Radiation thermometry is based on the principle that all materials radiate energy in the form of electromagnetic waves. The temperature of the body can be determined by measuring the frequency and intensity of the radiated energy. Theoretical foundations of radiation thermometry were established by Max Planck, Wilhelm Wien and Lord Rayleigh. Planck‚s equation relates the radiant flux density to an object‚s temperature and wavelength and is expressed as:
W =eC/(pl5(ed/lT - 1)
where W is the radiant flux density, C and d are constants, T is temperature, e is the emissivity and l is the wavelength.
The radiation range for biomedical applications is infrared, and the various detectors that have been used in radiation thermometry have included thermopiles, pyroelectric sensors, Golay cells, photoconductive cells and photovoltaic cells. One of the main advantages of radiation thermometry is the ability to make temperature measurements without direct physical contact with the body being measured.
Figure 4 Radiation thermometry
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Support for the development of this module was provided by the National Science Foundation and The Cooper Union for the Advancement of Science and Art.
Please send questions or comments to Professor Ron Adrezin or Professor Daniel Raichel.