Graphite Monochromator

Published: | Updated: December 22, 2020

Definition - What does Graphite Monochromator mean?

A graphite monochromator is a type of monochromator that uses highly purified pyrolytic graphite that is known to be capable of diffracting X-rays and neutrons with greater efficiency than other competitive materials.

It usually consists of a dispersing element, spherical mirrors and slits. A light source emits a broad spectrum of radiation of many wavelengths (colors) that is directed to a diffraction grating with the yellow color of the light source representing all colors. Light is dispersed by the diffraction grating at different angles depending upon its wavelength.

Graphite monochromators are produced in flat, singly bent or doubly bent shapes, and are classified by a mosaic spread.

Graphite monochromators offer amazing performance for demanding X-ray applications. Commercially available single bent focusing monochromator using graphite are three times more intense than lithium fluoride at the same resolution.

Corrosionpedia explains Graphite Monochromator

A monochromator is an optical system that selectively transmits a specific band of the electromagnetic spectrum. This device operates on the basis of the separation of wavelengths using refraction or diffraction. Typical applications include isolating a narrow stream of radiation from a continuous light source for absorption measurements and analyzing the emissions from atoms.

How a Graphite Monochromator Works

Like other types of monochromators, graphite monochromators separate polychromatic light, such as sunlight or light from a light bulb, into a wide range of individual wavelengths (many monochromatic wavelengths) and makes it possible for a narrow band of an individual wavelength to be selected. The light of a desired wavelength is directed onto a detector, sample or other components of the optical system.

The wavelength that passes through the monochromator is determined by rotating the diffraction grating to a desired angle, with the mirror and slit positions remaining fixed. When the diffraction grating is slightly rotated by a motor, the color of light that is desired passes through the exit slit. The detector measures the power of the light striking it, then converts the power value into an electrical signal.

The dispersive element used for grating monochromators is a reflecting diffraction grating, which provides a constant dispersion for all wavelengths and is independent of temperature. They produce a relatively large amount of scattered light and require the use of filters to block unwanted higher order light.

Applications for Graphite Monochromators

Potential applications for graphite monochromators include X-ray diffraction, neutron diffraction and light scattering.


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