Patent ID: 7847923

Claim:
A method of analyzing pulses from a flow cytometer in which particles in a fluid pass through an excitation volume of an electromagnetic radiation and interact with the electromagnetic radiation to generate signals in the form of pulses, the method comprising the steps of: generating a time-dependent pulse indicative of the characteristics of one or more particles passing through the excitation volume of the electromagnetic radiation; determining a measurement window by selecting a portion of the pulse with a starting point and an ending point above a predetermined value; calculating a first derivative of the pulse with respect to time over the measurement window; and calculating a velocity of the particle passing through the excitation volume using the first derivative from the following equation: V = α . k P where V is equal to the particle velocity, α is the maximum value of the derivative α=max[(Abs(derivative)], Abs is the absolute value function, P is the pulse height, and k is a scaling factor.