Abstract: A spark-excited fluorescence sensor (10) is provided which enables monitoring of various gas species (14), such as H.sub.2, CO.sub.x, NO.sub.x, N2, NH.sub.x and hydrocarbons added to a system as source fuels and/or additive agents, or discharged from a system as exhaust including pollutants, for more efficient use of fuels for optimizing performance of the system, and, also, for reducing pollutants in the atmosphere. The spark-excited fluorescence sensor of the invention comprises a spark plug (12) to excite molecules of the gaseous species, an optical fiber window (18) and an optical fiber bundle (20) to collect and transmit, respectively, the fluorescence, bandpass filters ( 24 ) to select predetermined wavelengths corresponding to the gases to be detected, detectors (26), and signal processor (28 ) . The output from the signal processor is then used to improve overall performance of the system.

Abstract: A highly stable high intensity atomic emission light source has a discharge region and the sample region each controlled by a separate heater. The sample region heater is controlled by a lamp stabilizer circuit which maintains the breakdown voltage within the discharge region at a constant level, thus providing a stable and high intensity light source.

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: A device for the individual adjustment of the intensity of several spectral lamps (1, 2), the radiation of which is combined into a common ray path (4), is distinguished by the fact that a device is provided for the modulation of the emission of each of the spectral lamps (1,2) with a different frequency, a beam-splitting mirror (8) for extraction of a part of the total radiation is inserted into the common ray path (4), a photoelectric receiver (9) is provided for the generation of an electrical signal which is proportional to the intensity of the extracted radiation, and frequency filters (11, 23) which are tuned to the modulation frequencies of the spectral lamps (1, 2) are arranged behind the photoelectric receiver (9), regulators, comprising a phase-locked loop (PLL) (12, 22), an automatic gain control (AGC) (13, 23) and a power amplifier (10, 20), for control of the intensity of the respective spectral lamp (1, 2) being allocated to the frequency filters.

Abstract: A light source for Zeeman spectroscopy wherein an anode in an ionizable gas is used for ion bombardment of a cathode having materials therein whose spectra is to be observed. The anode and cathode are mounted in a magnetically permeable housing which fits snugly between pole pieces of a magnet such that the magnetic field between pole pieces is perpendicular to the electric field between the anode and cathode so that the arc discharge therebetween is spacially limited to a narrow dimension, i.e., a line, for improved Zeeman atomic absorption spectroscopy.

Abstract: This invention provides an A.C., cyclic, current-controlled, phase retardation plate that uses a magnetic clamp to produce stress birefringence. It was developed for an Isotope-Zeeman Atomic Absorption Spectrometer that uses polarization modulation to effect automatic background correction in atomic absorption trace-element measurements. To this end, the phase retardation plate of the invention is a variable thickness, photoelastic, double-refracting plate that is alternately stressed and released by the magnetic clamp selectively to modulate specific components selected from the group consisting of circularly and plane polarized Zeeman components that are produced in a dc magnetic field so that they correspond respectively to Zeeman reference and transmission-probe absorption components. The polarization modulation changes the phase of these polarized Zeeman components, designated as .sigma. reference and .pi.