Image analysis & Time of transition (TOT)

Image analysis uses a CCD video camera microscope to acquire an optimal image of the particles' shape. The technique provides a variety of parameters such as Feret diameter, area, perimeter, shape factor and aspect ratio. This two-dimensional shape and size information is complemented by a Time of Transition (TOT) laser analysis. This time size mapping provides the particle size distribution.

The strength of the TOT theory is that it relates solely and directly to particle size, rather than to secondary properties from which size may be inferred.
A laser beam circularly scans the sample measurement volume. As the laser spot individually bisects the particles within the sample volume, interaction signals are generated. Since the beam rotates at a constant speed, the duration of interaction with the individual particles provides direct measurement of the particles' size. The measurements are performed on an Ankersmid CIS-100 Particle Size and Shape Analyzer.