Abstract: A pump is provided for use in a solid state mass-spectrograph for analyzing a sample gas. The spectrograph is formed from a semiconductor substrate having a cavity with an inlet, gas ionizing section adjacent the inlet, a mass filter section adjacent the gas ionizing section and a detector section adjacent the mass filter section. The pump is connected to each of the sections of said cavity and evacuates the cavity and draws the sample gas into the cavity. The pump includes at least one diaphragm and electrically-actuated resistor. The resistor generates heat upon electrical actuation thereby causing the diaphragm to accomplish a suction stroke which evacuates the cavity and draws the sample gas into the cavity. Preferably, the diaphragm is formed from a bilayered metal material having different thermal expansion rates or from a shape memory alloy.

Abstract: In an apparatus for detecting alarm molecules, residual alarm molecules are automatically removed during a clear-down mode before a subsequent air sample is to be introduced. The apparatus comprises a detector unit, a sensor unit and a filtering sub-unit including a pump and a filter. During a challenge, the pump in the sub-unit is turned off, and the air sample passes from the inlet port of the first unit through the second unit to the output port of the first unit, thereby depositing alarm molecules in the first unit and the second unit. During the clear-down mode, the pump in the sub-unit is turned on, and outside air enters through the output port of the first unit, mixes with air flow from the output of the second unit, and passes through the sub-unit. Filtered air from the sub-unit exhausts the first unit through the inlet port of the first unit and passes into the second unit, thereby cleaning the first unit and the second unit from the alarm molecules deposited therein during the challenge mode.

Abstract: The gas pressure in an ion mobility spectrometer is controlled to maintain near-constant pressure in the drift region by adjusting gas flows in response to a pressure transducer output. The pressure in the system may be referenced to ambient pressure. The increase in pressure stability achieved permits the expected drift times of target analytes to be determined much more accurately than otherwise, and thereby allows more specific detection parameters to be used. This in turn results in a significantly improved false alarm rate for the device.

Abstract: A sample inlet apparatus comprises a sample source (1) and a first enclosure (3), connected to the sample source via a first inlet (2). An analyser enclosure (7) is connected to the first enclosure (3) via a second inlet (5,15) substantially in alignment with the first inlet (2). Also provided is a second enclosure (10), connected to the analyser enclosure (7) via a third inlet (9) substantially in alignment with the first (2) and second (5,15) inlet, and vacuum pumps (4,11) for maintaining the first (3) and second enclosures (10) at a pressure lower than the sample source (1) and higher than that of the analyser enclosure (7) in use, whereby a molecular beam of sample molecules is generated along the axis of the inlet.

Abstract: A vacuum housing and pumping system for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof.

Abstract: The portable Contamination Analysis Unit (CAU) measures trace quantifies of surface contamination in real time. The detector head of the portable contamination analysis unit has an opening with an O-ring seal, one or more vacuum valves and a small mass spectrometer. With the valve closed, the mass spectrometer is evacuated with one or more pumps. The O-ring seal is placed against a surface to be tested and the vacuum valve is opened. Data is collected from the mass spectrometer and a portable computer provides contamination analysis. The CAU can be used to decontaminate and decommission hazardous and radioactive surface by measuring residual hazardous surface contamination, such as tritium and trace organics It provides surface contamination data for research and development applications as well as real-time process control feedback for industrial cleaning operations and can be used to determine the readiness of a surface to accept bonding or coatings.

Abstract: The system for analyzing multiple samples includes a plurality of portable of sample supports each for accommodating a plurality of samples thereon, and an identification mechanism for identifying each sample location on each of the plurality of sample supports. The mass spectrometer is provided for analyzing each of the plurality of samples when positioned within a sample receiving chamber, and a laser source strikes each sample with a laser pulse to desorb and ionize sample molecules. The support transport mechanism provided for automatically inputting and outputting each of the sample supports from the sample receiving chamber of the mass spectrometer. A vacuum lock chamber receives the sample supports and maintains at least one of the sample supports within a controlled environment while samples on another of the plurality of sample supports are being struck with laser pulses. The computer is provided for recording test data from the mass spectrometer and for controlling the operation of the system.

Abstract: Ion Mobility Spectrometry (IMS) equipment comprises an enclosed compartment (10) contained within which there is an IMS cell (12) and a body of absorbent material (14). Samples for detection by the cell (12) are introduced into the compartment (10) by means of a pinhole (30), the samples being drawn in by a negative pressure pulse within the compartment produced by means of a loudspeaker (40). A sample, once it has been drawn in and detected by the cell (12), will diffuse within the compartment (10) and any water vapour or other interfering species thus introduced will be absorbed by the absorbent material (14) so maintaining a clean, dry atmosphere within the device.

Abstract: A pump is provided for use in a solid state mass-spectrograph for analyzing a sample gas. The spectrograph is formed from a semiconductor substrate having a cavity with an inlet, gas ionizing section adjacent the inlet, a mass filter section adjacent the gas ionizing section and a detector section adjacent the mass filter section. The pump is connected to each of the sections of said cavity and evacuates the cavity and draws the sample gas into the cavity. The pump includes at least one piezoelectrically-actuated diaphragm. Upon piezoelectrical actuation, the diaphragm accomplishes a suction stroke which evacuates the cavity and draws the sample gas into the cavity. Preferably, the diaphragm is formed from a pair of electrodes sandwiching a piezoelectric layer.

Abstract: A gas analyzing system that includes a vacuum chamber containing a mass spectrometer and a sampling device for introducing a gas sample into the chamber. A sorption pump is operatively connected to the chamber which is capable of maintaining the chamber at a high vacuum. The pump includes a diffusion barrier that provides smooth pumping characteristics and repeatable short term system behavior when sample pulses are introduced into the system.

Abstract: An isotopic-ratio mass spectrometer comprises an r.f.

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: Ions generated under an atmospheric pressure pass through vacuum chambers partitioned through first, second and third fine holes. The ions are led to an MS part where the ions are mass-analyzed. A first vacuum chamber adjacent to an atmospheric pressure part has not vacuum pump for independently pumping this chamber. The first vacuum chamber is evacuated by a common pump together with a second vacuum chamber via a bypass hole formed in the wall having the second aperture. A pressure of the first vacuum chamber can be set to several 100 Pa, while a pressure of the second vacuum chamber can be set to several 10 Pa. Sufficient desolvation has been attained by an ion acceleration voltage of approximately 100 V in the first vacuum chamber, while a speed spread can be restrained. The ions are accelerated by approximately 10 V in the second vacuum chamber, an the speed spread can be restrained as low as possible.

Abstract: An apparatus for determining the concentration of a gas in a vacuum chamber is described. Internal to the vacuum chamber are one or more cathodes. The chamber is fed via a gas inlet and is connected to a separate measurement chamber for accommodating a measuring device via a connecting line between the two chambers. The connecting line in conjunction with a pumping means produces a pressure gradient between the interior of the vacuum chamber and the interior of the measurement chamber. One end of the connecting line, located within the vacuum chamber terminates directly in the central region of a cathode surfaces facing the interior of the chamber, and the length, as well as the cross section of the connecting line being dimensioned so that the pressure gradient between the interior of the vacuum chamber and the interior of the measurement chamber, is precisely that required for measurement.

Abstract: An ion trap mass spectrometer includes an ion trap region separated from an electron multiplier region by a baffle, and separate turbomolecular pumps for pumping each region to a different pressure level. The ion trap region can therefore be pumped to a higher pressure level than ca be used for the electron multiplier region, and the result and increase in pressure of damping gas in the ion trap region increases the sensitivity of the device.

Abstract: A plasma sampling interface for an inductively coupled plasma-mass spectrometry (ICP-MS) apparatus includes a sampler, a skimmer, insulating spacers for insulating the sampler and the skimmer from each other and from the remainder of the ICP-MS apparatus, and a DC bias voltage source for applying a DC bias voltage to the skimmer with the sampler either being grounded or being allowed to float. The plasma sampling interface increases the ion transmission through the ICP-MS apparatus by a factor of at least four to six over the ion transmission through a conventional ICP-MS apparatus in which both the sampler and the skimmer are grounded.

Abstract: A gas in a process chamber, such as a sputtering chamber, having a typical inside pressure of 10.sup.-1 to 10.sup.-3 Torr, is analyzed by a mass spectrometer, which should be used at a pressure range of lower than around 10.sup.-4 Torr. The method comprises evacuating a process chamber by a vacuum pump and supplying a gas to the process chamber, whereby a pressure in the process chamber is determined by the vacuum pump and the supplied gas, and that pressure in the process chamber is higher than a pressure in the vacuum pump, and analyzing the gas at a portion of or around the vacuum pump, which portion has a pressure lower than the pressure in the process chamber, by using a mass spectrometer.

Abstract: A mass spectrometer with quadrupole filter comprises a spectrometer chamber containing the ion source, its associated electron optical system, and a quadrupole filter. The chamber is designed in the form of a hollow sleeve closed at one end by a removable leak-tight cover mounted on a longitudinally-sliding motor-driven carriage which also supports the ion source and its optical system. The carriage is capable of selective displacement in translational motion between a closed position in which the ion source is in the work position and the cover is in the closed position, and an open position in which the carriage projects outside the casing at least to a partial extent and allows access to the ion source and its associated optical system.

Abstract: An apparatus for providing an ion vapor to be analyzed. A vaporizer probe, with a capillary tube extending into a vapor port of an ion source, has a release end which ejects a spray of vapor into a spray region of the ion source. Molecules of interest within the vapor may be ions pre-formed in solution or may be ionized by chemical ionization or plasma discharge ionization. A minor portion of the vapor is extracted from the spray chamber for mass analysis. The major portion is coaxially redirected from the spray chamber for return to the same port which receives the capillary tube of the vapor probe. A return tube is vacuum sealed to the port and is in fluid communication with a roughing pump which draws the ion vapor from the spray region through the ion source and the port for coaxial vapor backflow with the capillary tube. The ion source has a split-block structure for ease of both manufacture and routine maintenance.

Abstract: An open-split interface includes a connector body having four leg members projecting therefrom within a single plane, the first and third legs being coaxial and the second and fourth legs being coaxial. A tubular aperture extends through the first and third legs and a second tubular aperture extends through the second and fourth legs, connecting at a juncture within the center of the connector body. A fifth leg projects from the connector body and has a third tubular aperture extending therethrough to the juncture of the first and second tubular apertures. A capillary column extends from a gas chromatograph into the third leg with its end adjacent the juncture. A flow restrictor tube extends from a mass spectrometer through the first tubular aperture in the first and third legs and into the capillary columnm end, so as to project beyond the end of the third leg within the capillary column. An annular gap between the tube and column allows excess effluent to pass to the juncture.

Abstract: The invention resides in a method for analyzing gases according to the counterflow principle, comprising a mass spectrometer tube (3) located at the suction side of a molecular pump (2). The primary vacuum pressure is adjusted in such a way that basically ambiguous spectrometer indications can only result from a gas with low molecular weight reaching the mass spectrometer in counterflow to the molecular pump and not from a gas with higher molecular weight, which in itself would provoke a similar spectrometer indication.

Abstract: A multimode ionization source includes a resistive filament aligned with an exit cone orifice. The filament generates electrons that bombard molecules near the orifice. In electron impact mode, a pressure regulator selects a low pressure within an ionization chamber and gaseous analyte is injected through a gas inlet and ionized by electron bombardment. In chemical ionization mode, an intermediate pressure of reagent gas established; electrons ionize the reagent gas. Gaseous analyte is introduced is ionized by the reagent gas through chemical interaction. In thermospray mode, a high pressure is established and heated liquid analyte is introduced into the chamber as a spray which is ionized by ion evaporation; in a thermospray/chemical ionization submode, filament activation supplements ion evaporation. Ions produced in all modes can be directed to a mass analyzer for analysis.

Abstract: Disclosed is a plasma ion source mass spectrometer comprising an ion source in which a sample to be detected is ionized in plasma and a mass spectrometer which mass-separates and detects the ionized sample supplied from the ion source, characterized in that there is provided a gas introduction means for introducing into a region before the mass spectrometer a gas containing particles which can bring about a charge transfer reaction with background ions contained in particles supplied from the ion source or a gas containing particles which can bring about an energy transfer reaction with excited molecule contained in the particles supplied from the ion source. By providing such gas introduction means, background ions or excited molecule can be efficiently quenched and enhancement of sensitivity of plasma ion source mass spectrometer can be attained.

Abstract: An analysis system in which air in a specimen exchange chamber is evacuated by an oil-sealed rotary vacuum pump and which employs electron incorporates a purge gas supply means at the inlet side of the oil-sealed rotary vacuum pump. The purge gas supply means supplies a small quantity of purge gas when the air in the specimen exchange chamber is evacuated to the almost ultimate pressure of the pump.

Abstract: The invention comprises a mass spectrometer adapted for the determination of isotopic ratios which has several ion-collecting means disposed along its mass focal plane. Separate current amplifier means are provided for each ion collecting means and comprise an electrometer amplifying element, and an input resistor disposed in an inner box, itself disposed within a sealed evacuated housing. Means are provided for cooling the amplifier element to a temperature substantially below 20.degree. C. Means are provided for maintaining the temperature of at least the input resistor substantially constant. Cooling the amplifier element, typically to between 0.degree. and 5.degree. C., results in an unexpected reduction in low frequency noise which allows the time required to determine an isotope ratio to be reduced, thereby substantially increasing sample throughout.

Abstract: A moving belt interface for real-time, high-performance liquid chromatograph (HPLC)/mass spectrometer (MS) analysis which strips away the HPLC solvent as it emerges from the end of the HPLC column and leaves a residue suitable for mass-spectral analysis. The interface includes a portable, stand-alone apparatus having a plural stage vacuum station, a continuous ribbon or belt, a drive train magnetically coupled to an external drive motor, a calibrated HPLC delivery system, a heated probe tip and means located adjacent the probe tip for direct ionization of the residue on the belt. The interface is also capable of being readily adapted to fit any mass spectrometer.

Abstract: A counterflow helium mass spectrometer leak detector in which a helium sample passes in a reverse direction through a diffusion pump to a mass spectrometer for measurement. The diffusion pump includes a conventional foreline and a second foreline provided with an ejector stage. A test sample is coupled from a test port through a bypass valve to the conventional foreline in a high sensitivity mode and is coupled to the second foreline in a low sensitivity mode. In the low sensitivity mode, the bypass valve is closed. An apertured control plate in the diffusion pump controls the relative reverse rates of duffusion from each foreline to the diffusion pump inlet by controlling the rates of vapor flow an annular pumping stages and to the ejector stage. The ejector stage includes a nozzle for directing a stream of vapor into the second foreline so as to inhibit flow of helium into the diffusion pump and establish a lower reverse diffusion rate at the second foreline.

Abstract: A method and apparatus for reducing the amount of an external fluid which travels through an opening into an enclosed area. Also, a method and apparatus for protecting a surface area or plane from contact with or intermixing with an external fluid. The method, in general, comprises causing a fluid to flow, in laminar form, in proximity to or directly across an opening, a surface or an area plane to be protected. The depth or thickness of the flowing laminar fluid layer at its source of origin is at least about 0.05 times the distance across the opening, surface area or plane to be protected, in the principal direction of flow of the fluid at its source of origin. The width of fluid flow at its source of origin and transverse the direction of fluid flow is at least about as great as the maximum width of the opening, surface or area plane to be protected, transverse the direction of fluid flow. The Force Number of the fluid must range between about 0.

Abstract: An interface generally useful for liquid chromotography systems and methods is provided for the separation of an analyte of interest from a liquid solvent. The interface provides for separation and collection of solvent and the analyte of interest in a gaseous molecular state. In this manner, the ability to detect, identify, and quantify the analyte of interest using a variety of specific and non-specific detectors is made possible.

Abstract: An apparatus for quantitative secondary ion mass spectrometry comprising a sealed chamber for storing a sample containing a light impurity element which is to be analyzed, secondary ion generating means for bombarding a primary ion beam onto the sample so as to allow the sample to emit a secondary ion of the light element, and quantitative analyzing means for detecting the secondary ion so as to quantitatively analyze the light element contained in the sample. First evacuating means evacuates said sealed chamber to an ultrahigh vacuum during quantitative analysis. First cryopanel means is arranged to surround the sample, and first cooling means keeps said first cryopanel means at a cryogenic temperature during quantitative analysis so that said first cryopanel means adsorbs a gas present in said sealed chamber.

Abstract: A single-stage quadrupole mass analyzer is provided with a highly sensitive electron multiplier, a turbomolecular pump, and a mass correction lens placed between the quadrupole sensor unit and the turbomolecular pump. These components are arranged and selected to provide a substantial increase in sensitivity permitting the direct analysis of organic compounds in the gas phase in the ppb and high ppt concentration range. The placement of the mass correction lens and the area of its aperture has a pronounced effect on the detection limit, the optimum aperture area is a function of the mass of the molecules to be detected, and preferably an iris diaphragm is used to permit manual of automatic adjustment of the aperture area to a predetermined optimum for each of the different substances to be detected. Preferably the electron multiplier voltage is also variably selected and reset during the scanning of each fragment ion to optimize the signal-to-noise ratio of the electron mutiplier.

Abstract: An apparatus for mass-analyzing ions contained in plasma. A first vacuum chamber is maintained in a relatively low vacuum state and has a first aperture disposed adjacent to a plasma source for admitting therethrough the plasma into the first vacuum chamber. A second vacuum chamber is maintained in a relatively medium vacuum state and has a second aperture communicating between the first and second vacuum chambers. An ion extracting electrode is disposed in the second vacuum chamber for extracting ions contained in the plasma through the second aperture to form an ion stream composed of the extracted ions. A third vacuum chamber is maintained in a relatively high vacuum state and has a third aperture communicating between the second and third vacuum chambers.

Abstract: A multi-stage valve having a valve housing containing an inlet port and an outlet port that communicate through means of an elongated chamber formed in the housing. An outer sealing unit is mounted in the chamber and is adapted to close in sealing contact against one of the ports. A control orifice is passed through the first sealing unit to restrict the flow through the port when the unit is sealed thereagainst. A second inner sealing unit is mounted in the chamber behind the outer unit and is arranged to close thereagainst to seal the orifice. The two units are coupled by a lost motion mechanism which permits the sealing units to close in sequence between a fully closed position, an intermediate position wherein the flow through the valve is restricted by the orifice and a fully opened position wherein the flow through the valve is unrestricted.

Abstract: A device for sensitive analysis of unknown organic samples is disclosed. The device is particularly useful as an interface between a gas chromatograph and a mass spectrometer which has a high pumping capacity. The device comprises an interface internal to the mass spectrometer which may either be attached directly to an inlet probe inserted into a mass spectrometer or directly to the source body of a mass spectrometer. In both cases, the sample goes directly into the source cavity and an auxiliary vacuum system is not required for sample enrichment. For mass spectrometers with marginal pumping capacity, or when very low source pressures are required, the vacuum system may be augmented by designs which either partially or completely isolate the source and interface exhaust pumping systems from each other.

Abstract: A feed system for picking a sample tube off a magazine and introducing the sample tube into the inlet system of a mass spectrometer. The feed system comprises a pick-up tube (52) designed at its forward end to fit over a sample tube (16) resting on the magazine (22) and grip the sample tube (16). A carriage (40) supports the pick-up tube in a horizontal attitude and is driven towards and away from the inlet system (10) of the mass spectrometer by means of a motor driven pinion (46) engaging a rack (44) on the upper surface of the carriage (40). A cam track (50) raises the pick-up tube (52) after a sample tube (16) has been gripped to the level of the aperture (12) of the inlet system (10).

Abstract: Magazine for introducing samples into the inlet system of a mass spectrometer. The magazine (22) comprises a flat plate having upper and lower surfaces which are generally horizontal during use. A zig-zag groove (32) is formed in the lower surface engageable by a reciprocable pin (34) to advance the magazine (22) by increments relative to an aperture (12) of the inlet system (10) of the mass spectrometer and recesses (24) are formed in the upper surface of the magazine for receiving tubes (16) containing samples for analysis. The recesses (24) extend transversely to the direction of movement of the magazine (22) and are arranged at a regular pitch equal to that of the groove (32) in the lower surface.

Abstract: The invention relates to an inlet system for use in a mass spectrometer which comprises a capillary tube 10 for introducing ions for analysis into the ion source of the spectrometer. An expansion chamber 14 arranged at the end of the capillary tube 10 has an aperture sealingly connectable to a tube 16 containing a sample to be analyzed. A piston 18 disposed within the expansion chamber 14 acts as a closure member for opening and closing the said aperture. A pumping line 25 is provided for evacuating the expansion chamber 14 to low vacuum after communication is established between the expansion chamber and the sample tube 16 and the piston 18 seals off the pumping line from the expansion chamber 14 after a low vacuum has been achieved in the latter chamber to permit evacuation of the expansion chamber to 14 a higher vacuum by way of the capillary tube 10 to a diffusion pump evacuating the space within the mass spectrometer.

Abstract: A cock for low-pressure bleeding of a gas from a gaseous mixture, said cock having a body (1) with an inlet (12) and a pumping outlet (13) for the mixture and a bleed outlet orifice (15), and a valve (2) which co-operates with the valve body and is situated between said orifice and the inlet, wherein the valve includes a semi-permeable membrane with a first surface (6A) which communicates with said inlet and a second surface (6) which communicates with said bleed orifice, the valve assuming a first position in which it allows the mixture to pass directly from the inlet towards the bleed orifice when the pressure of the mixture is lower than a given pressure, and a second position in which it closes the bleed orifice when the pressure of the mixture is higher than said given pressure, the gas to be bled off then passing through said permeable membrane.

Abstract: Automatically controllable loading apparatus for a mass spectrometer or like equipment comprises a rotatable disc for holding a plurality of sample carriers for successive movement into a transfer position. A push rod transfers successive sample carriers from the transfer position to a loading position. Guide means guide the push rod during its transfer movement. The guide means include a shut-off valve adjacent the loading position. Sealing means define in a fixed position between the valve and the transfer position at least one vacuum chamber adapted to be exhausted for the purpose of equalizing the pressure at opposite sides of said valve.

Abstract: There is disclosed a secondary ion mass spectrometer to be used with other spectro analysis mechanisms where the sample holder is fixed in a main vacuum chamber having a secondary vacuum chamber communicating with the main chamber with a vacuum seal between the two in which a substantially 90.degree. spherical segment energy analyzer is disposed in the second vacuum chamber along with a quadrupole mass spectrometer and electron multiplier. A primary ion gun is disposed within the main vacuum chamber directing an ion beam at the samples to be tested and the secondary ions emitted are collected through a longitudinal extraction lens mechanism disposed between the 90.degree.

Abstract: An interface between a liquid chromatograph and a mass spectrometer is provided for conducting a liquid stream from the chromatograph to the spectrometer. The stream passes from the chromatograph continuously along a tapered concentrator wire toward the narrow end of the wire. The stream is heated in order to evaporate solvent therefrom and to increase the concentration of the solute therein. When the stream reaches the narrow end of the wire, the vacuum created by the mass spectrometer draws the stream through an elongated capillary tube which has a pointed carrier wire positioned therein. A gap is provided in the tube where the tube and the carrier wire intersect the concentrator wire. The capillary tube is either formed with a reduced diameter at one end adjacent the spectrometer or the carrier wire has a ball of solder at that end in order to partially restrict the flow through the tube.

Abstract: The accuracy of measurement of a constituent of a small volume of gas (such as the moisture within an integrated circuit package) is improved by improving the accuracy of the calibration of the spectrometer being used to make the measurement. The calibration is achieved by measuring with the spectrometer the known amount of the constituent in a reference sample of about the same size as the small volume of gas in the test sample.

Abstract: An apparatus for introducing a gaseous sample into a mass spectrometer is disclosed which includes a hollow antechamber or cavity disposed between the sample stream and the high vacuum enclosure. Orifice openings are provided in the antechamber which allow the antechamber to communicate both with the high vacuum enclosure and the sample stream. An electrically operated pulsed valve is used to admit a series of small volumes of sample by pulses of controlled duration and frequency such that the sample flow from the antechamber into the high vacuum enclosure can be made to resemble one of essentially constant flow.

Abstract: A gas leakage detection apparatus is described comprising a mass spectrometer with which there is associated a first pumping device for creating a relative vacuum in the apparatus, a selective pumping device having a first pumping speed for air and a second pumping speed for the gas which is to be analyzed, said second pumping speed being lower than the said first pumping speed, and a throttling device connected between the selective pumping device and the first pumping device, this throttling device having an opening chosen so as to let through a flow which is very small compared with the flow produced by the selective pumping device for the air.

Abstract: The mean molecular velocity or molecular weight of an unknown gas is determined by admitting the gas at a constant flow rate into an evacuated chamber of known volume, the gas being permitted to escape through a first flow cross section in a Knudsen flow. After a first steady state is reached, the gas density is measured and then a second flow cross section is opened between the evacuated chamber and a low-pressure zone. The measurement is repeated and the difference between the two values obtained and the gradient of the measurement is used to calculate the mean molecular velocity and the molecular weight.

Abstract: Herein disclosed is an atmospheric pressure ionization mass spectrometer having a mediate pressure region, wherein a jet separator is incorporated for playing a double role of differential pumping and concentration of the electric field, and wherein a gas jetting aperture of the jet separator and another aperture for introducing a gas to an analyzing region of the spectrometer are made of a conductive body and are adapted to be kept at different electric potentials.

Abstract: The sample crucibles inserted in a slide rod are introduced, through a high vaccum lock, into the ion source of a mass spectrometer. The slide rod, together with its drive, is mounted on a lock carriage which runs parallel to the direction of travel of the slide rod. The lock carriage has a separate drive and carries, on the end face which points towards the mass spectrometer, a stuffing box for the vacuum-tight passage of the slide rod. On the rear wall of the high vacuum lock is mounted an O-ring seal, which, with the lock carriage moved in, seals the remaining space between the rear wall of the lock and the end face of the lock carriage, in the region of the slide rod. The sample crucibles can be taken out selectively from the sample magazine, which can slide at right angles to the slide rod, by means of the holder mounted at the end of the slide rod.

Abstract: Device for introducing a specimen into and withdrawing the same from the interior of a chamber sealed from the surrounding environment. The device includes a test bar slidably and sealingly projecting through an opening in the chamber. The test bar has a first length portion which includes a specimen-supporting arrangement and which has a part that is in a sealing relationship with the opening in a first end position of the test bar in which the specimen-supporting arrangement is situated inside the chamber. The test bar further has a second length portion which has a part that is in a sealing relationship with the opening in a second end position of the test bar in which the specimen-supporting arrangement is situated externally of the chamber. A releasable coupling device detachably connects the two length portions of the test bar to one another.

Abstract: A method and inlet control system for controlling a gas flow sample to an evacuated chamber such as found in a mass spectrometer, is disclosed. The system utilizes a short inlet passage having an effective opening determined by a tapered diamond or steel tip needle adjacent to the inlet passage. The needle is positionally adjusted with respect to the inlet passage by being mounted on a piezoelectric crystal which is flexed by coupling thereto an electric potential derived by sensing the ions at the ionization chamber of a mass spectrometer, for example, and developing therefrom an electric signal indicative of the total pressure within the ionization chamber. The signal coupled to the piezoelectric crystal is preferably a pulse-width modulated signal with the needle maintaining the inlet passage closed except during the time that the piezoelectric crystal is flexed due to a received pulse.

Abstract: A mass spectrometer (MS) with unique magnetic pole pieces which provide a homogenous magnetic field across the gap of the MS magnetic sector as well as the magnetic field across an ion-type vacuum pump is disclosed. The pole pieces form the top and bottom sides of a housing. The housing is positioned so that portions of the pole pieces form part of the magnetic sector with the space between them defining the gap region of the magnetic sector, through which an ion beam passes. The pole pieces extend beyond the magnetic sector with the space between them being large enough to accommodate the electrical parts of an ion-type vacuum pump. The pole pieces which provide the magnetic field for the pump, together with the housing form the vacuum pump enclosure or housing.