T.O. 33B-1-1
Glossary 68
ends. At such locations the lines of force of the longitudinal field are leaving the bar in a direction normal to the
surface, which prevents them from intercepting transverse defects in those areas. The field induced by the transient
current does intercept such discontinuities.
QUENCHING OF FLUORESCENCE (MT, PT): The extinction of fluorescence by causes other than removal of the
black light (the exciting radiation).
R
RAD: The special unit of absorbed dose. One rad is equal to an absorbed dose of 100 ergs/gram or 0.01
Joule/kilogram (0.01 gray).
RADIATION (RT): The propagation of energy through matter or space in the form of waves. In atomic physics the
term has been extended to include fast-moving particles (alpha and beta rays, free neutrons, etc.). Gamma rays and X-
rays, of particular interest in atomic physics, are electromagnetic radiation in which energy is propagated in packets
called photons.
RADIATION AREA: An area, accessible to individuals, in which radiation levels could result in an individual
receiving a dose equivalent in excess of 5 mrem (0.05 mSv) in any one hour at 30 centimeters from the radiation source
or from any surface that the radiation penetrates.
RADIATION BURN (RT): A burn caused by overexposure to radiant energy.
RADIATION DAMAGE (RT): A general term for the alteration of properties of a material arising from radiation
exposure to X-rays, gamma rays, neutrons, heavy-particle radiation or fission fragments in nuclear fuel material.
RADIATION DETECTOR (RT): See DETECTOR.
RADIATION HAZARD (RT): A situation or condition that represents potential danger to health as the result of
exposure to ionizing radiation.
RADIATION MAZE (RT): An indirect route of access to a room that contains a radiation source. It is designed to
allow easy access when the source is turned off or is fully shielded, and to reduce radiation intensity outside the room to
acceptable levels when the source is turned on or exposed. Reduction of radiation intensity is achieved through
multiple scattering from walls and application of the inverse square law.
RADIATION METER (RT): An instrument consisting of one or more radiation detectors, associated electronics, and
an indicator of the magnitude of the measured radiation quantity.
RADIATION MONITOR (RT): A radiation meter that is designed and used to keep track of radiation levels in a
specific area, and to record those levels, or to provide an audible or visual signal when a predetermined level is
exceeded.
RADIATION PROTECTION GUIDE: The total amounts of ionizing radiation dose over certain periods of time which
may safely be permitted to exposed industrial groups. These standards, established by the Federal Radiation Council,
are equivalent to what was formerly called the “maximum permissible exposure.”
RADIATION PROTECTION (RT): A branch of the physical, biological, and chemical sciences applying to the
prevention of the risks presented by exposure of persons to ionizing radiation.
