R 325.5016 Definitions; Re to Ro.

Rule 16. (1) "Rem" means the absorbed dose in rads multiplied by appropriate modifying factors which are determined by the quality of radiation and the conditions of exposure and is the special unit of dose equivalent. For the purpose of these regulations, each of the following is considered to be equivalent to a dose of 1 rem: (a) An exposure of 1 roentgen of x or gamma radiation. (b) A dose of 1 rad due to x, gamma, or beta radiation. (c) A dose of 0.1 rad due to neutrons or high energy protons.* (d) A dose of 0.05 rad due to particles heavier than protons and with sufficient energy to reach the lens of the eye. * If it is more convenient to measure the neutron flux, or equivalent, than to determine the neutron absorbed dose in rads, 1 rem of neutron radiation may, for purposes of these regulations, be assumed to be equivalent to 14 million neutrons per square centimeter incident upon the body; or, if there exists sufficient information to estimate with reasonable accuracy the approximate distribution in energy of the neutrons, the incident number of neutrons per square centimeter equivalent to 1 rem may be estimated from the following table: Neutron Flux Dose Equivalents Neutron Energy (MeV) Number of neutrons per square centimeter for a dose equivalent of 1 rem (neutrons/cm2) Average flux to deliver 100 millirem in 40 hours (neutrons/cm2 per second) Thermal 970 x 106 670 0.0001 720 x 106 500 0.005 820 x 106 570 0.02 400 x 106 280 0.1 120 x 106 80 0.5 43 x 106 30 1.0 26 x 106 18 2.5 29 x 106 20 5.0 26 x 106 18 7.5 24 x 106 17 10 24 x 106 17 10 to 30 14 x 106 10 (2) "Research and development" means theoretical analysis, exploration, or experimentation; or the extension of investigative findings and theories of a scientific or technical nature into practical application for experimental and demonstration purposes, including the experimental production and testing of models, devices, equipment, materials, and processes. This definition does not apply to human use. (3) "Restricted area" or "controlled area" means an area access to which is controlled by a licensee or registrant for purposes of protection of individuals from exposure to radiation or radioactive materials. It does not include an area used for residential quarters, although a separate room in a residential building may be set apart as a restricted area. (4) "Roentgen" means 2.58 x 10-4 Coulombs/kilogram of air and is the special unit of exposure.