Material analysis using reflected light
AssigneeThe United States of America as represented by the Secretary of the Army
InventorJohn H. Pollard
Life of this patent
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Abstract
An apparatus and method for determining the relative proportions of two eents of a ternary compound from light reflected off a sample of the compound. The light is varied in wavelength and a graph of reflectance vs wavelength is stored. For a given compound of general form A.sub.x B.sub.1-x C, x may be determined by converting the stored graph to a graph of reflectance vs photon energy of the light, determining the photon energy of the light for the longest wavelength peak on the converted graph, and computing x from the equation E.sub.1 =a+bx+cx.sup.2 wherein a, b, and c are predetermined constants, and E.sub.1 is the photon energy in electron volts of the peak of interest.
Claims1
A method for quantitively dry testing a sample of ternary compound of the form A.sub.x B.sub.1-x C which includes the steps of:
- directing a variable wavelength light beam onto a surface of said compound;
- varying the wavelength of said light beam in a predetermined manner;
- detecting the reflectance of light from said surface as said wavelength is varied and plotting a graph thereof;
- replotting said graph as a graph of reflectance versus photon energy of the light;
- and
- determining the longest wavelength peak of said reflectance versus photon energy graph whereby the photon energy of said longest wavelength is designated E.sub.1 ;
- and
- computing x from the equation E.sub.1 =a+bx+cx.sup.2, wherein a, b, and c are predetermined constants for the compound.
Dependencies are inferred from the claim text.