Process and apparatus for identifying or characterizing small particles

Claim 1

A process for characterizing and identifying a single unknown microparticle within a range of interest on the basis of physical properties derived from measured optical observables comprising the steps of: A. Introducing microparticles one-at-a-time into a flowing laminar stream surrounded by a particle-free sheath of the same material as the stream; B. Passing said stream containing said entrained microparticles through a narrow beam of electromagnetic radiation; C. Surrounding said radiation beam and microparticle stream by means able to support a number of discrete detector means at selected angular locations about said radiation beam and microparticle stream, with said support means not obstructing the entrance and exit of either particle stream or radiation beam from said surrounding region and said number and locations of detector means being sufficient to yield a unique range of optical observable values characteristic of that expected from the microparticles of interest; D. Detecting the radiation scattered by each said microparticle as it passes through the radiation beam at each of the selected surrounding detector means; E. Converting each said detected scattered radiation intensity into a proportional numerical value; F. Storing said numerical values in a memory means with separate memory means corresponding to each discrete detector means; G. Deriving measured optical observable values by combining sufficient selected sets of stored numerical values to yield a set of optical observables spanning the range of observables characteristic of the particles of interest; H. Defining an optical observable map for a fixed range of optical observable values in terms of a set of physical parameters, each physical parameter restricted to a domain encompassing those characteristic of the microparticles of interest, and said map consisting of closed regions within which ranges the circumscribing physical parameters would result in an optical observable within the defining fixed range; I. Retrieving from memory means previously stored maps of optical observables, one map for each measured optical observable value and whose range of optical observable values bracket the corresponding computed value; J. Superimposing a sufficient number of said retrieved maps of optical observables to yield a unique and finite region of overlap; K. Identifying the range of each particle's physical parameters corresponding to the common overlap region of said retrieved maps; and L. Classifying and identifying the unknown microparticle by the values of the physical parameters defined by the optical observable map overlap region.

Claim 10

An apparatus for the characterization and identification of a microparticle by measurement of its optical observables containing A. Means for introducing microparticles one at a time into a flowing laminar stream surrounded by a particle-free sheath of the same material of the stream; B. Means for directing said stream containing said entrained microparticles through a narrow beam of electromagnetic radiation; C. Means, surrounding said radiation beam and microparticle stream, able to support a number of discrete detector means at selected angular locations about said radiation beam and microparticle stream, with said support means not obstructing the entrance and exit of either particle stream or radiation beam from said surrounding region and said number and locations of detector means being sufficient to yield a unique range of optical observable values characteristic of that expected from the microparticles of interest; D. Means for detecting the radiation scattered by each said microparticle as it passes through the radiation beam at each of the selected surrounding detector means; E. Means for converting each said detected scattered radiation intensity into a proportional numerical value; F. Means for storing said numerical values in a memory means with separate memory means corresponding to each discrete detector means; G. Means for deriving measured optical observable values by combining sufficient selected sets of stored numerical values to yield a set of optical obervables spanning the range of observables characteristic of the particles of interest; F. Means for passing said microparticle into subsequent electromagnetic beams, each beam and region of microparticle intersection being surrounded by detection means as in D, above; G. Means for repeating steps E to G above for each said subsequent electromagnetic field region; H. Means for collecting all said optical obervables of steps G through I and processing in a computer means to yield a combined set of optical observables, one subset of said combined set corresponding to the measurements with respect to each interaction of said microparticle with each electromagnetic beam.

Claim 11

An apparatus for the characterization and identification of a microparticle by measurement of its optical observables containing A. Means for introducing microparticles one at a time into a flowing laminar stream surrounded by a particle-free sheath of the same material of the stream; B. Means for directing said stream containing said entrained microparticles through a narrow beam of electromagnetic radiation; C. Means, surrounding said radiation beam and microparticle stream, able to support a number of discrete detector means at selected angular locations about said radiation beam and microparticle stream, with said support means not obstructing the entrance and exit of either particle stream or radiation beam from said surrounding region and said number and locations of detector means being sufficient to yield a unique range of optical observable values characteristic of that expected from the microparticles of interest; D. Means for detecting the radiation scattered by each said microparticle as it passes through the radiation beam at each of the selected surrounding detector means; E. Means for converting each said detected scattered radiation intensity into a proportional numerical value; F. Means for storing said numerical values in a memory means with separate memory means corresponding to each discrete detector means; G. Means for deriving measured optical observable values by combining sufficient selected sets of stored numerical values to yield a set of optical obervables spanning the range of observables characteristic of the particles of interest; F. Means for passing said microparticle into subsequent electromagnetic beams, each beam and region of microparticle intersection being surrounded by detection means as in D, above; G. Means for repeating steps E to G above for each said subsequent electromagnetic field region; H. Means for collecting all said optical obervables of steps G through I and processing in a computer means to yield a combined set of optical observables, one subset of said combined set corresponding to the measurements with respect to each interaction of said microparticle with each electromagnetic beam.