Accession Number:

ADA090404

Title:

Infrared Transmission Measurements through Screening Smokes: Experimental Considerations,

Descriptive Note:

Corporate Author:

ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERDEEN PROVING GROUND MD CHEMICAL SYSTEMS LAB

Personal Author(s):

• Holst,Gerald C.

Report Date:

1980-06-01

Pagination or Media Count:

14.0

Abstract:

In order to evaluate the effect of tactical screening smokes on infrared transmission, it is necessary to understand the complex interactions among many variables. The transmission depends upon the bulk properties of the material e.g., index of refraction, as well as the particle-size distribution, concentration, and pathlength. The measured or apparent transmission can be quite different from the true transmission because several simple basic facts are often overlooked. Therefore, it becomes quite difficult to compare data from different laboratories or from field tests because the experimental methodology is different at each location. In principle, it is possible to calculate the transmission of the smoke if the particle-size distribution, concentration, pathlength, and the complex index of refraction are known. But these parameters are not always known precisely, and one resorts to experimentation to define them. The experiment becomes that of introducing a smoke with unknown infrared properties between the target and the detector. The ratio of the signal received with smoke to that without smoke is taken as the transmission.

Descriptors:

• *SMOKE SCREENS
• *LIGHT TRANSMISSION
• *INFRARED RADIATION
• SPATIAL DISTRIBUTION
• MEASUREMENT
• PARTICLE SIZE
• REFRACTIVE INDEX
• CONCENTRATION(COMPOSITION)
• RANGE(DISTANCE)

Subject Categories:

• Ammunition and Explosives
• Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE