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Journal of Analytical & Bioanalytical TechniquesIs the Low-Resolution Mass Spectrometer Capable of Detecting Cancer at Early Stages?
In physics, a spectrometer is an apparatus to measure a spectrum. Generally, a spectrum is a graph that shows intensity as a function of wavelength, of frequency, of energy, of momentum, or of mass.
Optical spectrometers (often simply called "spectrometers"), in particular, show the intensity of light as a function of wavelength or of frequency. The deflection is produced either by refraction in a prism or by diffraction in a diffraction grating.
Magnetic spectrometers: 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
- <math>p = mv = qBr</math>,
Since Danysz' time, many types of magnetic spectrometers more complicated than the semicircular type have been devised.
The energy spectrum of particles of known mass can also be measured by determining the time of flight between two detectors (and hence, the velocity) in a time-of-flight spectrometer. Alternatively, if the velocity is known, masses can be determined in a time-of-flight mass spectrometer.
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.
- K. Siegbahn, Alpha-, Beta- and Gamma-Ray Spectroscopy, North-Holland Publishing Co. Amsterdam (1966)
- Jan Kazimierz Danysz, Le Radium 9, 1 (1912); 10, 4 (1913)
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