Abstract: A multi-purpose on-line or field-portable system and method for monitoring the presence and concentration of selected antigen-antibody reactions singly or in combination that result from the presence of specific microorganisms or free antigens present or suspended in aqueous solutions, during a given time period. The detection system comprises a detection column and two sensors mounted around the detection column. Each sensor consists of an electromagnetic radiation source and an appropriate detector for the electromagnetic radiation. The reacted analyte tends to accumulate at the sensor located at the bottom detection column. The lower sensor continually nulls against the upper sensor to subtract any optical effects due to non-reactants in the aqueous process or environmental stream. The response from the detector sensors drive an electric circuit, which provides an output signal. In the on-line automatic version, the signal can drive elements of a process system by switching automated valves.

Abstract: A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen's A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption.

Abstract: A calibration device for a laser ranging system includes an interferometer assembly and a beam path magnifier assembly which is optically coupled to the interferometer assembly to receive a calibration beam therefrom and to the laser ranging system to receive a laser ranging beam therefrom. The calibration beam and the laser ranging beam enter the beam path magnifier assembly such that they pass along equidistant paths and so that the calibration beam is detected by the interferometer assembly to provide a precise measurement of the distance the calibration beam traveled and the laser ranging beam is detected by the laser ranging system to provide a measurement of the distance traveled by the laser ranging beam along the calibration optical path. Comparison of the two readings provides calibration data for the laser ranging system. The beam path multiplier assembly includes means for varying a folded calibration optical path length to provide a range of calibration beam path lengths.

Abstract: An Atomic Absorption Spectrometer in which background absorption is compensated by means of a magnetic field causing a periodic line shift due to the Zeeman Effect, including a line emitting light source, an atomizing device, an optical system, by means of which the measuring light beam can be passed through an atom cloud of the atomizing device, an electromagnet, a converter circuit for converting the mains a.c. voltage into d.c. voltage applied to a capacitor, the winding of the electromagnet being located in the diagonal of a bridge circuit which is supplied with the d.c.

Abstract: In an atomic absorption spectrophotometer utilizing the direct Zeeman's method, plural lamps are installed in the light source unit in order to enhance the versatility and enable continuous analyses. Accordingly, a plurality of low pressure discharge tubes 14 and hollow cathode lamps 16 in total are mounted on a lamp holder 12 of the light source unit, and by rotating the lamp holder 12, an arbitrary lamp may be positioned at the light source position for measurement. When the low pressure discharge tube 14 is used as the light source, in order to perform background correction by the Zeeman's method, a permanent magnet or an electromagnet 24 for operating a magnetic field on the light source is disposed, and a polarizing unit 26 is disposed on the measurement optical path, so that the direction of polarization of the measurement light to be sent to an atomizing unit 26 is changed over between the atomic absorption measurement mode and the background correction mode.

Abstract: A lighting circuit part (26) is provided for lighting a hollow cathode lamp (1), to feed a large lighting current (I1) intermittently and periodically across an anode and a cathode by a control signal from a control part (22) while feeding a boost current (Ib) across a boost electrode and the anode in a part of a period when the lighting current (I1) flows across the anode and the cathode. Absorbance including both of atomic absorption of a sample and background absorption is detected with light emitted when the large current (I1) is fed across the anode and the cathode with feeding of the boost current (Ib) while absorbance by background absorption of the sample is detected with light emitted when the large current (I1) is fed across the anode and the cathode with no feeding of the boost current (Ib) so that difference between these absorbance levels is obtained to obtain true atomic absorption corrected as to background absorption. Thus, measurement is made in a high S-N ratio with background correction.

Abstract: A spectrometer using Zeeman background correction is disclosed which has a sample producer (100) for producing a cloud of atoms, an electromagnetic radiation source (102) for irradiating the atom cloud, a detector (104) for detecting the radiation after it passes through the atom cloud and an electromagnet (14) for applying a magnetic field to the atom cloud. A power supply and switching unit (106) for powering the electromagnet and switching the electromagnet on and off to create a Zeeman effect are provided. The switching unit has transistors (16-22, 40, 42, 50, 52) controlled by a control circuit (25), and the power supply includes a rectifier (10) and one or more capacitors (12, 12a, 12b). The switching time is typically on the order of 1-1.5 ms or less and the high voltage which is applied is on the order of 400-800 V.

Abstract: A Raman spectroscopy system and method for determining a zero-calibration level. A gas sample chamber is located within a resonant cavity. A light source is located to cause light to be incident on the gas sample, the light resonates in the resonant cavity. Typically, the light source and resonator cavity in conjunction form a laser source which propagates coherent, monochromatic laser light energy through the gas sample. This causes Raman scattering from the gases constituent in the gas sample. The amount of Raman scattered light is measured at detectors along with light due to dark noise inherent in the detectors and glow from the laser source, i.e., light at wavelengths other than the laser light wavelength produced by the laser source. The resonator cavity is obstructed, via a ball inserted into the path of the laser beam for example, to prevent resonance. If the light source and resonant cavity in conjunction form a laser, prevention of resonance causes cessation of lasing.

Abstract: An electro-optical detection system for detecting objects 12 embedded within a partially transmitting medium comprises means 20 to receive electro-magnetic radiation in two close spectral channels 28, 212: a signal channel 212 where the wavelength and bandwidth of the signal channel are optimized to correspond to the peak of transmission of the medium and a reference channel 28 where the wavelength and bandwidth are selected to correspond to a spectral region where attenuation in the medium is high. The signal and reference channels are then subtracted (213) so as to remove the effect of reflected radiation from the signal channel 212. The signal is processed digitally (218) to provide an enhanced image of the field of view. In a particular arrangement for detecting objects underwater a CCD TV camera 20 is used with three separate CCD detector arrays providing concurrent red (R), green (G), blue (B) output signals.

Abstract: Light from a discrete broadband visible and/or infrared light source is collimated and transmitted within an optical path that is open to an ambient environment through a spatial region of interest and is focused to a beam splitter, which splits the transmitted light into different beams and directs the different beams respectively to a pair of narrowband acousto-optical tunable filters (AOTF). One such AOTF is disposed for filtering one split transmitted light beam and is rapidly tuned through a predetermined series of different wavelengths that are characteristic of an energy absorption spectrum for a first given substance, or of a first predetermined set of given substances. The other AOTF is disposed for filtering the other split transmitted light beam and is rapidly tuned through a given substances.

Abstract: A spectroanalytical system with radiation dispersing apparatus for dispersing radiation into a spectrum for concurrent application to an array of exit ports; sample excitation apparatus for exciting sample material to be analyzed to spectroemissive levels for generating a beam of radiation for dispersion by the dispersing structure; the exit port array including a corresponding array of detectors including a first detector positioned adjacent a first exit port positioned to sense first order radiation from an element of interest and a second detector positioned adjacent a second exit port to sense second order radiation from the same element of interest; and processing apparatus for responding to outputs of the first and second detectors to provide a compensated output as a function of the quantity of the element of interest in the sample material.

Abstract: A sample disposed in a graphite tube in a furnace is subjected to thermal treatment at successive stages, drying, ashing and atomization and atomic absorption due to an element contained in the sample is measured. Amounts of inert carrier gas supplied to the graphite tube are different for different samples. The carrier gas flow rate at each of the stages is varied so as to reduce influences of background when each of the samples is treated. The carrier gas flow rate is varied, depending on the magnitude of a background signal measured on the basis of light which has passed through the graphite tube.

Abstract: A method and apparatus are provided for correction of spectra for stray radiation in a spectrometric instrument, involving a sequence of steps as follows. Spectral patterns are obtained with the instrument initially for monochromatic radiation at a plurality of selected calibration wavelengths. By computer program, the peak profile at the calibration wavelength in each pattern is replaced with a substitute based on the remaining pattern. The resulting data are interpolated to effect values denoted "stray proportions" for the ordered wavelengths of the instrument. Spectral data at each ordered wavelength are obtained with the instrument for a sample, and multiplied in the computer program by stray proportions for corresponding wavelengths to effect further sets of values denoted "stray portions" that are identified to the ordered wavelengths. Each set is identified to one of the wavelength increments of the instrument across the spectral range.

Abstract: A fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman-scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures.

Abstract: In order to provide a linear calibration graph when analysing samples by atomic absorption spectroscopy, a maximum absorbance value is determined conventionally for a given analyte. The individual absorbance values of a sample containing an unknown amount of the analyte are processed as a function of the maximum absorbance value in accordance with the function ##EQU1## The thus obtained corrected individual absorbance values are integrated with respect to time to yield a corrected time-integrated absorbance value which is proportional to the amount of analyte present in the sample. This amount is determined using a calibration factor obtained from the analogously corrected time-integrated absorbance value of a calibration sample containing a known amount of the analyte.

Abstract: Light, pulsed or continuous at a particular wavelength (e.g. 780 nm), fluoresces a specimen. The specimen may be combinations of an antigen (e.g. rubella) labelled with a fluorescent dye, unlabeled antigen or hapten and an antibody reactive with the antigen or hapten. The light polarized in a first direction (e.g. z-axis) parallel to the electric field of the incident light and in a second direction (e.g. x-axis) perpendicular to the first direction is measured. A second specimen is then provided with the antigen and the antibody but without the dye. The same light as discussed above excites the second specimen and polarizes the light. The light polarized in the first (z-axis) and second (x-axis) directions in the second specimen is measured. These measurements are processed in a microprocessor with the measurements in the z and x directions in the first specimen to identify the antigen or, when the antigen is known, to identify the concentration of the antigen in the first specimen.

Abstract: An improved method and apparatus for measuring polarized fluorescence emissions compensates for background emissions without separating a fluorescing material from background material. The method involves measuring the horizontally and vertically polarized components of the fluorescence emission at a primary wavelength and at least one secondary wavelength selected on the basis of the bathochromic shift of the spectrum of the fluorescence emissions from the fluorescing material as compared to the fluorescence emissions from the background. From these measurements, a factor representing the fraction of the total intensity of fluorescence emissions due to background fluorescence is determined. From this factor, the intensities of the vertically and horizontally polarized fluorescence emissions due to background fluorescence are derived and subtracted from the measurements at the primary wavelength to obtain intensities due solely to the material being analyzed.

Abstract: A double pass scanning monochromator for use in an optical spectrum analyzer includes an input optical fiber for emitting an input light beam, a diffraction grating for diffracting the input light beam to produce a spatially dispersed light beam, a slit for passing a selected portion of the dispersed light beam, a motor for rotating the diffraction grating, a shaft angle encoder for sensing grating position, and an output optical fiber. The light that passes through the slit is directed to the diffraction grating and is recombined by the diffraction grating to produce an output light beam. The light beam to be analyzed is incident on the diffraction grating during first and second passes. A polarization rotation device rotates the polarization components of the light beam by 90.degree. between the first and second passes so that the output of the monochromator is independent of the polarization of the input light beam.

Abstract: A laser radiation detection system using a spatial/wavelength filter to "ulate" the response of a detector as a function of wavelength, allowing discrimination of laser sources against broad spectral sources, as well as wavelength determination.

Abstract: An atomic absorption spectrometer contains a line-emitting first light source (16), an official system (20, 22, 28, 30, 34) for generating a measuring light beam (18) which passes through a test sample space (12) and impinges on a photoelectric detector (38). An atomization device (14) for atomizing a test sample is so arranged in the test sample space that the constituents of the test sample are present in atomic form in an atomization region traversed by the measuring light beam (18). A light beam (72) is emitted continuously by a second light source (70). A beam splitter (74) reflects the light beam from the second light source (70) as a reference beam into the optical path of the measuring light beam (18). The two light sources (16, 70) can be switched on alternately by switching means. The beam splitter (74) can be removed optionally from the optical path.

Abstract: A method of measuring and compensating stray light in absorbance analysis that use a multiple element array detector wherein one or more of the elements of the diode array are utilized to detect stray radiation in the absence of primary radiation including higher order diffracted radiation. In one aspect, the atmosphere is used to filter all primary radiation below a particular wavelength so that one or more array elements corresponding to detection below such wavelength can be dedicated to the detection of only stray radiation. Detection of higher order diffractions can be prevented by dividing the total spectrum into intervals and detecting these intervals in sequence. In another aspect, a diode array is designed to include additional elements along one side of the array outside the exposure of the primary radiation for the sole purpose of detecting stray radiation.

Abstract: A Zeeman atomic spectrophotometer comprising a sample heating means for atomizing a sample, a means for applying a magnetic flux to the atomized sample and a ceramic film coated on at least tips of pole pieces which are disposed facing the heated sample. As the tips of the pole pieces are coated with a ceramic film, the measuring accuracy of the Zeeman atomic absorption spectrophotometer becomes high and stable over a very long term.

Abstract: An atomic absorption spectrophotometer comprising means for setting the ashing temperature for that of the element having the lowest ashing temperature; means for setting the atomizing temperature for that of the element having the highest atomizing temperature; and means for effecting background correction utilizing Zeeman effect.

Abstract: An atomic absorption spectrometer with electrothermal atomization of the sample and background compensation by use of Zeeman effect comprises a furnace (130) for the electrothermal atomization of the sample which furnace is heated transverse to the direction of propagation of the measuring light beam (18) of the atomic absorption spectrometer and a switchable solenoid (44) for generating a magnetic field at the location of the sample which magnetic field extends parallel to the direction of propagation of the measuring light beam (18) such that the longitudinal Zeeman effect is obtained with switching on the solenoid (44). The solenoid (44) has pole pieces (46,48) with aligned apertures (50,52) for the passage of the measuring light beam (18). A contact carrier (96) is arranged on the pole pieces (48,50) in which contact carrier contacts (128,176) are supported in order to hold the transversely heated furnace (130), the axes of said contacts being perpendicular to the axis of the measuring light beam (18).

Abstract: A method of and a device for multi-element measurement of elements in a sample with correction for background emission. The method starts with atomizing a sample and then exciting the transformed atoms to emit light containing characteristic spectral lines for each element, followed by generating a spectrum of spectral lines characteristic of the elements, followed by measuring the intensity of selected spectral lines falling within a predetermined measuring range without changing their intensity. The next steps are sensing the background emission adjacent the selected spectral lines simultaneously with measuring the intensity of selected spectral lines and determining the concentration of each element from the measured intensity of the corresponding spectral line and sensed background emission.

Abstract: An atomic absorption spectrophotometric apparatus, which includes a first light source emitting plural specific spectra by changing the current of the first light source into relatively small and large currents, a second light source emitting a continuous spectrum, an atomizer for atomizing a sample, a beam combiner for directing the spectrum emitted from the first light source and the second light source to the atomized sample, a detector for detecting the plural specific spectra and the continuous spectrum which passes through the atomized sample, and a computer for obtaining spectrum absorbances of the plural specific spectra and the continuous spectrum from the outputs of the detector and obtaining a concentration of a specific element on the basis of a combination of the spectrum absorbances.

Abstract: An atomic absorption spectroscopy photometer comprising: sample atomizing means for heating to atomize a sample; a plurality of light sources disposed at a like number of light flux incidence positions for causing light having required wavelengths to enter the atomized sample; means for measuring the degrees of light absorption of a plurality of elements contained in the sample by detecting the fluxes of light which have passed through the atomized sample; a plurality of holder means for holding the plurality of light sources, the plurality of light sources being larger in number than the plurality of the light flux incidence positions; and means for setting required ones of the light sources of the plurality at the corresponding light flux incidence positions by moving the holder means.

Abstract: In a spectrophotometer having photodetectors positioned at fixed wavelengths, the photodetector is divided into three subdetectors, a main subdetector on the wavelength of interest and two background subdetectors located on each side of the main subdetector, the background subdetectors together having area equal to that of the main subdetector, the background subdetectors being connected in polarity reverse that of the main subdetector to correct for changes in background radiation.

Abstract: A solenoid serves for generating a magnetic field at the location of a sample which is to be atomized in an atomic absorption spectrometer. A shift of the absorption lines of the atoms in a sample relatively to the emission lines in a measuring light beam (18) passed through the atomized sample is effected by the magnetic field due to the Zeeman effect. The solenoid (44) comprises a pair of pole pieces (46, 48) between which an air gap is formed. An atomizing device atomizes the sample within this air gap. Field coils generate a magnetic flux through the pole pieces (46, 48), the air gap and a magnetic return path (76). The field coils (60, 62) are arranged on pole pieces (46, 48) close to the air gap. The windings of the field coils (60, 62) are formed by tubes (216) which are designed to permit passage of a cooling liquid therethrough.

Abstract: A method of correcting for background changes in a plasma emission detector comprising a photodetector array is disclosed. In the photodetector array a plurality of sensors are used to detect the emission lines from a discrete number of selected elements including carbon. It is shown that, to the first order, there is a correlation between the response at detectors other than the carbon detector with the response at a carbon detector. The exact extent of this correlation is highly dependent on the amount of nitrogen present in the carrier gas used in the system. A calibration curve can be generated which allows compensation at a frequency of interest as a function of the magnitude of the carbon signal. This curve will depend on the level of nitrogen in the carrier gas and can be empirically determined each time a new bottle of gas is connected to the system.

Abstract: What is disclosed is a method and a system for (trace) gas analysis, specifically NH.sub.3 analysis in flue gases exhausted from power plants or in industrial waste gases. In this method and system, a laser is reversed between two of its intrinsic resonance lines whereof one wavelength corresponds to an absorption maximum and the other corresponds to an absorption minimum of the gas to be detected. The extinction E and thus the concentration of the gas under analysis is derived from the ratio of the values of intensity attenuation at the two wavelengths.

Abstract: An atomic emission spectrometer for multi-element measurement of elements in a sample comprises an apparatus to atomize the sample and to excite the atoms for emitting characteristic spectral lines, a dispersion device which generates a spectrum of the light emitted by the atoms in a focal plane, and a plurality of semiconductor photodetectors, each of which is exposed to one of said characteristic spectral lines. A plurality of semiconductor photodetectors which are exposed to different spectral lines of different intensities of the line spectrum emitted by the atoms of the respective element are utilized so as to achieve a sufficiently large dynamic range for each element to be measured. For measuring each element, an evaluating circuit is arranged to select one semiconductor photodetector for which the intensity of the associated spectral line lies within a part of the measuring range of the semiconductor photodetector which is as favorable as possible.

Abstract: In an atomic absorption spectrometer, a burner 16 for atomizing a sample is movable between a first and a second position. In the first position, the "cloud of atoms" is formed in the area of the housing-fixed measuring light beam 14. In the second position, it is formed outside the measuring light beam. The measurement is made in the first position whereby the utilization of the energy of the measuring light beam is optimal. A drift compensation is made in the second position to take care of variations of the lamp intensity and of the detector sensitivity.

Abstract: In an atomic absorption spectrometer with an atomizing device (190) and a line emitting light source (16), an optical system (22,28 . . . ) for generating a measuring light beam (18), and a photo-electrical detector (38), which are arranged in a housing (10) which forms a sample cavity (12) accessible from the outside and which is passed through by a measuring light beam (18) and into which different atomizing devices can be optionally inserted, the atomizing device (190) with the specific components (104,124,126) is assembled to form an insert unit (100) in which the atomizing device (190) in the form of a graphite furnace has a well-defined position relatively to the insert unit (100) and which in turn can be inserted into the sample cavity (12) in a well-defined position to provide an entirely functioning atomic absorption spectrometer.

Abstract: In a background compensation in material analysis, the value of the background signal is separated from the value of a gross analyte signal generated by athermal radiation excitation after thermal excitation. The thermal atomization takes place in a stepwise manner by stepwise heating and each step is divided into a first part for the measurement of the gross analyte signal and a second part for the measurement of the background signal.

Abstract: In atomic absorption spectrophotometers such as Zeeman atomic absorption spectrophotometer, the present invention is characterized in that the correction timing of background absorption in sample light is made to coincide with that of reference light so as to improve the accuracy of the output signals of the spectrophotometer.

Abstract: A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium emission line, may be detected in the presence of interfering background radiation. A combustion flame is fed by a diverted portion of a process stream and the common end of a bifurcated or quadfurcated fiber optic light guide is adapted to collect light from the flame. The light is guided through the branches of the fiber optic cable to bandpass filters, one of which is adapted to each of the branches of the fiber optic light guide. The bandpass filters are centered at wavelengths corresponding to the emission lines to be detected and two separate filters are required for each species being detected. The first filter has a bandwidth of about 3 nms and the second filter has a bandwidth of about 10 nms. Light detectors are located to view the light passing through the bandpass filters and amplifiers are connected to receive signals from the light detectors.

Abstract: A method and apparatus for standardizing spectral line intensities in a spectral monochromator separate an input beam into a sample spectral line characteristic of a sample element, a reference spectral line, a standard spectral line and a background spectral band. At a first point in time an intensity I.sub.A of the sample line, a first intensity I.sub.R1 of the reference line and a first intensity I.sub.B1 of the background band are measured. At a second point in time an intensity I.sub.S of the standard line, a second intensity I.sub.R2 of the reference line and a second intensity I.sub.B2 of the background band are measured. An intensity ratio IR defined by the formula ##EQU1## is computed wherein the intensity ratio IR represents a standardized intensity of the sample line compensated for source fluctuations.

Abstract: In the atomic absorption or atomic fluorescence spectroscopy the problem exists to compensate the background absorption. For this purpose a measuring light beam, which is passed through a sample space, is frequency modulated by using the Doppler effect. This is achieved in that devices for generating a rate of change of the optical path length passing between two points of this path of rays of the measuring light beam (12) are provided in the path of rays of the measuring light beam (12). Different constructional solutions herefor are described. The optical path length can be varied cyclically by movable mirrors. But it is also possible to arrange a crystal (132) in the path of rays, the refractive index of which can be varied cyclically by applying an electric voltage to the field plates. (134 and 146).

Abstract: A process which extends the measurement range of Zeeman atomic absorption spectroscopy by linearization of the calibration curve in the region of relatively high sample concentration. The intensities of the Zeeman components I.pi.o, I.sigma.o, I.pi. and I.sigma.

Abstract: An apparatus and method for determining the zero line in atomic absorption spectrometers having an atomizer and a burner for atomizing the sample wherein the flow of oxidizing agent supplied to the atomizer is interrupted by means of a switching valve and an additional flow of oxidizing agent is supplied to the burner through a by-pass conduit by-passing the atomizer with the additional flow being equal to the flow of oxidizing agent to the atomizer during operation of the atomizer and the absorption of the measuring light beam defining the zero line.

Abstract: An absorption profile indicative of a relation in atomic absorption spectroscopy between the absorbance of a desired element and time has a constant half-width independent of the concentration of the desired element in a sample, and hence the half-width of absorption profile with respect to the desired element can be previously determined from data which is obtained by the measurement of a standard sample. In an atomic absorption spectrophotometer herein disclosed, the half-width of absorption profile is previously determined in the above-mentioned manner, and the true peak value of an absorption profile obtained by measuring a sample which contains the desired element at a high concentration, is calculated using the time width of this absorption profile at a predetermined absorbance and the previously-determined half-width.

Abstract: When a light emitted during the irradiation by a laser beam onto the surface of steel is spectrally separated and elements contained in the steel are analyzed quantitatively:an infrared pulse laser beam irradiates a sample such that an energy density on the surface of the sample becomes 2.0.times.10.sup.9 W/mm.sup.

Abstract: A double polarized light beam spectrophotometer of a light-source modulation type. A modulated light beam emitted by a light source is conducted through specimen atom vapor generated by a graphite atomizer. Wavelength of light undergone atom absorption is selected and spatially separated into a pair of linearly polarized light beams perpendicular to each other. The pair of the linearly polarized light beams separated are alternately passed through a chopper and received by a photoelectric conversion device to be converted into electric signals which are utilized for determining atomic absorption of the specimen. The phase of modulation of light radiated from the light source is synchronized with phase of a current supplied to the graphite atomizer for heating thereof and the switching timing of the chopper.

Abstract: A fluorescence spectrometer for multielement analysis including a source for atomizing a dispersed sample along an axis and a plurality of energizers and detectors preferably arranged in pairs about the source, with each of the pairs designed for analyzing one element. Preferably, the source is an inductively coupled plasma. Means is provided for each of the pairs to view a different segment of the source along its axis, depending on the element to be analyzed. Preferably, such means includes: a source movable along its axis; fiber optics interposed between the energizers and the source and between the source and the detectors; and a movable optical element interposed between the energizers and the source and between the source and the detectors. The spectrometer further features a polychromator for use in lieu of matched optical filters in the detectors and demountable hollow cathode lamps as energizers.

Abstract: An atomic absorption system comprising a radiation source that emits spectral line radiation characteristic of an element to be analyzed, an analysis region open to passage of the beam of radiation from the source and in which a sample of the substance to be analyzed is atomized, source control means for alternately energizing the source at a first intensity level to provide a radiation output that has a narrow spectral line at a wavelength of an element to be detected and at a higher intensity level to provide a radiation output of broader wavelength with intensity suppression at the wavelength of the narrow spectral line, electronic transducing means for developing an electrical signal corresponding to the sensed radiation intensity of the radiation beam that passes through the analysis region, and a log ratio circuit that utilizes integrated electrical signals corresponding to the two source energization intensity levels to provide background corrected concentration information on the element of interest i

Abstract: An atomic absorption spectrophotometer having a source, e.g., a hollow cathode lamp, of spectral radiation of a selected narrow band of wavelengths optically directed along an axis through an electrothermic sample atomizer and a field stop to a photoelectric detector. The sample atomizer is subjected to a substantially unipolar AC electromagnetic field having flux lines directed transversely to said axis to effect Zeeman splitting of the radiation into two orthogonally polarized components .pi. and .sigma.. Disposed in the optical path between the atomizer and detector is a stationary beam-splitting polarizer prism oriented so as to transmit the .sigma. polarized component and block the .pi. component. Mirrors are used exclusively in the optical systems so as to minimize the effect of dispersion and stray light.An electromagnet, used to generate the electromagnetic field, is connected to the AC power line in series with the diode and has a small capacitor connected across its coils.

Abstract: A Zeeman atomic absorption spectrophotometer which monitors atomic absorption signals after a sample is introduced into the chemical flame atomizing portion. A signal peak value is measured in the portion of atomic absorption signals rising after the sample is introduced, or in the portion of atomic absorption signals breaking after the introduction of the sample is discontinued. A relation between the peak value and the sample concentration establishes a monovalent function. According to the conventional method, a relation between an average value of atomic absorption signals within a predetermined period of time and the concentration of specimen establishes a divalent function, and it is difficult to measure the samples, particularly in high-concentration regions. According to the present invention, however, it is possible to measure the samples of even high concentrations without having to dilute the samples.

Abstract: In a Zeeman atomic absorption spectrophotometer, an atomic absorption signal in an atomization stage is observed. The length of time between an instant at which the signal initially attains a predetermined absorbance and an instant at which the signal attains the same predetermined absorbance for the last time during the atomization stage is measured. By utilizing this time measurement as an indication of concentration, the concentration of the sample can be measured at higher concentrations than the limit concentration in the analysis by a conventional apparatus of this kind.

Abstract: A method and apparatus for carrying out atomic spectroscopy, and particularly atomic absorption and atomic fluorescence spectroscopy. The method involves passing the emission spectrum of a light source through an atomized sample, changing the relationship between a selected emission line of the emission spectrum and a corresponding absorption line of the atoms of interest and measuring the absorption of that emission line by the sample before and after the aforementioned change in relationship. The change in emission and absorption line relationship can be effected by application of the Zeeman Effect, Stark Effect, or Doppler Effect. The apparatus, in one form, includes an electro-magnet operative to apply a magnetic field to the atomized sample and thereby cause splitting and shifting of the aforementioned absorption line, and the magnet is modulated to effect periodic variation of the spectral line relationship.