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Examination of Pollutants in the Atmosphere
The amount of impurities in a gas can be observed by a radiation
beam and detector, via the setup below.
Gas- absorbs a specific wavelength of radiation.
Infrared source- emits an IR beam.
Chopper- creates a pulsed radiation beam, which allows the
pyroelectric to form a continual signal.
Gas container- permissible to radiation, and holds the gas
in position.
Pyroelectric detects radiation by heating.
The voltage produced by radiation passing through the gas, is measured relative to a reference voltage, from radiation passed through vacuum.
The radiation heats the pyroelectric, and produces a voltage.
This voltage is measured, and the reduction in voltage quantifies the
drop in intensity of the radiation. From this, the partial pressure
of pollutant can be calculated.
Voltage
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