Abstract: The subject invention provides improved methods for injecting ions into a quadrupole ion trap mass spectrometer (QIT-MS). The methods of the subject invention are applicable to procedures involving atmospheric pressure laser desorption (AP-LD) of a sample to be investigated. Specifically, the subject invention involves controlling the pulse frequency of the laser such that the laser pulses are synchronized with changes in radiofrequency (RF) amplitude levels of the QIT-MS. Advantageously, by utilizing the methods of the subject invention it is possible to improve the accuracy and reproducibility of the results while improving duty cycle and reducing sample consumption.

Abstract: Disclosed herein is a mass spectrometer having an atmospheric pressure photoionization (APPI) source that comprises a discharge lamp coupled to a nebulizer, wherein the nebulizer is at, or near, atmospheric pressure. The discharge lamp curves around the vapor path and this coaxial design offers significant advantages over the prior art such as increased photon flux resulting in increased photoionization efficiency. One of the significant benefits of an increase in photon flux is that absorption of the UV radiation by solvents such as acetonitrile is minimized. The APPI source described herein also facilitates a larger photoionization interaction zone with effluent from the nebulizer, which may be heated. Additionally, no dopant is required in this coaxial APPI system.

Abstract: A mass spectrometer is disclosed having a gas collision cell. An AC or RF ion guide comprising a plurality of ring electrodes which preferably have the same internal diameter is provided within the gas collision cell. The ion guide extends upstream and/or downstream of the gas collision cell so that ions may be continuously radially confined as they pass from a vacuum chamber maintained at a relatively low pressure, through an inlet differential pumping aperture to the gas collision cell, through the gas collision cell and then out of the gas collision cell through an outlet differential pumping aperture.

Abstract: Certain exemplary embodiments provide a method for performing repeated quantitative analysis using an FTMS. The method can comprise a plurality of potential activities, some of which can be automatically, repeatedly, and/or nestedly performed, and some of which follow. From at least one predetermined sample source, a sample can be obtained and provided to an FTMS. At least one variable for the FTMS can be optimized. A plurality of outputs can be acquired from the FTMS. An identity of at least one predominant ionic component of the sample can be ascertained. A quantity of the at least one predominant ionic component can be determined.

Abstract: A method and apparatus for the analysis of a narrow range of fragment ions by application of a notched broadband waveform during ion accumulation within a quadrupole collision cell operated as a linear ion trap. The fragment ions are formed via the axial acceleration and collision activated dissociation of mass resolved precursor ions. A narrow band of frequencies is purposefully omitted from the spectrum, so that the secular frequency of a particular fragment ion will fall within this notch of absent frequencies and as a result will not experience resonant excitation and are retained in the linear ion trap. Simultaneously, all other ions are lost either through neutralization when they strike electrodes or through (additional) collision activated dissociation. Accordingly, a particular mass or range of masses, whose secular frequencies fall within the notch of absent frequencies in the notched broadband waveform, may be selectively accumulated during the collision activated dissociation event.

Abstract: In one embodiment, a miniaturized structure and associated method function as a mass spectrometer or analyzer and may, with modification, function as an ion generator. The miniaturized structure has a pair of generally planar parallel spaced electrodes which have projecting walls cooperating to define an ion generating chamber and an exit aperture. By controlling the electric field which is oriented perpendicular to an applied magnetic field, the ion beam may be separated into a plurality beams based upon mass to charge ratio with a predetermined mass to charge ratio emerging from the exit of the apparatus and when the apparatus is functioning as a mass spectrometer or analyzer impinges on an ion collector which responsively transmits information to a cooperating processor. Where it is desired to have it function as an ionizer the ion collector disposed adjacent the ion exit is eliminated.

Abstract: The present invention relates to ion fragmentation techniques by electron-ion reactions in multipolar radiofrequency fields like those in quadrupole ion traps or in ion guides, and devices to perform ion fragmentation by such techniques. The fragmentation techniques are useful for tandem mass spectrometry. The invention consists of the application of a magnetic field essentially parallel to the axis of the radiofrequency field to confine the electrons in the direction perpendicular to the magnetic field.

Abstract: There is provided a tandem mass spectrometry that, in a quadrupole ion trap, allows small mass-number product ions to be detected without lowering the sensitivity and the resolution. In the quadrupole ion trap, ions are produced by an ion source. Next, the ions are accumulated within a 3-dimensional quadrupole electric field formed by a pair of endcap electrodes and a ring electrode. Finally, the accumulated ions are isolated and dissociated, then being detected. In this quadrupole ion trap, there are provided a mechanism for introducing a laser light, and a mechanism for generating a supplemental alternating-current electric field at the time of the ion dissociation. Moreover, the direction of the supplemental alternating-current electric field and the introduction direction of the laser light are made identical to each other.

Abstract: An improved mass analyzer is set forth. In accordance with one embodiment, the mass analyzer employs a unique mass filter design that comprises an ion selection chamber in which ions are selected for detection based on their mass-to-charge ratio (m/Q) by subjecting them to a non-rotating, oscillating electric field that, ignoring any fringing effects, oscillates principally in a single coordinate plane (i.e., the y-z plane). The ions may be injected into the ion selection chamber at a significant angle with respect to the inlet of the chamber and in the single coordinate plane to raise the m/Q resolution to the desired level. In accordance with a further embodiment of the mass analyzer, an ion detection surface is arranged at the outlet of the ion selection chamber so that ions falling within a predetermined exit angle range are detected to the general exclusion of ions having other exit angles.

Abstract: An improved mass analyzer capable of parallel processing one or more analytes is set fourth. The mass analyzer comprises a mass filter unit having a plurality of ion selection chambers disposed in parallel with one another. Each of the plurality of ion selection chambers respectively includes an ion inlet lying in an inlet plane and an ion outlet lying in an outlet plane. The mass analyzer further includes a plurality of electrodes disposed in the ion selection chambers and at least one RF signal generator connected to the plurality of electrodes to produce a non-rotating, oscillating electric field in each ion selection chambers. A plurality of ion injectors are each coupled to inject an ion beam into the ion inlet of a respective ion selection chambers. The ions meeting predetermined m/Q requirements pass through the ion selection chambers to contact corresponding detection surfaces of an ion detector array.

Abstract: The present invention relates to an apparatus and method for focusing, separating, and detecting gas-phase ions using the principles of quadrupole fields, substantially at or near atmospheric pressure. Ions are entrained in a concentric flow of gas and travel through a high-transmission element into a RF/DC quadrupole, through a second high-transmission element, and then impact on an ion detector, such as a faraday plate; or through an aperture with subsequent identification by a mass spectrometer. Ions with stable trajectories pass through the RF/DC quadrupole while ions with unstable trajectories drift off-axis collide with the rods and are lost. Embodiments of this invention are devices and methods for focusing, separating and detecting gas-phase ions without the need for a vacuum chamber when coupled to atmospheric ionization sources.

Abstract: An improved mass analyzer is set forth. In accordance with one embodiment, the mass analyzer employs a unique mass filter design that comprises an ion selection chamber in which ions are selected for detection based on their mass-to-charge ratio (m/Q) by subjecting them to a non-rotating, oscillating electric field that, ignoring any fringing effects, oscillates principally in a single coordinate plane (i.e., the y-z plane). The ions may be injected into the ion selection chamber at a significant angle with respect to the inlet of the chamber and in the single coordinate plane to raise the m/Q resolution to the desired level. In accordance with a further embodiment of the mass analyzer, an ion detection surface is arranged at the outlet of the ion selection chamber so that ions falling within a predetermined exit angle range are detected to the general exclusion of ions having other exit angles.

Abstract: A technique for providing a grid for a gate such as utilized in gating a stream of ions or other particles in a spectrometer instrument. The grid of wires may, for example, be a so-called Bradbury-Nielson Gate that consists of a set of two electrically isolated sets of equally spaced wires that lie substantially in the same plane and alternate in potential. The method utilized to provide is to first fabricate a frame of an insulating substrate having a hole and depositing metal film patterns such that conductive portions are formed on either side of the hole. Conductive portions on either side form a series of terminating pads on the portion of the substrate closest to the hole and a bus bar. Grid wires are then formed by stretching a section of wire with desired constant tension across the hole and bonding the ends of the wire to a respective one of the pads on one side and bus bar on the other side. The method provides a rapid, inexpensive way to fabricate such modulating devices.

Abstract: A mass spectrometer that includes an ion source, an ion trap, and a light detection module. The ion trap has two end-cap electrodes and a ring electrode. The ring electrode is positioned relative to the end-cap electrodes to confine a charged particle from the ion source within a confinement region when an audio frequency voltage having a first amplitude is applied between the ring electrode and the two end-cap electrodes. The charged particle is ejected from the ion trap when the audio frequency voltage increases to a second amplitude. The light detection module includes a light source that illuminates the ejected particle and a light detector that detects light scattered from the ejected particle.

Abstract: An improved mass analyzer capable of parallel processing one or more analytes is set forth. The mass analyzer comprises a mass filter unit having a plurality of ion selection chambers disposed in parallel with one another. Each of the plurality of ion selection chambers respectively includes an ion inlet lying in an inlet plane and an ion outlet lying in an outlet plane. The mass analyzer further includes a plurality of electrodes disposed in the ion selection chambers and at least one RF signal generator connected to the plurality of electrodes to produce a non-rotating, oscillating electric field in each ion selection chambers. A plurality of ion injectors are each coupled to inject an ion beam into the ion inlet of a respective ion selection chambers. The ions meeting predetermined m/Q requirements pass through the ion selection chambers to contact corresponding detection surfaces of an ion detector array.

Abstract: Ion guides and systems and methods for involving the use of ion guides are disclosed. Briefly described, one exemplary system, among others, includes an ion guide. The ion guide includes a first structure and a second structure. The second structure is coaxially disposed within the first structure. The second structure includes at least three groups of opening the through a wall of the second structure that are distributed around a circumference of the second structure. In addition, at least one of the group of openings is offset from the other groups of openings by a multiple of a constant rotation angle around the circumference of the second structure.

Abstract: An improved method of operating a mass spectrometer having a linear ion trap wherein ions are axially ejected from the trap to a detector or subsequent mass analysis stage. The DC barrier field produced at the exit lens of the trap is scanned in conjunction with the scanning of other fields used to energize ions of select mass-to-charge ratios past the barrier field/exit lens. The technique can maximize the resolution obtainable from axial ejection over a wide mass range.

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 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 mass spectrometer (MS) which uses the Fourier transform ion cyclotron resonance (FTICR) technique to determine the mass of ions. The MS is prepared with a surface that guarantees that a particle striking the surface will have at least one contact with the cathode and will most likely be re-pumped before escaping into the vacuum chamber volume.

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: In a quadrupole mass spectrometer, a controlling portion controls a lens power source to temporarily change a voltage applied to an ion lens according to a timing for controlling a quadrupole power source, so that excessive ions do not pass through a quadrupole filter. Therefore, the excessive ions are diffused on the way to thereby prevent the excessive ions from reaching a detector. Thus, at the time of operation, a large quantity of ions, such as carrier gas molecular ions, unnecessary for the analysis is prevented from being introduced into the detector to deteriorate thereof.

Abstract: The invention relates to a tandem mass spectrometer and a method for scanning daughter ion spectra which uses a quadrupole mass spectrometer for selection of parent ions and another one for the measurement of the daughter ions. The invention consists of not using a conventional third quadrupole filter as a collision cell for fragmentation of the parent ions but an ion guide system with helically coiled wires, especially in the form of a double helix, in which the ions can be completely decelerated and can be actively fed to the outlet aperture.

Abstract: A field ionizing element formed of a membrane that houses electrodes therein that are located closer to one another than the mean free path of the gas being ionized. The membrane includes a supporting portion, and a non supporting portion where the ions are formed. The membrane may be used as the front end for a number of different applications including a mass spectrometer, a rotating field mass spectrometer, a thruster, an ion mobility element, or an electrochemical device such as a fuel cell.

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: It is intended to prevent occurrence of random noise in an ion trap mass spectrometer with an electron impact (EI) ion source during mass analyzing. Specifically, two gates are placed between a filament and an end cap electrode. Positive or negative voltage is applied to the two electrodes in such a manner as to prevent both ions and electrons from entering an ion trap region in a mass analyzing step. This eliminates random noise on a mass spectrum, thereby allowing mass spectrum measurement of smaller quantities of components. It also eliminates noise on a chromatogram, thus allowing quantitative analysis of smaller quantities of components.

Abstract: The invention relates to a device and a method for the alternating operation of ion sources at mass spectrometers equipped with RF multipole ion guides. Designing at least one of the RF multiple ion guides movable perpendicular to the axis, makes it possible to perform a vacuum-internal source exchange, without having to vent the vacuum system.

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: 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: A miniature multipole rod assembly, an apparatus and a technique for constructing such an assembly used for ion guide and mass spectrometers.

Abstract: The invention relates to a tandem mass spectrometer and a method for scanning daughter ion spectra which uses a quadrupole mass spectrometer for selection of parent ions and another one for the measurement of the daughter ions.

Abstract: A miniature multipole rod assembly which can be operated as an ion guide or a mass analyzer is constructed by bonding individual rods directly to plates which are separated by ceramic insulators. The multipole rod assemblies are constructed by using a fixture which locates and orients all elements during the process or bonding the rods to the disks.

Abstract: A quadrupole electrode assembly for a mass spectrometer and a method for forming the electrode assembly are provided. The quadrupole electrode assembly is comprised of an elongate outer tube, having an internal surface and an external surface wherein the outer tube is the outermost structure of the electrode assembly and supports a vacuum, and an electrode structure fused to the internal surface of the outer tube. Typically, there are four electrodes where each electrode includes an arced region having a conductive surface. The arced regions of the electrodes are aligned in parallel opposing pairs equidistant from a central axis. The four electrode structures can be four cylindrical glass tubes where the curvature of the arced region approximates a hyperbola. At least a portion of the surface of the arced region is a conductive region typically formed by applying a metal coating to the surface of the glass tube.

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

Abstract: Multipole technology is used generally for charged particle optics which includes separating, focusing, or collimating "charged particles" (i.e., ions, electrons, etc.). A primary application of multipole technology is mass filters and particularly quadrupole mass filters. A quadrupole mass filter has a quadrupole substrate having four poles, each having a generally hyperbolic cross section, and interconnected by bridges. The bridges have apertures that facilitate the construction of poles inside the quadrupole substrate and prevent the build-up of unwanted charge. A plating substrate for electroplating is bonded to each pole substrate with a thin-film adhesion layer. Poles are electroplated upon these plating substrates. A diffusion barrier layer prevents the portions of the plating substrates from migrating to the quadrupole substrate where they would undermine the thin-film adhesion layer.

Abstract: Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions.

Abstract: A mass spectrometer includes an ion source for ionizing a sample substance to provide an ion current of predetermined beam width and energy. A mass filter includes a plurality of drift tubes wherein succeeding drift tubes are of increasing length separated by gaps that increase in length. The ion current is supplied to the mass filter along with an alternating current electrical signal in a manner so that particles having a predetermined mass receive a predetermined maximum energy increase while traversing the mass filter and so that particles not having the predetermined mass do not receive the maximum energy increase. A detector is provided to create an energy barrier whereby only particles that receive the maximum energy increase will have sufficient to completely traverse the barrier. Particles which traverse the barrier are detected thereby to determine the amount of particles having a predetermined mass that were contained in the sample substance.

Abstract: This invention relates generally to a method of operating an ion trap mass spectrometer to determine the resonant excitation frequencies of trapped ions. This can be achieved by: (1) introducing sample ions into the ion trap volume: (2) adjusting the trapping fields so that parent ions having a mass-to-charge ratio of interest which are to undergo collision induced dissociation (CID) are trapped; (3) applying an excitation voltage of predetermined frequency and amplitude across the end caps of the ion trap; (4) scanning the frequency of the excitation voltage in a first direction and monitoring for ejection of the parent ions; (5) repeating steps (1) through (3) and scanning the frequency of the excitation voltage in an opposite direction and monitoring for ejection of the parent ions; (6) averaging the frequencies at which the ions are ejected; and (7) applying that frequency in a subsequent MS/MS scan to promote CID of the parent ions to form daughter ions.

Abstract: A non-invasive apparatus for continuously measuring the cardiac output and cardio-respiratory function includes a gas sampling device which is inserted into the mouth of a human subject. The gas sampling device may be a disposable endotracheal tube or a smaller disposable mouthpiece. Each of these gas sampling devices is provided with a plurality of passages for sampling the lung gases and for continuously sampling the gas pressure on opposite sides of a capillary restriction member. A miniature motor pump mass spectrometer module is mounted on the upper end of the endotracheal tube or mouthpiece. Electronic circuitry connected to the mass spectrometer permits constant visual monitoring of the cardiac output and cardio-respiratory function.

Abstract: A desired mass domain excitation profile is selected and converted to a frequency domain excitation spectrum in which the frequency of excitation is generally proportional to the inverse of the mass-to-charge ratio. In the direct method of the invention, the specified frequency domain spectrum is converted by inverse Fourier transformation to a time domain waveform and multiplied by an expanded window function. The time domain waveform is forward Fourier transformed to produce a second discrete frequency spectrum each frequency of which is assigned a phase scrambled such that maximum reduction of peak excitation voltage is achieved with no distortion of the excitation amplitude spectrum. The phase-scrambled frequency spectrum is inverse Fourier transformed to produce the final time domain waveform which is used to generate the electric field which excites the ions in an ion cyclotron resonance cell.

Abstract: A quartz quadrupole comprises a quartz substrate, conductive strips and low-conductivity strips. The substrate includes hyperbolic inner surfaces which provide the geometry for the conformed conductive strips to produce an appropriate electric field for mass filter operation. The use of quartz as a substrate material provides the thermal and electrical characteristics required by high performance mass filtering operations, including scanning mode operation to 800 amu and above. During such operation, potential field distortions by accumulated charge in cusp sections of the substrate are minimized by the low-conductivity strips, which are arranged to overlap longitudinal edges of the conductive strips. Formation of the quartz substrate is made possible by high precision machining, grinding and polishing of a refractory metal mandrel. The actual step of forming the substrate is simplified by the low thermal coefficient of expansion of the quartz.

Abstract: For eliminating undesirable charged low-mass particles from the measuring cell of an ion cyclotron resonance spectrometer the electrodes normally required for exciting the cyclotron movement are supplied with an rf voltage having a frequency twice as high as the resonance frequency of the trapping oscillation of the charged particles between the trapping electrodes provided perpendicularly to the homogenous magnetic field of the spectrometer. In this manner, the low-mass charged particles are excited to perform trapping oscillations in the direction of the homogenous magnetic field which cause the charged particles to overcome the trapping potentials and, thus, to be eliminated.

Abstract: Methods and apparatus for improving the performance of triple quadrupole tandem mass spectrometers consisting of constructing the collision cell surrounding the second quadrupole structure, into which collision gas is admitted, with end plates composed of leaky dielectric material which appear to radio-frequency electric fields as a dielectric and to dc electric fields as a conductor. The result is that the rf fringe fields extend farther away from the ends of the poles of the first and third analyzing quadrupole mass filter than do the dc fringe fields, thus keeping the ions on stable trajectories in the regions between the analyzing quadrupoles and the end plates of the collision cell, and improving the transmission of ions. The effect is enhanced by applying the same frequency and phase of the ac voltages applied to all three quadrupole structures.

Abstract: A timer circuit is powered by an alternating current (AC) from an AC source which current is rectified to produce direct current (DC) and used to energize a power transistor connected between the DC source and in a load. A separate timing control circuit responds to a selected one of a plurality of AC input signals to provide multiple time delay control signals for initially actuating the power transistor to provide a current flow to the load and, subsequently for turning off the power transistor. The timing circuit uses a controlled charging of a timing capacitor to trigger a unijunction transistor into conduction. The unijunction transistor, in turn, develops an output voltage for actuating an SCR. The SCR is connected with its current conducting path across the load, e.g., across a relay coil, and is used to short-circuit the relay coil when the SCR is actuated into conduction.

Abstract: The spark source spectrographic analysis process and apparatus utilizes an ion source with two electrodes connected to electrical excitation means making it possible to produce discharges between them and means for directing the ions formed in this source to a mass spectrograph, together with means which make it possible for the spectrograph only to analyze the ions produced by discharges having a given direction.

Abstract: Pulses of ionized gas mixtures are generated periodically, to be entrained and accelerated inside a vessel in a predetermined direction by magnetic waves traveling transverse to the plasma motion. Phase coherence between the pulse train and the magnetic waves is maintained. The forces exerted by the magnetic waves cause the ion mixture of each pulse packet to be sorted into several separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased. The waves then drive each packet into a separate branch of the vessel for recovery. The distance between these branches depends on the timing of the mixed pulse relative to the crest of the magnetic waves, on ion mass-to-charge differences, and on the intensity of the magnetic field. The separation efficiency may be enhanced by reducing the intensity of the magnetic field, by raising its frequency, and by shortening the mixed plasma packets while increasing their density.