Abstract: A method for trapping of a plurality of charged particles in a charged particle trap. The trap includes first and second electrode mirrors having a common optical axis, the mirrors being arranged in alignment at two extremities thereof. The mirrors are capable, when voltage is applied thereto, of creating respective electric fields defined by key field parameters. The electric fields are configured to reflect charged particles causing their oscillation between the mirrors. The method includes introducing into the trap, along the optical axis, the plurality of charged particles as a beam having pre-determined key beam parameters. The method further includes choosing the key field parameters for at least one of the mirrors such as to induce bunching among charged particles in the beam.

Abstract: An electron filter for trapping dissociated electrons in an ion implantation chamber. The electron filter typically includes at least one filter element which is connected to a voltage source for applying a positive voltage to the filter element. During an ion implantation process, dissociated electrons are drawn from the interior of the chamber and trapped in the filter element to prevent or reduce contamination of the substrates.

Abstract: The present disclosure is related to improved systems and methods for inducing infrared multiphoton dissociation (IRMPD) of an ion. In an exemplary embodiment, the system includes an ion dissociation chamber and an infrared waveguide coupled to the ion dissociation chamber. The infrared waveguide may be positioned to receive infrared energy from an infrared energy source and direct the infrared energy towards ions in the ion dissociation chamber for the purpose of fragmenting the ions. The infrared waveguide can be made of a hollow fused silica body with an inner infrared reflective layer. The infrared waveguide may be flexible. A system may further include a focusing lens, an infrared transparent window and an aperture housing that has an orifice. The ion dissociation chamber may be an ion trap, an ion guide or an ion reservoir.

Abstract: The invention relates to a time-of-flight mass spectrometer for injection of the ions orthogonally to the time-resolving axis-of-flight component, with a pulser for acceleration of the ions of the beam in the axis-of-flight direction, preferably with a velocity-focusing reflector for reflecting the ion beam and with a flat detector at the end of the flight section. The invention consists of using, both for acceleration in the pulser and for reflection in the reflectors, a gridless optical system made up of slit diaphragms which can spatially focus the ions onto the detector in the direction vertical to the directions of injection and flight axis, but which does not have any focusing or deflecting effect on the other directions. For some reflector geometries it is essential to use an additional cylindrical lens for focusing, and for other reflector geometries the use of such a lens may be advantageous.

Abstract: A high field asymmetric waveform ion mobility spectrometer (FAIMS) having spherical electrode geometry is disclosed. The spherical FAIMS includes an inner generally spherical electrode supported in a spaced-apart arrangement relative to an outer electrode. The outer electrode has a curved inner surface that maintains an approximately uniform spacing to the inner electrode. The space between the inner and outer electrodes defines an analyzer region, where an electric field is established by the application of an asymmetric waveform voltage and a direct current compensation voltage to at least one of the inner and outer electrodes. An ion inlet and an ion outlet are disposed within the curved inner surface of the outer electrode such that the shortest distance between the inlet and the outlet in any direction around the inner electrode is approximately a same distance.

Abstract: In an ion trap mass spectrometer, between an ion supply source and an ion trap, there are disposed an entrance gate electrode, an ion storing section for holding ions by accumulating them near an exit side by means of an RF voltage with an axial electric potential inclined from an entrance side to the exit side, and an exit gate electrode. When the ions are accumulated near the exit side, the exit gate electrode is opened to thereby introduce the ions in the pulse state into the ion trap. At this point, a voltage is not applied to a ring electrode of the ion trap, so that repulsion due to the voltage of the ring electrode is eliminated. Thereafter, when maximum amount of ions stay inside the ion trap, ring RF voltage is suddenly applied. Thus, the maximum amount of the ions can be introduced into the ion trap.

Abstract: The use of a segmented-ion trap with collisional damping is disclosed to improve performance (resolution and mass accuracy of single stage and tandem time-of-flight mass spectrometers. In the case of single stage spectrometers ions are directly injected from a pulsed ion source into the trap supplied with RF field and filled with gas at millitorr pressure. Subsequently, the ions are dynamically trapped by an RF-field, cooled in gas collisions and ejected out of the trap by a homogeneous electric field into a time-of-flight mass spectrometer. In the case of tandem mass spectrometric analysis the pulsed ion beam is injected into a time-of-flight analyzer to select ions-of-interest prior to injection into the trap at medium energy to achieve fragmentation in the trap.

Abstract: A high field asymmetric waveform ion mobility spectrometer (FAIMS) having spherical electrode geometry is disclosed. The spherical FAIMS includes an inner generally spherical electrode supported in a spaced-apart arrangement relative to an outer electrode. The outer electrode has a curved inner surface that maintains an approximately uniform spacing to the inner electrode. The space between the inner and outer electrodes defines an analyzer region, where an electric field is established by the application of an asymmetric waveform voltage and a direct current compensation voltage to at least one of the inner and outer electrodes. An ion inlet and an ion outlet are disposed within the curved inner surface of the outer electrode such that the shortest distance between the inlet and the outlet in any direction around the inner electrode is approximately a same distance.

Abstract: The present invention describes a method of selecting ions in an ion storage device with high resolution in a short time period while suppressing amplitude of ion oscillation immediately after the selection. In a method of selecting ions within a specific range of mass-to-charge ratio by applying an ion-selecting electric field in an ion storage space of an ion storage device, the method according to the present invention is characterized in that the ion-selecting electric field is produced from a waveform whose frequency is substantially scanned, and the waveform is made anti-symmetric by multiplying a weight function whose polarity reverses, or by shifting a phase of the waveform by odd multiple of &pgr;, at around a secular frequency of the ions to be left in the ion storage space. It is preferable that the frequency of the waveforms is scanned in a direction where the frequency decreases.

Abstract: A new detection scheme for time-of-flight mass spectrometers is disclosed. This detection scheme allows extending the dynamic range of spectrometers operating with a counting, technique (TDC). The extended dynamic range is achieved by constructing a multiple anode detector wherein the individual anodes detect different fractions of the incoming particles. Different anode fractions are achieved by varying the size, physical location, and electrical/magnetic fields of the various anodes. An anode with a small anode fraction avoids saturation and allows an ion detector to render an accurate count of ions even for abundant species.

Abstract: To control movement of ions in a mass spectrometer, an ion guide has means for generating an electric field along the ion guide, and also provision for generating a gas flow along the ion guide. This then subjects ions to forces, an electric field force and a drag force. These can be set to control motion of ions as desired. The ion guide can form part of ion mobility section, in which case the forces can be set to enhance separation of ions and to control elution of different groups of ions from the ion mobility spectrometer for subsequent analysis. Eluted ions can be selected to further analysis, e.g., collisional fragmentation followed by mass analysis in a time-of-flight instrument. The technique is applicable to other elements of a mass spectrometer; for example, the fragmentation cell can be configured so that ions therein are subjected to both drag forces and electric forces, to control movement thereof.

Abstract: The present invention provides an apparatus for selectively transmitting ions and trapping the ions within a defined 3-dimensional space at atmospheric pressure. The invention is based on the ion focussing principles of high field asymmetric wave-form ion mobility spectrometry in which an analyzer region is defined by a space between first and second spaced apart electrodes, the analyzer region having a gas inlet and a gas outlet for providing a flow of gas through the analyzer region. Ions which are introduced into the analyzer region are carried by a gas flow towards a gas outlet. At least one of the electrodes has a curved surface terminus located near the gas outlet and the gas flow is adjusted so that ions are trapped in a defined 3-dimensional space located near the tip of the terminus. Trapping of ions in a defined 3-dimensional space allows a more concentrated flow of desired ions.

Abstract: A method of separating ions according to mass in a mass spectrometer includes establishing a stream of ions traveling in a generally cycloidal path in an electric field and a magnetic field, subsequently causing the electric field to terminate for a predetermined period of time while maintaining the magnetic field thereby causing the electrons to travel in a generally circular path for a predetermined time period and subsequently reestablishing the electric field to cause further travel in a cycloidal path and providing a detector for receipt of some of the ions. A suitably programmed microprocessor is employed to control operation of the mass spectrometer and to receive electrical signals responsive to ions impacting on the detector to thereby provide information regarding the ions. Corresponding apparatus is provided.

Abstract: A high-current, high-gradient, high-efficiency, multi-stage cavity cyclotron resonance accelerator (MCCRA) provides energy gains of over 50 MeV/stage, at an acceleration gradient that exceeds 20 MeV/m, in room temperature cavities. The multi-stage cavity cyclotron resonance accelerator includes a charged particle source, a plurality of end-to-end rotating mode room-temperature cavities, and a solenoid coil. The solenoid coil encompasses the cavities and provides a substantially uniform magnetic field that threads through the cavities. Specifically, the MCCRA is provided with a constant magnetic field sufficient to produce a cyclotron frequency a little higher than the RF of the accelerating electric field. A plurality of input feeds, each of which respectively coupled to a cavity, are also provided. According to an embodiment of the invention, the beam from the first cavity passes through a cutoff drift tube and is accelerated further with a cavity supporting a still lower radio-frequency electric field.

Abstract: Apparatus and methods are disclosed for manipulating charged particles. The charged particles are directed from a source thereof into a zone. A first electrical potential is generated in the zone. Simultaneously, a second electrical potential is generated outside the zone. The second electrical potential penetrates into the zone and combines with the first electrical potential to form an oscillating electric potential field having predetermined characteristics sufficient to manipulate the charged particles. The manipulating of the charged particles includes, e.g., transporting, collisional cooling, collisional induced dissociating and collisional focusing. In one embodiment an apparatus comprises a hollow first element and a hollow second element. The second element is disposed within the first element. The second element has at least two openings in a wall thereof. The openings are elongated and radially disposed with respect to the axis of the second element.

Abstract: A mass spectrometer is disclosed which includes an ionizer, a collector slit disposed at a predetermined distance from the ionizer, and an electrostatic field source disposed between the ionizer and the collector slit. The electrostatic field source has a selected amplitude which is substantially uniform within a space between the ionizer and the collector slit. The electrostatic field is oriented substantially perpendicular to a line between the ionizer and the collector slit. The mass spectrometer includes a magnetic field source disposed between the ionizer and the collector slit. The magnetic field source induces a substantially uniform magnetic field within the space. The magnetic field has a direction perpendicular to both the electrostatic field and to the line between the ionizer and the collector slit. The spectrometer includes a detector disposed behind the collector slit.

Abstract: A combinatorial chemistry system allows for the dual processing of different molecules coated on a library of beads. The system includes beads coated with different molecules on each bead, a bead holder, screening equipment and characterization equipment. Molecules on the beads are both screened and characterized simultaneously.

Abstract: An ion cyclotron resonance cell having a large ion trapping volume is described. The cell includes elongated spaced concentric electrodes having a common axis in which the trapping volume is the space between the electrodes. The cell may also include trapping electrodes disposed at the ends of the elongated concentric electrodes.

Abstract: A laser-cooled fluorescence mass spectrometry apparatus includes an ion trap for trapping sample ions, laser-cooled ions, and probe ions therein; a first irradiating device for irradiating the sample ions, the laser-cooled ions, and the probe ions in the ion trap with a first laser beam for cooling the ions; a second irradiating device for irradiating the sample ions, the laser-cooled ions, and the probe ions in the ion trap with a second laser beam for detecting temperature changes in the ions; a detecting device for detecting the temperature changes in the ions; a first ion source for the sample ions; a second ion source for the laser-cooled ions; and a third ion source for the probe ions. The probe ions may be different ions than the laser-cooled ions, or the probe ions may be the same ions as the laser-cooled ions.

Abstract: A plasma mass spectrometer comprises a plasma torch (1) for generating ions from a sample introduced into a plasma (2), a nozzle-skimmer interface (3,5) for transmitting said ions into a first evacuated chamber (11), ion guiding means (12), an apertured diaphragm (18) dividing said first evacuated chamber (11) from a second evacuated chamber, and an ion mass-to-charge ratio analyzer in the second chamber for producing a mass spectrum. The ion guiding means comprises a multipole rod-set (13,14,15), means for applying an AC voltage between rods in the set, and means (22) for introducing into said ion guiding means an inert gas selected from the group comprising helium, neon, argon, krypton, xenon and nitrogen so that the partial pressure of said inert gas inside said rod-set is at least 10−3 torr. Interfering peaks in the spectrum, such as Ar+, are thereby reduced.

Abstract: An ion-deflecting device is located between a mass spectrometer and a detector, and undesired signal sources are prevented from reaching the detector during the ion-trapping period by switching the voltage applied to the detector between the ion-trapping period and the mass-analyzing period. A first voltage is applied to the detector during an ion-trapping period while a second voltage is applied to the detector during a mass-analyzing period. An ion-deflecting device deflects ions such that they do not reach the detector during an ion-trapping period while they do reach the detector during a mass-analyzing period. This way, the life of the detector is increased.

Abstract: An ungated, time-of-flight ion mass spectrograph utilizing a continuous ion beam that is rastered (swept) by electrostatic deflection plates at the entrance of a time-of-flight drift tube is described. After an ion is deflected, it follows a trajectory in the drift tube that depends on the phase of the raster and is detected by a position-sensitive detector. The detected position provides information concerning the time when the ion entered the drift tube. This information, when combined with knowledge of the raster voltage at the time that the ion was detected, provides a method for determining the time-of-flight of the ion in the drift tube. Using the time-of-flight and the distance traveled in the drift tube, which is also determined by the detected position of the ion, ion speed is determined. Ion mass-per-charge ratio can then be determined for a monoenergetic ion beam.

Abstract: A double-focusing mass spectrometer apparatus includes a first cylindrical sector electrode defined at a first radial distance from a axis with the first cylindrical sector electrode having an upper and lower edge and a second cylindrical sector electrode surface defined at a second radial distance from the axis with the second cylindrical sector electrode having an upper and lower edge corresponding to the upper and lower edge of the first cylindrical sector electrode. An ion path is defined between the first and second cylindrical sector electrodes. A first magnet pole and a second magnet pole are positioned proximate the upper and lower edges of the first and second cylindrical sector electrodes, respectively, for providing a magnetic field in the ion path. A first and second array of electrodes, e.g.

Abstract: For delivery of ions from a higher pressure ion source to a mass analyzer operating at high vacuum, high pass ion filtration is effected within a dielectric capillary interface between the higher pressure ionization chamber and the lower pressure environment of a mass analyzer, by application of electrical potentials to end electrodes and to at least one electrode associated with the dielectric capillary between the ends, to create an end-to-end electric field generally opposing gas flow-assisted movement of ions from the upstream end to the downstream end, and to create a steeper voltage gradient along an upstream portion than along a downstream portion of the capillary. The voltage gradient along the steeper upstream portion of the capillary is sufficiently steep to cause ions having drift velocities below a lower limit to stall within the capillary. The respective potentials may be adjusted to increase the steepness of the upstream voltage gradient to increase the drift velocity lower limit.

Abstract: An ion mobility spectrometer has two opposing wall elements connected by at least one spacer with parallel, mutually assigned, planar, gas-guiding wall surfaces with opposing conductor structures to generate a drift field. The ratio of distance of the gas-guiding wall surfaces to the field-generating width of the conductor structure perpendicular to the drift direction is less than 1:2 and is advantageously 1:3 to 1:10.

Abstract: A multiple-pole electrode assembly is disclosed for use in mass spectrometers or other applications such as ion traps or ion guides. The disclosed apparatus provides a rod mounting and connection assembly in which equally spaced rectangular rods are embedded in spaced, dimensionally stable insulating materials. This structure is more conveniently and inexpensively manufactured than previously available multiple pole electrode assemblies.

Abstract: An ion cyclotron resonance cell having a large ion trapping volume is described. The cell includes elongated spaced concentric electrodes having a common axis in which the trapping volume is the space between the electrodes. The cell may also include trapping electrodes disposed at the ends of the elongated concentric electrodes.

Abstract: A quadrupole ion trap mass analyzer in which the trapping volume is defined by spaced linear rods in which linear elements located between the spaced linear rods produce image currents produced by motion of ions in the trapping volume.

Abstract: A linear plasma mass filter includes a container which is shaped as a rectangular prism. Magnetic coils encircle the container for generating a uniform magnetic field (B) in the container, and electrodes are mounted on the container for generating an electric field (E) in the container. Specifically, the electric field is rectilinear in that all of the electric field lines are parallel to each other. Further, the electric field is oriented perpendicular to the magnetic field to create crossed electric and magnetic fields (E×B). A plasma source is provided for injecting a multi-species plasma into the container which includes relatively low mass particles (M1), and relatively high mass particles (M2). Both M1 and M2 are responsive to the magnetic field with respective cyclotron orbits of a first diameter (D1) and a second diameter (D2).

Abstract: An apparatus and method for providing a low energy, high current ion beam for ion implantation applications are disclosed. The apparatus includes a mass analysis magnet mounted in a passageway along the path of an ion beam, and a magnetic device adapted to provide a multi-cusped magnetic field in the passageway, which may include a plurality of magnets mounted along at least a portion of the passageway. The magnets may cooperatively interact to provide a multi-cusped magnetic field along at least a portion of the passageway. The multi-cusped magnetic field may be superimposed on the dipole field at a specified field strength in a region of the mass analyzer passageway for a given low energy ion beam. The invention thus provides enhancement of beam plasma within a mass analyzer dipole magnetic field for low energy ion beams without the introduction of externally generated plasma.

Abstract: The present invention discloses novel methods and apparatuses for mass spectrometry. In the methods and apparatuses of the invention, ions are accumulated in an ion reservoir and dissociated with coherent radiation prior to mass analysis. These methods and apparatuses are amenable to mass spectrometric analysis of biomolecules and are particularly usefuil for the sequencing of oligonucleotides, peptides and oligosaccharides.

Abstract: Disclosed is an ion trap mass spectrometer improved to obtain a high sensitivity without the lowering of resolution. By fitting a mesh electrode to an aperture (an ion sampling aperture or an ion extracting aperture) made in endcap electrodes constituting an ion trap mass analysis region, a radio frequency electric field in the mass analysis region is not disturbed even if the diameter of the aperture is set to a large value to heighten ion transmission efficiency. By fitting a shield electrode for preventing collision of ions with an insulated ring constituting an outer wall of the mass analysis region, charging up of the insulated ring is prevented to improve stability of detection signals. Furthermore, by arranging a shield member for shielding stray charged particles detouring through the circumference of the mass analysis region to approach an ion detector, generation of noises based on these stray charged particles is prevented.

Abstract: The present invention describes a quadrupole mass analyzer with linear ion trap. The quadrupole mass analyzer functions in a dual-mode. A conventional transmission mode operates with external ionizer supplying ions to the quadrupole analyzer. In an ion trap mode, DC endcap electrodes are attached to the rf quadrupole cylinder to form a trapping chamber where ions are confined. The preferred mode is based on a segmented cylinder electrode geometry which produces a substantially quadrupolar field distribution as used in a conventional four-rod quadrupole mass analyzer. Electrodes are generated from a cylinder that has been segmented along its length into some number of electrically isolated electrodes.

Abstract: A charge-exchange device is disclosed which is able to considerably reduce, without the use of foils, radio activation caused by a beam deflection angle and, which also implements a further efficiency and reduction of a laser output. The charge-exchange device is provided with an undulator and an optical resonator. The undulator magnetic field which has been generated by the undulator generates the Lorentz electric field by interaction with the relativistic velocity of H.sup.0 neutral beam being injected. The optical resonator amplifies the photon density of the laser beam and causes it to collide against the injected H.sup.0 neutral beam, thereby resonantly exciting the H.sup.0 beam to the principal quantum number of 4. The H.sup.0 beam which has been resonantly excited or excited by the relativistic Doppler effect in the undulator magnetic field is ionized to H.sup.+ ion by the Lorentz electric field.

Abstract: A technique to produce a device for generating an electric field is disclosed. This electric field may be customized to direct movement of charged particles in a predetermined manner. Moreover, this device is readily installed and removed from a charged particle analyzer to facilitate interchange with other devices capable of generating electric fields with different characteristics. The device may be provided by etching an electrically conductive layer clad to a flexible dielectric substrate to define a predetermined conductive pattern. This pattern is then oriented relative to a charged particle pathway and an electric potential applied to generate the desired electric field.

Abstract: A mass spectrometer comprises an ion source (11), an ion injection arrangement (12), field generator defined by shaped electrodes (14, 16) and a detector (18) to detect ions. The electrodes (14, 16) are shaped so as to provide therebetween a field of substantially hyper-logarithmic form whereby ions can be trapped within a potential well of the field for analysis.

Abstract: Curved rf multipole ion guides or angled linear rf multipole ion guides are designed to be rotatable or shiftable. Thus, the direction of guided ions can be altered by rotating or shifting these ion guides. In a mass spectrometer equipped with a multitude of ion sources, this allows to switch between ion sources without venting the vacuum system.

Abstract: A high-temperature octopole/collision apparatus features coaxially heated rf emitting octopole rods coacting with a collision oven cell. The rods are maintained at a slightly higher temperature than the oven cell to prevent condensation of the sample on the poles and to ensure a well characterized operating temperature necessary for absolute cross-section measurements.

Abstract: A method and mass spectrometer system for trapping ions within an ion trap by increasing the flight path of ions therein. An ion beam is produced by external ion source and is directed to the ion trap which comprises at least one trapping electrode in proximity to an exit region of the ion beam from the ion trap. A retarding DC voltage is applied to the trapping electrode during ion accumulation time for creating a fringing reflection field and for retaining ions within the ion trap.

Abstract: A compact mass spectrometer apparatus is presented to enable accurate qualitative and quantitative analyses of target ions. The apparatus can operate in a relatively poor vacuum in the range of 10.sup.-2 to 10.sup.-3 torr compared with the conventional requirement of 10.sup.-6 to 10.sup.-8 torr while providing precision results with lesser number of electrodes than the conventional mass spectrometer. The separation of the ionic species is achieved through two effects: flight time differentials produced by varying mass/charge ratios of the sample ions; as well as high frequency resonance separation by synchronizing the injection of ions with high frequency electric field applied to an electrode system having equi-potential space and high frequency space. The resulting dispersion in the wide energy spectra of the sample ions serves to accurately identify the sample ions both qualitatively and quantitatively.

Abstract: A method of fragmenting ions in conventional nonlinear ion traps using collisions of ions with molecules of a collison gas with excitation of the secular oscillations of the ions. A mixture of frequencies for resonant excitation, with a frequency limit which prevents the ions from being excited beyond the maximum oscillation amplitude between the end caps.

Abstract: A mass spectrometry method in which notch-filtered noise is applied to an ion trap to resonate all ions except selected parent ions out of the region of the trapping field. Preferably, the trapping field is a quadrupole trapping field defined by a ring electrode and a pair of end electrodes positioned symmetrically along a z-axis, and the filtered noise is applied to the ring electrode(rather than to the end electrodes) to eject unwanted ions in radial directions (toward the ring electrode) rather than toward a detector mounted along the z-axis. Application of the filtered noise to the trap in this manner can significantly increase the operating lifetime of such an ion detector. Also preferably, the trapping field has a DC component selected so that the trapping field has both a high frequency and low frequency cutoff, and is incapable of trapping ions with resonant frequency below the low frequency cutoff or above the high frequency cutoff.

Abstract: A quadrupole mass analyzer in which a pair of heat sink plates 16, 17 and springs 18 clamp ceramic holders 13, 14 that hold the four rod electrodes 12 of the quadrupole unit. The dielectric heat generated in the ceramic holders 13, 14 by the high frequency alternating electromagnetic field due to the AC voltage applied on the four rod electrodes 12 is promptly transferred to the heat sink plates 16, 17. Thus displacement of the four rod electrodes 12 or loss of symmetry is prevented when mass of ions is analyzed.

Abstract: An ion trap which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10.sup.9 and commercial mass spectrometers requiring 10.sup.4 ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products.

Abstract: A mass spectrometric apparatus is disclosed which has quadrupole electrodes to which a DC voltage and a high-frequency voltage are applied in a superposed manner, and measures a mass spectrum by scanning particular mass numbers of ions passing through respective stable regions by changing the DC voltage and the high-frequency voltage in very small steps every predetermined time interval step while keeping a relationship in magnitude between the DC voltage and the high-frequency voltage in the stable regions which provide stable trajectories of the ions of the respective mass numbers.

Abstract: Ion packets of different masses are dispersed according to their mass-to-charge-ratio by dispersion electrodes by means of deflection voltages continuously varying between free selectable start and end values as a function of time with adjustable voltage gradients such that voltages varying with a suited function of time make the mass window of the dispersed ion packets visible at the detector and independent of the analyzed masses. The mass resolution increases with the masses.

Abstract: An ion mobility spectrometer having a housing with an analyzer positioned therein. The analyzer includes first and second longitudinally spaced apart electrodes which are preferably cylindrical in configuration. The space between the electrodes defines an analytical gap which is in communication with a source of carrier gas. An ionization source such as a .beta.-emitter or corona discharge is juxtaposed with the analytical gap and source of sample media and includes an ion aperture for ions to enter said gap. The spectrometer includes an ion detector for measuring ions. An electrical controller connected to the first and second electrodes for impressing a first direct potential and second periodic asymmetrical potential capable of creating a transverse electrical field therebetween during the flow of carrier gas in the analytical gap. Preferably, a third low voltage ripple potential is impressed in series with the first two potentials.

Abstract: A mass spectrometry method in which notch-filtered noise is applied to an ion trap to resonate all ions except selected parent ions out of the region of the trapping field. Preferably, the trapping field is a quadrupole trapping field defined by a ring electrode and a pair of end electrodes positioned symmetrically along a z-axis, and the filtered noise is applied to the ring electrode (rather than to the end electrodes) to eject unwanted ions in radial directions (toward the ring electrode) rather than toward a detector mounted along the z-axis. Application of the filtered noise to the trap in this manner can significantly increase the operating lifetime of such an ion detector. Also preferably, the trapping field has a DC component selected so that the trapping field has both a high frequency and low frequency cutoff, and is incapable of trapping ions with resonant frequency below the low frequency cutoff or above the high frequency cutoff.

Abstract: A cycloidal mass spectrometer having a housing which defines an ion trajectory volume, an electric field generator for establishing an electric field within the ion trajectory volume, and an ionizer for receiving gaseous specimens to be analyzed and converting the same into ions which travel through orthogonal electric and magnetic fields and impinge upon a collector. The spectrometer is designed to have a plurality of ions of different mass to charge ratios impinging on the collector generally simultaneously. A processor determines the mass distribution of the ions impinging upon the collector. A plurality of electric field plates are electrically insulated from each other and may be sealed so as to define the ion trajectory volume. In another embodiment, an assembly of electric field plates are disposed within a vacuum enclosure. A miniature ionizer preferably has a miniature filament. The cycloidal mass spectrometer and ionizer may be miniaturized so as to provide for a small, readily portable instrument.

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.