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Two-dimensional optical imaging methods and systems for particle detection

  • US 8,154,724 B2
  • Filed: 12/02/2008
  • Issued: 04/10/2012
  • Est. Priority Date: 12/04/2007
  • Status: Active Grant
First Claim
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1. 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.

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