Abstract: Provided is a plasma diagnostic apparatus includes a probe unit, which is inserted into a plasma or disposed at boundary of a plasma, the apparatus includes: a signal supplying unit having a signal supplying source; a current detecting/voltage converting unit for applying a periodic voltage signal applied from the signal supplying unit to the probe unit, detecting the magnitude of the current flowing through the probe unit, and converting the detected current into a voltage; and a by-frequency measurement unit for computing the magnitude and phase of individual frequency components of the current flowing through the probe unit by receiving the voltage output from the current detecting/voltage converting unit as an input.

Abstract: An ion balance monitor for simultaneous monitoring of the positive and negative ion production rates, and therefore ion concentration, by measurement of currents resulting from the presence of airborne ions as created for example by an air (gas) ionizer. Additionally it examines the ion balance by comparing the aforementioned currents. Information acquired in this way can be used in real time monitoring of the ionizer. Ion balance and production rate of ions of both polarities can be recorded by the ion monitor, regardless of the type of the ionizer. The ion monitor can provide a feedback signal needed to keep an ionizer system in balance.

Abstract: A mass spectrometer 10 comprises an ion source 12 which generates nebulized ions which enter an ion cooler 20 via an ion source block 16. Ions within a window of m/z of interest are extracted via a quadrupole mass filter 24 and passed to a linear trap 30. Ions are trapped in a potential well in the linear trap 30 and are bunched at the bottom of the potential well adjacent an exit segment 50. Ions are gated out of the linear trap 30 into an electrostatic ion trap 130 and are detected by a secondary electron multiplier 10. By bunching the ions in the linear trap 30 prior to ejection, and by focussing the ions in time of flight (TOF) upon the entrance of the electrostatic trap 130, the ions arrive at the electrostatic trap 130 as a convolution of short, energetic packets of similar m/z. Such packets are particularly suited to an electrostatic trap because the FWHM of each packet's TOF distribution is less than the period of oscillation of those ions in the electrostatic trap.

Abstract: A technique for reducing a parasitic DC bias voltage on a sensor monitors the parasitic DC bias voltage on a first element of the sensor. A controlled bias voltage that is applied between the first element of the sensor and a second element of the sensor is then modified to substantially maintain the parasitic DC bias voltage at a desired potential.

Abstract: Gas detection and identification apparatus that receives a flow of a mixture of a carrier gas and an analyte gas and detects and identifies the components of the flowing gas mixture by Penning Ionization Electron Spectroscopy (PIES).

Abstract: The invention provides an interface assembly for delivering an ionized analyte from an ionization apparatus into an ion mobility spectrometer. This allows analysis of biological and non-biological samples, even non-volatile solids, via differential mobility spectrometry, without fragmentation of molecules. The invention also provides portable sample analysis systems that operate at ambient pressure. Systems of the invention may be used for high molecular weight species detection, for example, drinking water contaminants, pathogenic biological agents, bio-organic substances, non-biological material, peptides, proteins, oligonucleotides, polymers, bacteria, and hydrocarbons.

Abstract: A biological aerosol detector is provided. The biological aerosol detector uses a semiconductor optical source with an ultraviolet emission band to excite biological molecules in an aerosol sample. Filtering optics are configured to attenuate radiation from a secondary emission band of the optical source to prevent false signals due to scattering of secondary emission band radiation from non-biological molecules. An intake/exhaust manifold that includes an intake pipe that fits within a concentric exhaust pipe is also provided. The intake/exhaust manifold planarizes the flow of the sampled aerosol to maximize the time of irradiation. An electrostatic sampling grid is also provided to selectively draw biological molecules having a net charge into the optical chamber.

Abstract: An electron-emitting cathode consists of an electrically conducting emitter layer attached to a side wall which consists of stainless steel and a gate which is fixed at a mall distance inside a concave emitter surface of the emitter layer. The cathode surrounds a reaction area containing a cylindrical grid-like anode and a central ion collector which consists of a straight axial filament. An ion collector current reflecting the density of the gas in the reaction region is measured by a current meter while a gate voltage is kept between the ground voltage of the emitter layer and a higher anode voltage and is regulated in such a way that an anode current is kept constant. The emitter layer may consists of carbon nanotubes, diamond-like carbon, a metal or a mixture of metals or a semiconductor material, e.g., silicon which may be coated, e.g., with carbide or molybdenum. The emitter surface can, however, also be a portion of the inside surface of the side wall roughened by, e.g., chemical etching.

Abstract: Disclosed herein are an apparatus for and method of measuring the composition and the pressure of the discharged gas from an ion gauge by using a residual gas analyzer. In this regard, there are provided a vacuum container 200 divided into a pressure container 210 and a discharge container 220 by means of a partition 235 having an orifice 230 formed thereon; an ion gauge 100 mounted at the pressure container 210 side of the vacuum container 200 for discharging the gas at the time of vacuum formation; a residual gas analyzer 240 mounted at the pressure container 210 side of the vacuum container 200 for measuring the composition and the pressure of the residual gas; pump means disposed at one side of the discharge container 220 of the vacuum container 200 for discharging the inside gas; and heating means disposed at the vacuum container 200 for heating the vacuum container 200 to a predetermined temperature.

Abstract: Methods for determining characteristics of a plasma are provided. In one embodiment, a method for determining characteristics of a plasma includes obtaining metrics of current and voltage information for first and second waveforms coupled to a plasma at different frequencies, determining at least one characteristic of the plasma using the metrics obtained from each different frequency waveform. In another embodiment, the method includes providing a plasma impedance model of a plasma as a function of frequency, and determining at least one characteristic of a plasma using model. In yet another embodiment, the method includes providing a plasma impedance model of a plasma as a function of frequency, measuring current and voltage for waveforms coupled to the plasma and having at least two different frequencies, and determining ion mass of a plasma from model and the measured current and voltage of the waveforms.

Abstract: Chemical analysis of impurities in buffer gas is provided at various pressures up to atmospheric. Identification of the impurities is carried out by analyzing energy of electrons releases via ionization of the impurity atoms or molecules in their collisions either with excited atoms of buffer gas or with monochromatic photons. To produce excited metastable atoms a pulsed plasma is ignited between plane anode and cathode, and electrons energy is measured in afterglow by determining second derivative of electric current in dependence of voltage applied between these electrodes. Another way, electrons energy can be analyzed by positioning a grid between anode and cathode and by using an external radiation source to ionize the impurities in equipotential space between the grid and the anode. Inter-electrode gap and gas pressure must be chosen so that distortions in the electrons energy distribution due to collisions with buffer gas should not exceed a prescribed value.

Abstract: An ionization gauge for isolating an electron source from gas molecules includes the electron source for generating electrons, a collector electrode for collecting ions formed by the impact between the electrons and gas molecules, and an electron window which isolates the electron source from the gas molecules. The ionization gauge can have an anode which defines an anode volume and decelerates and retains the electrons in a region of the anode. The ionization gauge can have a plurality of electron sources and/or collector electrodes. The collector electrode(s) are be located within the anode volume. The ionization gauge can be a Bayard-Alpert type that measures pressure.

Abstract: Method and apparatus for detecting or suppressing electrical arcing or other abnormal change in the electrical impedance of a load connected to a power source. Preferably the load is a plasma chamber used for manufacturing electronic components such as semiconductors and flat panel displays. Arcing is detected by monitoring one or more sensors. Each sensor either responds to a characteristic of the electrical power being supplied by an electrical power source to the plasma or is coupled to the plasma chamber so as to respond to an electromagnetic condition within the chamber. Arcing is suppressed by reducing the power output for a brief period. Then the power source increases its power output, preferably to its original value. If the arcing resumes, the power source repeats the steps of reducing and then restoring the power output.

Abstract: A plasma potential measuring method is conducted by: providing a measurement space surrounded by a radio-frequency electric field in plasma atmosphere; varying a floating potential at an electrode located in the measurement space by the ponderomotive effect acted only on electrons; and determining as a plasma potential a value of the floating potential at the time when an ion current flown into the electrode begins to lower.

Abstract: The invention proposes a method for operating an evaluation circuit for an electrochemical cell wherein the evaluation circuit is switched on for a first time period and is switched off for a second time period. The ratio between the first and the second time periods is selected to be less than 1. The measurement value of the electrochemical cell undergoes a current amplification in the evaluation circuit.

Abstract: An apparatus includes semiconductor processing equipment. A particle detecting integrated circuit is positioned in a vacuum environment, the particle detecting integrated circuit containing a device having a pair of conductive lines exposed to the vacuum environment. The pair of conductive lines is spaced at a critical pitch corresponding to diameters of particles of interest. A computer system is linked to the particle detecting integrated circuit to detect a change in an electrical property of the conductive lines when a particle becomes lodged between or on the lines.

Abstract: A sensor having a nanotube grown on and supported by thermal bimorph structures. The nanotube rests on a heat sink during sensing gas or a liquid and is moved from the heat sink when the nanotube is heated to desorb gas or liquid from it. The heatsink may function as a gate along with the bimorph structures as the other terminals of a transistor. Current-voltage and current-gate voltage characteristics may be obtained of the nanotube as a device like a transistor. These characteristics may provide information on a gas or liquid absorbed by the nanotube.

Abstract: Systems and methods of generating ions at atmospheric pressure are presented. These systems and methods include spatially dependent analysis of a sample using an effusive ionization source. Systems and methods of isolating samples at atmospheric pressure are presented. These systems and methods include using a barrier to prevent metastables or electrons from an effusive ion source from reaching a sample unless the sample is in an analysis position. Systems and methods of using metastables in collisionally induced dissociation are presented.

Abstract: A multi-function detecting pen is described. The multi-function detecting pen includes a head module, a detecting chips module, a power module, a lighting module, and a control module. The head module is disposed at a front portion of the pen and the detecting chips module is followed. The detecting chips module may include at least one pressure detecting chip for measuring a pressure, e.g. tire pressure, and/or a gas detecting chip for measuring a gas concentration, e.g. alcohol concentration. The detecting chips module may further include a temperature detecting chip for measuring a temperature, e.g. ambient temperature or tympanum temperature. The head module may further include a switchable or a replaceable adapter for coupling to the corresponding object and keeping the head module clean.

Abstract: A method for determining the voltage sensitivity of the distance between the mirrors of a Fabry-Perot interferometer in a measuring device, which is intended to measure a predefined gas (CO2), of which at least one absorption maximum or minimum is known. At least two calibration point are defined device specifically using a reference gas (N2) in controlled conditions. A ‘virtual’ signal-control-voltage sensitivity curve, is formed with the aid of the calibration points formed using the reference gas (N2), ratios of the measurement points of the predefined gas (CO2) and of the corresponding values of the reference-gas curve are formed, and at least one voltage value corresponding to the minimum or maximum is defined from the ratios, in which case, on the basis of the wavelengths of the absorption minima or maxima of the gases (CO2, N2) being measured, the voltage sensitivity of the distance between the mirrors can be defined unequivocally.

Abstract: A photoionization detector includes a housing, electrical contacts within the housing and an easily removable and replaceable photoionization chamber within the housing. The photoionization chamber includes a cathodic electrode and an anodic electrode which may be coated with a thin layer of material. The photoionization chamber and the associated cathodic electrode and anodic electrode are removable from within the housing as a unit. The photoionization chamber makes electrical connection with the contacts when seated within the housing regardless of the orientation of the photoionization chamber about an axis.

Abstract: A particle counter counts particles in aerosol having a particle size of from 2 nm to 50 nm in an operating pressure range from an atmospheric pressure through a reduced pressure to a low vacuum and calculate a particle size distribution. The particle counter charges particles in the aerosol and applies an electrostatic field thereto, and mixes the aerosol with a non-charged sheath gas flow shaped like a laminar flow whereby the respective particles separate into traces depending on their particle size where they can be counted. Further, by using an electron multiplier for exciting cluster ions to detect the charged particles and operating it as a high-pass filter, even if the number density of the particles is small, it is possible to effectively count the particles.

Abstract: A vacuum ionization gauge (30) includes a cathode (31), an anode ring (33), a shield electrode (32), an ion educed electrode (34), a reflector (35) and a collector (36). The cathode is positioned corresponding to a first opening of the shield electrode, and the ion educed electrode is positioned corresponding to an opposite second opening of the shield electrode. An ion educed hole (341) is defined in a middle of the ion educed electrode. The reflector has a curving surface generally surrounding the second opening of the shield electrode. The collector is positioned at a center of the curving surface of the reflector and points toward the ion educed hole. The anode ring is positioned in the middle of the shield electrode. The vacuum ionization gauge is small volume and has low power consumption and improved sensitivity.

Abstract: A polarographic densitometer has a voltage applying circuit, a sensor unit, an impedance reduction circuit, and a current/density conversion unit. The voltage applying circuit applies specified voltage, and the sensor unit includes a group of electrodes to produce a current output in response to any reaction caused in a specimen when the specified voltage is applied by the voltage applying circuit. Furthermore, the impedance reduction circuit reduces impedance of the specimen between the electrodes of the group, and the current/density conversion unit converts the current output of the sensor unit when the impedance is reduced by the impedance reduction circuit into the density of specific material in the specimen.

Abstract: A gas detector especially adapted for use with gas chromatographs contains two capillary tubing electrodes through which a gas flows. The inner ends of the electrodes are coaxial and are separated by a gap. The outer end of one of the electrodes forms a gas inlet. The gas detector also contains a coaxial dielectric tube spaced apart from and surrounding the electrodes axially, a means for applying a sufficient voltage across the gap between the electrodes to create a discharge within the gas, and a means for measuring a change in properties of the gas as it passes through the gap between the electrodes.

Abstract: A cold cathode ion gauge is provided that is suitable for use in a high vacuum and in the presence of contaminating gases. By decreasing the discharge current and, more precisely, decreasing the charge current density received by the gauge electrodes, and using certain type of materials for the gauge electrodes, the mechanism by which insulating films are deposited on surface of the electrodes is attenuated and the life of the gauge is significantly prolonged. The gauge discharge current can be decreased by providing a large resistor in series with the anode, while the charge current density can be decreased by using an electrode with larger surface area, which can be achieved by fabricating grooves or fans on electrodes and by using low electron backscattering and low secondary emission materials, like carbon. Another concept of constant current mode is also proposed in this invention for extending the lifetime of CCIGs that are used for vacuum containing unfriendly gases.

Abstract: Carbon nanotubes are formed on projections on a substrate. A metal, such as nickel is deposited on the substrate with optional platforms, and heated to form the projections. Carbon nanotubes are formed from the projections by heating in an ethylene, methane or CO atmosphere. A heat sensor is also formed proximate the carbon nanotubes. When exposed to IR radiation, the heat sensor detects changes in temperature representative of the IR radiation. In a gas sensor, a thermally isolated area, such as a pixel is formed on a substrate with an integrated heater. A pair of conductors each have a portion adjacent a portion of the other conductor with projections formed on the adjacent portions of the conductors. Multiple carbon nanotubes are formed between the conductors from one projection to another. IV characteristics of the nanotubes are measured between the conductors in the presence of a gas to be detected.

Abstract: An ionisation vacuum gauge for measuring the residual pressure of a gaseous material remaining in a container (10), more particularly after operation of a vacuum pump comprises an electron-emitting cathode (31) made by exploiting the nanotube technology, a grid (13; 33; 133; 133?) for accelerating the electrons emitted by the cathode, and a plate (15; 35) collecting the ions and/or the ionised positive molecules of the gas. Measuring the plate current by a galvanometer allows for determining the value of the residual pressure inside the container.

Abstract: A method, apparatus and program product for differential particle detection in electronic devices is provided. A first particulate sensor is positioned in proximity to an air intake of the electronic device. A second particulate sensor is positioned in proximity to the air exhaust of the device. A comparator compares the particulate concentrations detected by the first and second particulate sensors. Differential particle detection between the air intake and air exhaust of an electronic device enables early detection of potential fire conditions existing within the electronic device.

Abstract: An ionization detector includes a third (fence) electrode (55) between the counter electrode (53) and the sensing electrode (54). The fence electrode (53) is maintained at or near the potential of the sensing electrode (54) and traps charge movement (electrolytic current) along the detector walls associated with condensation and/or contamination within the detector. In a photoionisation detector, the fence electrode is also adapted to trap photo-induced current originating from the cathode (53). Current drawn from the fence electrode (53) provides a measure of the degree of contamination or condensation within the detector and of lamp efficiency.

Abstract: An apparatus for detecting dust in a variety of environments which can include radioactive and other hostile environments both in a vacuum and in a pressurized system. The apparatus consists of a grid coupled to a selected bias voltage. The signal generated when dust impacts and shorts out the grid is electrically filtered, and then analyzed by a signal analyzer which is then sent to a counter. For fine grids a correlation can be developed to relate the number of counts observed to the amount of dust which impacts the grid.

Abstract: An ionization gauge for isolating an electron source from gas molecules includes the electron source for generating electrons, a collector electrode for collecting ions formed by the impact between the electrons and gas molecules, and an electron window which isolates the electron source from the gas molecules. The ionization gauge can have an anode which defines an anode volume and retains the electrons in a region of the anode. The ionization gauge can have a plurality of electron sources and/or collector electrodes. The collector electrode(s) can be located within the anode volume or outside the anode volume. The ionization gauge can have a mass filter for separating the ions based on mass-to-charge ratio. The ionization gauge can be a Bayard-Alpert type that measures pressure or a residual gas analyzer that determines a gas type.

Abstract: The present invention relates to an ionisation vacuum gauge for measuring the residual pressure of a gaseous material remaining in a container (10), more particularly after operation of a vacuum pump. The gauge comprises an electron-emitting cathode (17), a grid (13) for accelerating the electrons emitted by the cathode and a plate (15) collecting the ions and/or the ionised positive molecules of the gas, wherein said plate is placed outside said grid. Measuring the plate current by a galvanometer allows determining the value of the residual pressure inside the container.

Abstract: An apparatus (14) for and method of measuring impedance in a capacitively coupled plasma reactor system (10). The apparatus includes a high-frequency RF source (150) in electrical communication with an upper electrode (50). A first high-pass filter (130) is arranged between the upper electrode and the high-frequency RF source, to block low-frequency, high-voltage signals from the electrode RF power source (66) from passing through to the impedance measuring circuit A current-voltage probe (140) is arranged between the high-frequency source and the high-pass filter, and is used to measure the current and voltage of the probe signal with and without the plasma present. An amplifier (250) is electrically connected to the current-voltage probe, and a data acquisition unit (260) is electrically connected to the amplifier.

Abstract: A Langmuir probe for measuring characteristics of a plasma driven by radio frequency (RF) power comprises an elongated conductor 10 having an exposed tip 1 for insertion into an RF plasma and an outer end 3 for connection to external measuring circuitry. In order to reduce distortion over a range of RF frequencies, the probe includes an RF voltage divider 11, 12, 13, 14 in series between the tip and outer end of the conductor.

Abstract: The present invention relates to a radial disk type ion mobility spectrometer, comprising: an ionizing chamber which is made of a cylindrical tube, and includes an inlet for supplying sample gas therethrough, an ionizing means for ionizing the supplied sample gas to generate ions having a predetermined polarity, and a slit formed by cutting away a part of a cylindrical wall corresponding to a predetermined width for discharging the ions therethrough; a shutter grid installed adjacent to the slit of the ionizing chamber for controlling passage of the ions through the slit; a drift chamber which is a hollow tube having a predetermined thickness and including an outer cylindrical wall having a predetermined diameter and an inner cylindrical wall having an inner diameter equal to an outer diameter to the ionizing chamber so that an annular space is formed between the inner and outer cylindrical walls, of which a part of the inner cylindrical wall corresponding to a width larger than that of the slit is cut away s

Abstract: A gas analyzing apparatus including a reactor for decomposing a target substance contained in a gas to produce a product gas containing a decomposition product, a contacting chamber connected to the reactor and having a quartz oscillator disposed therewithin. The quartz oscillator has opposing surfaces each provided with an electrode, at least one of the electrodes being reactable with the decomposition product so that the decomposition product when contacted with the reactable electrode is reacted with the reactable electrode to cause a frequency deviation which is detected by a frequency measuring device.

Abstract: A photo-ionization detector having an adjustable drive power for a UV lamp implements a calibration operation that determines measurement signals for a series of drive power levels and based on the resulting measurement signals selects one or more drive power levels for normal operation of the PID. The calibration operation permits use of UV lamps having a wider range of performance levels and thereby improves manufacturing yields and extends the useful life of the PID. During normal operation, the PID further fine-tunes the drive power level to compensate for expected or measured degradation in lamp performance. Accordingly, between calibrations, the PID maintains a more uniform UV intensity for more accurate measurements. To expand the measurement range of the PID, the calibration process can select two or more power levels for use when measuring different gas concentrations.

Abstract: Apparatus and methods are disclosed for analyzing particles, such as coarse particulates, fine particulates (e.g., diesel particulate matter), and combustion aerosols, using light-scattering sensors and/or ionization-type sensors. In one disclosed embodiment, a particle monitor includes an ionization module and a controller adapted to receive an output signal from the ionization module. The controller is operable to translate the output signal into the mass concentration of particulate matter within the ionization chamber. In another embodiment, a particle monitor includes a light-scattering sensor and an ionization sensor. The monitor is configured to measure separate mass concentrations of sub-micrometer particles and larger dust particles in an atmosphere having both types of particles.

Abstract: A sensor having a nanotube grown on and supported by thermal bimorph structures. The nanotube rests on a heat sink during sensing gas or a liquid and is moved from the heat sink when the nanotube is heated to desorb gas or liquid from it. The heatsink may function as a gate along with the bimorph structures as the other terminals of a transistor. Current-voltage and current-gate voltage characteristics may be obtained of the nanotube as a device like a transistor. These characteristics may provide information on a gas or liquid absorbed by the nanotube.

Abstract: An unheated planar sensor element for determining the concentration of a gas component in a gas mixture, in particular the oxygen concentration in the exhaust gas of an internal combustion engine, has a sensor foil made of a solid electrolyte with an outer electrode exposed to the measuring gas, and an inner electrode exposed to a reference gas, as well as a reference-gas channel, which is covered by the sensor foil on one side and accommodates the inner electrode. To produce a small-volume, cost-effective unheated sensor element for use in small combustion engines having low power output yet sufficiently satisfactory measuring accuracy, the reference-gas channel is sealed on the underside by an additional sensor foil made of a solid electrolyte, and covered by an inner electrode lying inside the reference-gas channel and an outer electrode exposed to the measuring gas.

Abstract: A method for controlling the non-uniformities of plasma-processed semiconductor wafers by supplying the plasma with two electrical signals: a primary electrical signal that is used to excite the plasma, and a supplemental electrical signal. The supplemental signal may be composed of a plurality of electrical signals, each with a frequency harmonic to that of the primary signal. The phase of the supplemental signal is controlled with respect to the phase of the primary signal. By adjusting the parameters of the supplemental signal with respect to the primary signal, the user can control the parameters of the resultant plasma and, therefore, control the non-uniformities induced in the semiconductor wafer.

Abstract: An ion sening circuit comprises a bridge sensing circuit and a differential amplifying circuit. The bridge sensing circuit detects the ion concentration of the solution in the operation mode of constant voltage and constant current. The differential amplifying circuit compares the output of the bridge sensing circuit and a floating reference voltage, thereby the delivered voltage to the bridge sensing circuit, such that the opeation mode of constant voltage and constant current is formed accordingly. The main features of the disclosed circuit are that it grounds the reference electrode and floats the source terminal. The drawbacks of not being manufactured with intergrated circuits by CMOS technology and low benefits when applied to sensor arrays are avoided by the disclosed circuit.

Abstract: A flavor monitoring system comprises a photo-ionization detector based sensor for measuring the amount of flavor in flavored cigarette filters The sensor has an intake port and an exit port open to the atmosphere. An enclosure with a removable cover is connected to the intake port of the sensor, and the enclosure is constructed and arranged to receive a flavored cigarette filter to be analyzed. The photo-ionization detector based sensor draws a gaseous sample from the flavored filter within the enclosure, ionizes the flavor sample and displays a reading representative of the amount of flavor in the filter. Subsequently the reading may be converted to a flavor amount in milligrams by multiplying the reading by a correlation factor.

Abstract: A probe for measuring plasma properties in a processing chamber, comprises a conductive rod having a front portion and a rear portion. The front portion of the conductive rod comprises a probe surface adapted to be coplanar with an interior wall of the chamber. The probe also includes an insulating sheath circumscribing the conductive rod.

Abstract: In semiconductor manufacturing equipment having a residual gas analyzing apparatus for analyzing the composition of residual gas in a process chamber of the equipment a heater of the residual gas analyzer is interlocked with a heater of the process chamber. The residual gas analyzer includes an ion detector, and the heater of the residual gas analyzer has a filament and a heating jacket surrounding a portion of the ion detector. A relay connects a power source of the heater for the process chamber to the heater of the residual gas analyzer. Power is supplied to and cut off from the heater of the residual gas analyzer in response to heater on/off signals used for controlling the operation for the heater for the process chamber.

Abstract: A system for measuring plasma electron densities (e.g., in the range of 1010 to 1012 cm?3) and for controlling a plasma generator. Measurement of the plasma electron density is used as part of a feedback control in plasma-assisted processes, such as depositions or etches. Both the plasma measurement method and system generate a control voltage that in turn controls the plasma generator. A programmable frequency source sequentially excites a number of the resonant modes of an open resonator placed within the plasma processing apparatus. The resonant frequencies of the resonant modes depend on the plasma electron density in the space between the reflectors of the open resonator. The apparatus automatically determines the increase in the resonant frequency of an arbitrarily chosen resonant mode of the open resonator due to the introduction of a plasma and compares that measured frequency to data previously entered.

Abstract: A device (10) for detecting the presence of an airborne, electrically conductive particle, the device including spaced conductors (24,26) and a circuit (12) for detecting when the electrically conductive particle forms a conducting path between the spaced conductors (24,26). The conductors (24,26) are provided in a grid (14) of alternate elongate conductors, and the circuit (12) applies a voltage to one set (24) of conductors sufficient to detect and destroy the particle when it creates a conductive path to the alternate set (26) of conductors.

Abstract: A symmetrically wired device and a process for measurement of the concentration of ions, especially hydrogen (H+) ions, in a measurement liquid. The device comprises a pH-sensitive measurement electrode, a reference electrode and a comparison electrode, all located in the measurement liquid and which places the measurement liquid at a definable ground reference. The device forms a difference signal referenced to the ground reference from the difference between a measurement signal (?pH) of the measurement electrode and the reference signal (?ref) of the reference electrode. The difference signal is dependent on the ion concentration in the measurement liquid. The device compensates for the noise potential (?chem) arising between the comparison electrode and the measurement electrode by setting a reference potential (?bez) on the comparison electrode, such that ?ref assumes a zero value.

Abstract: A sensing system for a target includes a member with an embedded charge, at least one input electrode, at least one output electrode, at least one common electrode, one or more probes, an input system, and an output monitoring system. The input and output electrodes are spaced from and on substantially opposing sides of the member from the common electrode. At least one of the member and the input and output electrodes is movable with respect to the other. The probes which engage with the target hazardous substance are connected to the at least one of the member and the input and output electrodes which is movable with respect to the other. The input system is coupled between the at least one input electrode and the at least one output electrode and provides an input signal. The output monitoring system is coupled between the at least one output electrode and the at least one common electrode and detects a change in an output signal when the target engages with the movable member or electrode.