Measurement of Total Cross Sections of Water Drops at 5 mm Wavelength Utilizing the 'Shadow Theorem'

摘要

Total 5 mm wavelength cross sections of falling water drops with radii between 1.25 mm and 3.38 mm were measured at two droplet temperature intervals, 25C to 28C and 2C to 5C, using the shadow theorem which relates the imaginary part of forward scattering coefficient to the total cross section. The experimental total cross section values were a little smaller than the theoretical values of the total cross sections of spherical water drops, and the differences between the experimental cross sections of the drops at the two temperatures were comparable to the experimental errors. Measurements were also made of total cross sections of metal spheres with radii between 1.98 mm and 4.35 mm as a preliminary verification of the theorem and were found to be in good agreement with theoretical values. (Author)