Abstract: This instrument can measure parameters of a plasma accurately and easily even though the plasma is exited by a high-frequency. The instrument for measuring parameters of a plasma generated in a vacuum chamber by high-frequency discharge at a given frequency comprises a wire (106) for electrically connecting a first electrode (101) arranged in a space where a plasma is produced and a terminal (110) arranged outside the vacuum chamber for taking out signals, and a first insulator (105) so arranged as to cover at least a part of the surface of the wire therewith. The absolute value of the impedance at the given frequency between the first electrode and the ground when looking into the terminal side from the first electrode is five times or more the absolute value of the impedance at the given frequency between the first electrode and the plasma in a state where no direct current flows through the first electrode.

Abstract: A method and apparatus for accurately characterizing the electron density and distribution of a confined plasma on the basis of high-frequency, broadband electromagnetic measurements is disclosed herein. The technique involves noninvasive, broadband measurement of electromagnetic transmission through a plasma. In one implementation, multivariate analysis techniques are employed to correlate features of the resultant spectra with plasma characteristics such as electron density or electron distribution. Alternately, such techniques are used to correlate the resultant spectra with parameters relating to conditions under which the plasma is generated. More specifically, the quantitative plasma characterization technique involves generating a set of broadband calibration spectra by measuring transmission of electromagnetic energy through a calibration plasma. Each broadband calibration spectrum is obtained using a different set of reference parameters being related to predefined quantitative characteristics.

Abstract: A sensor (10) includes a gate electrode (20) overlying a channel region (34). A gap (22) between the gate electrode (20) and the channel region (34) allows a surface (28) of the gate electrode (20) to be exposed to a chemical. Upon exposure to the chemical, a surface potential or an electrical impedance of the gate electrode (20) may change. Comparing the changes in surface potential versus the changes in electrical impedance provides a method to distinguish between similar chemical species and also to extend the detection range of the sensor (10).

Abstract: A method of determining the effect of a test substance on any life stage of at least one clone of a Centroptilum triangulifer mayfly comprising (A) identifying and selecting at least one clone of Centroptilum triangulifer as a test clone to be subjected to the test substance; (B) exposing each test clone to the test substance for a predetermined time; and (C) determining the effect of the test substance on each test clone by at least one of (i) observing the test clone for a lethal or sublethal effect and (ii) Sacrificing the test clone, and analyzing the sacrificed test clone for at least one of (a) the presence of at least one of the test substance and any of its metabolites, (b) the quantity of at least one of the test substance and any of its metabolites, and (c) a lethal or sublethal effect of at least one of the test substance and any of its metabolites.

Abstract: A halogenated hydrocarbon (HHC) detector is formed from a silent discharge (also called a dielectric barrier discharge) plasma generator. A silent discharge plasma device receives a gas sample that may contain one or more HHCs and produces free radicals and excited electrons for oxidizing the HHCs in the gas sample to produce water, carbon dioxide, and an acid including halogens in the HHCs. A detector is used to sensitively detect the presence of the acid. A conductivity cell detector combines the oxidation products with a solvent where dissociation of the acid increases the conductivity of the solvent. The conductivity cell output signal is then functionally related to the presence of HHCs in the gas sample. Other detectors include electrochemical cells, infrared spectrometers, and negative ion mobility spectrometers.

Abstract: A thin-film gas sensor and manufacturing method of the same is disclosed which includes a silicon substrate; an insulating layer formed on the surface of the silicon substrate; a heater formed in zigzag on the surface of said insulating layer; a temperature sensor formed in zigzag on the surface of the insulating layer in parallel with the heater; an interlayer insulating layer for electrically insulating the heater and temperature sensor formed on the insulating layer; a plurality of electrodes formed on the interlayer insulating layer placed between the heater and temperature sensor; a plurality of pairs of gas sensing layers disposed in an array on the electrodes and for reacting on detected gas; and a plurality of gas shielding layers formed on one gas sensing layer out of the pair of gas sensing layers and for shielding the detected gas so that the gas sensing layers do not react on the detected gas.

Abstract: Method and apparatus for the analysis of one or more analytes present in a sample that may be dissolved in a hostile solvent and carried in a first fluid. The first fluid is combined with a first detector fluid to provide a fluid mixture which flows across the surface of an ionization source. The analytes are ionized by means of an ionization process in which electrical charge is transferred from the ionization source and converted into gas phase ion species. The ion current is collected and measured at a collector electrode adjacent to the ionization source. The flow of the first detector fluid is reduced during the presence of the solvent at the ionization source so as to suppress a chemical reaction that heretofore would degrade the sensitivity of the detector.

Abstract: The objective of the invention is a method for detection of alien matter contents in gas, in which method the gas and the substances contained in it are ionized in an ionization room (1). By the present methods impurities in gases cannot be determined fast and in small concentrations. In the method of the invention the ions contained in the gas are separated in a separation section (2) into positive and negative ions, of which at least the ions of either sign are led into a narrow analyzer channel (4). There, due to the capillary force, they are forced to move in the middle section of the channel, from where they are deflected by electric fields of different strength caused by different voltages (U1-U10) into an electrode located at the edge of the channel, where they cause ion current (I1-I10).

Abstract: A device and method is described for joining two or more small particles to form a composite levitated particle. The size of the particles joined may be in the range 0.1 micrometer to 30 micrometers. The device utilizes a linear quadrupole electrodynamic levitator with storage rings at right angles to the levitating electrodes. The storage rings move the charged particles to desired positions with DC electric fields. Particles with different sign but unequal charge are then joined by means of displacements caused by the DC fields of the storage rings. The initial particles and the final composite particle are retained free of any contact with substrate in the levitating fields of the linear levitator.

Abstract: Methods and apparatus for in sire isolation of volatile organic compounds from groundwater using electrolytically-generated purge gas are disclosed. One preferred method includes electrolytically generating a purge gas from the ground water, passing the purge gas through the groundwater (in situ) to purge volatile organic compounds from groundwater, collecting the purge gas along with the purged volatile organic compounds, and detecting (in situ) the presence and/or amount of purged volatile organic compounds in the purge gas. One preferred apparatus includes a generally cylindrical cell incorporating the necessary electrodes, one or more ionization sources and detectors.

Abstract: A surface ionization detector for detecting organic molecules such as illicit drugs and non-organo-nitrate explosives includes a heated surface and a collector electrode. A sample containing trace amounts of the organic molecules in ambient air is directed over the heated surface maintained at a temperature in the range of 500.degree. C. to 800.degree. C., thereby causing the molecules to decompose into fragments. A polarization voltage between 18 V and 24 V is applied to ionize the fragments which are then collected by the collector electrode. An electrometer connected to the collector electrode measures the current and a change in the current indicates the presence of ionized fragments, and thereby indicates the presence of the organic molecules. The temperature of the heated surface and the polarization voltage are optimized for detection of particular organic molecules.

Abstract: An apparatus and method for the sensitive detection of atmospheric and/or surface absorbed nitrocompounds has been developed. The apparatus and method may be employed to detect the presence or absence of propellants, explosives, and nitropollutants. The unique feature herein is that the apparatus and method employ one laser operating at or near 226 nm. The laser photofragments the target molecule and facilitates the detection of the characteristic NO fragment, by resonance-enhanced multiphoton ionization (REMPI) and/or laser-induced-fluorescence (LIF) via its A.sup.2 .SIGMA..sup.+ -X.sup.2 II.sub.i transitions. The analytical utility of this apparatus and method has been demonstrated on numerous compounds, such as, DMNA, nitromethane, nitro-benzene, TNT, and RDX. With the present system, a limit of detection of 8 and 24 ppb is obtained for RDX and TNT, respectively, using only 100 micro-Joules per pulse of laser energy.

Abstract: A resistively-heated furnace such as a graphite furnace is employed to atomize a sample for electron ionization and mass spectrometric analysis. Wide-ranging sample types such as biological tissue, semi-solid and nonhomogeneous materials, as well as bulk organic and inorganic chemicals, can be effectively and accurately analyzed with the instrument and instrumental method with little if any sample preparation.

Abstract: The presence of decay is determined in wood by testing a sample. The wood tested may be standing timber, cut timber or when coated in building structures. The testing occurs in very short time intervals so that tests can be carried out on timber in mills and the like. The method of testing includes heating a portion of a wood sample at a temperature in the range of about 220.degree. to 350.degree. C. to evaporate analytes from the wood, conveying the analytes in a sample gas flow into an ionizing chamber of an ion mobility spectrometer detector, ionizing the analytes within the ionizing chamber at a temperature in the range of about 220.degree. to 350.degree. C., generating an ion drift time signature in the detector, and comparing the signature with predetermined signatures representing decay in wood.

Abstract: A method and apparatus to produce an ion mobility signature representing a wood sample provides a method of comparing signatures to identify the species of the wood sample. A method of producing an ion drift time signature representing a wood species comprises heating at least a portion of a wood sample at a temperature in the range of about 220.degree. to 350.degree. C. to desorb and produce trace vapors from the wood sample, ionize the trace vapors at a temperature in the range of about 220.degree. to 350.degree. C., pulse ions through a gate into a drift region, measure the time of arrival of the ions and the ion flux for each pulse, with a collector electrode, located at the end of the drift region to produce an ionic signal, and amplify and average the ionic signal to provide an ion drift time signature for the wood sample.

Abstract: An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and a region for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source for ionization of a broad class of compounds.

Abstract: The objects of the invention are attained in an apparatus for performing a method of analysis of organic compounds in chromatography, comprising a chromatographic column sealingly connected with the housing of a surface ionization detector having coaxially arranged inside, a collector and a thermoemitter with current leads, the housing of the surface ionization detector being provided with an opening for an auxiliary gas feed line and an opening for delivering the spent gases. The thermoemitter includes a closed-end sleeve with a heating element in contact with the external non-working surface of the thermoemitter. The collector includes a hollow cylinder spaced from the inner ionizing surface of the thermoemitter, and the outlet portion of the chromatographic column being received inside and throughout the length of the collector.

Abstract: An apparatus for continuously measuring the hydrocarbon concentration in a gas flow includes at least one flame ionization detector with a combustion chamber housing electrodes between which a current flows due to ionization in the area of a burner flame. The combustion chamber of the flame ionization detector is connected to a suction pump in form of a venturi tube for applying an underpressure in the combustion chamber so as to allow especially sample gas but also burner gas and oxidizer to be drawn into the combustion chamber.

Abstract: An analyzing method of an Inductively-Coupled Radio Frequency Plasma (ICP) apparatus including a switch valve means for switching the flow of a sample which comprises the steps of: first switching the switch valve to the side of a plasma torch only during an ICP analyzing time; first supplying an induction coil a first radio frequency electric power and the plasma torch first volume of gas to cause plasma; analyzing the plasma; second switching the switch valve to an exit side of the sample during the times except for the ICP analyzing time; and second supplying the induction coil a second radio frequency electric power and the plasma torch second volume of gas to keep pilot light plasma, and an apparatus for use in such method; whereby the plasma is maintained at a condition of a pilot light except for analyzing, and a running cost is reduced.

Abstract: A method is described for the quantitative measurement of traces of gas, particularly CO.sub.2 and CH.sub.4 which constitute impurities in impure inert gases such as rare gases and nitrogen, by means of the use of a known analyzer for reducing gases which uses a bed of mecuric oxide and makes the measurement by an optical method of the mercury vapors produced which are proportional in to the concentration of the impurities to be detected. The method of the present invention subjects the impure inert gas to an electric discharge which may be at a high voltage, capable of ionizing the impurities before the impure inert gas is made to pass through the bed of mecuric oxide. The device according to the invention comprises, between a gas-chromatographic separation column and the analyzer, an electrode within a passage through which flows the gas to be analyzed and in which there is an ionizing discharge.

Abstract: An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and means for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source and provides a means for ionization of a broad class of compounds.

Abstract: Apparatus for detecting gas in a sample gas in a carrier gas stream and including a windowless ionization detector having a pulsed power supply which is switchable at a rate which provides a pulse period shorter that the transit time of ions to be detected to the collector electrode of an ionization chamber of the detector. Switching allows any signal due to ion detection to be separated from background noise due to other effects in the chamber.

Abstract: The invention provides a method for the quantitative and/or qualitative characterization of substances which are contained in a gaseous carrier medium. Modifications of the surface of small solid particles suspended in a carrier gas may be measured with very high sensitivity by the application of the photoelectric effect. Thereby, an aerosol is chemically modified, e.g. by admixing a gaseous agent or a gas mixture, or by subjecting it to an electromagnetic radiation, and subsequently the resulting variation of the photoelectron emission from the suspended particles is recorded. By measuring the variation of the photoelectric effect during the admixing or variation of a gaseous agent to the aerosol to be examined or during a variation of the electromagnetic radiation, to which the aerosol to be examined is subjected, the suspended particles may be classified in one or several steps.

Abstract: Diborane is detected in air with high sensitivity (ppb range) and selectivity. The invention is thus suitable for the monitoring of work places and rooms, the emission of plants, etc. The detection is based on an aerosol ionization gas analysis. In addition to an amine, a reagent which does not react with amine is added to the air stream and reacts with the diborane to form a compound which forms aerosols with the amine. The aerosols obtained by this reaction constitute the main measuring effect. When using SO.sub.2 in concentration.gtoreq.3.5 ppm, disturbances due to the SO.sub.2 content of the air are eliminated.

Abstract: A method for analyzing specific chemical substances in a gaseous environment which utilizes a thermionic source formed of multiple layers of ceramic material composition, an electrical current instrumentality for heating the thermionic source to operating temperatures in the range of 100.degree. C. to 1000.degree. C., an instrumentality for exposing the surface of the thermionic source to contact with the specific chemical substances for the purpose of forming gas phase ionization of the substances by a process of electrical charge emission from the surface, a collector electrode disposed adjacent to the thermionic source, an instrumentality for biasing the thermionic source at an electrical potential which causes the gas phase ions to move toward the collector, and an instrumentality for measuring the ion current arriving at the collector.

Abstract: Method and apparatus for analyzing specific chemical substances in a gaseous environment comprises a thermionic source formed of multiple layers of ceramic material composition, an electrical current instrumentality for heating the thermionic source to operating temperatures in the range of 100.degree. C. to 1000.degree. C., an instrumentality for exposing the surface of the thermionic source to contact with the specific chemical substances for the purpose of forming gas phase ionization of the substances by a process of electrical charge emission from the surface, a collector electrode disposed adjacent to the thermionic source, an instrumentality for biasing the thermionic source at an electrical potential which causes the gas phase ions to move toward the collector, and an instrumentality for measuring the ion current arriving at the collector.

Abstract: A cation emission type halogenated hydrocarbon gas detecting element comprising a cation source, a heating means and an ion collector electrode, which is characterized in that said cation source consist essentially of .beta.-Al.sub.2 O.sub.3, wherein substantially all cation species occupy a position in the crystal lattice structure of the source. By employing .beta.-Al.sub.2 O.sub.3, the detecting element can be more miniaturized and can work at lower temperature than a conventional cation emission type electrode comprising the cation source made of steatite.

Abstract: A combustion control process and apparatus provides a reference flame of known or constant composition which is in ionic communication with the main flame which is to be controlled. Both the reference and main flames are supported by electrically insulated burner nozzles and the flames are in mutual electrical communication through ionized gases. The potential difference is measured between the flames by way of the nozzles and is used in the air-fuel ratio adjustment of the main burner. Additionally, the main burner can function as a reference point in combination with a zirconia oxygen sensor to ascertain potential differences therebetween, which differences reflect the air-fuel mixture of the main flame.

Abstract: The presence of volatile metal carbonyls, e.g., nickel tetracarbonyl and iron pentacarbonyl, in fluid streams can be measured simultaneously by a gas chromatograph using squalane as the stationary liquid phase and a constant current, electron capture detector.

Abstract: The invention relates to apparatus for detecting a constituent gas in a gas flow. Means is provided for removing the constituent gas from a sample flow and directing this sample flow together with a reference flow containing the constituent gas through an equilibrator means wherein contaminants can be removed before the sample gas and the reference gas are compared in detector means, for example, an electron capture detector. The apparatus and method are also applicable to the detection of a liquid in a flow thereof.

Abstract: An ion mobility spectrometer for analysis of a gaseous sample wherein only nitrogen and phosphorus containing molecules of the sample are ionized. The spectrometer is of the type having an ion source for ionizing the sample gas and a shutter for gating ions into a drift region, wherein an electric field gradient exists. The ion source includes a bead which comprises a thermally stable material, such as a ceramic or glass, having an alkali metal compound on its surface. The bead is immersed in a gaseous mixture of hydrogen and air, and is heated to a temperature of 200.degree.-1000.degree. C. The bead selectively ionizes phosphorus and nitrogen containing molecules of the sample upon contact with the bead.