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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 ?
The collimator's sapphire optics guarantee high resistance to the radiation of multi-kilowatt CW or pulsed lasers, along with reduced thermally-induced focus shift and spherical aberration, because of high thermal conductivity and water cooling.
The texture analysis is influenced by the correction factor at each Ps angle, which is dependent on the 2th position and width or size of the receiving slit and collimator.
When making a laser collimator, find a small laser that will fit inside the pipe, and cut the pipe so there's enough length for the laser and three or four inches more.
The Rinn[R] universal rectangular collimator insert (Rinn Corp, Elgin, Ill) hereafter referred to as "Universal" was fitted over the circular collimator end resulting in a 33 cm source to-end distance (Figure 1a).
1) and [sup.239]Pu [alpha]-activity in Pushchino with a west-directed collimator. The calculated difference in local time is equal to 179-180 min.
To comply with this requirement, the dimensional stability and consistent functionality of the sensor components such as the collimator and TGP were important consideration factors.
At the detector input, a collimator was fixed with 4.5 mm diameter for all measurements, while at the source output it was possible to fix collimators of different diameters.
In group A, planar and SPECT imaging were done with the LEHR collimator, whereas an MEGP collimator was used in group B.
This phantom was imaged following our standard protocol (16 projections, 2 min/projection) with the seven-pinhole collimator imaging head.
Lever guns, pumps, and some semiautos, however, still require an optical collimator for boresighting.
The optical collimator reproducing the solar divergence represents the core of every laboratory set-up employed to characterize solar components.
When it came to designing a multi-leaf collimator (MLC) device, ViewRay ( took on the challenge to produce an end product that would be more accurate than others on the market.