Glossary cont'd - hdbk11080139

DOE-HDBK-1108-97

Radiological Training for Accelerator Facilities

Student's Guide

GLOSSARY (continued)

Cryostat: An instrument or device that maintains low temperature for superconducting magnets.

Cyclotron: A cyclic accelerator in which the charged particles spiral outward from the center of the

machine as they gain energy.

Decommissioning: The process of closing and securing a nuclear facility, or nuclear materials storage

facility, so as to provide adequate protection from radiation exposure and to isolate radioactive

contamination from the human environment.

Depleted Uranium: Uranium having a percentage of uranium-235 smaller than the 0.7% found in natural

uranium.

Derived Air Concentration (DAC): The airborne concentration that equals the ALI divided by the volume

of air breathed by an average worker for a working year of 2,000 hours (assuming a breathing volume of

2,400 m3).

Detector: Any device that can detect the presence of an energetic electromagnetic radiation particle or

nuclear fragment and measure one or more of its properties.

Electromagnetic Radiation: A traveling wave motion resulting from changing electric or magnetic

fields. Familiar electromagnetic radiations range from X-rays and gamma rays of short wavelength,

through the ultraviolet, visible and infrared regions, radar and radio waves of relatively long wavelength.

Enclosed Beam: All possible X-ray beam paths are fully contained in protective enclosures so that no

part of the body can intercept the beam during normal operation.

Electron volt: A unit of energy equivalent to the energy gained by an electron in passing through a

potential difference of one volt.

Exclusion Area: Any area to which access is prohibited for the purpose of protection of individuals.