THE EFFECT OF DUSTS ON THE TRANSMISSION OF INFRARED RADIATION THROUGH THE ATMOSPHERE
Porton technical paper
CHEMICAL DEFENCE EXPERIMENTAL ESTABLISHMENT PORTON DOWN (UNITED KINGDOM)
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The attenuation of a collimated beam of infrared radiation by dusts and aerosols of solid substances has been investigated experimentally. It is concluded that atmospheric dusts are not likely to exhibit any significant absorption bands in the wavelength range 1.5 to 6.0 microns which includes the region of interest in operating C. W. alarms. Typical dusts having a number median diameter at 1 micron were found to attenuate a beam of radiation by about 50 at 2.0 microns and 52 at 2.2 microns in a path containing 1.gsq m concentration x wavelength. These figures suggest that the operation of a sensitive C. W. alarm based on the differential absorption of infra-red radiation at two adjacent wavelengths in the 2 micron region would be affected by the presence of dust raised by the wind or by the passage of vehicles if the value of the concentration-pathlength product were in excess of 100 mgsq m.
- Defense Systems
- Chemical, Biological and Radiological Warfare