Abstract: Method for specific detection of one or more analytes in a sample. The method includes specifically associating any one or more analytes in the sample with a scattered-light detectable particle, illuminating any particle associated with the analytes with light under conditions which produce scattered light from the particle and in which light scattered from one or more particles can be detected by a human eye with less than 500 times magnification and without electronic amplification. The method also includes detecting the light scattered by any such particles under those conditions as a measure of the presence of the analytes.

Abstract: An optical particle detection system produces an optical beam which is scattered by particles in a probe volume area. The particles may scatter the beam to the detector. The optical beam is a hollow shaped beam which may be circular/doughnut shaped, or made be of any other hollow shape. The particle passes across the beam, and those particles which pass through the center of the beam are detected as being desired particles to detect. This system may be used to detect particle concentration, and size. In addition, by producing an asymmetric beam, particle direction can also be detected.

Abstract: A turbidity sensor for measuring a full range of particulate content in a turbid environment, including a method thereof. The turbidity sensor includes a laser light source for emitting laser light through the particulate content. The turbidity sensor additionally includes at least one light-sensitive detector located proximate to the laser light source for the detection of light scattered from particles of the particulate content that come into contact with laser light emitted from the laser light source, thereby permitting the accurate measurement of the turbidity of the turbid environment. A plurality of light-sensitive detectors may be employed, including a back scatter detector, a side scatter detector, a forward scatter detector, and a direct transmission detector. The light-sensitive detectors may be arranged in a geometric configuration of light-sensitive detectors with respect to the laser light source.

Abstract: A method for determining the number or concentration of virus particles in a sample by use of a light scattering detector. The method may be used to quantitate purified virus preparations or virus samples containing contaminants, including ultraviolet light-absorbing contaminants, such as proteins. The method is useful for quantitation of viruses for use in gene therapy, oncolytic viruses for tumor cell lysis and virus-based vaccines.

Abstract: The present invention provides a particle-measuring system and the particle measuring method that is provided in a processing system for generating an atmosphere including atmospheric air or a gas exhausted from within a processing chamber by a vacuum pump, and for processing a wafer W relating to a semiconductor manufacturing in this atmosphere, and that is installed on an exhaust pipe connecting between an exhaust opening of the processing chamber and the vacuum pump, for measuring the number of particles included in the exhaust gas.

Abstract: A cavity ring-down spectroscopy device and method suitable for materials with low and high absorption coefficients. An optical signal introduced into an optical cavity resonates through a length of fiber amplifier coupled to the optical cavity. The optical signal resonates through a fiber amplifier active section resulting in a gain compensating for optical losses. The gain obtained by use of the fiber amplifier is then modulated between two predetermined levels. By virtue of employing an optical fiber, the cavity ring down spectroscopy device and method is insensitive to misalignment and therefore iminently capable of portability.

Abstract: The proposed holographic particle image velocimetry (HPIV) system employs holograms of two time-separated particle fields, illuminated by separate reference beams on a single recording medium. 90-degree scattering is utilized for the object wave, in order to improve Numerical Aperture and resolve the third dimension of the hologram. The proposed HPIV system then uses substantially the same optical geometry for the reconstruction process. A CCD camera is utilized to extract particle subimages, thin slice by thin slice, and a centroid-finding algorithm is applied to extract centroid locations for each volume. The concise cross correlation (CCC) algorithm for extracting velocity vector fields from the centroid data is an important enabling feature of the proposed system. Correlations are calculated between subsets of centroids representing the images or cubes, and velocity vectors are computed from the individual correlations.

Abstract: A method and apparatus for determining particle size distribution in undiluted suspensions using spectral measurements of transport-scattering co-efficients using continuous photon-migration techniques is provided. Particle size distribution for concentrated suspensions is determined by a regularized inverse algorithm and may be obtained without a priori distribution function assumptions.

Abstract: A turbidity sensor apparatus and method for measuring very low concentrations of particles in a fluid. The turbidity sensor comprises a laser light source for emitting laser light through a fluid. Such a fluid may be hydraulic fluid, oil, water utilized in water purification systems, or other translucent fluids. The turbidity sensor includes a first light-sensitive detector located 90 degrees to incident laser light emitted from the laser light source, and a second light-sensitive detector located at an angle obtuse to the incident laser light emitted from the laser light source, wherein the first and second light-sensitive detectors respectively measure side scattered light and forward scattered light reflected from particles contained within the fluid that come into contact with laser light emitted from the laser light source, thereby providing an accurate and reliable measurement of very low concentrations of particles within the fluid.

Abstract: The invention relates to a method for carrying out mixing in a thin liquid layer, which is arranged between essentially parallel walls at a capillary distance from each other. The mixing is carried out by subjecting the walls to a motion essentially in the plane of the liquid layer, balancing the motion against the capillary force exerted by the walls on the liquid, and selecting the interface between the liquid layer and the surrounding medium so that it functions as an elastic membrane. The invention also concerns a cuvette which is designed for mixing according to the method.

Abstract: A turbidity sensor apparatus and method for measuring very low concentrations of particles in a fluid. The turbidity sensor comprises a laser light source for emitting laser light through a fluid. Such a fluid may be hydraulic fluid, oil, water utilized in water purification systems, or other translucent fluids. The turbidity sensor includes a first light-sensitive detector located 90 degrees to incident laser light emitted from the laser light source, and a second light-sensitive detector located at an angle obtuse to the incident laser light emitted from the laser light source, wherein the first and second light-sensitive detectors respectively measure side scattered light and forward scattered light reflected from particles contained within the fluid that come into contact with laser light emitted from the laser light source, thereby providing an accurate and reliable measurement of very low concentrations of particles within the fluid.

Abstract: The present invention relates to a backscattering apparatus and method for optical scanning along a circular path using one or more optical illuminators and receivers. More particularly, it relates to an apparatus and method of focusing one or more beams of light into one or more beam spots, scanning the common beam spot(s) across a circular path and receiving light backscattered from the beam spot(s) with one or more detectors. A rotationally mounted scanning optics having an optical axis parallel to but not coaxial with the axis of rotation is used to accomplish these functions. A motor may be operatively linked to the scanning optics to cause the same to rotate at a constant angular velocity whereby, with appropriate signal generating detector and signal processing electronics, the number and size of particles suspended in a fluid medium exposed to the beam spot(s) can be determined.

Abstract: The high numerical aperture flow cytometer of the present invention includes a flow cell and a laser input. The laser input emits a beam of light that is oriented substantially orthogonally to the flow of blood cells through the flow cell such that laser light impinges upon the blood cells as they pass through the flow cell. A portion of the beam from the laser input that impinges upon the blood cells in the flow cell is scattered at a substantially right angle to the beam of laser input (“right angle scatter”). A second portion of the beam from the laser input that impinges upon the cells in the flow cell is scattered at a much lower angle than 90°.

Abstract: A preferred OPTICAL BLACK™ ionic anodize process of the present invention applies a porous anodic oxide coating to a component part in a standard sulfuric acid anodizing bath (with or without organic additives). A modified alternating electric current is then applied to the porous oxide coating to remove excess anodizing electrolyte and to allow the coloring solution access to the pores. The oxide coating is electrolytically colored in a low pH acid bath containing a tin salt, sulfuric acid, and organic additives. Alternating current carries additional tin salt to the base of the pores where the tin salt is reduced to metallic tin or tin oxide. Others metals or metallic salts could be employed. Component parts treated by the OPTICAL BLACK™ ionic anodize process can be advantageously employed in optical systems, such as particle detectors, to reduce or eliminate stray light.

Abstract: A device and a method enable the rapid, quantitative evaluation of a large collection of ligands for binding affinity with a certain immobilized receptor, the improvements being that binding pan be detected without the need for a label and that binding is carried out in solution phase at a high rate. The instrument has at least two embodiments, one is based on a sensitive absorption photometer and the other on a sensitive light scatter photometer operating at a specific resonance wavelength, &lgr;R, of small, metallic, colloidal particles. The resonance is present in small particles having a complex refractive index with real part n(&lgr;) approaching 0 and imaginary part k(&lgr;) approaching 2 simultaneously at a specific wavelength &lgr;R. The particles are substantially spherical and substantially smaller than &lgr;R. The receptor is immobilized on a suspension of such particles and ligand binding is detected by a change in optical absorption or light scatter at the resonance wavelength.

Abstract: An integrating nephelometer is modified to measure 180° backscattering from an aerosol. A laser is mounted outside a housing of the nephelometer and produces a coherent light beam that is directed into a sample volume of the nephelometer, substantially along an optical sensing axis (<4° off the optical axis). Light from the laser beam that is reflected by an aerosol travels back along the optical sensing axis toward a photomultiplier tube (PMT) light detector, which thus produces a signal indicative of the backscattering from the aerosol. A portion of the laser beam is conveyed into the housing of the nephelometer through an optical fiber for use as a reference beam. A motor-driven chopper disk disposed across the optical axis is divided into an open sector, a calibration sector (with a very low transmission), and a flat black light absorbing sector.

Abstract: A smoke alarm having both an ionization detector and a photoelectric detector coupled to each other to generate an alarm signal when either of the detectors senses a potential fire. The smoke detector includes a power supply circuit having both an AC power supply and a DC battery power supply. During normal operating conditions, the AC power supply operates both the ionization detector and the photoelectric detector of the smoke alarm. Upon power interruption, the DC battery supply provides power to operate both the ionization detector and the photoelectric detector. The smoke alarm includes an interconnect that allows multiple smoke alarms to be coupled together.

Abstract: According to the present invention, there is provided a light scattering type particle detector in which the S/N ratio is improved. In the light scattering type particle detector, a particle detecting region D is formed by irradiating laser light La on sample fluid and scattering light Ls due to particles which pass through the particle detecting region D is received with the light receiving array 5. The light receiving array 5 is formed to be circular by arranging a plurality of photoelectric converters Pd1-Pdn in a plane alignment. The adder 6 adds the output from the plurality of the photoelectric converters Pd1-Pdn.

Abstract: The high numerical aperture flow cytometer of the present invention includes a flow cell and a laser input. The laser input emits a beam of light that is oriented substantially orthoganilly to the flow of blood cells through the flow cell such that laser light impinges upon the blood cells as they pass through the flow cell. A portion of the beam from the laser input that impinges upon the blood cells in the flow cell is scattered at a substantially right angle to the beam of laser input (“right angle scatter”). A second portion of the beam from the laser input that impinges upon the cells in the flow cell is scattered at a much lower angle than 90°. This scatter is termed “low angle forward scatter light” and has an angle of from about 2° to about 5° from the orientation of the original beam from laser input. A right angle scatter light detector is oriented to receive the previously mentioned right angle scatter light.

Abstract: A method for determining the number or concentration of virus particles in a sample by use of a light scattering detector. The method may be used to quantitate purified virus preparations or virus samples containing contaminants, including ultraviolet light-absorbing contaminants, such as proteins. The method is useful for quantitation of viruses for use in gene therapy, oncolytic viruses for tumor cell lysis and virus-based vaccines.

Abstract: A turbidimeter array system is described in which a common light source and a common detector are used in conjunction with a plurality of test sample chambers for measuring the turbidity of a sample in each of the numerous chambers sequentially. Many embodiments are described for using a common light source and a common detector. The system is cost efficient because the most expensive components are shared.

Abstract: The present invention is directed to a device for evaporative light scattering detection that can be used for a wide range of sample types and mobile phases. The device may be quickly converted between a single flow and a split flow configuration through the use of a retractable impactor.

Abstract: A method for quantifying the concentration of hemoglobin in a cell, and indicia of anemia, comprises determining the wavelength of the longitudinal mode of a liquid in a laser microcavity; determining the wavelength of the fundamental transverse mode of a red blood cell in the liquid in the laser microcavity; and determining if the cell is anemic from the difference between the wavelength of the longitudinal mode and the fundamental transverse mode. In addition to measuring hemoglobin, the invention includes a method using intracavity laser spectroscopy to measure the change in spectra as a function of time for measuring the influx of water into a red blood cell and the cell's subsequent rupture.

Abstract: A particle size distribution analysis apparatus wherein there are provided a sample measurement zone adapted to contain a sample of particles, a light emitting means adapted to provide a source of light incident upon the measurement zone, and a detection means adapted to measure light levels at different scattering angles and to output signals to a computation means, enabling the size of particles contained within the sample to be determined, wherein the light emitting means comprises a first light source emitting a substantially monochromatic first wavelength of light and a second light source emitting a substantially monochromatic second, different, wavelength of light.

Abstract: An optical scattering particle counter uses optical scattering and heterodyne detection techniques to overcome the lower limit on particle size detection stemming from background light scattering by the fluid carrier in which a particle is immersed. The particle counter uses a heterodyne technique to exploit a basic physical difference between target particle scattered light and the background light. For gas-borne particulate monitoring, the carrier gas molecules have a pronounced temperature-induced Maxwell-Boltzmann translational velocity distribution and an associated Doppler broadened spectral scattering characteristic that are dissimilar to those of the target particle. The Doppler broadened background Rayleigh light is orders of magnitude spectrally wider than that scattered by a particle in a particle detector view volume. This difference in bandwidth allows the local oscillator light to "tune in" the target particle light in a beat frequency signal and "tune out" the background radiation.

Abstract: Particles generated within a semiconductor wafer process chamber are monitored by emitting a rastered laser beam into the process chamber and detecting a two-dimensional image of scattered radiant energy within the process chamber. A video frame representing a matrix array of pixel intensities is produced and processed by a processor. The processor receives first and second video frames, the first frame representing a matrix array of pixels of a background image of the process chamber before a wafer processing is started and the second frame representing a matrix array of corresponding pixels of a target image of the process changer after a wafer processing is started. Differential intensities between the pixels of the background image and corresponding pixels of the target image are detected and a decision is made on the detected intensities to produce an output signal representing presence or absence of the particles.

Abstract: A method for the quantitative acquisition of flow patterns in fluid flows in which a medium (e.g., a gas or a liquid) and the particles contained therein and carried in the flow are set in motion in a transparent flow object. The method provides that a flow object is transilluminated by a laser light fanned out on a plane parallel to the longitudinal axis of the flow object. A scattering of the laser light by the particles is detected by a camera positioned at a right angle to the longitudinal channel axis and moving in the vertical and horizontal directions, and can be analyzed with an analysis unit connected downstream from the camera. The analysis unit is calibrated by quantitatively comparing an image, which has an object-to-image ratio and which is recorded inside the flow object by the camera, to an image having an object-to-image ratio and recorded outside the flow object.

Abstract: In a particle detector, a stream carrying particles to be measured is passed through a laser beam. A pair of optical collection systems are arranged perpendicular to the laser beam, opposing each other. The optical collection system reflects light signals indicative of particles sensed in the sensing region to a pair of detector arrays. Each detector array has a plurality of detectors to detect the particle signals, as well as other noise. One detector from each array monitors the same sensing region. The signals from the detectors are processed through a noise cancellation circuit. The noise cancellation circuit first amplifies each detector signal through a photo-amp. Then, the signals of the detectors in one detector array are paired up with corresponding signals of detectors, spaced at least two detectors away, in the other detector array. The paired-up signals pass through differential amplifiers, which essentially cancel the light fluctuation noise.

Abstract: System for, and method of, monitoring airborne particulate, including particulate of the PM.sub.2.5 class. The system for monitoring airborne particulate includes an optical sensor to measure size characteristics of sampled airborne particulate and a humidity sensor to measure relative humidity. An adjusted airborne concentration value is then produced in response to the measured size characteristics and to the humidity measurement. According to one embodiment the optical sensor is implemented as a multi-wavelength nephelometer, e.g., two-wavelength nephelometer. According to another embodiment the humidity sensor is placed relatively near the optical sensing region and makes a relative humidity measurement.

Abstract: A device for counting and measuring particles provides an analysis of the particle characteristics and includes a processing system 27, comprising a control subsystem 13, including a microprocessor subsystem 20 and a terminal devices 21, an analog-digital subsystem 14, comprising an amplifier 15 and a pulse former 24, and a light detecting system 11, providing particle detection. An improved device determines the size of particles by the quantity of the strobe pulses of the strobe pulse sequence within each strobe pulse pack, formed from the amplified and converted output of the light detecting system 11. The quantity of the identical strobe pulse packs characterizes the quantity of the particles with an appropriate identical size.

Abstract: A pump establishes gas flow in a particle counter. A pair of shafts having lobes is mounted in a first housing and serves to establish a gas flow path through a second housing which defines a view volume where particles are counted by light scattering or obscuration of a beam intersecting the light flow path. The lobes of the first housing do not contact each other or the walls of the housing, thereby limiting particles to those suspended in the gas flow.

Abstract: A method and apparatus for determining the flow of abrasive particles in a micro abrasive blasting machine. The machine propels abrasive particles using a carrier stream of compressed gas, typically air, nitrogen or carbon dioxide. The machine mixes the abrasive particles such as aluminum oxide, glass bead, sodium bicarbonate, or silicon carbide, with the carrier gas stream. This mixture is then directed at a work piece through a hard nozzle, typically carbide or sapphire. The apparatus operates on a particle flow detection area upstream of the nozzle through which the carrier stream containing the abrasive particles flows. The apparatus analyzes the fluctuations in the optical transmissivity of the carrier stream containing the abrasive particles to determine the flow of the abrasive particles in the carrier stream.

Abstract: The Nephelometer comprises an illumination device (10) and a detector device (19). By means of the illumination device (10), a sample to be analyzed being arranged in a chamber (16) is illuminated, the scattered light emanating from the sample being detected by the detector device (19). A central shading element (17) arranged in a plane conjugate to the light source (11) of the illumination device (10) is located between the sample chamber (16) and the detector device (19). The detector device (19) further comprises another shading element (20) located in a plane conjugate to the exit opening shutter (15) of the illumination device (10). Direct light from the sample to be analyzed is absorbed by the central shading element (17), while the further shading element (20) absorbs stray light exiting from the exit opening shutter (15) of the illumination device (10) and impinging on the entrance lens arrangement (18) of the detector device (19) without passing through the sample.

Abstract: An improved particle monitoring sensor is described which uses a variety of techniques to prolong the effective life of the optical surfaces within the particle monitoring'sensor. Substantially inert purging gas is directed over the particle monitoring sensor windows, which are normally exposed to a harsh operating environment. The surfaces of these windows are heated by heating elements in direct thermal contact with the windows. In addition, a restrictive slit is placed over the detector window to reduce the exposed area and to increase the velocity of gas flowing over the window surface. While this slit reduces the detector's field of view, the signal loss is reduced by using a linearly polarized light source and aligning the elongated slit's major axis with the direction of polarization.

Abstract: In a method for monitoring particulates in stacks or ducts a back-scatter monitor uses a solid-state laser to emit a collimated beam, the intensity of which is controlled via feedback from a reference detector. The beam is split so that part goes to a reference surface for calibration checks, and part is directed to pass at a selected angle through a gaseous sample. Optical energy scattered from particles in the sample is detected by viewing optics to provide an indication of particulate concentration. The beam steering mechanism can direct the optics to view scattering along a selectable axis that intersects the laser beam at a specified location within the gaseous sample. The method can be used to determine the opacity of the gaseous sample providing a basis for correlation to particulate loading of that portion of the particulates that are of a size comparable to the wavelength of light.

Abstract: A rate nephelometer of the type useful in automated chemical analyzers is provided. The nephelometer includes a laser for generating a polarized laser beam having an S-wave component and a P-wave component. The beam is split by a beam splitter specially constructed so that a known proportion of one of the two polarized portions of the beam is directed to a reaction container. In the reaction container, a first polarized component of the laser beam is used in a nephelometric chemical analysis. The remainder of the laser beam passes through the beam splitter to a laser control light detector. Before the remainder of the laser beam reaches the laser control light detector, however, the polarized component which is not used in nephelometric chemical analysis is filtered out. The laser control detector uses the non-filtered portion of the laser beam to control the output of the laser.

Abstract: A compact optical probe is disclosed particularly useful for analysis of emissions in industrial environments. The instant invention provides a geometry for optically-based measurements that allows all optical components (source, detector, rely optics, etc.) to be located in proximity to one another. The geometry of the probe disclosed herein provides a means for making optical measurements in environments where it is difficult and/or expensive to gain access to the vicinity of a flow stream to be measured. Significantly, the lens geometry of the optical probe allows the analysis location within a flow stream being monitored to be moved while maintaining optical alignment of all components even when the optical probe is focused on a plurality of different analysis points within the flow stream.

Abstract: A gas-borne optical scattering particle counter uses intracavity optical scattering and heterodyne detection techniques to overcome the lower limit on particle size detection stemming from background light scattering by the gaseous carrier in which a particle is immersed. The particle counter uses a heterodyne technique to exploit a basic physical difference between target particle scattered light and the background light. The carrier gas molecules have a pronounced temperature-induced Maxwell-Boltzmann translational velocity distribution and an associated Doppler broadened spectral scattering characteristic that are dissimilar to those of the target particle. The Doppler broadened background Rayleigh light is orders of magnitude spectrally wider than that scattered by a particle in a particle detector view volume. This difference in bandwidth allows the local oscillator light to "tune in" the target particle light in a beat frequency signal and "tune out" the background radiation.

Abstract: A device provides a precise counting and measuring the particles and includes a capillary particle flow system, comprising at least one of a plurality of capillary particle flow channels, the axes of which intersect each other and a light beam at a point, belonging to the focus of the particle detecting system. Each capillary particle flow channel is intended for the passage of the predetermined size particles. A device also includes the synchronously operating blower and purger, the inlet and outlet filters, a control system, and the extended inlet and outlet particle flow tubular systems, the valves, providing a synchronous connection of the appropriate capillary particle flow channels to the inlet and outlet executive systems.

Abstract: A particle detector (10, 12, 70) employs an upconversion laser medium (22, 72) to produce emission radiation (32) at an emission wavelength (56) that is less than the wavelength of the pumping radiation (26). The shorter emission wavelength (56) provides a significant increase in the scattering intensity (I.sub.sc) detected by the particle detector (10, 12, 70), based on the equation I.sub.sc =I.sub.o k/.lambda..sup.4, where I.sub.o represents the intensity of emission radiation (32), .lambda. represents the wavelength (56) of the emission radiation (32), and k represents a coefficient related to particle size. In addition, the emission wavelength (56) of the upconversion laser medium (22, 72) can be frequency doubled to excite biological chromophores such as tryptophan, NADH, and flavin compounds that absorb in the UV spectral range and emit fluorescence at longer wavelengths that can be discretely detected to determine the presence of biological particles.

Abstract: A nephelometer and nephelometer/turbidimeter combination of the type useful in automated chemical analyzers is provided. The combination includes a laser for generating a polarized laser beam having an S-wave component and a P-wave component. The beam is split by a beam splitter specially constructed so that a known proportion of one of the two polarized portions of the beam is directed to a reaction container. In the reaction container, a first polarized component of the laser beam is used in a nephelometric chemical analysis. The remainder of the laser beam passes through the beam splitter to a laser control light detector. Before the remainder of the laser beam reaches the laser control light detector, however, the polarized component which is not used in nephelometric chemical analysis is filtered out. The laser control detector uses the non-filtered portion of the laser beam to control the output of the laser.

Abstract: Light emitted from a light emitting element is converted into parallel light by a lens, and a light receiving element detects scattered light occurring due to particulate existent in a fan-shaped field pattern spreading along the optical path of the parallel light. Since parallel light is used, stray light can be processed within a limited space. Furthermore, since the scattered light of parallel light which occurs due to the particulate is detected using the fan-shaped field pattern, particulate detection can be performed on volumes of air at a high signal-to-noise ratio.

Abstract: A particle detector employs a resonant cavity having a chromium doped colquiriite crystal lasing medium, such as an Cr:LiSrAlF.sub.6 crystal, adjacent to an intra-cavity view volume. The resonant cavity is defined by two spaced apart mirrors, with the crystal positioned between them, defining a light path through the crystal, but most of the light does not escape past the mirrors. The view volume is positioned in the light path, between the first mirror and the laser medium, to introduce particles into the resonant cavity so that light impinging thereupon produces scattered light. A detector is disposed to sense light scattered from the view volume and produces signals proportional to the light sensed. Harmonic generators are used in alternate embodiments to produce sub-micron wavelengths. Optical coatings on mirrors forming cascaded cavities are used to isolate a harmonic wavelength in a cavity containing the view volume.

Abstract: Intracavity particle detection is disclosed using optically pumped laser media. A laser medium, positioned within a laser cavity, is end-pumped by an optical pump source to excite the laser medium to provide laser light within the laser cavity, and a detecting region, also positioned within the laser cavity and capable of having particles, or particle-containing fluid, therein, is exposed to the laser light whereby light is affected, as by being scattered, by particles in the detecting region with the scattered light being indicative of particles, such as small particles having a size of between 0.05 and 10 microns, causing the light to be scattered so that the scattered light, when collected, can be used to provide an output indicative of particles at the detecting region.

Abstract: A particle counter of the condensation nucleus type wherein a primary stream of fluent material containing particles enlarged by vapor condensate of a working fluid flow through a viewing volume. A secondary stream of fluent material, termed purge gas, surrounds the primary stream of fluent material as the primary stream traverses the view volume, thereby providing a boundary layer of fluent material, reducing turbulence of the primary stream. The two streams are merged after passing through the view volume and the merged stream is drawn into one or more coalescent filters for conversion of vapor to working fluid which is then recycled for reuse, thereby extending the life of the working fluid and preventing escape of vapor which might contaminate the ambient environment.

Abstract: A method for counting, by ranges of size, particles flowing through a particle sensor including the steps of flowing a particle through the sensor, thereby producing a voltage pulse which is sampled over a period of time. Sampling yields a plurality of voltage values which includes a latest value and a former value. The latest value is compared with the former value and when less than the former value, the method finds, in a table of threshold voltages, the size range for the particle. A counting bin corresponding to the size range for the particle is then incremented. The former value may be the value immediately preceding the latest value or it may be several "counts" prior to such latest value. The new particle sensor has an inlet, sensing volume, exhaust port, light collection system and an electronic system coupled to the light collection system. The electronic system is programmed to count particles, by size, in any of several unique ways.

Abstract: A particle detector employs a laser having a solid-state lasing medium, such as an Nd:YAG crystal, disposed in a resonant cavity, and includes an intracavity view volume. The resonant cavity is defined by two spaced apart mirrors, with the laser medium positioned between them, defining a light path. A pump source is optically coupled to drive the laser medium to produce coherent light having a first wavelength. The view volume is positioned in the light path, between the first mirror and the laser medium, to introduce particles into the resonant cavity so that light impinging there-upon produces scattered light. A detector is disposed to sense light scattered from the view volume and produces signals proportional to the light sensed. A displaying device, such as a pulse height analyzer, is in electrical communication to receive the signals produced by the detector to quantitatively display the intensity of the light sensed.

Abstract: When a intensity of a signal from a light detector 14 to measure a scattered light exceeds a predetermined value, a motion of a particle 20 is displayed as a locus of the scattered light, by means of extending an exposure time of the scattered light to the light detector, or by means of increasing a pulse oscillation frequency of a laser beam 13, or by means of extending a pulse width of the laser light. And then a straight line connecting start and terminal points of the locus is displayed to superimpose on the locus. An origin of the particle is estimated by extending the straight line beyond the start point, and a destination point of the particle is estimated by extending the straight line beyond the terminal point. A mass of the particle is estimated by dividing a projective length of the straight line in a vertical direction by the exposure time of the scattered light.

Abstract: The present invention discloses a mask defect inspection apparatus for optically detecting a defect on a mask having a circuit pattern, which comprises an illumination system for illuminating the mask with inspection light; a first light receiving optical system for receiving the inspection light reflected by the mask; a second light receiving optical system for receiving the inspection light transmitted by the mask; a first spatial filter for shielding the inspection light passing through a central region including the optical axis of the first light receiving optical system in an optical Fourier transform plane for the circuit pattern in the first light receiving optical system; a second spatial filter for shielding the inspection light passing through a central region including the optical axis of the second light receiving optical system in an optical Fourier transform plane for the circuit pattern in the second light receiving optical system; a first detector for photoelectrically converting the inspecti

Abstract: Disclosed is a particle sensor having a light beam with a beam long axis and an air flow tube with an inlet end and a particle exit mouth. In an aspect of the invention, the cross-sectional area of the flow passage at the inlet end is greater than the cross-sectional area of the exit mouth. This enlarged area dramatically reduces pressure drop along the tube. The exit mouth is in registry with the light beam and is elongate in a direction substantially parallel to the beam long axis. Thus, particles flowing through the mouth pass through the beam. In another aspect, the invention includes a centrifugal blower which is light in weight and which may be battery powered.