composition of type 1100 aluminum is 99.00 percent minimum aluminum and 0.12% copper.