A composite metal, usually in the form of sheet or bar, composed of two or more metal layers so bonded
that the composite metal forms a structural member.
To form a metallic product of two or more bonded layers.
LAMINATIONS: Discontinuities in plate, sheet or strip caused by pipe, inclusions, or blowholes in the original ingot;
after rolling they are usually flat and parallel to the outside surface.
LAMINOGRAPHY: A special form of tomography which is used for limiting an inspection to a single plane in the
material; images of the condition along the plane of interest are brought into sharp focus while other images are
smeared or blurred.
LAP: A surface defect, appearing as a seam, caused by folding over hot metal, fins or sharp corners and then rolling or
forging them into the surface, but not welding them.
LATENT IMAGE (RT): The metallic silver image of the material radiographed brought out by the developing process.
LATITUDE (RT): Latitude, most closely aligned with contrast, is the range of thickness that can be transferred or
recorded on a radiograph within the useful reading range of film density. A high contrast has little latitude whereas a
low contrast film will have great latitude.
LATTICE: The repetitive three-dimensional arrangement of atoms in a solid.
LAW: Liquid Active Waste.
LAW OF RECIPROCITY, PHOTOGRAPHIC (RT): See RECIPROCITY LAW.
LD (RT): See MEDIAN LETHAL DOSE.
LEAD EQUIVALENT (RT): The thickness of lead affording the same attenuation of radiation under specified
conditions, as the material in question.
LEAD GLASS (RT): Glass containing a high proportion of lead compounds, used as a transparent shielding material.
LEAD RUBBER (RT): Rubber containing a high proportion of lead compounds. It is used as a flexible shielding
LEAD-RUBBER GLOVES (PROTECTIVE GLOVES) (RT): Gloves incorporating lead rubber as a shielding material.
LEAD SCREENS: See SCREENS, LEAD.
LEAK: A hole or void in the wall of an enclosure, capable of passing liquid or gas from one side to the other under
action of a pressure or concentration difference existing across the wall.
LEAKAGE (RT): The undesired release of radioactive material from a sealed source.
LEAKAGE FIELD: See FIELD, LEAKAGE.
LEAKAGE RADIATION (RT): Radiation other than the useful beam emitted from an X-ray tube assembly or source
LEAKAGE RATE: The quantity of gas per unit time at a given temperature and pressure, that flows through a leak or
leaks; normally expressed in standard cubic centimeters per second (STD. cm3/s).