LEAK TEST (RT): A method capable of detecting the leakage of radioactive material from a sealed source.
LEAK TESTING (PT): Method of applying penetrant to one surface and developer to the opposite side of a structure to
detect flaws that extend entirely through the structure.
LEAKER-PENETRANT: The type of penetrant especially designed for leak detection.
LENGTH/DIAMETER RATIO (MT): A ratio of the length and diameter of a part for the purpose of calculating the
amperes required for longitudinal magnetization.
LICENSED MATERIAL: Source material, special nuclear material, or by-product material received, possessed, used,
or transferred under a general or special license issued by the Atomic Energy Commission.
LICENSED MATERIAL (RT): Source material, special nuclear material, or byproduct material received, possessed,
used, or transferred under a general or special license issued by the Nuclear Regulatory Commission or an Agreement
LIFT-OFF (ET): A measure of the gap between the face of a surface probe and the surface being inspected. It is a
measure of the coupling between the probe and the material being inspected.
LIFT-OFF COMPENSATION (LIFT-OFF ADJUSTMENT) (ET): Procedures for instrument adjustments whereby
impedance variations caused by a variable gap between an eddy current surface and the test part are suppressed. This
adjustment is designed to provide a better signal-to-noise ratio for eddy current inspection.
LIFT-OFF EFFECT (ET): The effect observed in the test system output due to a change in magnetic coupling between a
test specimen and a probe coil whenever the distance of separation between them is varied.
LIGHT METAL: One of the low-density metals such as aluminum, magnesium, titanium, beryllium or their alloys.
LIGHT METER (MT, PT): A device used to measure the light intensity of a black light in foot candles or micro-watts
per square centimeter, whichever is appropriate.
LIMIT FREQUENCY: A mathematically derived frequency value used to establish impedance diagrams.
LINDEMANN GLASS (RT): Glass of low X-ray absorption containing lithium, boron and beryllium.
LINEAR ABSORPTION COEFFICIENT: See ABSORPTION COEFFICIENT, LINEAR.
LINEAR ACCELERATOR: An apparatus used to accelerate electrons to high velocities by means of a high frequency
electrical wave traveling along a tube in the linear direction of the electron beam.
LINEAR DISCONTINUITIES: Ragged lines of variable width. May appear as a single jagged line or exist in groups.
They may or may not have a definite line of continuity.
LINEAR ENERGY TRANSFER (LET) (RT): The energy lost by a charged particle per unit distance of material
traversed. It can be expressed as electron volts per meter, or some convenient multiple or submultiple, such as KeV per
LINEAR INDICATIONS: An indication having length three or more times its width.
LINEARITY: See VERTICAL LINEARITY and HORIZONTAL LINEARITY.
LINE FOCUS (RT): See EFFECTIVE FOCAL SPOT.