Abstract: A method and apparatus for ascertaining the content of an ingredient of flux in automatic soldering machines, in which the attenuation or transmission of electromagnetic radiation by the flux is measured, and the content of this ingredient is ascertained by comparison of the measured value with known values, stored in memory, wherein to avoid contamination of the measured flux and the production of new waste substances, the attenuation or transmission is measured in a frequency range in which a strong attenuation by the ingredient to be determined occurs; and moreover a comparison measurement of a reference medium is performed at the same frequency; and finally, the difference between the two measured values is used for comparison with the known values stored in memory.

Abstract: A double beam detector system for liquid chromatography includes a light source and slits to effect two beams of radiation symmetrical to an optical axis and focused through a common point. A concave reflective dispersion grating is disposed on the optical axis which is folded at the grating. A collimating lens directs the beams parallel to the optical axis into a pair of detector cells. The collimating lens and entrance lenses for the cells are selected so that the common point is imaged on exit windows of the cells. The grating has a curvature selected cooperatively with the collimating lens, entrance lenses and relevant distances so as to focus the entrance slits at respective entrance windows for the cells. The beam size is constricted to less than the cell bore size by selected parameters of the collimating lens and the entrance lenses.

Abstract: Vacuum gauge that detects and measures the partial pressure of a gas in a chamber, from pressures ranging from atmospheric to ultra-high vacuum. The gauge utilizes electromagnetic radiation, that is generated in the vacuum chamber by a electromagnetic radiation source. When the partial pressure of water vapor is being measured, the light source used emits low wavelength UV light in the 184 and 254 nanometer range. For other gases, different light sources emitting different UV wavelengths or different electromagnetic radiation are used. The electromagnetic radiation traverses the interior of the vacuum chamber, and impinges upon a detector. As this light passes through the interior space between the source and the detector, it strikes the particular, residual gas molecules that are being detected. These impacts scatter the light and/or absorb the light, so that there is less photonic energy striking the detector.

Abstract: A process for controlling and optimizing chemical industrial processes for the preparation of dyes, fluorescent whitening agents and their intermediates, which process comprises controlling and optimizing those processes by differential analysis of the UV/VIS absorption spectra of at least one starting compound and of at least one reaction product. The advantage of this process is that the actual state of a process can be constantly measured, assessed, and used for feed-back and feed-forward control.

Abstract: This invnetion relates to a high pressure sealed window assembly which does not result in substantial shear forces being applied to the window, and in particular to such a window assembly for transmitting ultraviolet light in high pressure chromatographic detectors. The window has opposed faces through which light is transmitted and angled surfaces extending toward each other away from corresponding points on the outer edge of the opposed surfaces. Sealing rings, preferably shaped to conform to the shape of the angled surfaces, bear against such surfaces and precompression forces are applied through the sealing rings to precompress the window, preferably over substantially its entire volume. When pressure is applied to one face of the window, the precompression forces must be overcome before such pressure can result in shear forces being developed in the window.

Abstract: In a method of and an apparatus for spectroscopic quantitative analysis of gases in gas mixtures, periodically alternating monochromatic light of at least two wavelengths is used. The light of one wavelength is characteristic whereas light of the other wavelength is uncharacteristic of the transmission of the gas to be determined. The transmission generates electrical signals comprising harmonic components of at least one uneven Fourier frequency of an emission period, the amplitude of which is proportional to the concentration of the gas to be determined in the gas mixture, the Fourier frequency disappearing together with the concentration.

Abstract: A device and method for measuring the concentrations of components of a fluid stream. Preferably, the fluid stream is an in situ gas stream, such as a fossil fuel fired flue gas in a smoke stack. The measurements are determined from the intensity of radiation over a selected range of radiation wavelengths using peak-to-trough calculations. The need for a reference intensity is eliminated.

Abstract: The present invention is directed to an apparatus for use in .sup.196 Hg separation and its method of operation. Specifically, the present invention is directed to a nested reactor chamber useful for .sup.196 Hg isotope separation reactions avoiding the photon starved condition commonly encountered in coaxial reactor systems.

Abstract: A photometric analyzer for measuring differential total reduced sulfur in a sample gas stream is provided. It includes a supply for a sulfur bearing gas sample, an oven having an inlet connected to the supply for converting TRS to SO.sub.2 and an outlet through which the gas sample is discharged. A valve is connected to the outlet of the oven. An SO.sub.2 bypass line is connected between the supply and the valve. A sample cell with transparent ends has an inlet adjacent one end connected to the valve for alternately receiving sample gas from either the oven or the bypass line and has an outlet adjacent the other end. A pump connected to the sample cell outlet draws the gas sample through the sample cell. A light source at the one end of the sample cell directs light of a predetermined wave length through the sample cell. A light sensing device at the other end detects the amount of light passing through the sample cell at any given time and provides an output signal to an analyzer.

Abstract: Circularly polarized monochromatic electromagnetic radiation of a wavelength correlating the maximum absorbance of a sample compound is directed through a flowing solution containing the sample compound, which exhibits circular dichroism activity, and a plurality of other compounds. Measurement of the circular dichroism effect and comparison of an alternating current signal corresponding to the circular dichroism absorption to a direct current component allows for the constant monitoring of the concentration of the sample compound in the flowing solution. The flowing solution may be under high temperature and pressure and may comprise a supercritical fluid.

Abstract: High pressure liquid chromatography apparatus for use in the analysis of optically-active materials comprises a semiconductor laser diode radiation source 10, a test sample holder 13 through which radiation from the radiation source passes to a detector 16. A polariser 11 and analyser 15 cooperate with a modulator 12 which modulates the rotation of the polarisation of radiation from the laser.

Abstract: A gas analyzer arrangement for detecting the presence or quantity of a gas of interest includes a source of electromagnetic radiation for directing a light beam through a light conditioning device such that the light beam is collimated into a parallel beam of light. The conditioned light beam is then directed through a gas sample cell which contains a sample of the gas of interest. The gas of interest has associated therewith, vibrational rotational absorption lines specific to that gas and which are effective for altering the light beam according to the absorption characteristics thereof. The altered light beam is then directed to a birefringent etalon device which has been sized specifically to match those absorption lines of the gas of interest.

Abstract: A sample of a hydrocarbon oil containing asphaltenes is chromatographically analyzed by forming a mixture of the oil with a weak solvent. The mixture is passed in contact with a column of a stationary phase of fine solid particles of fully functionalized material, followed by a weak solvent. The solvent, after recovery from the column, is analyzed for aromatics by UV-absorption of UV radiation in the range 200 to 400 nm. The absorbance of the UV light by the irradiated eluents across the UV wavelength range is monitored and the integral of absorbance is derived as a function of photon energy across the wavelength range. The magnitude of the derived integral in at least one time interval corresponding with aromatics in the eluent from the stationary phase is measured as an indication of the level of aromatics in the oil sample. The weak solvent may be followed by a strong solvent which, in turn, may be followed by a strong solvent which is modified by the addition of a hydrogen bonding solvent.

Abstract: A low cost optical system which incorporates a low ultraviolet output tungsten halogen light source and solid state photodetectors and circuitry in such a way as to provide reliable fluorometric test results. The attainment of reliable results using such components is made possible by incorporating highly ultraviolet transmissive optics to maximize ultraviolet light throughput and by using solid state circuitry together with a filter wheel having both light blocking and light passing regions in a manner which fully accounts for noise and dark signals associated with solid state photodetectors.

Abstract: A centrifuge sample is optically scanned during centrifuging. The sample, placed in a centrifuge rotor having a cell with top and bottom windows, is spun until stratification and discrete layering occurs within the sample. Such layering occurs on layers that are precisely normal to the radius of the centrifuge at the point of sample and parallel to the spin axis of the centrifuge. A slit scanner having a slit normal to the sample plane transverses the width of the sample below the cell to detect with precision the precise location of the strata in the cell. A light source is reflected by a toroidal mirror having two radius of curvature. One radius of curvature is selected to collimate rays of light parallel to the layer of the sample. The mirror is ruled with respect to the other radius of curvature to chromatically classify light to preselect band width. Rotation of the mirror preserved collimation but enables selected scanning light frequency.

Abstract: A non-destructive method for the early detection of the formation of orga deposits or a biofilm on the internal surface of a conduit through which a fluid passes comprises allowing the fluid to flow through a conduit, passing a light beam, e.g., IR or UV light, through the fluid and the deposits in a direction transversal to the surface thereof, detecting and measuring the transmitted portion of the light beam after it has emerged from the fluid and the deposits, conducting these measurements at least twice at a set time interval, the first time before any materials deposit, and calculating % variation absorbed light during the time interval, which value is proportional to the organic materials or biofilm deposited and a method of removing at least a portion of organic deposits or a biofilm deposited on the internal surface of a conduit through which a fluid flows comprises allowing the fluid to flow through a conduit having a deposited organic layer or biofilm, passing a light beam, e.g.

Abstract: A sample of a hdyrocarbon oil containing asphaltenes is chromatographically analyzed by forming a mixture of the oil with a weak solvent. The mixture is passed in contact with a column of a stationary phase of find solid particles of fully functionalized material, followed by a weak solvent. The solvent, after recovery from the column, is analyzed for aromatics by UV-absorption of UV radiation in the range 200 to 400 nm. The absorbance of the UV light by the irradiated eluents across the UV wavelength range is monitored and the integral of absorbance is derived as a function of photon energy across the wavelength range. The magnitude of the derived integral in at least one time interval corresponding with at least aromatics in the eluent from the stationary phase is measured as an indication of the level of aromatics in the oil sample. The weak solvent may be followed by a strong solvent which, in turn, may be followed by a strong solvent which is modified by the addition of a hydrogen bonding solvent.

Abstract: An optical analyzer and a developer recirculation system is used to determine the amount of photoresist polymer dissolved in a quantity of developer solution and the sensor output signal is utilized by a control computer to control the admission of fresh developer solution to replace used developer and maintain a fixed level of dissolved photoresist polymer to keep the developer bath at a fixed level of chemical activity.

Abstract: The present invention relates to a split stream flow cell which is used for a UV detector of liquid chromatography and in which a UV light for detecting absorption of the light is transmitted through a sample solution flowing in the cell. It is an object of the present invention to reduce the influences of both the flow effect and the liquid lens effect without cell volume being made too large. To this end, a split stream flow cell of the present invention comprises a split flow channel (12) which passes through a cell block (10) and which has a central portion communicating with an inlet channel (18), both ends communicating with an outlet channel (38), and both sides symmetrical with respect to the central portion, the diameter thereof being increased from a given position in the central portion toward both ends.

Abstract: To improve the accuracy and reduce the sensitivity of interference absorptions in a method for determining the concentration of formaldehyde in a medium by an absorption measurement in the range of at least one characteristic absorption band of the formaldehyde and, in the appropriate instance, subtraction of an interference absorption which is determined by at least one absorption measurement in a wavelength range outside of the characteristic absorption band of the formaldehyde, it is proposed that a discharge be maintained at a current strength of several milliamperes in a hollow-cathode lamp filled with molecular nitrogen at a pressure of less than 2 millibar to generate the radiation for the absorption measurement, that the absorption measurement be performed on at least two different characteristic absorption bands of the formaldehyde with absorption coefficients at a previously known ratio to one another which lie in the range of emissions of the gas discharge in the hollow-cathode lamp, that the ratio

Abstract: A centrifuge sample is optically scanned during centrifuging. The sample, placed in a centrifuge rotor having a cell with top and bottom windows, is spun until stratification and discrete layering occurs within the sample. Such layering occurs on layers that are precisely normal to the radius of the centrifuge at the point of sample and parallel to the spin axis of the centrifuge. A slit scanner having a slit normal to the sample plane transverse the width of the sample below the cell to detect with precision the precise location of the strata in the cell. A light source is reflected by a toroidal mirror having two radius of curvature. One radius of curvature is selected to collimate rays of light parallel to the layer of the sample. The mirror is ruled with respect to the other radius of curvature to chromatically classify light to preselect band width. Rotation of the mirror preserved collimation but enables selected scanning light frequency.

Abstract: The presence and concentration of a light absorbing constituent in a fluid medium is determined in-situ by immersing in such medium a probe having a prism at one end whose refractive index is greater than that of the medium and causing light including a wavelength absorbable by such constituent to traverse an optical path through the prism and undergo successive attenuated total reflections. At each reflection some of the light will be absorbed by the constituent. The intensity of light emerging from the prism is measured at one or more wavelengths, including one absorbable by such constituent. The concentration of the constituent is determined by comparison of the measured intensity with values obtained from like measurements performed on like mediums containing known concentrations of the constituent.

Abstract: The invention relates to a method of analyzing solutions and dispersions of dyes or their precursors and intermediates by optical and/or spectroscopic measurements, which method comprises using apparatus based on the principle of attenuated total reflection as sensor system. The advantage of the invention is that even highly concentrated, strongly colored solutions can be analyzed without prior dilution, as can also dye dispersions without separation of the solids content.

Abstract: A method of regulating combustion by rapid-response monitoring of the gaseous effluents leaving a combustion chamber, especially the chamber of an internal-combustion engine, includes the steps of emitting ultraviolet radiation to a zone of small volume traversed by at least part of the gaseous effluents leaving the combustion chamber; receiving at least part of the ultraviolet radiation which has passed through this zone; measuring the degree to which the ultraviolet radiation has been absorbed by a chemical compound contained in the gaseous effluents; and governing at least one parameter influencing combustion within the combustion chamber as a function of the degree of absorption.

Abstract: A spectroanalytical gas measuring apparatus has a radiation source (36), a transmitting condensor (19), an objective (13) and a beam divider (11) which deflects at least a part of the radiation reflected back to the apparatus by a reflector (40) to a polychromator or spectrometer (32). The transmitted radiation falls after the beam divider (11) onto a deflecting mirror (12) which is adjustable between two positions and which directs the light to an objective reflector (13). The objective reflector (13) reflects the radiation to a follow-up mirror (15) arranged opposite to the beam passage opening (14). At least one long and one short focal length objective reflector (13) are provided in order to ensure different ranges of distance in conjunction with the adjustable deflecting mirror (12).

Abstract: The invention provides a new method and apparatus for measuring the concentration of ultra-violet light absorbing organic materials liquids, particularly in pure or ultra-pure water, the speed and convenience being such that it is possible to take successive readings with periods as short as ten seconds. The apparatus can be mounted directly in or as a by-pass to a process stream, giving the capability of constant monitoring with virtually instant microprocessor-controlled response to measurements outside a pre-set range. The water to be measured passes upwards in a cylindrical opaque-walled sample cell at the upper end of which is mounted an intense light source, preferably a Xenon flash tube, and at the lower end of which is mounted two transmission photodetectors, which have in front of them respective narrow-band optical transmission filters in the ultra-violet and visible regions.

Abstract: A method of determining the concentration of a chelated ferric ion in a solution comprising measuring the ultraviolet (UV) light absorption of the solution at the wavelength of about 237 to about 241 nanometers (nm). The measured absorption is then correlated to a previously-determined value of the chelated ferric ion for the measured UV absorption value.

Abstract: A method of detecting and quantitating cell malignancy in biological tissue is provided and initially includes preparing a tissue sample having a substantially constant thickness. The tissue sample was impinged by filtered electromagnetic energy within an approximate bandwidth between 255.0-265.0 nm with a preferred wavelength of 260.0 nm. A standard Zeiss microscope was used to observe and measure the nuclear material with the microscope being fitted with quartz optics. The volume of nuclear material being examined was maintained relatively constant by selecting an aperture smaller in diameter than the magnified image of the nucleus being examined in combination with the subtantially uniform thickness of the tissue samples. The electromagnetic energy subsequent to being reflected from the tissue sample was passed through a second optical filter having an approximate filtering capacity in the range of 260.0 nm.

Abstract: An instrument for spectroscopy according to this invention uses a metal halide lamp, in which at least mercury and dysprosium halide are enclosed, as the light source for the purpose of effecting measurements for a wavelength region extending from the ultraviolet to the visible light with a single light source. This metal halide lamp has a spectre, which is effective in a wavelength region extending from about 200 nm to about 700 nm.

Abstract: A method and apparatus for making a quantitative determination of gaseous sulfur. The sulfur is illuminated with light having one or more spectral lines selected from a first group of peaks including positive peaks at wavelengths in nm of 263, 265.5, 268, 270.5, 273, 276, 279 and 282, and from a second group of peaks including negative peaks at wavelengths in nm of 264.5, 267, 269.5, 272, 275, 278 and 281. The absorption by the sulfur of the illuminating light is measured and this absorption is analyzed to determined sulfur content.

Abstract: An apparatus and method for monitoring the flow of mercury in a system. The equipment enables the entrainment of the mercury in a carrier gas e.g., an inert gas, which passes as mercury vapor between a pair of optically transparent windows. The attenuation of the emission is indicative of the quantity of mercury (and its isotopes) in the system. A 253.7 nm light is shone through one of the windows and the unabsorbed light is detected through the other window. The absorption of the 253.7 nm light is thereby measured whereby the quantity of mercury passing between the windows can be determined. The apparatus includes an in-line sensor for measuring the quantity of mercury. It includes a conduit together with a pair of apertures disposed in a face to face relationship and arranged on opposite sides of the conduit. A pair of optically transparent windows are disposed upon a pair of viewing tubes. A portion of each of the tubes is disposed inside of the conduit and within each of the apertures.

Abstract: A simple optomechanical method and apparatus is described for substantially reducing the amplitude of unwanted multiple-interference fringes which often limit the sensitivities of tunable laser absorption spectrometers. An exterior cavity is defined by partially-transmissible surfaces such as a laser exit plate, a detector input, etc. That cavity is spoiled by placing an oscillating plate in the laser beam. For tunable diode laser spectroscopy in the mid-infrared region, a Brewster-plate spoiler allows the harmonic detection of absorptances of <10.sup.-5 in a single laser scan. Improved operation is achieved without subtraction techniques, without complex laser frequency modulation and without distortion of the molecular lineshape signal. The technique is applicable to tunable lasers operating from UV to IR wavelengths and in spectrometers which employ either short or long pathlengths, including the use of retroreflectors or multipass cells.

Abstract: A beam of radiation is directed into a liquid sample cell containing a sample to be analyzed in solution. The illumination emanating from the sample cell as a result of the beam of radiation from the radiation source is diffracted into a polychromatic spacially divergent beam and directed to a linear array of photovoltaic photodetectors with different spectral segments of the beam being intercepted by different photodetectors of the array. The signals from the photodetectors are separately and substantially simultaneously sampled and held to thereby obtain data usable for a high-accuracy wide-spectrum chromatogram.

Abstract: A holographic grating spectrophotometer for detecting ozone and sulphur dioxide in the atmosphere is described which provides automatic calibration and which provides automatic linearity correction for the photomultiplier tube. Automatic calibration is provided by using a computer to control a stepper motor to move the grating so that the photomultiplier tube receives maximum intensity at the calibration wavelength of 302.1 nm from a mercury source. Automatic linearity correction is obtained by cycling a wavelength selection mask across exit slits located in the focal plane of the device and firstly combines separately taken counts of two different wavelengths and comparing this sum with the sum of counts of these wavelengths taken simultaneously. The difference is used to calculate photomultiplier tube deadtime and improve accuracy of the results.

Abstract: The invention relates to apparatus 1 for monitoring the intensity of a UV source, for example a water sterilizer, in which there is an optical detection unit (2) which detects UV radiation and converts that radiation into an electrical signal which is comparable to the intensity of the UV radiation detected, the optical detection unit (2) being operatively connected with a device including a converter (8) and adapted to indicate the intensity of UV radiation from the source dependent on the electrical signal from the optical detection unit.

Abstract: A simple and sensitive arrangement for determining the presence of specific substances in a liquid is provided for determining the presence of oil in water. The arrangement comprises a light source which emits diffused UV light through the liquid to be tested, a detector which receives the UV light, and a processing circuit which is driven with a measured signal from the detector. The processing circuit generates an alarm signal if the measurement signal which increases with intensity of the detected UV light becomes smaller than the predetermined value.

Abstract: A non-evacuated photodiode for detecting far-uv radiation. The photocathode is a cylindrical element surrounded by an annular anode. The photocathode is constructed of a metal (e.g., nickel) that emits electrons only in response to far-uv radiation of 140 nanometer or shorter wavelengths. A window (e.g., magnesium fluoride) is positioned at the entrance to the photodiode, to filter out far-uv radiation with wavelengths shorter than about 100 nanometers. The window and photocathode material serve to make the photodiode sensitive to radiation in a wavelength range to greater than 100 to 140 nanometers. A high-temperature perfluoroethylene material is used as an insulating layer for spacing the window from the anode and for spacing the anode from the photocathode. The photodiode is used in a gas chromatography detector.

Abstract: A spectrophotometer is shown in which a deuterium lamp emits a plurality of frequencies of interest the beam passes through a filter for selecting the wavelength of the light desired to be incident onto the sample and then onto a beam splitting plate which diverts a relatively small friction of the beam to a first reference photocell. The remaining portion of the beam then is incident directly on a sample tube. The sample tube may be so designed that its transparent walls form a lens focusing the beam on the sample to be tested. The beam then passes through the further wall of the sample tube and is detected by a second testing photocell, the output of which may be compared to the output of the reference photocell to provide a signal indicative of the relative amplitude of the testing beam.

Abstract: A method and apparatus are described for detecting the presence and amount of elemental oxygen in a sample cell. The intensity of extreme ultraviolet light passing through the sample cell at a wavelength band overlapping at least one of the Schumann-Runge absorption lines of oxygen is detected and compared with a predetermined non-absorbed condition of the ultraviolet light. The non-absorbed condition may be achieved by narrowing the wavelength band such that the band does not overlap the Schumann-Runge absorption line, or may be achieved by detecting the ultraviolet light passing through a reference cell. Also described is a novel ultraviolet source in which a cold zone captures neutral atoms of the emission gas to reduce the affect of resonance absorption of emitted ultraviolet light by such neutral atoms.

Abstract: A diagnostic technique to histologically detect malignancy and other tissue properties is performed by pressing a solid tissue sample between a pair of planar parallel plates transparent to ultraviolet light to a fraction of the original thickness of the sample and by subsequently passing focused ultraviolet light therethrough. The ultraviolet light is passed transversely to the planar glass plates and the emerging angularly distributed light is analyzed to determine a dignity parameter of the sample containing diagnostic information. In addition, a density parameter is obtained as a function of the portion of the ultraviolet light passing through the sample along the optical axis of the focused light. A diagnosis is obtained on the basis of the relationship between the dignity parameter and the density parameter.

Abstract: In the monitoring of gas or vapor concentrations in a gas sample by comparing the transmission of light through the sample at different wavelengths corresponding to behaviorial maxima and minima of the gas, the different wavelengths are selected by permitting light to fall alternately on different sets of slits in an entrance mask of a spectroscope so that light diffracted by a grating in the spectroscope at the wavelengths represented by the slits in the two sets will fall on an exit slit in an exit mask of the spectroscope and thence pass to a photodetector. This arrangement enables the shift between the different sets of wavelengths to be achieved without introducing mechanical jitter, since the photodetector output may be electronically gated so as to be measured only for predetermined periods when light is passing first through one and then through the other set of slits.

Abstract: A method for testing and treating distillate fuel being stored for long periods of time for emergency power generation applications and the like, including measuring the percent transmittance of a fuel sample with ultraviolet before and after heating at a preselected temperature below the boiling range of the distillate fuel for a sufficient period of time to accelerate polymerization where the sample is made to reach such preselected temperature within about five minutes; and comparing the percent transmittance measurements to determine the suitability of the fuel for continued storage with or without the addition of further polymerization inhibitors and/or depolymerizers.

Abstract: An optical multi-beam gas measuring apparatus is intended for detecting specific content in a gas of extraneous gases which absorb the same wavelength of the measuring radiation. The apparatus comprises a source of radiation and a gas vessel through which the gas mixture to be measured is conducted and the radiation is detected. The radiation directed through the vessel is picked up by an exchangeable detecting unit which contains a prism for splitting radiation which has passed through the gas mixture into several partial beams corresponding to the number of gas components to be measured. A prism is selected for this purpose and it is used in association with optical filters arranged in the path of the beams in conjunction with detectors which are electronically arranged for detecting the selected gases and measuring the value thereof.

Abstract: A liquid chromatography apparatus comprises a detector part having as a light source a metal halide lamp filled with tantalum halide, mercury and rare gas.

Abstract: A process for detecting the population count of microorganisms in an aqueous medium by means of ultraviolet spectrophotometry. The specimen is first filtered and the resulting filtrate then centrifuged to concentrate the microbial cells in a pellet layer. The microbial cells are then redispersed in an aqueous solution having a volume less than the volume of the original specimen and the absorption of ultraviolet light by the redispersed solution at wavelengths within the range of 260-280 nanometers is measured. The concentrated microbial cells may be lysed in order to release nucleic acid and protein components from the cellular wall structure.

Abstract: Novel photometric apparatus advantageously having a conical shaped flow-cell comprising a light source proximate the narrow end and a photosensitive detector at the wider end of the cell. The flow-cell adequately compensates for a lens effect that has been discovered to be a substantial factor in electro-magnetic energy absorption studies on liquid streams. A light beam from the light source is passed through an elliptical aperture to render the beam substantially circular prior to entering the flow-cell.

Abstract: The laser-triggered high voltage rail gap switch includes two parallel electrodes in a high pressure environment of SF.sub.6 and Ar. A pulsed UV laser directs a coherent beam parallel to the electrodes to initiate multichannel breakdown in the gap between the electrodes. This breakdown is enhanced by including an organic additive such as fluorobenzene or tri-n-propylamine in the gas mixture.

Abstract: The UV radiation triggered rail-gap switch applies a high voltage from a low impedance source to a low impedance load. The switch includes first and second parallel elongated electrodes spaced to form a uniform gap along their length. The first electrode is adapted to be connected to the high voltage source, while the second electrode is adapted to be connected to the low impedance load. When a voltage from the source is applied to the electrodes, one electrode will be positive relative to the other electrode. In addition, the cross-section of each of the electrodes is sufficiently smooth to prevent points of high field concentration between the electrode. This cross-section is defined by the field enhancement factor of each electrode which is preferably less than 1.5. The switch also includes an enclosure in which the electrodes are located and which contains a gas mixture for maintaining the breakdown threshold between the electrodes. A preferred gas mixture includes Ar, N.sub.2, and SF.sub.

Abstract: A fluorescent gas analyzer for analyzing gases by the fluorescence method. A flashtube which is operated in its pulse mode is used as a light source. First and second optical detectors respectively detect light of a first and second wavelength range, the light of the first wavelength range being emitted by the light source and the light of the second wavelength range being emitted from a gas sample irradiated by the light source. A pair of integrators respectively integrate the outputs of the first and second detectors. Processing means, including sample and hold circuits and a synchronous detector, are used to further process the signals so that the system output is independent of deterioration of the light source and fluctuations in the strength of the light source output and independent of stray capacitance effects.

Abstract: A wavelength-modulated derivative spectrometer is disclosed which enables continuous measurement of trace amounts of NH.sub.3 in stack gas which includes a high concentration of SO.sub.2, and which in general enables measurement of low amounts of a substance having a relatively broad-band absorption spectrum present in a gas together with a high concentration of a substance having a relatively narrow-band periodic spectrum structure, with interference resulting from the latter substance being substantially eliminated.