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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 ?
Six months after the contract is awarded, the collimators should be ready for delivery.
In addition, subject feedback was solicited on the use and preference of the collimators.
Regular changes in the fine structure of histograms revealed in the experiments with collimators which isolate beams of alpha-particles flying at certain directions.
As sensitivity is mostly limited by the diameter of the collimator, alternatives to recover it include the use of large sets of imagers with single pinhole collimators or the use of multipinhole collimators, taking special care to avoid or limit the overlapping of individual projections on each detector.
Each of the collimators contains sixty leaves that are arranged in two opposing banks of thirty.
Using the data of the small angle scattering process that was obtained, a multi-diaphragm collimator has been designed.
In addition, a new device, the multileaf collimator, allows for the collimation of the x-ray beam during treatment.
FDA 510(k) clearance was granted to Varian's Millennium MLC-120 multileaf collimator (MLC), a device used with its medical linear accelerators for increasing the cancer-killing energy directed at tumors, while minimizing the radiation dose to surrounding healthy tissue.
Delivery and supplies collimators and compensators Brass pre-uisnes plexiglass for the Proton Therapy Center of the Institut Curie (Orsay).
In a given collimator, both PXI chassis run LabVIEW Real-Time on the controller for reliability and LabVIEW FPGA on the reconfigurable I/O devices in the peripheral slots to perform the collimator control.
Varian Oncology Systems is the market leader in multileaf collimators, with more than 700 systems installed worldwide, more than all its competitors combined.