Calibration and testing of optical single-particle-size spectrometers with monofilament fibers as substitute particles

A particle simulator is presented which consists of one or more uniform fibers held in place across an obscured opening in an opaque frame. The monofilament fibers act as test particle substitutes for making quick and accurate checks of the calibration, depth-of-field, and particle-counting capability of single-particle counters. The tests demonstrate that counts from identical fibers can be reproduced accurately in a narrow interval of indicated particle diameters with an apparent monodispersity similar to that of latex spheres. By selecting the fiber diameter and color or by combining the fibers with simple optical filters, it is possible to simulate monodisperse particles of any diameter down to at least the 0.1 micron limit of conventional light-scattering particle-sizing techniques.