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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 ?
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).
This phantom was imaged following our standard protocol (16 projections, 2 min/projection) with the seven-pinhole collimator imaging head.
With the addition of the InCise Multileaf Collimator, the CyberKnife M6 Series can be used to treat large and irregular tumors more efficiently with excellent dose gradients, according to the company.
The team chose Maxon's EPOS2 Module 36-2 compact digital positioning controllers for their small form factor, which allowed them to package 60 channels of motion control for each collimator.
If the film is completely flat against the plane of the film-holding piece, the film itself will be parallel to the plane of the collimator ring.
It integrates a micro Green Laser Pump with a hand-controlled, nine-lens Linear Optical Collimator, and features one-hand thumb controls to adjust the laser beam diameter and illumination intensity.
The target reticle on the collimator may be much blighter when boresighting the new FLIR.
Using the data of the small angle scattering process that was obtained, a multi-diaphragm collimator has been designed.
With the aid of the multileaf collimator, IMRT fields can treat targets more efficiently because they allow the physician to better conform the high-dose region to the tumor.
Ipswich Hospital's multi-leaf collimator has 120 computer-controlled mechanical "leaves" or "fingers" that control the shape, size, and timing of the beam to deliver an exact dose directly to the tumor.