EFFECTS OF EDGE MATERIAL ON WIDE ANGLE DIFFRACTION.
UTAH UNIV SALT LAKE CITY
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Precision photometric traces of light diffracted 70 deg into the shadow region were made for four different diffracting edges. Two of the half planes were gold plated, one silver plated, and one copper plated. Light of wave-lengths 4358 A or 5461 A was normally incident on the edge for all cases. Intensity traces as a function of diffracting angle were made for light polarized perpendicularly and parallel to the edge for both wave- lengths. The distance from the edge to the photometer was 19.5 cm. The diffracted light was measured by a liquid-nitrogen-cooled 1P21 electron photomultiplier photometer. A new solid state amplifier system was used to lend high stability to the measurements taken. Although experimental conditions do not rigorously satisfy Sommerfelds boundary conditions, comparison is made with Somerfeld theory to show in general how the patterns for the different metals vary. The light intensity ranged over 10 to the 9th power part of that observed at the geometrical shadow. In general the traces agree to within an order of magnitude with Sommerfeld theory. The different metals and wavelengths exhibited a pronounced effect on the intensity distribution and polarization of the light diffracted into the shadow region. Author