Abstract: A detector may be provided with an array of sensing elements. The detector may include a semiconductor substrate including the array, and a circuit configured to count a number of charged particles incident on the detector. The circuit of the detector may be configured to process outputs from the plurality of sensing elements and increment a counter in response to a charged particle arrival event on a sensing element of the array. Various counting modes may be used. Counting may be based on energy ranges. Numbers of charged particles may be counted at a certain energy range and an overflow flag may be set when overflow is encountered in a sensing element. The circuit may be configured to determine a time stamp of respective charged particle arrival events occurring at each sensing element. Size of the sensing element may be determined based on criteria for enabling charged particle counting.

Abstract: A low power mass spectrometer (LPMS) includes an ionization source for generating an ionized sample beam; ion focusing optics for focusing the sample beam; and a static magnetic field region contained within an electric field-free drift region created between magnets acting as equipotential electrodes combined with a third equipotential surrounding electrode for receiving the focused sample beam and deflecting ions therein to different points on a detector array in accordance with an individual mass thereof. The LPMS operates at less than 1.2 Watts and has a physical footprint equal to or less than 12 inches at its largest length.

Abstract: A low power mass spectrometer (LPMS) includes an ionization source for generating an ionized sample beam; ion focusing optics for focusing the sample beam; and a static magnetic field region contained within an electric field-free drift region created between magnets acting as equipotential electrodes combined with a third equipotential surrounding electrode for receiving the focused sample beam and deflecting ions therein to different points on a detector array in accordance with an individual mass thereof. The LPMS operates at less than 1.2 Watts and has a physical footprint equal to or less than 12 inches at its largest length.

Abstract: A secondary electron multiplier includes: a conversion dynode for emitting a secondary electron in response to an incident ion; a plurality of dynodes configured to have multi-stages from second to final stages for receiving the secondary electron; and a first voltage applying device for applying a first negative voltage to the conversion dynode and sequentially dividing the first negative voltage to apply to each of the second-stage and subsequent dynodes, wherein the secondary electron multiplier is configured to sequentially multiply the emitted secondary electron by the second-stage and subsequent dynodes. In the secondary electron multiplier, any of the second-stage and subsequent dynodes have a second voltage applying device for applying a second negative voltage. The secondary electron multiplier has an improved ion detection efficiency without a large reduction of a usable period thereof, thereby enhancing the sensitivity of a mass spectrometer.

Abstract: The present invention provides systems and methods for measuring the isotope ratios of one or more trace gases based on optical absorption spectroscopy methods. The system includes an optical cavity containing a gas. The system also includes a laser optically coupled with the optical cavity, and a detector system for measuring absorption of laser light by the gas in the cavity.

Abstract: A method of ion source fabrication for a mass spectrometer includes simultaneously forming aligned component portions of an ion source using direct metal laser fusing of sequential layers. The method can further include forming the component portions on a base plate made from a ceramic material by applying fused powder to the base plate to build the component portions thereon.

Abstract: A closed-loop ion guide is disclosed comprising a plurality of electrodes having apertures through which ions are transmitted in use. Ions are injected into the closed-loop ion guide and may make several circuits of the closed-loop ion guide before being ejected from the ion guide. In a mode of operation the ion guide may be arranged to separate ions temporally according to their ion mobility.

Abstract: A method and an apparatus are described to improve the separation capacity of an ion analyzer incorporating at least two stages of ion mobility analysis. The new invention utilizes possible use of different mixtures of gases and dopants in each stage, control over different concentrations of gases and dopants in each stage, and allowance of passage of the selected ions from one stage to the next while avoiding the mixing of the gases and dopants among stages. The new invention also includes a method to reduce the time required to identify the physical properties in a set of ion filters where at least one of the filters is a scannable ion mobility analyzer. The present invention also includes how to provide a set of scannable ion mobility analyzers operating in series, wherein each stage can be operated as a filter, or allowing for the passage of all ions.

Abstract: An ion detection system for detecting ions whose velocity varies during an operating cycle. The ion detection system includes a dynode electron multiplier (e.g., a microchannel plate (MCP)) having a bias voltage input, and a bias voltage source to apply a bias voltage to the bias voltage input of the dynode electron multiplier. With a fixed bias voltage applied to its bias voltage input, the dynode electron multiplier has a gain dependent on the velocity of ions incident thereon. The bias voltage applied by the bias voltage source to the bias voltage input of the dynode electron multiplier varies during the operating cycle to reduce the dependence of the gain of the dynode electron multiplier on the velocity of the ions incident thereon.

Abstract: An inorganic mass spectrometer capable of measuring a relevant and large or the full mass spectral range simultaneously may include a suitable ion source (e.g., an ICP mass spectrometer with an ICP ion source), an ion transfer region, ion optics to separate ions out of a plasma beam, a Mattauch-Herzog type mass spectrometer with a set of charged particle beam optics to condition the ion beam before an entrance slit, and a solid state multi-channel detector substantially separated from ground potential and separated from the potential of the magnet.

Abstract: A system for measuring size segregated mass concentration of an aerosol. The system includes an electromagnetic radiation source with beam-shaping optics for generation of a beam of electromagnetic radiation, an inlet sample conditioner with adjustable cut-size that selects particles of a specific size range, and an inlet nozzle for passage of an aerosol flow stream. The aerosol flow stream contains particles intersecting the beam of electromagnetic radiation to define an interrogation volume, and scatters the electromagnetic radiation from the interrogation volume. The system also includes a detector for detection of the scattered electromagnetic radiation an integrated signal conditioner coupled to the detector and generating a photometric output, and a processor coupled with the conditioner for conversion of the photometric output and cut-size to a size segregated mass distribution.

Abstract: An active detector and methods for detecting molecules, including large molecules such as proteins and oligonucleotides, at or near room temperature based on the generation of electrons via field emission (FE) and/or secondary electron emission (SEE). The detector comprises a semiconductor membrane having an external surface that is contacted by one or more molecules, and an internal surface having a thin metallic layer or other type of electron emitting layer. The kinetic energy of molecules contacting the semiconductor membrane is transferred through the membrane and induces the emission of electrons from the emitting layer. An electron detector, which optionally includes means for electron amplification, is positioned to detect the emitted electrons.

Abstract: Described is a method for analyzing the metabolites of a biological sample which comprises quantitatively determining one or more metabolites in said sample in a way that said quantitative determination resolves isotopic mass differences within one metabolite, said method being characterized in that the sample comprises or is derived from a cell which has been maintained under conditions allowing the uptake of an isotopically labeled metabolizable compound so that the metabolites in said cell are saturated with the isotope with which said metabolizable compound is labeled. This method may further comprise, prior to quantitative determining the metabolites, combining the biological sample (i.e. the first biological sample) with a second biological sample in which the metabolites are not isotopically labeled or are isotopically labeled differently from the first biological sample; and determining in said biological samples the relative quantity of metabolites which differ by their isotopical label.

Abstract: Tandem time-of-flight mass spectrometry method and apparatus permits an ion gate to be time set optimally at all times if the instrumental conditions are modified. Delayed extraction conditions for the mass-to-charge ratios of plural reference substances and optimum values of the time for which the ion gate is opened are measured and stored in a data table. Delayed extraction conditions and opening time of the ion gate which optimize the mass resolution at the mass-to-charge ratio of the desired precursor ions are found based on values stored in the table.

Abstract: A monitor that can detect at least one molecule. The monitor includes a housing with a passage that can receive a sample, and a photocathode that is located within the housing. The monitor also includes a first ultraviolet light source that can direct ultraviolet light onto the photocathode to create electrons that ionize molecules within the sample, and a detector that is coupled to the housing to detect at least one ionized molecule. The monitor enables electron ionization (EI) of a sample for chemical analysis without the disadvantages of current methods that use a hot filament or other thermal cathode devices.

Abstract: A wind and temperature spectrometer (WTS) may detect the angular and energy distributions of neutral atoms/molecules and ions in two mutually perpendicular planes. The measured energy distribution at a known angle near the peak may be used to infer the full wind vector W. A WTS having a single ion source may be used in conjunction with a crossed small-deflection energy analyzer (SDEA). The crossed SDEA may combine the angular and energy distributions in the two mutually perpendicular planes into a single spectrometer with a single optical axis. A WTS having a single ion source may use less energy and occupy less space than a WTS with two ion sources.

Abstract: An approach to extending the dynamic range of the detector of a mass spectrometer is described. In one embodiment, in the case of high intensity beams, means are provided to deflect the ion beam, after the collector slit (1), on to an attenuator (4), which may be a grid or an array of small holes, through which only a small fraction of the ion beam reaches the ion detector (6). Use of an array of holes ensures that the recorded signal is insensitive to the distribution of ions within the beam. The beam passes directly to a detector if the signal is of low intensity.

Abstract: Systems and methods are provided for optimizing the performance of a mass spectrometer system when multiple measurements are made. For example, the total settling time of different components or stages of a mass spectrometer, such as a tandem mass spectrometer, are decreased by optimally ordering the measurements.

Abstract: A system and method for detecting an analyte of interest in a sample is provided. The method includes passing a set of ions obtained from the sample through an ion mobility spectrometer to filter out ions that are not ions of interest and to generate an ion mobility spectrum. A mass spectrum of at least some of the ions is generated using a mass spectrometer. The method also includes determining that the analyte of interest is in the sample when peaks of interest are found in one or more of the ion mobility spectrum and the mass spectrum, and the peaks of interest follow a predetermined pattern of peaks associated with the analyte of interest or are confirmed by ion mobility spectrometry.

Abstract: A system for measuring size segregated mass concentration of an aerosol. The system includes an electromagnetic radiation source with beam-shaping optics for generation of a beam of electromagnetic radiation, an inlet sample conditioner with adjustable cut-size that selects particles of a specific size range, and an inlet nozzle for passage of an aerosol flow stream. The aerosol flow stream contains particles intersecting the beam of electromagnetic radiation to define an interrogation volume, and scatters the electromagnetic radiation from the interrogation volume. The system also includes a detector for detection of the scattered electromagnetic radiation an integrated signal conditioner coupled to the detector and generating a photometric output, and a processor coupled with the conditioner for conversion of the photometric output and cut-size to a size segregated mass distribution.

Abstract: A mass spectrometer includes a linear multipole electrode, an auxiliary electrode that applies a DC potential on the center axis of the linear multipole electrode, and a DC power supply that supplies a DC power to the auxiliary electrode. The DC potential slope formed on the center axis of the multipole electrode is changed according to the measuring condition. The ejection time of ions can be adjusted optimally by adjusting the potential slope so as to satisfy the measuring condition. If the ejection time of ions is shortened, confusion of different ion information items that might otherwise occur on a spectrum can be avoided. If the ejection time of ions is lengthened, detection limit exceeding can be avoided and ions can be measured efficiently, thereby highly efficient ion measurements are always assured.

Abstract: A device having an air sampler, an electrospray apparatus, and a fluorescence excitation and detection system. The air sampler is capable of moving air suspected of containing a biological or chemical aerosol particle into a chamber. The electrospray apparatus is capable of spraying a charged solution into the chamber to coat the aerosol particles with a coating. The solution has a fluorescent-labeled biological or chemical marker capable of specific binding to the aerosol particle. The fluorescence system is capable of detecting fluorescence of the fluorescent label in the coating. A method of detecting the aerosol particle by: moving air suspected of containing the aerosol particle into a chamber; spraying the charged solution into the chamber with an electrospray apparatus, such that a coating of the solution is formed around the particle; exciting the fluorescent label; and detecting fluorescence of the fluorescent label.

Abstract: An MS/MS spectrometric analysis method obtains throughput and mass resolving power of precursor ions. In a mass spectrometer, ions, which are introduced and accumulated in an ion trap unit, are resonance-extracted mass-selectively. A profile of precursor ions at the m/z axis of the ion trap and a profile at the mass analyzer portion, which performs mass analysis of the ions extracted from a collision induced dissociation portion, is obtained by performing a measurement when the injection energy to the collision induced dissociation portion is low, and when the injection energy to the collision induced dissociation portion is high. The profile at the m/z axis of the ion trap of the obtained two-dimensional spectrum is substituted with the profile at the m/z axis of the mass analyzer portion. In this way, the m/z of both the precursor ions and the fragment ions can be determined with high mass resolving power.

Abstract: An apparatus and method for estimating size segregated aerosol mass concentration in real time and using a single detector. A beam of electromagnetic radiation is passed through a particle stream made of a test or field aerosol. The single detector outputs an electrical signal proportional to the electromagnetic radiation scattered thereupon. The electrical signal may be conditioned to produce an integrated signal for measuring radiation scattered from all the particles in the interrogation volume, a pulse height from an individual particle within the volume, and/or a time-of-flight measurement from the individual particle. The integrated signal can be correlated to particle mass concentration. The pulse height signal and the time-of-flight signal may be converted to infer the size of the individual particle. Attendant size distributions for the particle sizes may also be obtained. Using known or assumed particle properties, the mass concentration may be estimated from the size distribution.

Abstract: According to an embodiment, an apparatus for measuring the uniformity of a beam of charged particles at an exposure location includes a plurality of Faraday cups, each cup including an electrometer for determining the current collected by said cup, at least one multi-channel low current scanner card electrically coupled to the electrometers, a processor electrically coupled to said at least one scanner card, computational analysis software for receiving signals from said processor and calculating beam parameters, and display software for generating a graphical representation of the beam parameters calculated by said computational analysis software.

Abstract: A sample S is irradiated with a two-dimensionally spread ray of laser light to simultaneously ionize substances within a two-dimensional area on the sample. The resultant ions are mass-separated by a TOF mass separator 4 without changing the interrelationship of the emission points of the ions. The separated ions are then directed to a two-dimensional detector section 7 through a deflection electric field created by deflection electrodes 61 and 62. The two-dimensional detector section 7 consists of a plurality of detection units 7a arranged in parallel, each unit including an MCP 8a, fluorescent plate 9a and two-dimensional array detector 10a. The magnitude of deflecting the flight path of the ions by the deflection electric field is changed in a stepwise manner with the lapse of time from the generation of the ions so that a plurality of mass analysis images are sequentially projected on each detection unit 7.

Abstract: An active detector and methods for detecting molecules, including large molecules such as proteins and oligonucleotides, at or near room temperature based on the generation of electrons via field emission (FE) and/or secondary electron emission (SEE). The detector comprises a semiconductor membrane having an external surface that is contacted by one or more molecules, and an internal surface having a thin metallic layer or other type of electron emitting layer. The kinetic energy of molecules contacting the semiconductor membrane is transferred through the membrane and induces the emission of electrons from the emitting layer. An electron detector, which optionally includes means for electron amplification, is positioned to detect the emitted electrons.

Abstract: A method and apparatus, such as a spectrometer, are provided for facilitating the detection of an gamma signal in a manner that effectively discriminates the gamma signal from noise. A spectrometer may be provided which includes an gamma converter for converting gamma signals which impinge thereupon into corresponding pairs of electrons and positrons. The spectrometer also includes a deflector for separately deflecting the electrons and the positrons as well as electron and positron detectors for separately detecting the deflected electrons and positrons, respectively. As such, an gamma signal can be identified in instances in which the deflected electrons and positrons are detected in coincidence.

Abstract: An ion detector comprises an ion guide with electrodes arranged about a first axis; a positive ion detection device with an ion inlet at a first side of the ion output section offset from and at an angle to the first axis; and a negative ion detection device with an ion inlet at a second side opposite the first side, offset from and at an angle to the first axis. A negative voltage bias applied to the positive ion device accelerates positive ions toward the inlet along a path including a component along a second axis orthogonal to the first axis. A positive voltage bias applied to the negative ion detection device accelerates negative ions toward the inlet along a path that includes a component along the second axis orthogonal to the first axis in a direction generally opposite to the path of the positive ions.

Abstract: The present invention achieves an ion mobility spectrometer which is small-sized but has higher selectivity. In an interior of a drift tube, air flow moving from a detector side to an ion source side is generated, and there are arranged, in order from an upstream side of the air flow to a downstream side thereof, a first region where a flow rate increases in a flow direction, a second region where the flow rate is constant, and a third region where the flow rate decreases. Light irradiation mechanisms for dissociating an ion are provided in the second region.

Abstract: A data acquisition system and method are described that may be used with various spectrometers. The data acquisition system may include an ion detector, an initial processing module, and a spectra processing module. The initial processing module is provided for receiving, sampling, and processing ion detection signals received from the ion detector, and for supplying processed signals to the spectra processing module. The initial processing module includes a horizontal accumulation circuit that combines a fractional number of adjacent samples of the ion detection signals into bins. The number of adjacent samples to combine into bins may vary as a function of: (1) the time of arrival at the ion detector corresponding to that sample; (2) the mass corresponding to that sample; (3) the resolution corresponding to that sample; and/or (4) an operational mode of the spectrometer. The spectra processing module receives the processed signals and generates spectra.

Abstract: A novel instrument and method for TOF/TOF mass spectrometry is offered. A spiral trajectory time-of-flight mass spectrometer satisfies the spatial focusing conditions for the direction of flight and a direction orthogonal to the direction of flight whenever ions make a turn in the spiral trajectory. An ion gate for selecting precursor ions is placed in the spiral trajectory of the spiral trajectory time-of-flight mass spectrometer. Electric sectors are placed downstream of the ion gate.

Abstract: A low-cost and high-ion-transmission-ratio ion-mobility spectrometry filter, including an ion source, a first drift region in which a gas flow direction and a DC electric-field direction are opposite to each other, a second drift region in which a gas flow direction is provided, the gas flow direction being different from the gas flow direction in the first drift region, and being opposite to a DC electric-field application direction in the second drift region, an intermediate region having an electric field for causing ions to travel between the first drift region and the second drift region, and a detector for detecting ions which have passed through the first drift region and the second drift region.

Abstract: Analysis of biological small molecules such as toxins, spores or cells is achieved by miniature mass spectrometer apparatus and apparatus attached thereto for vaporizing and ionizing a liquid sample fed into an evacuated vaporization chamber as an electrospray. The mass spectrometer apparatus includes: a collimation chamber, a repeller assembly, an internal ionization chamber, a mass filter and ion separation chamber, a drift space region, and a multi-channel ion detection array so as to permit the collection and analysis of ions formed over a wide mass range simultaneously. The vaporization chamber includes an output port adjacent the input to the collimation chamber so as to maximize the amount of vaporized material being fed into the mass spectrometer apparatus.

Abstract: Systems and methods are provided for optimizing the performance of a mass spectrometer system when multiple measurements are made. For example, the total settling time of different components or stages of a mass spectrometer, such as a tandem mass spectrometer, are decreased by optimally ordering the measurements.

Abstract: An analyzing electromagnet constituting an ion implanter has a first inner coil, a second inner coil, three first outer coils, three second outer coils, and a yoke. The inner coils are saddle-shaped coils cooperating with each other to generate a main magnetic field which bends an ion beam in the X direction. Each of the outer coils is a saddle-shaped coil which generates a sub-magnetic field correcting the main magnetic field. Each of the coils has a configuration where a notched portion is disposed in a fan-shaped cylindrical stacked coil configured by: winding a laminations of an insulation sheet and a conductor sheet in multiple turn on an outer peripheral face of a laminated insulator; and forming a laminated insulator on an outer peripheral face.

Abstract: The charged-particle beam system includes a non-axisymmetric diode forms a non-axisymmetric beam having an elliptic cross-section. A focusing element utilizes a magnetic field for focusing and transporting the non-axisymmetric beam, wherein the non-axisymmetric beam is approximately matched with the channel of the focusing element.

Abstract: A mass spectrometer includes: an ion source for ionizing a specimen to generate ions, an ion transport portion for transporting the ions, a linear ion trap portion for accumulating the transported ions by a potential formed axially, and a control portion of ejecting the ions within a second m/z range different from a first m/z range, from the linear ion trap portion, and substantially at the same timing as the timing of accumulating the ions within the first m/z range from the transport portion into the linear ion trap portion. The ion transportation portion having a mass selection means for selecting the ions in the first m/z range.

Abstract: A focal plane detector assembly of a mass spectrometer includes an ion detector configured to detect ions crossing a focal plane of the spectrometer and an electrically conductive mesh lying in a plane parallel to the focal plane, positioned such that ions exiting a magnet of the mass spectrometer pass through the mesh before contacting the ion detector. The mesh is maintained at a low voltage potential, relative to a circuit ground, which shields ions passing through the magnet from high voltage charges from other devices, such as microchannel plate electron multipliers. The mesh may be mounted directly to the magnet or positioned some distance away. The detector array may include any suitable device, including a faraday cup detector array, a strip charge detector array, or a CCD detector array.

Abstract: In an analyzing chamber for a mass analyzer, a body of the analyzing chamber may include an inlet through which an ion beam enters and an outlet through which the ion beam leaves. A shielding section may be installed on a sidewall. The shielding section may prevent the ion beam traveling along a path in the body from causing damage to the sidewall of the body. A detector may be interposed between the sidewall of the body and the shielding section. The detector may detect an ion beam leaking through the shielding section. Accordingly, damage to the sidewall of the body may be sufficiently reduced and/or prevented.

Abstract: An ion mobility spectrometer may include an inner electrode and an outer electrode arranged so that at least a portion of the outer electrode surrounds at least a portion of the inner electrode and defines a drift space therebetween. The inner and outer electrodes are electrically insulated from one another so that a non-linear electric field is created in the drift space when an electric potential is placed on the inner and outer electrodes. An ion source operatively associated with the ion mobility spectrometer releases ions to the drift space defined between the inner and outer electrodes. A detector operatively associated with at least a portion of the outer electrode detects ions from the drift space.

Abstract: An ion mobility spectrometer may include a flow channel having an inlet end and an outlet end. A deflection electrode is positioned within the flow channel so that a non-linear electric field is created between at least a portion of the flow channel and at least a portion of the deflection electrode when an electrostatic potential is placed across the deflection electrode and the flow channel. The ion mobility spectrometer also includes means for producing ions at a position upstream from the leading edge of the deflection electrode, so that ions produced thereby are deflected by the deflection electrode into the non-linear electric field. A detector positioned within the flow channel for detects ions from the non-linear electric field.

Abstract: An apparatus for detecting particles, comprising a plurality of electrically conductive structures disposed on a support element. The structures are electrically insulated from one another and each structure can be electrically connected to an electronic read-out device. The structures receive a beam of particles in a direction forming an angle of incidence with the support element. A trough is disposed between each two successive structures as viewed in the beam direction. And at least partial overlap exists between each two successive structures. The apparatus can be disposed in the focal plane of a mass spectrometer.

Abstract: A charged particle detector and method are disclosed providing for simultaneous detection and measurement of charged particles at one or more levels of particle flux in a measurement cycle. The detector provides multiple and independently selectable levels of integration and/or gain in a fully addressable readout manner.

Abstract: An in-situ ion sensor is disclosed for monitoring ion species in a plasma chamber. The ion sensor may comprise: a drift tube; an extractor electrode and a plurality of electrostatic lenses disposed at a first end of the drift tube, wherein the extractor electrode is biased to attract ions from a plasma in the plasma chamber, and wherein the plurality of electrostatic lenses cause at least one portion of the attracted ions to enter the drift tube and drift towards a second end of the drift tube within a limited divergence angle; an ion detector disposed at the second end of the drift tube, wherein the ion detector detects arrival times associated with the at least one portion of the attracted ions; and a housing for the extractor, the plurality of electrostatic lenses, the drift tube, and the ion detector, wherein the housing accommodates differential pumping between the ion sensor and the plasma chamber.

Abstract: Mass spectrometers for trace gas leak detection and methods for operating mass spectrometers are provided. The mass spectrometer includes an ion source to ionize trace gases, such as helium, a magnet to deflect the ions and a detector to detect the deflected ions. The ion source includes an electron source, such a filament. The method includes operating the electron source at an electron accelerating potential relative to an ionization chamber sufficient to ionize the trace gas but insufficient to form undesired ions, such as triply charged carbon.

Abstract: The invention provides an apparatus for combining ions and charged particles. In general, the apparatus contains: a) a multipole device having an ion exit end; b) a mass analyzer; and c) a source of charged particles. The apparatus is configured so that charged particles produced by the source of charged particles pass through the mass analyzer and into the multipole device via the ion exit end of the multipole device.

Abstract: Mass spectrometer systems for measuring mass/charge ratios of analytes are described. A mass spectrometer system includes a vacuum flange, a PCB base plate coupled to the vacuum flange, and an ion optic assembly coupled to the PCB base plate. The PCB base plate may include signal-processing electronics. The system may include an electrical cable coupled to the PCB base plate for supplying power, control, and I/O to the ion optic assembly and the signal processing electronics. Alternatively, a mass spectrometer system includes a PCB base plate and an ion optic assembly. The PCB base plate has a sealant portion and an electrical portion. The ion optic assembly is coupled to the electrical portion. The system may include a vacuum housing for enclosing the ion optic assembly. The vacuum housing is coupled to the sealant portion of the PCB base plate for sustaining a vacuum while the system is in operation.

Abstract: A mass spectrometer includes a main magnet having spaced-apart polepieces which define a gap, the main magnet producing a magnetic field in the gap, an ion source to generate ions and to accelerate the ions into the magnetic field in the gap, the ion source located outside the gap, and an ion detector to detect a selected species of the ions generated by the ion source and deflected by the magnetic field. The ion detector is located in the gap at a natural focus point of the selected species of ions. The mass spectrometer may be used in a trace gas leak detector.

Abstract: A magnetic sector mass spectrometer is disclosed comprising an ion detector (11) wherein a reflecting electrode (13) is used to divide an ion beam in the direction of mass dispersion into two separate ion beams. The two ion beams are directed onto two detectors which preferably comprise two or more conversion dynodes (15a, 15b) and two or more corresponding microchannel plate detectors (14a, 14b) to detect electrons produced by the conversion dynodes (15a, 15b). If the signal from the two detectors differs substantially then the ion beam can be determined to include interference ions. Conversely, if the signal from the two detectors is substantially the same then the ion beam can be determined to be substantially free from interference ions.