Abstract: A modified light scattering cell, and associated method, whereby an eluant of very small dimension transverse to its direction of flow is entrained successively by two sheath flows and presented to a fine light beam that illuminates the entrained eluant as it flows through the light beam. The light scattered by the entrained eluant is collected by detectors outside of a transparent flow cell enveloping the sheath flow entrained eluant. The windows of the transparent flow cell through which the light beam enters and leaves are far removed from the scattering eluant and kept clear of eluant-contained particles by means of flow components that will form subsequently one of the eluant sheath flows employed. The eluant source is typically from a fine capillary such as found in capillary electrophoresis, capillary hydrodynamic fractionation, and flow cytometry applications.

Abstract: A nephelometer instrument capable of measuring from zero to 10,000 NTUs. The instrument includes four light detectors, three of which are positioned such that they measure light scattered at specific directions by a liquid sample. The fourth detector measures light transmitted through the sample. A removable light filter is also included. The light beam is focused on the front surface of the sample cell.

Abstract: A flow of liquid containing floating fine particles is formed in a flow path, thereby causing successive movement of the particles. A light beam having intensity distribution from a laser is focused on the liquid flow, whereby the particle is optically trapped at the irradiating position, thus being stopped against the liquid flow or being slowed by a braking force. This phenomenon is utilized in controlling the spacing of the particles in the flow or in separating the particles.

Abstract: There is provided a method and apparatus of detecting minute impurities in the entire body of a fluid. Part of the passage through which the fluid flows is constituted by a transparent member. Light is emitted in a direction substantially parallel to the longitudinal axis of this part of the fluid passage so as to envelop the same. Light scattered by impurities in the fluid is observed from a direction substantially perpendicular to the direction of the passage to detect any minute impurities in the fluid. The method and apparatus is well-suited for use in systems which extrude molten resin in the formation of plastic products used in an electrical environment in order to detect impurities in the resin which could adversely affect the performance of the products.

Abstract: A turbidity sensor is provided with two plates which each have an aperture formed therethrough. The apertures are aligned to define a light passage from a light source such as a light emitting diode. By properly selecting the gap between the two plates and the size of the two apertures, the angle of divergence light emanating from the light source can be controlled and reduced to a magnitude that prevents light from passing directly from the light source to a scattered light detector of the turbidity sensor. The arrangement avoids the necessity of using expensive focusing lenses.

Abstract: The incorporation of certain classes of solid state lasers into light scattering instrumentation is desirable because of their compact structure. However, mode hopping often causes the output power produced by such lasers to be unstable. The frequency of such output power fluctuations is often so broad that output power monitoring means, characteristic of the light scattering instrumentation into which such lasers are incorporated, cannot track accurately the temporal output power fluctuations. A method, and associated apparatus, is described whereby the laser drive current is modulated at low frequency and amplitude sufficient to induce and thereby control mode hopping so as to permit accurate measurement of the ratio of light scattering signals to the laser output power.

Abstract: An apparatus for the analysis of individual particle characteristics from an aerosol or other suspension of particles, of the type having a scattering chamber (15) with an ellipsoidal reflector (17) and an orifice leading to a rear chamber (20), and a monochromatic light source (10) adapted to transmit a collimated beam of light (11) along the main axis of the reflector (17) to impinge on a stream of the particles reflector (17), has an optical system (17, 32, 33, 34) arranged to collect light back-scattered from a particle, through a solid angle of at least 3.pi., pass the light to a a ccd video recorder (36) having a two dimensional array of a multitude of sensors.The recorder (36) is associated with a data processor (37) and with an imaging screen (35) positioned such that rays of light scattered from the particle and imaged thereon by the optical system (17, 32, 33, 34) are monotonically ordered with respect to the angle of scattering of the rays from the particle.

Abstract: The disclosure involves a particle sensor having a mirror cavity unobstructed by masks and the like. A light detector is at the mirror secondary focal point and well outside the mirror cavity. A variation includes a beam splitter and a secondary light detector to improve detection of larger particles. A second embodiment includes a pair of elliptical mirrors offset along the light beam. Light reflected by the second mirror represents only changes in laser power and light scattered by gas molecules. The resulting signal is subtracted from that produced by the first mirror to obtain a relatively "clean" signal useful to assay very small particles.

Abstract: Optical apparatus having an optical fiber to receive light incident thereon at one end, and a detector located adjacent the other end of the optical fiber to receive light passing through the optical fiber and emitting from the other end thereof to be incident on the detector for analysis purposes.

Abstract: Apparatus for determination of particle sizes and/or distributions of particle sizes comprises a light source which radiates parallel light of high coherence through a measuring zone (14) in which the particles to be measured are disposed. The light beam diffracted at the particles is imaged by an imaging device (18) onto a photo-detector (20) which is coupled to an evaluating unit (22). The imaging device (18) is provided with several different focal lengths which can be selectably brought into the beam path of the overall device. At the start of a measuring process a control device causes the distribution of particle sizes initially to be determined with the use of the longest focal length and employment of evaluation mathematics valid for this focal length.

Abstract: A device for analyzing fine particles in a sample gas includes a light source for emitting light, a convergent device for converting the light emitted by the light source into a convergent light beam having a light focus point and an energy density sufficient to dissociate the fine particles to be analyzed. The device also includes a transparent analyzer tube having a window for admitting the convergent light beam and a throat located at the light focus point of the convergent light beam, the analyzer tube receiving the sample gas and passing the sample gas through the throat. The device includes a light collecting device for collecting, through the analyzer tube, light emitted from dissociated fine particles, dissociated by the convergent light beam in the throat of the analyzer tube, and an analyzing device for analyzing the light from the dissociated fine particles collected by the collecting device.

Abstract: A method for determining whether a particular sample vial has bacterial growth includes the steps of introducing a first light into the sample vial and measuring the intensity of the reemerging light. One then introduces a second light which is different from the first light and has either a different wavelength, or is introduced at a different location than the first light. The reemerging intensity from the second light is also measured. A ratio quantity is calculated based on the two reemerging intensities, and the calculated ratio is compared to expected ratios for both positive and negative samples. It has been found that a comparison of the reemerging light intensities provides a very good indication of whether a particular sample is a positive or negative sample. Various methods and formulas for calculating the ratios may be utilized.

Abstract: A method (and corresponding apparatus) for determining the size distribution of small particles within a dispersing medium utilizing a particle analyzer that measures the angle of scattered light, including the step of sequentially irradiating the particles within the dispersing medium with each of a plurality of light sources positioned at different angles. The scattered light developed by sequentially irradiating the particles is focused, utilizing at least one collector lens, onto a detector array associated with each such lens and the angular distribution of scattered light associated with each of the plurality of light sources is sequentially measured utilizing each detector array associated with a given lens. Finally, the measured angular distributions of scattered light associated with the plurality of light sources, is translated into a size distribution for the particle ensemble contained in the dispersing medium, using well known inversion techniques, such as deconvolution.

Abstract: In a method for measuring solid concentrations in liquids, the light from two differently modulated sources (Q1, Q2) directed on the liquid is measured at the same time and processed in a combined multi-beam measuring process consisting of a 90.degree. light scatter (Q1, P, D4; Q2, P, D3) and back-scatter process (Q1, P1, D1; Q2, P3, D2) and the solid concentration is found therefrom. The process is suitable for the simultaneous measurement of both extremely low and extremely high solid concentrations by using a 90.degree. light scatter process for low concentrations and a back scatter process for high concentrations. The multi-beam process which is based on two measurements through exactly the same window areas makes it possible effectively to compensate for undesired soiling of the window areas. Mechanical devices for cleaning the window areas and to eliminate interfering light scatter are proposed.

Abstract: A method and apparatus which measures a particle size distribution of each content of powdery contents. Particle size distributions of a plurality of mixtures are calculated by blending the contents in various proportions, referring to the previously measured particle size distribution of each content, then determining the relationship between particular particle sizes in the plurality of particle size distributions and a mixing proportion. A particle size distribution of a mixture blended with the contents is measured, finding the particular particle size in the previously calculated particle size distributions of the mixture, and an actual mixing proportion of the contents in the mixture is estimated from the found particle size and the relations previously determined.

Abstract: In the method and apparatus for inhibiting a scattered component in a light having passed through the interior of an examined object, a light is radiated to the examined object, the sum of a straight advancing light component and scattered light component of the light having passed through the interior of the examined object is detected, only the scattered light component of the light having passed through the interior of the examined object is detected and the straight advancing light component is detected by an operation using the two detected outputs. In the scattered component inhibiting method and apparatus, a light modulated with a period larger than the delay of the propagating time by the scatter in the examined object is radiated to the examined object, the light having passed through the interior of the examined object is detected and the straight advancing light component is extracted by extracting a predetermined phase of the detected output.

Abstract: A particle size measuring device which includes a laser and photo-sensors for measuring the spatial intensity distribution of diffracting and scattering light upon the specimen. An arithmetic unit is provided for calculating particle size distribution on the basis of the measured spatial intensity distribution, and a first judging device for monitoring outputs from selected photo-sensors so as to see if the monitored outputs exceed a first reference so as to know that the specimen is present in the optical system. A second judging device is use for storing the outputs of all the photo-sensors when the specimen is present in the optical system, and seeing if a maximum value of the outputs falls within a range defined by a second and third reference so as to know that the concentration of the specimen is optimal for measuring.

Abstract: A method and apparatus for identifying an object having non-specific outer boundaries, such as a leukocyte, includes a device for tracking, in two dimensions, the position of the object to be identified. An identification device for identifying the object tracked by the device includes a coherent light beam emissions source, a lens assembly to direct the coherent light beam from the source to the object to be identified, a detection device for detecting the light beam which is transmitted through the object, the detection device provided with a plurality of circular or semicircular coaxial sections, the center of which is at the axis of the coherent light beam in the plane on which Fraunhofer's diffraction patterns are formed. Finally, an identification apparatus is provided which uses the output of the detection device to provide various characteristic parameters which are utilized to identify the object.

Abstract: A forward scattering loss compensated smoke sensor or smoke detector and a back scattering loss compensated smoke detector are disclosed. Both systems include first and second light sources for supplying a light signal into a fluid containing particulates. Both systems also include first and second photodetector devices for detecting directly transmitted, forward scattered and/or back scattered light. A ratiometric value or signal is produced in accordance with direct versus scattered detected light levels. The selection of forward versus back scattering particulate detection devices and methods is driven by the efficiency of the scattering which is a function of light source frequencies and particulate size.

Abstract: A structure and a method use a non-invasive particle monitor to detect particles in a process chamber for a "down sputtering" metal deposition process. In one embodiment, only non-spherical particles are detected using a single laser beam of a predetermined polarization is used, and the phase shift in the polarization due to the passing of a particle through the laser beam is measured. In another embodiment, two closely spaced orthogonally polarized laser beams are used, and the differential intensity of the laser beams is measured when a particle passes through one of the laser beams. In another embodiment, shield tubes for housing optical components are used to prevent coating of the optical components and to prevent deposition to take place outside the shielded area. Internal electric and magnetic fields are used to drive particles through the laser beams for particle detection.

Abstract: A portable scatterometer and/or an angular radiated light measurement instrument that uses a measurement head which includes a double tapered fiber optic bundle with a concave front face to simultaneously collect partial or full hemispherically scattered light reflected from a point on a surface illuminated by a depolarized, telescopically focused, laser diode source, the light rays being received by each fiber normal to its face. The image of the collected light beams is minified and coupled by the fiber optic bundle into an anti-blooming CID camera with an x-y scanning area array which converts the light beams to electrical signals. In a unique real time, computer-controlled, data acquisition and reconstruction process, a frame grabber and a unique algorithm are used to collect over 200,000 points of light, reconstruct the data into a 2D or 3D scatter profile and display the results, all within one second.

Abstract: This invention measures the change of a fluid's refractive index with changes in the concentration of a solute dissolved therein. A determination of this quantity is required for many types of chemical analyses especially for the determination of molecular weights. The fluid is restricted to a thin capillary channel (11) within a transparent material (10) such as glass. A fine light beam (18) is incident upon the capillary at an angle close to the critical angle. The axes of the light beam and capillary intersect at a point within the capillary defining thereby a plane within which the refraction occurs. A position sensing (27) device is placed to measure the displacement of the beam twice refracted during its passage through the capillary channel, said measure being used to generate a numerical value of the ratio dn/dc, where dc is the change of solute concentration resulting in a change dn of the solution's refractive index.

Abstract: An improved method of collecting quasi-elastic light scattering (also known as QELS) data and time-average intensity simultaneously is disclosed, as is a novel apparatus therefor. The apparatus utilizes a novel optical element having a pair of diametrically aligned slits on a masking disc that eliminates the need of index matching fluids that are currently required to eliminate flare from the sample cell walls at the cell-sample and the cell-air interfaces. The novel optical element allows improved angular resolution and on-axis resolution for the fluctuation data obtained.

Abstract: An improved method of collecting quasi-elastic light scattering (also known as QELS) data and time-average intensity simultaneously is disclosed, as is a novel apparatus therefor. The apparatus utilizes a novel optical element having a pair of diametrically aligned slits on a masking disc that eliminates the need of index matching fluids that are currently required to eliminate flare from the sample cell walls at the cell-sample and the cell-air interfaces. The novel optical element allows improved angular resolution and on-axis resolution for the fluctuation data obtained.

Abstract: An optical particle counter generates a signal indicating an amount of radiation scattered by aerosols in a sample flow. Smoke can be discriminated from other aerosols in the sample flow by analyzing the AC component of the signal. Smoke has a much higher signal-to-noise ratio than that of larger particles such as dust and fog.

Abstract: A fire alarm system which radiates light towards a smoke detecting space. Scattered light resulting from smoke that may exist in the smoke detecting space is judged by a receiver with respect to the type of smoke that may prevail in the space. The presence of a fire is judged by comparing the light that has been received with a set threshold level. The threshold level is set to different levels in accordance with the type of smoke detected.

Abstract: A method and apparatus for analyzing fluid by a multi-fluid modulation mode is characterized by subjecting a plurality of sample fluids (which may be different or a single sample fluid divided into a plurality of systems) to a fluid modulation by reference fluids at various frequencies, respectively. An analytical portion provided with only one sensor is simultaneously and continuously supplied with the respective sample fluids. An output signal from the sensor in the analytical portion is divided into signal components of the respective modulation frequencies for the respective sample fluids to rectify and level, whereby obtaining analyzed values about the respective sample fluids is achieved.

Abstract: The invention relates to a method and an apparatus for determining the size or the size distribution of fine particles. A single particle or a group of particles are shone by a parallel polarized beam of a single wave length and the scattered intensity on the plane of polarization of the incident beam is measured by a photodetecting array. For a single particle the size is determined from the peak scattering angle at which the profile of the product of the scattered intensity and the scattering angle has the peak. On the other hand, for a group of particles, the size distribution is determined from the angular variation of the scattered intensity or the profile of the product of the scattered intensity and the scattering angle measured on the plane of polarization of the incident beam.

Abstract: An apparatus for calibration of optical flying-height testers includes a calibrated micropositioner (100), having a base surface (102) which is permanently attached to a flat horizontal platform (106) and a top surface (104). A transducing head (108) is rigidly, but removably, mounted onto the top surface of the micropositioner. A convex bottom surface (114) of a transparent lens (112), supported on screws (116, 118, and 120), is positioned directly above the transducing head. The lens is preloaded against the tips of the screws by springs (124, 126, and 128). A prism (132) is centrally positioned onto a flat top surface (130) of the lens. The prism contains working planes (136 and 138) which serve as light-energy entrance and exit surfaces and a planar bottom surface (142) which maintains optical contact with the flat top surface of the lens.

Abstract: The lidar arrangement (1) has a transmitter (3) for linearly polarized radiation (12), a receiver (5) with a first receiving device which measures intensity of the backscattered radiation (15) coinciding approximately with the transmitted radiation cone (12) in a polarization plane of the cone and in a perpendicular polarization plane, wherein the receiver further includes a second receiving device which measures the intensity of backscattered radiation (17) outside the transmitted cone (12), the outer backscattered radiation has the shape of a conical shell which surrounds the backscattered conical shell of the first mentioned backscattered radiation (15) and of the transmitted cone (12); the received separate radiation cones (15 and 17) are split in a polarization analyzing optical element into two mutually perpendicular partial light beams, each consisting of an inner partial beam portion (15a, 15b) and an outer partial beam portion (17a and 17b), the inner and outer partial beam portions are separately de

Abstract: A method of and an apparatus for determining the individual existence of first and second groups of particles contained in a fluid and differing in characteristics from each other that are capable of, e.g., during an automatized ion exchange operation, individually distinguishing anionic and cationic ion-exchange resin particles and capable of easily monitoring their regeneration state. A plurality of beams comprising different wavelength bands are emitted from light-emitting elements, projected onto a subject of measurement containing first and second particles, and received by light-receiving elements, and the reflectivities of the beams are measured. When the ratio of the reflectivity of a first of the beams to that of a second of the beams is above a predetermined value, the subject of measurement is determined to contain particles of the first kind, whereas when that ratio in reflectivity is below the predetermined value, the subject of measurement is determined to contain particles of the second kind.

Abstract: A mixture is prepared by mixing carriers to which a substance specifically reacting on an object substance adheres with a sample containing the object substance. The mixture is irradiated by light having an intensity gradient to concentrate the carriers at and near the irradiated positions by the optical pressure of the light. The efficiency of an agglomeration reaction of the carriers is thereby increased. A qualitative or quantitative measurement of the object substance is performed by detecting a state of agglomeration of the carriers within the mixture.

Abstract: An apparatus for measuring a wide range of particle sizes in of a sample fluid with two separate light sources is provided. The individual light sources can be compensated to take into account any variations in transmission factors through the sample fluid prior to calculating the particle size distribution. Additionally, any fluctuations in the light source can also be measured to provide a compensation factor for the measured light intensities.

Abstract: A particular size measuring apparatus uses laser light and monochrome beams of different wavelengths to measure a wide range of particle sizes. The monochrome beams are obtained from a lamp source and are changed in wavelength by a group of band-pass filters, whereby different ranges of particle sizes can be measured for the respective single wavelengths and thus the range of particle sizes capable of being measured can be expanded.

Abstract: Detection apparatus employs a plurality of conduits, a plurality of photosensors, and a laser in a multi-port forward-scattering geometry to detect particles for each of a plurality of spatial sections (S.sub.1, . . . S.sub.n) of an enclosure. The photosensors are provided in two sets arranged at two different scattering angles to discriminate smoke from other particulate matter in sample flows which flow along the conduits and intersect the laser beam. The sample flows are discharged into a plenum and removed from the plenum via a single manifold. The laser can be backed up by an auxiliary laser.

Abstract: In a method and an apparatus wherein carriers sensitized by an antibody or an antigen are caused to react to a specimen sample and the condensation of the carriers caused by the antigen-antibody reaction is optically detected by the use of flow cytometry, thereby measuring the antigen or antibody in the specimen sample, a plurality of kinds of carriers differing in optical characteristic are sensitized by different kinds of antibodies or antigens, respectively, whereby a plurality of kinds of antigens or antibodies in the specimen sample are measured at a time.

Abstract: A flow cytometer has a flow cell containing a flowing stream of a number of particles which flow one at a time in a straight line based on hydrodynamic methods, a radiator for radiating a light on the particles flowing through the flow cell, a forward scattered light detector for detecting light scattered in the same direction as the radiating light, and a right angle signal light detector for detecting light radiated in a right angle with respect to the direction of the radiating light. The flow cell and the forward scattered light detector are contained in a single mount, and the mount is supported on a bench through an adjusting mechanism. In this way, the flow cell and the forward scattered light detector can be adjusted without disturbing their locations relative to each other.

Abstract: A method is disclosed based on a single injection into a modified HPLC line by which means the light scattering data required to characterize the injected molecular suspension in terms of its weight-average molecular weight, z-average square radius, and second virial coefficient may be measured and collected. The method requires that a molecular suspension at a fixed concentration be prepared and injected into a flowing stream of pure solvent following standard liquid chromatographic procedures. The sample is then passed directly to a mixing chamber whose volume is preferably several times that of the injected volume. After this mixing, the sample enters a light scattering detector where its absolute scattering intensity as a function of angle is measured for each eluting fraction. From the data so-recorded, the concentration of each fraction may be calculated and a Zimm plot may be made to yield the required molecular parameters.

Abstract: A fertility analyzer includes a laser beam impinging on a sperm sample in a capiliary, a first optical system including at least a first lens focusing the laser beam in the sample, and a second optical system including at least a second lens, a first diaphragm determining the volume element of the sample to be monitored, a second diaphragm determining the space angle of scattered light and a light intensity detecter. A signal processing device stores the signals from the light detector during a predetermined time separately for beams outgoing from the sperm sample in at least two chosen directions and computes at least two features having relation to the fertility of the sperm sample. A separator included in the combination of the first and second optical systems sorts out a determinable small section of the beam outgoing from the sperm sample in a direction lying in a plane approximately parallel to a plane including the capillary.

Abstract: Two arrangements are disclosed to provide high resolution measurement of sub-micrometer and micrometer particle size distributions. In a first arrangement, scattered light is measured over a wide range of scattering angles. At the same time, light scattered at low scattering angles is measured with high angular resolution. In the second arrangment, an improved Polarization Intensity Differential Scattering (PIDS) measurement is made possible by providing an interrogating light beam of selected wavelength including a first component having a linear polarization plane and a second component having a differential linear polarization plane, wherein the linear polarizations of the components are orthogonal. Photodetecting arrays in one or more scattering planes detect light scattered by the particles at least at two scattering angles.

Abstract: A particle measurement apparatus is disclosed in which a laser beam is projected at a sample containing particles to be measured in a measurement zone and light scattered by particles in the sample is evaluated to thereby determine properties of particles in the sample. The apparatus includes a plurality of light receiving systems for receiving scattered light arranged at different angles relative to the axis of the laser beam. The amplitude of scattered light signals from the light receiving systems are compared with predetermined values. The arrangement is such that particles are counted by size only when the scattered light signals from the light receiving systems exceed a predetermined value, enabling false signals caused by noise and the like to be eliminated and assuring more accurate measurements.

Abstract: An apparatus and method which provides a measure of the asymmetry as well as the size of individual fluid borne particles. Laser-light scattering techniques are employed to obtain data on the particles, which is then compared to data on known particle shapes to ascribe an asymmetry factor to the particles.

Abstract: A device for determining the characteristics of particles in suspension in a liquid, comprising a sampling device (2) for injecting samples of particles; a fractionator (3) for sorting those particles as a function of their length; an optical measurement cell (4) which receives the output of the fractionator, and a programmable controller (6) for calculating the values of the intensities and combinations of those values in the various directions of the optical radiation. The optical measurement cell includes a laser for transmitting polarized, coherent light through the particles in suspension and for collecting the light diffracted in various directions.

Abstract: A non-imaging particle counter 10 utilizing one or more detectors 25 which directly collect light scattered by particles in a fluid traversing a sensing volume 63. The detectors 25, are non-imaging, non-focusing, optic-less light collection devices, such as large area photodiodes. The detectors 25 are arranged and configured proximate the sensing volume 63, but such that the beam of light 60 is not operatively incident thereon. The beam of light 60 is provided by a laser 50 and is shaped by a focusing/collimating lens 54. The beam of light 60 passes through several apertures 51-53 to reduce stray/background light in the system. The detectors 25 are oriented at an angle with respect to the plane formed by the longitudinal axis of the beam and the flow of fluid, wherein stray light 61 strikes the detectors 25 at an angle greater than the acceptance angle of the detectors 25, while scattered light strikes the detectors 25 at an angle less than the detectors' 25 acceptance angle.

Abstract: An apparatus for detecting and counting particles in a gas stream flowing at a preselected rate, wherein the apparatus includes a multi-tier inlet manifold and a plurality of sensors. The inlet manifold divides an aggregate sample flow into a plurality of substantially identical partial sample flows. Each partial sample flow enters one of the functionally duplicative sensors and is intersected by an incident beam to define a view volume. Particles contained within the partial sample flows scatter light as the particles pass through the view volume. The scattered light is directed to a photodetector which provides a signal having characteristics corresponding to the sensed light. Particle detection in each view volume is operationally independent of the others, but the information is combined to provide a total particle count of the aggregate sample flow.

Abstract: Methods and apparatus for measuring the intensity of light scattered by particles suspended in a sample volume illuminated by an interrogating light beam directed along an input axis, utilizing plural Fourier optical systems having lenses arranged for illuminating multiple photodetectors. The lenses of each Fourier optical system can be of different optical powers, for providing low power and high power optical trains. A low power optical train provides high resolution measurements of light scattered within a small angular range at low angles relative to the input axis, while a high power optical train provides lower resolution measurements of light scattered within a larger angular range at higher angles.

Abstract: Apparatus is provided for measuring non-absorptive scattering with an exceptionally high degree of accuracy. In the preferred mode, the apparatus can also be used to measure absorptive scattering, thus providing a method of distinguishing absorptive scattering from scattering due to transparent moieties (i.e. non-absorptive scattering). The approach of the invention promises to significantly expand the use of optical systems in quality control. The general concept of the invention relies on symmetric heterodyne scattering. Specifically, two beams at slightly differing optical frequencies are directed to intersect at some arbitrary angle. Transparent objects within the intersection volume scatter light from each beam into the other. After intersecting, the two beams are directed to separate photodetectors which mix each transmitted beam with the scattered light from the other beam.

Abstract: A portable particle analyzer is compact and can determine the size, geometry and number of particles in a sample of fluid. A laser beam (15) intercepts the flow of fluid (17) at the first focal point of a parabolic mirror (11). Light is scattered and collected by radiation collectors (13) and low angle scattered radiation is detected in a second chamber (19) by reflection by an ellipsoid mirror (20) towards a radiation collector (21). Photomultiplier units (23) convert the radiation collected into electrical signals for analysis.

Abstract: An apparatus and method for particle detection which includes a plurality of sample regions. A sensor body has internal walls which define spaced apart sample regions, with each sample region having an inlet port and an exhaust port. An aggregate sample flow is divided into partial flows which are directed from the inlet port to the exhaust port of an associated sample region. A light source, typically a laser, is positioned to project an incident beam along a light path which intersects each of the partial sample flows through the sample regions. Particles contained within the partial sample flows scatter light as the particles pass through the incident beam. The light from a sample region is directed to a photodetector which provides a signal corresponding to the sensed light. Particle detection in each sample region is operationally independent of the others, but the information is combined to provide a total particle count of the aggregate sample flow.

Abstract: A method and apparatus for determining the amount and size of particles and bubbles in a liquid process medium. The invention comprises the steps of providing a collimated light source to generate a light beam of a known wavelength, and directing it to illuminate a liquid sampling volume within a cell positioned within a sensor housing constructed to collect the light scattered by particles and/or bubbles within the sample caused by the impingement of the light beam. The scattered light is then separated into forward, and/or right angle and back scattering portions, and converted into separate electrical signals for each scatter direction. Since the scattering coefficient is a direct function of the density of the sampling volume, the presence of bubbles reduces the density and the amount of radiation scattered in the backward direction.