Patent ID: 8154724

Claim:
A method for detecting a single particle in a fluid flow, said method comprising the steps: providing said fluid flow having said particle, said flow having a flow direction; exposing said fluid flow to a beam of electromagnetic radiation, wherein interaction between said single particle and said beam of electromagnetic radiation generates scattered or emitted electromagnetic radiation from said single particle; directing at least a portion of said scattered or emitted electromagnetic radiation from said single particle onto a plurality of detector elements provided in an array of a two-dimensional detector; detecting at least a portion of said scattered or emitted electromagnetic radiation directed onto said plurality of detector elements, wherein at least a portion of said detector elements of said array generate output signals corresponding to intensities of said scattered or emitted electromagnetic radiation from said single particle; measuring output signals for at least a portion of said detector elements of said array; identifying a particle detection signature for said single particle comprising a pattern of a plurality of output signals of detector elements each having an output signal greater than or equal to a threshold value for a given detector element; wherein the threshold value for each detector element of said particle detection signature is greater than or equal to 2.5 times a standard deviation of noise for that detector element; wherein said particle detection signature comprises a longitudinal component corresponding to a distribution of intensities of said scattered or emitted electromagnetic radiation along said flow direction; said longitudinal component comprising 2 or more directly neighboring detector elements provided along a longitudinal axis corresponding to said flow direction; and analyzing the particle detection signature to provide an indication or measurement of a characteristic of the particle, thereby detecting said single particle in said fluid flow.