Abstract: A slide motion sampling valve for use with a particle study device and carrying an expansive type microsyringe having a minimum trapped volume. The sampling valve is formed of a slidably movable member carrying a trapping volume, an expansive element and ejection port in the form of a fine aperture, and a stationary element sealingly engaged with said movable member and carrying an opening leading to the entrance of the sheath flow arrangement. The valve operates between a conditon where the ejection port and the opening are aligned and a condition where communication to the entrance is blocked whereby to isolate the trapping volume from said entrance except during ejection of the predetermined amount. One embodiment described employs a linear sliding motion while another embodiment employs a rotating sliding motion.

Abstract: In an apparatus in which particles which may include biological cells are passed through an optical sensing zone to measure their spatial radiant energy distribution for the purpose of identifying and/or characterizing the particles or cells, a structure and method are provided for increasing the usefulness of a geometric configuration of photovoltaic detectors such as a known assembly of generally concentric rings of such detectors usually including some wedge-shaped detectors. These are provided in a generally planar form and the invention provides structure which captures radiant energy in a flow cell of a particular type before projecting the energy to the detector. In particular an ellipsoid, paraboloid, hyperboloid or similar reflector which is symmetrical about its optical axis is utilized first to capture the radiant energy on angles which could include most forward and/or backward angles and all azimuthal angles and then deviating the same to the detector assembly mentioned.

Abstract: A tandem arrangement of sensing zones is established by alternately arranged electrodes and dielectric plates, each sensing zone has a particle sensing aperture, through which microscopic particles in an electrolyte suspension pass and electric current flows. The apertures are aligned. This tandem sensing zone arrangement improves the signal-to-noise ratio of a particle analyzing apparatus in which it is employed.

Abstract: A particle analyzer for a sample suspension of particles originating in a container in which: a flow director is mounted between the container and a first chamber, a particle sensing aperture is mounted between the first chamber and a second chamber, a liquid sheath is introduced into the first chamber for hydrodynamically focusing the particles through the sensing aperture, an electrical current passes through the sensing aperture for generating impedance signals, the pressure drop is regulated across the flow director to assure a constant flow of the suspension through the flow director and the aperture, and the flow director is formed into an optical element for viewing the sensing aperture.

Abstract: Disclosed is a particle analyzing apparatus including a first vessel of particulate electrolyte suspension, and an electrolyte-containing first chamber, and an electrolyte-containing second chamber, a sensing aperture formed in a wall between the vessel and the first chamber, a cleaning orifice formed in a wall between the first chamber and the second chamber, an electrical current passing through the sensing aperture to generate detectable signals with the passage of the particles through the sensing aperture, and a fluid recirculating system providing a fluid path from the second chamber through a filter for removing the particles to the first chamber, which is powered by waste kinetic energy of the suspension exiting from the sensing aperture.

Abstract: In an apparatus in which particles are passed through an optical sensing zone to measure their radiant energy distribution such as, for example, light scattering characteristics for the purpose of identifying the particles, means and a method are provided for deviating the collected light in accordance with predetermined different paths to a plurality of different photodetecting devices. The deviation is effected independently of collection by optical radiant energy transmitting or reflecting means. The different photodetecting devices enable the measurement of energy directed along the particular path which is identified with that device. The paths are established by the deviating means rather than permitted to evolve by the scattering phenomena themselves whereby the photodetecting devices can be located in convenient arrangements and may be conventional in construction.

Abstract: A particle analyzing apparatus comprising a reflector chamber containing an electrolyte and having a concave reflector surface with a first focus and a second focus; entraining structure, having an introduction tube for providing and moving a stream of particles suspended in an electrolyte solution through the first focus; a source of radiant energy for illuminating the particles as they pass through the first focus to produce a source of detectable radiation signals, which reflect off the concave reflector surface to be subsequently collected and analyzed; an exit tube coaxially aligned with the introduction tube; a sensing orifice mounted in the tip of the introduction tube or the exit tube; and a pair of energized electrodes disposed in the electrolyte solution on either side of the orifice, whereby the orifice creates a constricted electrical path in which the stream of particles generate electrical impedance signals as they move therethrough.

Abstract: In an apparatus in which particles are passed through an optical sensing zone to measure their light scattering characteristics for the purpose of identifying the particles, means and a method are provided for deviating the collected light in accordance with predetermined different paths to a plurality of different photodetecting devices. The deviation is effected simultaneously with collection by optical radiant energy reflecting means. The different photodetecting devices enable the measurement of energy scattered along the particular path which is identified with that device. The paths are established by the combined collecting and deviating means rather than permitted to evolve by the scattering phenomena themselves whereby the photodetecting devices can be located in convenient arrangements and may be conventional in construction.

Abstract: Measurement of the energy and direction of radiation, typically scattered light, produced by particles passing through an optical sensing zone is improved in focusing of the scattered light and flexibility in the choice of focal length for positioning of photoresponsive devices.The improvement is obtained by collimating the collected scattered light entering a deviating device, typically a fresnel prism, and then focusing the emerging separate, independent beams for measurement.Collimation can be obtained using optical elements including lens systems or reflective systems such as those employing parabolic reflection.

Abstract: There is disclosed an illuminator and collector apparatus and method for fluorescence analysis wherein illumination of a stream of particles produces fluorescent light. A reflector, having a concave reflector surface with a first focus disposed in the stream of particles, has reflected therefrom organized illuminating radiation, such radiation converging upon the first focus to stimulate the particles into producing the fluorescent light. The fluorescent light emanates from the first focus, a portion of which is reflected from the concave reflector surface. This fluorescent light which is focused on the second focus contains no (or negligible) amount of illuminating radiation and is collected for subsequent detection and processing.

Abstract: Disclosed is a radiation collector apparatus and method primarily for counting and analyzing a flow of dilute particulate material, such as blood cells, sperm cells and the like, through the use of light detection. The radiation collector apparatus comprises a reflector chamber having an ellipsoidal reflector surface with a pair of elipsoidal foci defining a first focus, f.sub.11, and second focus, f.sub.12, and a second reflector surface with a primary focus, f.sub.21, positioned at the same point as focus f.sub.12, and a secondary focus, f.sub.22. The second reflector surface has the configuration of one of the conic sections of revolution. In operation the radiation collector apparatus is provided with an intensifed beam of light and a stream of particulate material aligned to intersect the intensifed beam of light at focus f.sub.11. Detectable light signals, after two reflections, are received in a focused beam by a photosensitive detector.

Abstract: Disclosed is a radiation collector apparatus and method primarily for counting and analyzing a flow of dilute particulate material, such as blood cells, sperm cells and the like, through the use of radiation detection. The radiation collector apparatus comprises a reflector chamber having an ellipsoidal reflector surface with a pair of ellipsoidal foci defining a primary focus and secondary focus. A window is formed in the ellipsoidal reflector surface and is centered on a symmetry axis defined by the primary and secondary foci. In operation the radiation collector apparatus is provided with an intensified beam of radiation and a stream of particulate material aligned to intersect the intensified beam of radiation at one of the ellipsoidal foci. Detectable radiation, either directly or after one or more reflections, proceeds through the window in an organized beam for detection.

Abstract: Disclosed is a radiation collector apparatus for analyzing particles by irradiating the particles to produce a source of detectable radiation, wherein the radiation collector apparatus comprises a reflector chamber having an ellipsoidal first reflector surface truncated in a plane of a minor axis of the same by a planar second reflector surface. Detectable radiation emanating from a primary focus of the first reflector surface either directly or after one or more reflections proceeds through a window formed in one of the reflector surfaces for subsequent processing. In another embodiment a dichroic second reflector surface is provided.

Abstract: A method and apparatus for obtaining information on and identifying particles in a liquid suspension wherein the particles in suspension are moved in a stream through a plurality of sensing zones such that each particle passes through the sensing zones serially. As each particle passes through a sensing zone a particular characteristic of the particle will be measured and its time relationship with the preceding and succeeding particle passing through that zone will also be preserved to form a pattern of time relationships. The pattern of time relationships and the particle characteristics at a particular sensing zone will be correlated with the pattern of time relationships and particle characteristics at either a preceding or succeeding sensing zone in order to correlate all of the characteristics for the particle.The stream may also be passed to a substrate and the particles laid out on the substrate in a particular spatial pattern.

Abstract: A sample ejection system includes a sample ejecting device which receives and temporarily stores an aliquot of sample. A thermal expansion device in the sample ejecting device operates upon application of energy to expand and eject a predetermined volume of sample. Thermal conduction structure coupled to the sample ejecting device operates in a first mode to cool and contract the expansion device.

Abstract: For use in a particle analyzer of the well known type, in which a microscopic aperture-defined sensing zone separates two bodies of electrolyte and particles in the electrolyte are caused to pass through the sensing zone; a first pair of sensing electrodes and a second pair of power electrodes are positioned with one electrode of each pair being on opposite sides of the aperture. A feedback circuit measures the constant D.C. voltage component between the sensing electrodes and feeds same back to the power electrodes, to cause the analyzer to be independent of power electrode polarization. The sensing electrodes are coupled to an output circuit, including a high input impedance voltage detecting amplifier, to enable the analyzer to operate accurately independent of changes in electrolyte conductivity. The connections to the sensing electrodes permit only negligible current to flow in them and thereby minimize their polarization.

Abstract: A method and apparatus for correcting a particle pulse count subject to coincidence error is disclosed wherein particle pulses, developed in response to passage of particles in a particulate system through a sensing zone, are counted for a predetermined period of time. The predetermined period of time is increased or extended in response to each pulse counted by a time increment that is related to a characteristic of the counted pulse, such as the pulse width, duration, or amplitude. The total additional time period allows the counting of additional particle pulses such that the total count at the end of the extended time period is an error corrected count for the number of particles detected in the predetermined time period.

Abstract: An apparatus for identifying particles such as cells in a liquid suspension includes a particle scanning device containing a suspension of the particles. The suspension moves in a stream through a sensing zone in the device, which, for example, may be a Coulter type particle detector, and out of the sensing device to a waste receptacle. As each particle in the suspension passes through the sensing zone, it will produce a particle pulse whose measurements represent at least one physical characteristic of the particle. A particle collecting substrate is positioned adjacent the stream departing the scanning device. A counting device, coupled to the scanning device and the substrate, operates only in response to the particle pulse for each sensed particle selected to develop a particular count signal and to direct the stream and the selected particle therein to a particular location on the substrate corresponding to the particular counting signal.

Abstract: A method and apparatus are disclosed wherein an a.c. signal charges droplets sprayed into a chamber as the droplets are formed. The frequency of the a.c. signal is high enough so that the individual droplets are charged differently than their neighbors. The differently charged droplets create a nonuniform electric field within the chamber. The nonuniform electric field causes particles, entering the chamber in a fluid medium such as air, to be attracted to and attach to the droplets thereby precipitating out of the fluid medium.

Abstract: A flow chamber which is particularly useful in slit-scan photometry and which has a predetermined configuration for orienting generally flat oval particles such as squamous cells in the direction of fluid flow such that the maximum cross-sectional area of each particle is substantially normal to a light path traversing the flow of particles at an observing station situated along the flow path of the particles.