ANALYSIS OF THE TECHNIQUES FOR MEASURING PARTICLE SIZE AND DISTRIBUTION FROM FRAUNHOFER DIFFRACTION PATTERNS
Abstract
The location and size of particles within a volume which is stationary or dynamic can be found by two techniques of coherent optics. In the first technique the volume is illuminated with coherent light and the resulting diffraction patterns are recorded in the far-field (Frauhofer region) of the particles. The particle information is found from the resultant density variations on the film. In the second technique the developed negative (a Fraunhofer hologram) is illuminated with coherent light and the particle field is reconstructed in three dimensions. This investigation is an analysis of these two techniques and their relative merits. Because magnification is important in the second technique the methods of magnifying the volume are discussed. It is found that reconstructing the volume from the hologram yields particle information which is easier to obtain than the information resulting from the diffraction patterns. The volume is also found to be easily and uniformly magnified by an imaging lens in the reconstruction process.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1968
- Accession Number
- AD0674741
Entities
People
- Ronald A. Belz
Organizations
- Arnold Engineering Development Complex