Section 325.5020. Definitions U and V.

(1) "Unrefined and unprocessed ore" means ore in its natural form before any processing, such as grinding, roasting, beneficiating or refining.

(2)         "Unrestricted area" or "uncontrolled area" means an area access to which is not controlled by a licensee or registrant for purposes of protection of individuals from exposure to radiation or radioactive materials, or an area used for residential quarters.

(3)      "Useful beam" means the radiation which passes through the tube housing port and the aperture of the beam-limiting device when the exposure switch or timer is activated.

(4)         "Variable-aperture beam-limiting device" means a beam-limiting device which has capacity for stepless adjustment of the x-ray field size at a given source-image receptor distance.

(5)     "Visible area" means that portion of the input surface of the image receptor over which incident x-ray photons produce a visible image.

History: 1954 ACS 85, Eff. Dec. 3, 1975; 1954 ACS 98 Eff. Mar 9, 1979.