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(kol -ă-may-ter) A device used to produce a parallel or near parallel beam of light or other radiation in an instrument. One example, used in spectroscopes, is a converging lens or mirror at whose focal point is a narrow slit upon which light is focused from behind.



an optical device used to produce beams of parallel rays. A collimator consists of an objective lens or concave mirror in whose focal plane the illuminated object is placed. The opening of an opaque stop, such as a narrow slit of constant or adjustable width, is most commonly used for this purpose. The relative positions of the lens and the object are set by attaching them inside the body of the instrument, which is usually tubular. The blackened inner walls of the instrument’s body absorb rays whose direction does not coincide with the direction desired.

The parallel nature of the beam emerging from a collimator is approximate. Rays emanating from one point of the object cannot be exactly mutually parallel because of diffraction and aberrations of the lens. The finiteness of the dimensions of the object results in the spreading of beams coming from various points on the object. The focal distance, the focal aperture, and the quality of correction of aberrations of the lens, as well as the shape and dimensions of the object, are selected according to the purpose of the collimator and the conditions of its use.

Collimators are used in astronomy to align large measuring instruments and determine their collimation error, in spectral instruments to produce light beams that are directed into a dispersing system, and in various measuring, testing, and opticomechanical instruments used for alignment. They are part of autocollimating devices.


An instrument which produces parallel rays of light.
A device for confining the elements of a beam within an assigned solid angle.
References in periodicals archive ?
2 presents the result of comparison of 60-minute histograms constructed at measurements with collimator rotated 3 times a day counter-clockwise in a plane of celestial equator.
2 Influence of Machine Settings: Integration Time and Collimator Size
Due to the difficulties in measuring the axial divergence accurately and since there is no reason to suppose axial and equatorial divergence to differ (the capillaries are circular and the whole assembly possesses a cylindrical symmetry), the two divergences will be considered equal at the exit of the collimator.
The Iris Collimator allows the CyberKnife System to efficiently deliver different sized beams from each treatment position (as opposed to delivering with one collimator size from many positions, then switching to a new size to deliver from many positions, then switching to the next size and so on).
A multileaf collimator is a device with many computer-controlled mechanical "leaves" or "slats" that continually shape the treatment beam as the radiation is delivered from different angles around the patient.
The astronauts employed a 3-D laser imaging camera system produced by Ottawa- based Neptec which incorporates LightPath's patented Fusion(TM) collimators to reliably deliver laser energy in extreme environmental conditions.
manufacturer and integrator of precision molded aspheric optics, high performance fiber-optic collimators, isolators and advanced manufacturing technologies, is pleased to announce the addition of collimators over an extended wavelength range.
Currently, when performing SPECT imaging, researchers place pinhole collimators on gamma cameras to obtain high-resolution images, but the tradeoff for this high resolution is a smaller field of view.
LightPath manufactures optical products including precision molded aspheric optics, proprietary collimator assemblies, GRADIUM(R) glass products, laser components utilizing proprietary automation technology, higher-level assemblies and packaging solutions.
Collimator setting, patient table movements, tube and detector position, and oblique tracking can be managed without leaving the patient's side.
Kaman will design and fabricate the structural, electrical, mechanical and software control systems for the collimator.