Abstract: There is disclosed herein a novel spectral background corrector system which, by employing light refracting techniques, causes wavelength scanning or modulation which allows substantial elimination of spectral background.

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.

Abstract: A method and apparatus for simultaneous multielement atomic absorption analysis, comprising use of a continuum source and a high resolution echelle polychromator modified for wavelength modulation, and a high speed data acquisition system (SIMAAC). The method and apparatus is capable of measuring as many as 16 or more elements simultaneously with either flame, electrothermal or other means of atomization. Double beam operation and dynamic background correction are achieved on all channels. Linear dynamic range of up to six orders of magnitude can be achieved for each channel.

Abstract: A dual beam spectrophotometer includes signal processing circuitry for producing sample-dark and reference-dark signals. The dark signals substracted from the sample and reference signals are the average of the dark signals produced on each side of the sample and reference pulses. The signal processing circuitry may comprise four sample and hold circuits which store the sample signal, reference signal and first and second dark signals, a resistive combining network for the two dark signals and first and second substractor circuits. The first substractor circuit provides the sample-dark signal at its output while the second substractor circuit provides the reference-dark signal at its output.

Abstract: High resolution scattering spectra are obtained from irradiation of a sample with monochromatic light without disturbing the position of the sample, the spectra being characterized by freedom from artifacts due to the presence of optical components which distort the intensities of the scattered spectra. Scattered light from an irradiated sample and light from a white light source of constant or known emissivity are passed through the optical components and dispersed and measured with a monochromator and detector. The so-measured light intensities of the scattered light from the irradiated sample and the light from the white light source are ratioed at each wavelength to yield a light intensity representative solely of the scattered light from the irradiated sample, which is then displayed as a function of wavelength.

Abstract: A dual beam Fourier-type spectrometer is disclosed incorporating distinct sample and reference beams which enter the Michelson-type interferometer on the same side of the beam splitter and propagate at slightly different angles through the interferometer. The portions of both beams which emerge from the side of the beam splitter opposite the input side are directed to two separate optical detectors, the outputs of which are electronically subtracted. In a preferred embodiment, the interferometer is of the refractively scanned type, wherein the increased field-of-view facilitates the use of beams having different propagation angles.

Abstract: A method and apparatus are described for measuring the concentration of a molecule of selective spectrum in a sample substance in which errors from spurious light signals due to diffused light or from spurious fluorescent or phosphorescent light due to traces of other molecules in the sample substance are eliminated. The invention subjects the sample substance to light of a first wavelength in the absorption spectrum of the molecule to be measured and obtains a signal representative of light emission from the molecule with the spurious light signals superimposed thereon.

Abstract: A method of detecting a small elemental spectral source in a larger, spectral background, including producing a first interferogram of each element of an object area including the source and background; producing a second complementary interferogram of each element of that object area; projecting onto a detector images of the first and second interferograms and defocussing one of the first and second interferograms for providing a fluctuating elemental interferogram output from each element of the detector which receives an interferogram derived from the element of the object area that contains a source which spectrally distinguishes from the background, while reducing the output corresponding to each element containing no source to a constant and non-fluctuating level.

Abstract: This invention relates to an apparatus and a method for spectroscopically analyzing substances, by fluorescent or resonant detection. An atomic cloud of a reference element is generated by cathodic sputtering and irradiated with radiation emitted from a substance of unknown composition. Generation of the atomic cloud is ceased and the inherent radiation of the atomic cloud allowed to decay. Any fluorescent or resonant radiation of the atomic cloud is then detected to determine the presence or concentration of the reference element in the unknown substance. Further, the amount of background radiation is detected by determining the amount of radiation extant when the concentration of atoms in the atomic cloud has decreased to substantially zero. The invention also provides an abnormal glow discharge lamp having two or more windows, the lamp being particularly suitable for use with the apparatus. The lamp further has a hollow anode with a transverse planar cathode.