Non-orthogonal particle detection systems and methods
AssigneeParticle Measuring Systems, Inc.
InventorsJohn Mitchell, Jon Sandberg, Dwight A. Sehler
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Abstract
Described herein is a particle detection system capable of spatially resolving the interaction of particles with a beam of electromagnetic radiation. Using a specific electromagnetic beam cross sectional shape and orientation, the detection sensitivity of a particle detection system can be improved. Also provided are methods for detecting and sizing particles in a manner that has low background signal and allows for spatially resolving the scattering or emission of electromagnetic radiation from particles.
Claims38
A particle detection system comprising:
- a flow cell for containing a fluid flowing through said flow cell in a flow direction;
- a source for generating a beam of electromagnetic radiation having a cross sectional profile having a major axis and a minor axis, said source positioned to direct said beam through said flow cell, wherein particles contained within said fluid interact with said beam, thereby generating scattered or emitted electromagnetic radiation;
- and
- a two-dimensional detector positioned in optical communication with said flow cell for receiving at least a portion of said scattered or emitted electromagnetic radiation, wherein said two-dimensional detector is positioned non-orthogonal to said flow direction.
A method of detecting particles, said method comprising the steps of:
- providing particles in a fluid having a flow direction;
- passing a beam of electromagnetic radiation having a cross sectional profile having a major axis and a minor axis through said fluid, wherein an angle between said major axis and said flow direction is non-orthogonal and wherein said particles interact with said beam thereby generating scattered or emitted electromagnetic radiation;
- and
- detecting at least a portion of said scattered or emitted electromagnetic radiation with a two-dimensional detector, thereby detecting said particles.
A method of spatially resolving an interaction of particles with a beam of electromagnetic radiation, said method comprising the steps of:
- providing particles suspended within a fluid flowing in a flow direction;
- passing a beam of electromagnetic radiation through said fluid, wherein said beam has a cross sectional profile having a major axis and a minor axis and wherein an angle between said major axis and said flow direction is non-orthogonal and wherein said particles interact with said beam thereby generating scattered or emitted electromagnetic radiation;
- and
- directing at least a portion of said scattered or emitted electromagnetic radiation onto a two-dimensional detector, thereby spatially resolving said scattered or emitted electromagnetic radiation in a first direction parallel to a propagation axis of said beam and in a second direction parallel to said major axis of said cross sectional profile of said beam.
A method of sizing a particle, the method comprising the steps of:
- providing a particle suspended within a fluid flowing in a flow direction through a flow cell;
- passing a beam of electromagnetic radiation through said fluid, wherein said beam has a cross sectional profile having a major axis and a minor axis and wherein an angle between said major axis and said flow direction is non-orthogonal and wherein said particle interacts with said beam thereby generating scattered or emitted electromagnetic radiation;
- imaging at least a portion of said scattered or emitted electromagnetic radiation onto a two-dimensional detector;
- determining an intensity of said scattered or emitted electromagnetic radiation imaged onto said two-dimensional detector;
- and
- comparing said intensity of said scattered or emitted electromagnetic radiation imaged onto said two-dimensional detector with one or more threshold reference values, thereby determining a size of said particle.
Dependencies are inferred from the claim text.