Abstract: To reduce noise in an absorbance monitor in which the light source is a deuterium lamp, an aspheric condensing mirror focuses light from an approximately 0.6 mm-high by 2 mm-wide part of the central bright spot in the deuterium lamp through a slit in an aperture plate which blocks all other light and an aspheric monochromator mirror focuses the light onto a plane reflective diffraction grating, which: (1) is mounted for orbiting about an axis parallel to the longitudinal axis of the slit; and (2) adjusted so that, as it orbits it reflects a selected wavelength of light to a beam splitter. Each beam is focused upon and transmitted through a different one of two equal oval apertures optically at least as large as the height of the image of the aperture near the lamp.

Abstract: This invention relates to an optical absorptiometer which is characterized by a light source unit of a broad wavelength having a source of constant energy which is collimated into two light beams, one of which is transmitted through the liquid to be measured, and another beam which is transmitted through a conductor and acts as a reference beam, and a detector unit which contains two photocells, one photocell for measuring the beam transmitted through the liquid to be measured, and another photocell which measures the reference beam, a position in the absorptiometer for optically placing the liquid to be measured between the source unit and the detector unit, and means for measuring the energy difference between the light beams of the measured liquid and the reference beams in terms of absorbance, and means for converting this result to an electrical signal.

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 fluid sample cell for spectroscopic analysis of a fluid sample includes a fluid-tight compartment for the containment of a fluid sample which is defined by a radiant energy transmissive top, a side wall and a bottom. The bottom comprises a plurality of sectors and a Fresnel disc, whereby radiant energy passing through the compartment impinges upon at least one of the sectors and is specularly reflected from a reflecting surface of the sectors to respective focal points of the sectors.

Abstract: A colorimeter for continuously monitoring the concentration of an ionic species in an aqueous solution comprises a source 30 of optical radiation, a flow cell 10 including three flow chambers 11, 12 and 13 interconnected so that a sample of the solution can pass through each flow chamber in succession, and photodetector devices 41, 42 and 43 positioned to respond to radiation transmitted through the solution in the flow chambers 11, 12 and 13, respectively. The lengths of the three flow cells are different from each other to provide a continuous real-time calibration check based upon photodetector responses to radiation transmitted through different quantities of the solution. Electronic circuitry interconnecting the radiation source 30 and the photodetector devices 41, 42 and 43 maintains the intensity of the radiation emitted by the source 30 at a substantially constant value.

Abstract: Methods of measuring the crill content of pulp suspensions are disclosed. The methods include passing a first light radiation, preferably ultraviolet light, having a wavelength comparable to the particle diameter of the crill, through the pulp suspension, passing a second light radiation having a wavelength longer than the first wavelength but shorter than the mean pulp diameter through the pulp suspension, collecting both light radiations after they have transilluminated the pulp suspension, and measuring absorbencies for both of these collected light radiations so that the crill content can be determined therefrom.

Abstract: A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

Abstract: A double beam photometric flow cell for high pressure liquid chromatography having illuminated sample and reference passageways therein, the sample passageway receiving flowing fluid sample fractions for analysis. Regulating apertures control the relative amount of light passed through the passageways such that the light energy through the reference passageway exceeds that through the sample passageway. This reduces the contribution of the reference path to "shot noise" in the photometer output signal.

Abstract: A dye laser (FIG. 1, 5 or 6) includes a pumping laser source (e.g. 11), an optical resonator (e.g. 13-15), and a dye solution or dye cell (e.g. 12) disposed in the path of the pumping laser light in the resonator. The dye cell disclosed herein comprises a pair of closely spaced transparent discs (21). A motor (26) serves to spin the discs at a high rate of speed. The pumping laser light in the resonator is focused on the discs at a predetermined angle (i.e. the Brewster angle). New, unbleached dye is injected axially with respect to the discs so that the spin force causes a radial flow of the dye solution between the spinning discs and, of course, past the pumping laser light spot.

Abstract: A colorimeter in which a light source, a collimating lens and a band pass filter are supported by a housing that is movable with respect to a stationary beam dividing assembly in a direction at least substantially transverse to the optical axis of the light from the source. The assembly separates the incoming collimated and filtered light into a sample beam and a reference beam which are directed back toward the housing in directions parallel to the optical axis. The movement of the housing toward or away from the sample produces an increase or decrease in the intensity of the light illuminating the sample and a corresponding decrease or increase in the intensity of the light at the reference detector. The arrangement is such that the apparatus may be readily adjusted to obtain accurate colorimeter readings even for samples having abnormally high or low density characteristics.

Abstract: The temperature of the dye bath in a vat or trough (1) is controlled in dependence on absorption change, which is photometrically sensed. A command value of dye acceptance speed related to temperature of the dye within the vat is provided, compared with actual temperature, and a control signal is derived which, in turn, controls a heat exchanger supplied, selectively, with a heating or cooling medium in order to control dye acceptance of at least one predetermined dye component of the bath by the material therein.

Abstract: A chromatograph detection system for differentiating pure components of a chromatogram for accurate measurement or collection of such components. The light beam passing through a single detector flow cell is split and absorbance is detected at two differing wavelengths. Undesirable overlapping components are eliminated by scaling the chromatogram at one wavelength to equal the chromatogram at the other wavelength, and then subtracting the chromatograms. Purity of component substances is determined by continuously dividing the chromatogram signals to determine the absorbance ratio and its characteristics over time.

Abstract: Spectrum analyzer for the light absorption of a solution comprising a small transparent measuring cell containing the solution; a light source; means for dividing the beam of light of the source into two beams, one being the reference beam and the other the measuring beam transmitted respectively to a reference absorber element and to the measuring cell; means for selecting the measuring wavelength; means for modulating the reference and measuring beams which have respectively traversed the absorber element and the measuring cell; means for detecting the energies of each of the modulating beams after they have traversed the reference absorber element and the sample; the modulation means comprising alternate transparent and bireflecting sectors in front of each of the beams which have passed through the reference absorber and the measuring cell, said sectors being associated with means for selecting the wavelength of the beams in such a way that, as a function of the successive positions of the sectors relativ

Abstract: A colorimeter in which a beam dividing assembly is supported on a movable carriage intermediate the sample and reference detectors. The assembly separates the incoming collimated light into a sample beam and a reference beam. The movement of the carriage toward or away from the sample produces a decrease or increase in the intensity of the light illuminating the sample and a corresponding increase or decrease in the intensity of the light at the reference detector. The arrangement is such that the apparatus may be readily adjusted to obtain accurate colorimeter readings even for samples having abnormally high or low density characteristics.

Abstract: Apparatus and method for determining the concentration of a constituent in a sample using chromatographic and optical measuring techniques. A sample containing a constituent to be analyzed is fractionated by a chromatographic column. A light beam is passed through the constituent fraction in the column, and the light absorbance (or transmittance) is measured. The fluid carrier (or solvent) eluting through the column will generally increase the transmissivity of the light passing through the column due to a difference between the indices of refraction of the carrier fluid and the chromatographic packing material. Such increased transmissivity will generally offset any decrease in the transmittance due to trace amounts of the constituent in the sample. The optical measurement is compensated to nullify such increased transmissivity, so as to allow measurement of such trace amounts of constituents.

Abstract: A color monitoring device is provided for measuring the concentration of a colored component in a flowing gas or liquid stream in which polychromatic light is passed through a frosted lens, then through a transparent sight tube through which the flowing stream passes, then through a second frosted lens, then through a sight mask which divides the light into two beams, one beam then passing through a first filter and the second beam passing through a second filter, the light beams passing through the filters then being directed to a first and second photoconductor, respectively. The first filter is one which absorbs light which is absorbed by the colored component to be measured and passes all other light. The second filter is one which passes light absorbed by the colored component and absorbs light of substantially all other wave lengths.

Abstract: An improved Colorimeter which can be used to analyze samples in either a stationary mode (e.g. in a test tube) or in a flow-through mode wherein the sample flows through the apparatus. The Colorimeter is equipped with means to direct the illuminating radiation selectively to either mode of sample.