useful beam


Also found in: Dictionary, Thesaurus, Encyclopedia.

beam

 [bēm]
a unidirectional, or approximately unidirectional, emission of electromagnetic radiation or particles.
useful beam in radiology, that part of the primary radiation that is permitted to emerge from the tubehead assembly of an x-ray machine, as limited by the aperture or port and accessory collimating devices.
beam splitter a device that reflects light from the output phosphor of an image intensifier to a photographic recording. Called also image distributor.
References in periodicals archive ?
Remember: Aprons only protect against secondary or scatter radiation, never the primary or useful beam.
Gordon, a physicist at the Jacob Blaustein Institute for Desert Research at Ben-Gurion University of the Negev in Sede Boqer, and his colleagues knew that radiation from the sun is more than sufficient to match a medical laser's output, but they faced the problem of how to concentrate sunlight into useful beams.