Glossary cont'd - doe-hdbk-1108-2002

DOE-HDBK-1108-2002

Radiological Training for Accelerator Facilities

Handouts

Glossary - Continued

Neutron: Elementary particle with a mass approximately the same as that of a hydrogen

atom and electrically neutral.

Nucleus: The small, central, positively charged region of an atom that carries essentially

all the mass.

Pion: A cosmic particle with a mass about 273 times that of an electron and a half-life of

2/100,000,000 (2 x 10-8) of a second. Positive, negative, and neutral pions exist.

Primary Beam: Radiation that passes through the window, aperture, cone, or other

collimating device of the source housing. Sometimes called useful beam.

Prompt radiation: Radiation resulting from the accelerator beam or the interaction of the

accelerator beam with surrounding matter that ceases shortly after the beam is removed.

Activation products and area contamination are not considered prompt radiation.

Proton: An elementary nuclear particle with a positive electric charge and an atomic

weight of approximately one.

Radiation: Radiation refers to the emission and propagation of waves or particles

through matter or space. Matter absorbs energy from radiation. In a microwave oven, for

example, food absorbs energy from microwave radiation and is heated and cooked.

Radiation alarm system: A system providing notification, including activation of a

radiation warning system, that a radiation condition exists that exceeds preset limits. An

alarm system may initiate mitigating action.

Radiation warning light: A system that alerts personnel to a potential or actual change in

the radiation level in a working environment. A warning system does not initiate

mitigating actions.

Radioactivation or Activation: The process of producing a radioactive material by

bombardment with neutrons, protons, or other nuclear particles.

Redundancy: Duplication or repetition of elements in electronic or mechanical

equipment to provide alternative functional channels in case of failure.

Scattered Radiation: Radiation that, during passage through matter, has been deviated in

direction. It may have been modified also by a decrease in energy.

Scram switch: An interlock that is intended for emergency use only. Scram switches are

usually placed within exclusion areas where personnel may be caught during pre-start-up

or actual operations.

Search: (This is commonly referred to as a sweep.) A physical inspection carried out

under controlled conditions to ensure that no personnel are left inside exclusion areas.