THE EFFECT OF DUSTS ON THE TRANSMISSION OF INFRARED RADIATION THROUGH THE ATMOSPHERE
Abstract
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.g/sq 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 mg/sq m.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1965
- Accession Number
- AD0360346
Entities
People
- W. L. Dennis