Pulse width for particle sizing.

The widths of optical pulses in flow cytometry contain information about the size of particles. This size information is independent of many of the factors that affect light scatter as a measure of particle size, and any light scatter or fluorescence signal can be used to measure pulse width. For fluorescence signals, the pulse width can be predicted theoretically for many particle shapes, and quantitative size calibration is possible. To be a meaningful independent parameter, the pulse-width measurement must be independent of the pulse amplitude. This unit provides protocols for determining the signal range over which amplitude independent pulse-width measurements can be made and methods for calibrating the pulse-width measurements to particle diameter. Calibration and application examples are provided and briefly discussed.