Spectrometer

Source: Wikipedia, the free encyclopedia.
For the field of study, see Spectroscopy.
An XPS spectrometer

A spectrometer (

mass spectrometer measures the spectrum of the masses of the atoms or molecules present in a gas. The first spectrometers were used to split light into an array of separate colors. Spectrometers were developed in early studies of physics, astronomy, and chemistry. The capability of spectroscopy to determine chemical composition drove its advancement and continues to be one of its primary uses. Spectrometers are used in astronomy to analyze the chemical composition of stars and planets, and spectrometers gather data on the origin of the universe
.

Examples of spectrometers are devices that separate

molecules by their mass, momentum, or energy. These types of spectrometers are used in chemical analysis and particle physics
.

Types of spectrometer

Optical spectrometers or optical emission spectrometer

Main article: Optical spectrometer
Spectrum of light emitted by a deuterium lamp in the UV, visible and near infrared part of the electromagnetic spectrum.

Optical absorption spectrometers

Optical spectrometers (often simply called "spectrometers"), in particular, show the intensity of light as a function of wavelength or of frequency. The different wavelengths of light are separated by refraction in a prism or by diffraction by a diffraction grating. Ultraviolet–visible spectroscopy is an example.

These spectrometers utilize the phenomenon of

absorption spectrum (dark lines). Because each element leaves its spectral signature in the pattern of lines observed, a spectral analysis can reveal the composition of the object being analyzed.[1]

A spectrometer that is calibrated for measurement of the incident optical power is called a spectroradiometer. [2]

Optical emission spectrometers

metals
to determine the chemical composition with very high accuracy. A spark is applied through a high voltage on the surface which vaporizes particles into a plasma. The particles and ions then emit radiation that is measured by detectors (photomultiplier tubes) at different characteristic wavelengths.

Electron spectroscopy

Main article: Electron spectroscopy

Some forms of spectroscopy involve analysis of electron energy rather than photon energy. X-ray photoelectron spectroscopy is an example.

Mass spectrometer

Main article: Mass spectrometry

A

mass spectrometer is an analytical instrument that is used to identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions.[3]

Time-of-flight spectrometer

The energy spectrum of particles of known mass can also be measured by determining the time of flight between two

time-of-flight mass spectrometer
.

Magnetic spectrometer

A positive charged particle moving in a circle under the influence of the Lorentz force F

When a fast charged particle (charge q, mass m) enters a constant magnetic field B at right angles, it is deflected into a circular path of radius r, due to the Lorentz force. The momentum p of the particle is then given by

,
mass spectrometer
.

Since Danysz' time, many types of magnetic spectrometers more complicated than the semicircular type have been devised.[5]

Resolution

Generally, the resolution of an instrument tells us how well two close-lying energies (or wavelengths, or frequencies, or masses) can be resolved. Generally, for an instrument with mechanical slits, higher resolution will mean lower intensity.

See also

References

  1. ^ Open access icon OpenStax, Astronomy. OpenStax. 13 October 2016. <http://cnx.org/content/col11992/latest/>
  2. ISBN 978-3-902842-23-7
    .
  3. S2CID 99611182. Archived from the original
    (PDF) on 2018-10-08. Retrieved 2015-06-15.
  4. ^ Jan Kazimierz Danysz, Le Radium 9, 1 (1912); 10, 4 (1913)
  5. ^ a b K. Siegbahn, Alpha-, Beta- and Gamma-Ray Spectroscopy, North-Holland Publishing Co. Amsterdam (1966)
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