Term Categories: Glossary

high-energy, short wavelength electromagnetic radiation emitted by a nucleus. Energies of gamma rays are usually between 0.010 and 10 mev. X-rays also occur in this energy range, but are non-nuclear origin. Gamma radiation usually accompanies alpha and beta emissions and always accompanies fission. Gamma rays are very penetrating and are best attenuated by dense materials like lead and depleted uranium.

Refers to measurements analyzed according to their constituent frequencies. The usual alternative is time-domain measurements.

The number of waves that pass a given point in a specified unit of time.

Flux, or lines of force, leaking from pole to pole outside a magnet.

Flexural waves occur in bars or plates and refers to the flexing, or bending, of a bar or plate. The velocity of flexural waves depends on their frequency or wavelength, and the bending mode (shape).

A defect

A discontinuity in a solid material with a very fine opening to the surface, but possessing length and depth greater than the width of this opening; usually depth is many time the width.

The attenuation of a signal’s components based on a measurable property (usually frequency). Filtering usually involves a numerical operation that enhances only a portion of the signal.

A crack-like discontinuity, open to the surface, but filled with some foreign material-oxide, grease, etc.- which tends to prevent penetrants from entering.

Cracks in a material formed from repeated stress, none of which exceeded the maximum stress of the material