Accession Number : ADP004372

Title :   Infrared Material Optical Damage by Rain,

Corporate Author : OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES CHATILLON-SOUS-BAGNEUX (FRANCE)

Personal Author(s) : Deom,A. ; Gauffre,G. ; Balageas,D. L.

Report Date : 1984

Pagination or Media Count : 7

Abstract : A comprehensive study of the optical damage and erosion of various infrared materials is conducted using a rotating arm. The optical damage is characterized by the evolution of the sample modulation transfer function (MTF). The velocity dependence for MTF deterioration is similar to that of the mass loss: occurrence time of damages is inversely proportional to a high-exponent power law of the velocity. For some materials like magnesium fluoride (MgF2), the optical damage occurs in synchronism with the erosion. Inversely, for others like zinc selenide (AnSe), optical damage occurs very early before the beginning of the erosion. Consequently, the screening of candidate materials for irdome must be based on transmission tests, or better on MFT tests, rather than on erosion tests. (Author)

Descriptors :   *Infrared domes, Materials, Infrared radiation, Losses, Mass, Time, Rain, Zinc selenides, Deterioration, Erosion, Test methods, Infrared optical materials, Magnesium compounds, Modulation, Transfer functions, Damage, Optical properties, Velocity

Distribution Statement : APPROVED FOR PUBLIC RELEASE