DHS 157.03(216)(216) “Mobile medical service supplier” means a mobile service that carries or receives radioactive materials for medical use at a client’s address. DHS 157.03(217)(217) “Mobile x-ray equipment” means x-ray equipment mounted on a permanent base with wheels or casters for moving while completely assembled. DHS 157.03(218)(218) “Moderator” means a material that decreases the energy of neutrons. DHS 157.03(219)(219) “Monitoring” means the measurement of radiation, radioactive material concentrations, surface area activities or quantities of radioactive material and the use of the results of these measurements to evaluate potential exposures and doses. DHS 157.03(219m)(219m) “Movement control center” means an operations center that is remote from transport activity and that maintains position information on the movement of radioactive material, receives reports of attempted attacks or thefts, provides a means for reporting these and other problems to appropriate agencies, and requests and coordinates appropriate aid. DHS 157.03(220)(220) “Moving beam radiation therapy” means radiation therapy with any planned displacement of radiation field or patient relative to each other or with any planned change of absorbed dose distribution. It includes arc, skip, conformal, intensity modulation and rotational therapy. DHS 157.03(221)(221) “Multiple tomogram system” means a computed tomography x-ray system that obtains x-ray transmission data simultaneously during a single scan to produce more than one tomogram image. DHS 157.03(221m)(221m) “Nationally tracked source” means a sealed source containing a quantity equal to or greater than category 1 or category 2 thresholds of any radioactive material listed in ch. DHS 157 Appendix T. In this context a sealed source is defined as radioactive material that is sealed in a capsule or closely bonded, in a solid form and which is not exempt from regulatory control. It does not mean material encapsulated solely for disposal, or nuclear material contained in any fuel assembly, subassembly, fuel rod, or fuel pellet. Category 1 nationally tracked sources are those containing radioactive material at a quantity equal to or greater than the category1 threshold. Category 2 nationally tracked sources are those containing radioactive material at a quantity equal to or greater than the category 2 threshold but less than the category 1 threshold. DHS 157.03(222)(222) “NARM” means any naturally occurring or accelerator-produced radioactive material. DHS 157.03(223)(223) “Natural radioactivity” means radioactivity of naturally occurring nuclides. DHS 157.03(224)(224) “Natural thorium” means thorium with the naturally occurring distribution of thorium isotopes, which is essentially 100 weight percent thorium-232. DHS 157.03(225)(225) “Natural uranium” means uranium with the naturally occurring distribution of uranium isotopes, which is approximately 0.711 weight percent uranium-235, and the remainder by weight essentially uranium-238. DHS 157.03(226)(226) “Negative pressure respirator — tight fitting” means a respirator in which the air pressure inside the facepiece is negative during inhalation with respect to the ambient air pressure outside the respirator. DHS 157.03(227)(227) “Neutron absorber” means a material that absorbs neutrons emitted from radioactive material. DHS 157.03(228)(228) “Noble gas” means a chemically inert gas that does not combine with other elements. DHS 157.03(228m)(228m) “No-later-than arrival time” means the date and time that the shipping licensee and receiving licensee have established as the time at which an investigation will be initiated if the shipment has not arrived at the receiving facility. The no-later-than arrival time may not be more than 6 hours after the estimated arrival time for shipments of category 2 quantities of radioactive material. DHS 157.03(229)(229) “Nominal tomographic section thickness” means the full width at half-maximum of the sensitivity profile taken at the center of the cross-sectional volume over which x-ray transmission data are collected. DHS 157.03(230)(a)(a) For electron irradiation, the distance from the scattering foil, virtual source or exit window of the electron beam to the entrance surface of the irradiated object along the central axis of the useful beam. DHS 157.03(230)(b)(b) For x-ray irradiation, the virtual source or target to isocenter distance along the central axis of the useful beam. For non-isocentric equipment, this distance shall be that specified by the manufacturer. DHS 157.03(230m)(230m) “Non-fixed contamination” means contamination that can be removed from a surface during normal conditions of transport. DHS 157.03(231)(231) “Nonstochastic effect” or “deterministic effect” means health effects, the severity of which varies with the dose and for which a threshold is believed to exist. Radiation-induced cataract formation is an example of a nonstochastic effect. DHS 157.03(232)(232) “Normal form radioactive material” means radioactive material that has not been demonstrated to qualify as special form radioactive material. DHS 157.03(233)(233) “Notice of violation” means a written notice provided in response to an alleged infraction of ss. 254.31 to 254.45, Stats., this chapter, the conditions of a license or an order issued by the department. DHS 157.03(235)(235) “Nuclear waste” means a quantity of source, byproduct or special nuclear material required to be in NRC-approved specification packaging while transported to, through or across a state boundary to a disposal site, or to a collection point for transport to a disposal site. DHS 157.03(235m)(235m) “Open-beam x-ray equipment” means an open-beam x-ray system in which the beam path could be entered by any part of the body at any time. DHS 157.03(236)(236) “Optically stimulated luminescent dosimeter” or “OSL” means a dosimeter containing a crystalline solid for measuring radiation dose plus filters to help characterize the type of radiation encountered.