Abstract: Apparatus for detecting particulates (46) within a medium in a chamber (10) comprises a photo-detector (14) which is maintained at a stable low temperature by a Peltier type cooling device (42). Scattered light from the particulate (46) is focused by a spherical lens (34) onto the input face (30) of a rod lens (22). The latter has an optical pitch of 0.5 and transfers the image to its output face (25) whence it passes via a light pipe (18) to the sensitive area (16) of the photo-electric device (14). The rod lens (22) provides an inexpensive means for transferring the light and which provides a thermal barrier. Thus, although the photo-electric device (14) is held at a low temperature, the input face (30) of the rod lens (22) can be held at the temperature of the medium within the chamber (10) and is not subjected to the formation of mist or ice.

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: The liquid nephelometer has an elongate, tubular housing for containing a liquid sample to be measured for the concentration of foreign materials, a light source located adjacent one or both ends of the housing for directing a beam of light along an axial path through the housing, a light restrictor having a aperture of reduced cross sectional area to divide the interior of the housing into a first or sensing chamber having a known volume and a second chamber and to limit the passage of the scattered light between the two chambers, and light detecting means for detecting light scattered by foreign material in the liquid present in one or both of the chambers and producing a signal representative of the concentration of such foreign material.

Abstract: A semiconductor production control and measuring unit for a two-dimensional detection and control of concentration and pressure distribution of process particles within a process chamber, which forms part of a semiconductor production device and in the interior of which a vacuum can be generated with the aid of a vacuum pump. A light fan source produces a substantially parallel light fan within the process chamber, the light fan penetrating the area of the process chamber which is to be examined with regard to concentration distribution or pressure distribution, the wavelength of the light emitted by the light fan source being so short that the process particle have imparted thereto an excitation energy sufficient for fluorescent radiation. A camera is disposed at an angle with respect to the light fan and it covers the area to be examined. In the spectral region of the fluorescent radiation of the process particles, the camera has a quantum efficiency which detects the fluorescent radiation.

Abstract: Disclosed is a particle measurement method and apparatus for measuring particle properties in which a laser beam is projected into a detection region in a medium containing particles to be measured, and a photoelectric detector having a predetermined dynamic range is used to detect the laser light scattered by the particles in the medium to produce signals which are evaluated to measure the particle properties. The polarization of the laser beam and the intensity of the scattered light are regulated in accordance with the range of particle sizes measured so that the intensity of the scattered light is within the dynamic range of the photoelectric detector. This arrangement makes it possible to expand the range of particle sizes with an improved resolving power in particle measurement without multi-valued ranges.

Abstract: This flow cytometer includes 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 a light scattered in the same direction as the radiating light, a right angle signal light detector for detecting light radiated in a right angle with respect to the direction of the radiating light, whereby the right angle signal light detecting assembly is disposed on a mount, with one end of the mount being elastically supported on a supporting member and the other end being disposed on another supporting member by an adjustment mechanism, whereby adjusting the inclination of the light axis of the right angle signal light detecting assembly is made easier so that the light axis can always be perpendicular to the radiated light.

Abstract: A method and an apparatus for high-precision scattered light measurements characterized in that:in the optical path of a laser beam from the laser light source, the cross section of the laser beam is adjusted, and the laser beam is irradiated into a specimen fixed relatively to the laser beam to cause scattered lights to be scattered from the specimen;the angular distribution of the scattered lights is measured by adjusting the cross section for observing the scattered light in the optical path of the scattered light and scanning relatively with the specimen as its center; and by obtaining rapid and minute changes in the scattering intensities against minute changes in the scattering angles caused by the minute ununiformity in the structure of the specimen, the optical characteristics of transparent materials are evaluated.

Abstract: An apparatus or method identifies and quantifies components of a sample medium filling a gap of an assembly of a transparent tube and a cylindrical float located substantially coaxially with the tube. This identification or quantification is made based on the high angle scatter and/or fluorescence of the medium. A polarized monochromatic or biochromatic light beam of the wavelength for which the tube is transparent projects through an optical focusing and/or scanning system to illuminate a section of the gap with a line of light positioned parallel to the longitudinal axis of the tube but displaced laterally therefrom. Means position and rotate the tube about its longitudinal axis producing a complete circumferential illumination of the sample medium sections in the gap. Light filtering and detecting means normal to the illumination axis detects high angle light scattering properties and/or fluorescence properties from the sample medium.

Abstract: A particle monitor for a processing chamber exhaust line is disclosed which incorporates exhaust line heating, purge gas flow over surfaces such as optical windows in the exhaust gas line, and a thermally and electrically insulating particle monitor mounting arrangement. The features collectively protect the particle monitor from electrical disturbance and from the heated inlet and maintain the optical surfaces clean and free of depositions from the exhaust gas flow for an extended period. The arrangement also suppresses etching of the optical surfaces.

Abstract: A scatter signal is produced from light scattered by a precipitate formed by a chemical reaction and non-specific scatter sources. A blanking signal is produced from light scattered only by the non-specific scatter sources that contribute to the scatter signal, and the blanking signal is subtracted from the scatter signal to dynamically produce a signal indicative of the difference between the scatter signals to reduce the effects of non-specific scattering sources in determining the rate of change of the light scattered by the precipitate. One of the scatter signals may be stored and then combined with the other, or the signals may be measured simultaneously and then combined.

Abstract: An improved apparatus for measuring fine particles in a liquid includes a nozzle for spouting water from within one end of a cell towards an opposite end thereof. An incident light beam traverses the spouted water to scatter light towards a light detection system exteriorly of the cell. The detection system includes a stop for excluding scattered light from being detected and which resulted from fine particles outside a central portion of the spouted liquid.

Abstract: An oximeter that measures both the total hemoglobin concentration in whole, undiluted blood and the percentage of the hemoglobin saturated with oxygen. The oximeter uses red and infrared light-emitting diodes to illuminate a capillary tube filled with a sample of whole, undiluted blood. Light scattered by the blood travels a short distance down the length of the capillary tube and reaches a photodetector, the output of which is amplified, digitized, and fed to a microprocessor. The microprocessor computes the total hemoglobin concentration as a nonlinear monotonic function of the infrared light intensity. Oxyhemoglobin saturation is computed from the ratio of the logarithms of the intensities of red and infrared light. The invention provides a measurement of oxygen saturation without calibration shifts present in other oximeters due to fluctuations in total hemoglobin concentration.

Abstract: A real-time particle sensor is provided which can monitor particles near the surface of a disk in a computer disk drive system and in the region between disks in a multiple disk stack. A laser and lens are housed in a compact cartridge which is mounted on an actuator arm of a disk. Photocells which are also mounted on the actuator arm detect light scattered by particles passing through the laser beam, and so generate an electrical signal used to count the detected particles. The sensor's small size allows a separate sensor to fit in each of the regions between adjacent disks in a stack of disks, or near the surface of a single disk.

Abstract: A particle suspension is irradiated with a laser beam, and side-scattered light from a single particle irradiated in an irradiating zone is detected as one or a plurality of particle signals. The degree of complexity of the particle nucleus is determined by extracting high-frequency signal components contained in the particle signal, and the degree of symmetry of the particle nucleus is determined by extracting the magnitude of a difference between this single particle signal and a signal obtained by flipping over the particle signal in terms of time. The degrees of complexity and symmetry of the particle nucleus serve as data for particle analysis.

Abstract: An optical measuring device for measuring the fat contents of milk comprises a light source, an optical condenser, a glass test tube provided for holding a set amount of the milk the fat contents of which must be measured, a lens, a photosensitive element, for example of the CCD type, and a digital display, all enclosed in a metal housing which also holds a control electric and electronic system, the fat contents of the milk being measured by detecting, by means of the photosensitive element, the diffusion depth of the light projected by the light source on the milk held in the test tube and reflected on the photosensitive element by the fat particles.

Abstract: An apparatus for measuring particles in liquid in which a laser beam is projected into the liquid containing particles to be measured which are caused to flow into a measurement zone in a measuring cell, and light scattered from the particles passing through the measurement zone is received by the light receiving means to measure characteristics of the particles. The light receiving means is disposed with its optical axis nearly perpendicular to the axis of projection of laser light. The measuring cell has inlet and outlet liquid passages communicating with the measurement zone, the liquid passages having cylindrical portions which communicate through inclined portions with the measurement zone to assure a laminar flow of the liquid through the measurement zone.

Abstract: A measuring instrument for simultaneous in situ determination of the spectral scatting and absorption coefficient, which can also be called an extinction meter, has a modulated light source and an optical system encompassing the hemisphere; the optical system has a multiply folded ray path with a focal point in the volume to be measured, and through this system the measurement signal is projected to detectors. The scattering measurement signals, which are maximally enlarged in this way, are then separated from those for the absorption. The extinction meter also has not only an integrating nephelometer for monitoring purposes but also a transmission meter for low transmission factors. Because of the small three-dimensional size and the streamlined shape of the measuring portion of the extinction meter, the extinction meter can be carried in aircraft and surface vehicles.

Abstract: A method of immunoassay for analyzing a bodily fluid for the presence of an analyte relies on observing substantially the entire course of a precipitin reaction from initiation to substantial completion of the precipitation, defining a mathematical function which represents the amount of precipitation versus time and contains constants which can be adjusted so that the function matches the observed precipitation versus time curve, and fitting the observed data to the mathematical function by adjusting the constants so that the mathematical function matches the observed precipitation versus time curve as closely as possible. Values for the maximum rate of precipitation and for the time interval from initiation of the precipitation to the time of maximum rate of precipitation are calculated from the mathematical function. A reference curve is generated using standard containing known concentrations of analyte according to conventional analytical procedures.

Abstract: Method and apparatus for analyzing particles based on different depolarizing structure associated with the different particle types. Cells in a flow cytometer are illuminated with a linearly polarized light, producing scattered depolarized light whose intensity range, at a selected measuring angle, and in a suitable discriminating space, is used to analyze different particle types.

Abstract: Disclosed is an apparatus for measuring particles or particulates in a fluid in a measuring cell provided with a measuring window through which a laser beam is projected or through which light scattered from the particles passes. The surface of the measuring window is spherical with a radius of curvature whose center is at a point on which the laser beam converges for measurement. With this arrangement, light focused on the convergence point or light coming from the point always passes through the interface between the window and the fluid in the cell at an angle that is normal thereto. Thus no reflection of the light passing through the window occurs at the interface with the result that fluctuations of the refractive index of the fluid in the cell do not effect the focusing point of the light.

Abstract: A plurality of parallel spaced cylindrical capillary tubes contain single cells and/or cell colonies in a medium and gel-like agarose, and the tubes are carried by a frame-like holder supported by a motor driven X-Y translation stage of an automated microscope. The microscope also incorporates an electronic optical detector and an object lens located under the tube holder. The entire contents of each tube are internally illuminated by a precision light beam emitted from a helium-neon laser and reflected by a set of precisely positioned mirrors so that the beam extends axially through each tube when the tube extends across the vertical axis of the object lens. The contents of the tubes are sequentially scanned under the control of special softward within a personal computer, and the intensity of the light reflected outwardly from each cell or cell colony is sensed by the detector and recorded in the computer along with the axial location of the reflecting cell or cell colony.

Abstract: A particle counter for measuring the concentration and particle-size distribution of minute particles in a fluid by irradiating the particles with a laser beam from a direction that is substantially perpendicular to the fluid flow direction and by detecting the light scattered from the particles. The laser beam, prior to irradiating the particles, is flattened with a lens system and its otherwise Gaussian photointensity distribution is converted to a square pattern with a slit member. The light scattered from a central portion of the fluid is detected and formed into a real image with a focusing lens system and a detecting slit that cuts the real image only in the irradiating direction. The scattered light may be detected from a third direction that is substantially perpendicular to the flow direction and the irradiating direction.

Abstract: In a particle detector, a stream entraining particles to be measured is passed through a laser beam. Light scattered in two different directions from the laser beam by particles are detected by photodetectors and a coincidence circuit detects simultaneous pulses generated by both photodetectors to discriminate against noise and to disable the integration function in baseline control circuits for preamplifiers amplifying the output signals from the photodetectors. In an alternative embodiment arrays of photodetectors are arranged to detect light scattered in different directions from the sample stream. Optics are provided to focus light scattered from different positions in the sample stream upon different photodetectors in each array so that simultaneous particles in the sample stream can be detected.

Abstract: A laser light scattering and spectroscopic detector is provided which includes a probe comprising an optical fiber coupled to a graded index microlens. The angular aperture and the divergence of the probe are designed specifically to satisfy the scattering volume and coherence requirements for laser light scattering and spectroscopic measurements. The detector includes a housing which defines an elongate cell therein and a selected number of detector ports extending at various angles with respect to the cell. A method is provided for detecting scattered light which includes the steps of positioning the probe inside or outside the scattering medium at a selected angle with respect to the laser beam.

Abstract: A dynamic light scattering apparatus (10) comprises a laser (12) optically coupled to a light scattering sample (26) via a first monomode optical fibre (18) and a first lens (22). The lens (22) produces a beam waist (24) in the sample (26), and scattered light is collected by a receive lens (30) and a second monomode optical fibre (34). The second fibre (34) has an end face in the Fourier plane (84) of the receive lens (30, 70), and defines an aperture matched to a single Airy disc (82) of the lens (30, 70). The receive fibre (34) accordingly receives a single spatial mode of light scattered from the sample (26), this mode corresponding to a single plane wave to which many scatterers contribute. The receive fibre (34) also attenuates unwanted spatial modes because of its monomode character. A photodetector (36) detects light transmitted by the receive fibre (34).

Abstract: An optical system for use in a flow particle detection apparatus is disclosed as having a light source for directing light onto flow partricles, a condenser lens for condensing signal light emitted from the flow particles, a photodetector for receiving signal light exiting from the condenser lens, an aperture provided between the condenser lens and the photodetector for removing undesired light, and a convergence-type collimating lens provided between the aperture and the photodetector, the aperture being disposed at a front focal position of the convergence-type collimating lens, and an exit pupil of the condenser lens and a photosensitive surface of the photodetector being located respectively at conjugate points of the convergence-type collimating lens.

Abstract: An integrating sphere for detecting particles in an aerosol has a diffuse reflectant interior surface and a plurality of photodetectors. The aerosol passing through aligned ducts which are spaced at the center of the integrating sphere, and a beam of collimated light, such as a laser beam, projects transversely through the aerosol in the space. Particles in the aerosol scatter the light, and the scattered light is detected simultaneously by the photodetectors within the integrating sphere. A coincidence detection circuit is used to detect the number of times scattered light is simultaneously detected by the photodetectors and, thereby, count the number of particles in the aerosol.

Abstract: An optical system for irradiation comprising a light source, a lens, an optical fiber, a rectangular waveguide, an objective lens and a prism and an optical system for receiving light comprising an objective lens, an aperture and an optical fiber are arranged with their optical axes intersecting one another at a point P in a measuring volume. In the optical system for irradiation, the light emitted from the optical fiber and having an intensity distribution expressed by a normal distribution curve is changed to a light having a uniform intensity distribution and a rectangular cross section, which is irradiated through the prism to the point p in the measuring volume. A light scattered at an angle of 90.degree. by a particle flowing through the measuring volume is guided through the optical system for receiving light to a photodetector which converts the scattered light to an electric signal (current) called a scattered light pulse.

Abstract: A method and apparatus for separating particles by means of a contra-flow centrifuge, wherein a monitor system is used to analyze or control the separation process. The monitor system used impinges a monochromatic light beam on a sample of the separated particles, and measures the light scattering not only in the beam-forward direction, but also in the beam-reverse and beam-lateral directions. This reduces the processing time and increases the reliabiity of output data.

Abstract: A flow field seeded with small particles is illuminated by collimated, monochromatic laser light sheet 16. Doppler shifted scattering from particle motion is imaged by an optical system 22. An optical frequency-to-intensity converter 24 is located at the image plane such that the transmitted image contains a simultaneous two-dimensional measurement of flow velocity along a direction determined by a laser beam and observer (converter) direction. These images can be observed directly or through a TV-2-D array camera and monitor or processed through a computer system 28.

Abstract: A fine particle measuring method of this invertion is characterized in that the laser beams for forming the scattered lights comprises the following features.

Abstract: A plurality of parallel spaced cylindrical capillary tubes contain single cells and/or cell colonies in a medium and gel-like agarose, and the tubes are carried by a frame-like holder supported by a motor driven X-Y translation stage of an automated microscope. The microscope also incorporates an electronic optical detector and an object lens located under the tube holder. The entire contents of each tube are internally illuminated by a precision light beam emitted from a helium-neon laser and reflected by a set of precisely positioned mirrors so that the beam extends axially through each tube when the tube extends across the vertical axis of the object lens. The contents of the tubes are sequentially scanned under the control of special software within a personal computer, and the intensity of the light reflected outwardly from each cell or cell colony is sensed by the detector and recorded in the computer along with the axial location of the reflecting cell or cell colony.

Abstract: A particle analyzing apparatus has an irradiating optical system for irradiating a particle to be examined with a light beam, a measuring optical system for measuring the light scattered by the particle, a device provided in the irradiating optical system for varying the form of the light beam, and a device provided at a position in the measuring optical system optically conjugate with the position of the particle to be irradiated with the light beam and adapted for varying the form of viewing field when the form of the light beam is varied.

Abstract: A particle detector includes optical fiber for conducting short wavelength radiation received from a radiation source through a chamber in which a semiconductor wafer is being processed. Light that is scattered by contaminant particles in the process chamber is sensed by an optical fiber pickup, and pulse signals are generated by a photosensing means to provide an indication of the number of particles within the process chamber.

Abstract: An apparatus and method for detecting particles in a clean environment provides for forming a beam of electromagnetic radiation into an instantaneous scattering volume and scanning the scattering volume in space defined by a flow cell. Particles are transported by fluid means into the space occupied by the scattering volume and individual particles are multiply scanned while passing through the scanning scattering volume. A fluid conduit is provided to transport the fluid and the particles and windows are provided to transmit the radiation beam into the space defined by the flow cell and to transmit scattered radiation from the particles out of the space. The radiation from the particles is collected and detected to provide an output signal. In the preferred embodiment, the output signal is analyzed to determine the concentration of the particles in the fluid and to determine the size and velocity of each individual particle.

Abstract: A fluorescent analyzer including a light source which irradiates a sample with direct light, a first wave selector for passing a predetermined wavelength of light emitted from the light source, a sample cell for holding the sample which is irradiated by light passed by the first wave selector, a second wave selector arranged sidewards of the sample outside a direct path of light from the light source passing straight through the sample for passing light of a second predetermined wavelength emitted from the sample upon irradiation by direct light from the light source, a first light detector for producing a first output signal indicative of the amount of light of the second predetermined wavelength passed by the second wave selector, a second light detector for producing a second output signal indicative of the amount of direct light of the first predetermined wavelength passing straight through the sample, a correction circuit for performing a predetermined correction on the amplitude of the first output sign

Abstract: An apparatus for measuring particles in a liquid, with the apparatus including an arrangement for allowing a sample liquid to flow out from a nozzle into a gas in a stream, an arrangement for radiating light into the sample liquid stream coaxially with the axis of the stream, and an arrangement for collecting ways of light scattered by particles contained in the sample liquid stream at a point outside and by a side of the sample liquid stream and then detecting the collective light rays.

Abstract: An arrangement for in situ determination of the quantity of turbid matter, aerosol and/or dust in flue gas which flows through a flue by measurement of intensity of light irradiated by means of an optical transmitter in the flue, and dispersed on solid or fluid dispersion particles. The dispersion light is detected by a detector which is arranged outside of the bundle of rays of the transmitter and provided with a wide angle focusing optic. A woodsche horn absorbs the not dispersed part of the bundle of rays of the transmitter. The light source of the transmitter is formed as a xenon spark discharger with intensity maximum in the region of 350-600 nm, the detector signal is evaluated by an evaluating electronic circuit. The arrangement determines extremely low quantities of harmful matter.

Abstract: Disclosed is a method and apparatus for measuring particles in a fluid by irradiating the fluid containing the particle with a laser beam and analyzing the laser light scattered by the particle to determine the characteristics of the particle. An elliptical laser beam is projected into a particle detection area in which the particles to be measured are caused to flow. The laser light scattered by the particle is received for photoelectric conversion into a time-series photoelectric signal in a direction along which the particle flows. The photoelectric signal is subjected to a moving average process to determine a time width during which the signal exceeds a predetermined level to cause the change in intensity of the scattered light. This change is recognized as a change in intensity caused by the passage of the particle through the particle detection area when the time width falls within a certain range.

Abstract: A concentration of antigen substances contained in a sample is measured by detecting light scattered by latex particles coated with antibody substances which are specifically reactive with the antigen substances to be measured. The scattered light is received by a photodetector and an output signal of the photodetector is supplied to a fast Fourier transform unit to derive a power spectrum density of the scattered light. Then a white level of the power spectrum density is derived, and the concentration of the antigen substances in the sample is detected from the white level with the aid of a calibration curve representing a relationship between the concentration and the white level.

Abstract: A coherent laser light flux is projected into a cell made of transparent quartz and light scattered from particles suspended in an antigen-antibody reaction liquid contained in the cell is detected by a photomultiplier by means of a collimator. An output electrical signal from the photomultiplier is sampled at different time instances and samplings are supplied to a fast Fourier transformer to derive a plurality of power spectrum desnities of fluctuation in intensity of the scattered light. A plurality of power spectrum densities are averaged to generate a mean power spectrum density. An amount of antigen contained in the reaction liquid is measured in accordance with the mean power spectrum density.

Abstract: A monitor for particles of various materials which counts the number of the particles on real-time and in situ basis. The monitor comprises a unit for illuminating an object to be inspected with an illumination light beam of a predetermined cross-sectional area, a unit for detecting a change in optical mode of the illumination light beam caused by the particles being contained in the inspected object and illuminated with the illumination light beam, the illuminating and detecting units being of a unitary structure, and a unit for counting an amount of the particles contained in the inspected object by using a change in intensity of an optically mode changed light beam.

Abstract: An apparatus for measuring particles contained in a sample liquid has a cylindrical cell having an incident light transmitting portion, a transmitted light transmitting portion diametrically aligned with the incident light transmitting portion, and a light transmitting portion at an angle to the diameter between the incident light transmitting portion and the transmitted light transmitting portion. An inlet at one end of the cell admits sheath flow liquid having the same index of refraction as the sample liquid, and an outlet is provided at the other end of the cell.

Abstract: The invention relates to a method for the illumination of particles contained in a medium for an optical analysis, and to an optical particle analyser. The medium (1) thereby makes contact with a window (2), and a light beam illuminating the particles is directed into the medium through the window in order to form an image of the particles. In order to enable an accurate quantitative and qualitative analysis carried out directly from the medium, the light beam is modified into a beam (5) having a predetermined thickness in the direction of the normal of the window. The beam (5) is directed to advance in the medium containing the particles close to and substantially in parallel with a window surface (6) making contact with the medium in order to illuminate particles (10) contained in a predetermined volume part (9) of the medium for the formation of an optical image (8).

Abstract: A coherent laser light flux is projected into a cell made of transparent quartz and light scattered from particles suspended in an antigen-antibody reaction liquid contained in the cell is detected by a photomultiplier by means of a collimator. An output electrical signal from the photomultiplier is sampled at different time instances and samplings are supplied to a fast Fourier transformer to derive a plurality of power spectrum densities of fluctuation in intensity of the scattered light. A plurality of power spectrum densities are averaged to generate a mean power spectrum density. An amount of antigen contained in the reaction liquid is measured in accordance with the mean power spectrum density.

Abstract: A photoelectric smoke detector is equipped with a light emitter for radiating light into a measuring space. A light receiver detects scattered light caused by the presence of smoke in the measuring space. The measuring chamber is constructed as a light trap such that the light beam radiated by the light emitter is multiply reflected and cannot reach the light receiving element of the light receiver.

Abstract: The sample air inlet nozzle into a particle counter test cell is formed with an elongated, flattened tip to provide a thin, flat laminar flow jet which intersects a laser beam. A secondary tube surrounding the nozzle provides a sheath of air which helps maintain the jet shape.

Abstract: A particle analyzing apparatus is provided with an irradiating optical system for applying a light beam to a particle to be examined flowing through a circulation portion in a flow cell, a photometering optical system for photometering the light from the particle to be examined irradiated by the irradiating optical system, and moving means for rendering a base bed on which the flow cell and the photometering optical system are placed movable relative to the irradiating optical system.

Abstract: In an apparatus for analyzing a particle flowing in a flow section of a flow cell, at least two non-parallel index beams are projected onto the flow cell to detect a focusing state of a measuring optical system with respect to the flow section, the beams reflected by first and second walls of the flow cell are detected, and the obtained output pattern is used to determine the focusing state.

Abstract: There is provided a flash reflector for maximizing the intensity of light passing into an air sampling chamber of a smoke detector which enables a reduction in power requirements for the light source. The reflector includes a concave reflecting element to focus light from each infinitesimal cross-sectional element off the arc of ionized gas in a flash tube the light output from the whole length of the tube which is optionally of U-shape being focused into the central region of the sampling chamber.