Abstract: A double grid anode is characterized in that said anode is comprised of a first cage-like anode made of a metal grid or wire gauze that permits that passage of electrons and that has an open end, a second anode which also consists of a metal grid or wire gauze located at the open end side of said first anode, a hot-cathode filament arranged around the outer periphery of said first anode, and an ion-extraction electrode which faces said anode.

Abstract: The disclosed negative ion source uses a solid-state element having a semiconductor portion, which source includes a region adapted to dissociate molecules of hydrogen or deuterium in said solid-state element by dissolution, another region adapted to convert the atoms generated through the dissociation of said molecules into negative ions as said atoms reach the proximity of surface of said solid-state element through diffusion process by resonance transition of electrons in said solid-state element and to liberate the thus produced negative ions from said surface by hot electrons in said solid-state element, wherein the dissociation, electronic resonance transition, and liberation continuously occur in succession.

Abstract: An ion source apparatus of surface ionization type comprises an emitter tip in the form of a round rod having a sharp-pointed end, an ion source material holder for holding the emitter tip coaxially within a crucible made of a material of a high melting point, the crucible having an opening formed in a bottom wall thereof through which the sharp-pointed end of the emitter tip extends outwardly, the ion source material is being filled in the crucible so as to enclose the outer periphery of the sharp-pointed end of the emitter tip, a filament for emitting electrons with which the emitter tip is bombarded from below, a heating power supply for the filament, an ion beam extracting electrode disposed between the emitter tip and the filament and maintained at a potential of a substantially the level as that of the filament, and an accelerating voltage power supply for applying a high voltage between the ion beam extracting electrode and the emitter tip to accelerate the electrons and ion beam.

Abstract: A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them.

Abstract: An improved crossed-beam charge-exchange ion gun in which a synthetic plasma is formed by injecting an electron beam into a collimated molecular beam just before the molecules are ionized by charge exchange with a crossed primary ion beam, thereby forming a secondary ion beam from the ionized but space-charge-neutralized and substantially undeflected molecular beam. The plasma thus formed extends to an aperture stop in an aperture tube which extends upstream from an anode downstream of which anode a cathode is placed. A field is formed within the cathode/anode space and within the aperture tube into which the plasma extends. The sheath edge of the plasma within the tube is curved by the field to form a meniscus, and the aperture, being smaller in area than the secondary ion beam upstream of the aperture, both collimates the secondary ion beam and acts as a lens stop for the subsequent immersion lens formed by the meniscus and the field region.

Abstract: The present invention provides, in a preferred embodiment, a cylindrical stainless steel cathode with end pieces thereon to form a cathode chamber within. In addition, in a preferred embodiment, there is a stainless steel rod which passes axially through the cathode chamber and which is electrically insulated therefrom at the end pieces. The stainless steel cathode has first and second apertures formed therein with the first to be connected to a source of ionizable gas and the second to act as the opening through which there passes a stream of ions to an ion beam target. A magnetic flux source is coupled to the cathode chamber to pass magnetic flux therethrough and a voltage source is connected between the anode and the cathode to provide an electrostatic field therebetween whereby when ionizable gas is fed into the cathode chamber, it is ionized and a stream of ions emanates from the second aperture.

Abstract: A technique for providing an ion beam of variable focussing (concentration) is described using a flexible grid for extracting and accelerating ions from an ion plasma. The grid is electrically conducting and will bow depending on a voltage difference between it and the ion plasma. This bowing of the grid from its initial planar configuration provides focussing of the ion beam. The amount of focussing depends upon the amount the grid is bowed, which in turn depends upon the voltage difference between it and the ion plasma. The same ion source/flexible grid combination can be used for different operations as for example, providing a collimated, low energy ion beam over a large area and then for providing a focussed ion beam of high energy onto a small area.

Abstract: A single-ring magnetic cusp low gas pressure ion source designed for use in a sealed, nonpumped neutron generator utilizes a cathode and an anode, three electrically floating electrodes (a reflector behind the cathode, a heat shield around the anode, and an aperture plate), together with a single ring-cusp magnetic field, to establish and energy-filtering mechanism for producing atomic-hydrogen ions.

Abstract: A gas is introduced into a discharge chamber of an ion source apparatus, and a gas discharge is performed between a thermionic cathode and an anode. Ions are extracted from the plasma formed in this gas discharge by a grid electrode. The thermionic cathode has a hollow cylindrical shape. A cathode chamber is defined by the thermionic cathode and a cylindrical partition wall supporting it. A columnar auxiliary electrode is coaxially inserted in the thermionic cathode. An A.C. voltage from a power source unit is supplied between the thermionic cathode and the auxiliary electrode such that effective power for keeping the thermionic cathode at a positive potential with respect to the auxiliary electrode is higher than that for keeping the auxiliary electrode at a positive potential with respect to the thermionic cathode.

Abstract: Method and device for furnishing an ion stream by causing gas to flow through a discharge aperture having a diameter of at most 20 .mu.m into an evacuated chamber and ionizing said gas by means of one or a plurality of focused electron beams downstream of said aperture in which the ionization is effected immediately downstream of said discharge aperture.

Abstract: An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

Abstract: An ionization source is disclosed for use with mass spectrometers and electron capture species detectors having an ionization light source excited so as to illuminate a fluid sample which flows past the light source whereby electrons are photoelectrically generated by a light source. Means are also provided to accelerate the photoelectrons and to extract heavy ions generated by the accelerated photoelectrons from the fluid sample. Further means are provided to focus the extracted heavy ions so that they may be detected. Also included is a means to maintain a vacuum between the light source and the sample and the detector.

Abstract: The invention relates to an ion source.This source comprises a gas ionization chamber, an electron source and means for oscillating the electrons in the chamber, so as to produce an ionization zone of the gas. The means for oscillating the electrons comprise two identical electron lenses, whose axes coincide with the oscillation direction, two spherical concave mirrors turned towards one another and positioned respectively on either side of the two lenses and whose centers respectively coincide with the foci of the lenses, the electron source being positioned at the focus of one of the two lenses.Application to the analysis of gases by mass spectrometry.

Abstract: A reservoir, extracting electrode and circular tungsten filament are maintained at high positive D.C. potential relative to a grounded electrode. Thermal electrons emanated from the filament irradiates and heats the bottom of the reservoir. As a result, powdered CsI held in the reservoir is melted and then forms a liquid CsI cone-shaped portion below the capillary formed at the reservoir bottom. Vaporized CsI molecules are created by further heating the cone-shaped portion, and are ionized by electron beam irradiation, so that a Cs.sup.+ ion beam is obtained.

Abstract: A magnetic filter for an ion source reduces the production of undesired ion species and improves the ion beam quality. High-energy ionizing electrons are confined by the magnetic filter to an ion source region, where the high-energy electrons ionize gas molecules. One embodiment of the magnetic filter uses permanent magnets oriented to establish a magnetic field transverse to the direction of travel of ions from the ion source region to the ion extraction region. In another embodiment, low energy 16 eV electrons are injected into the ion source to dissociate gas molecules and undesired ion species into desired ion species.

Abstract: Process for producing highly charged ions making it possible to ionize a gas of neutral atoms by electron impact, the gas being introduced into an ultra-high frequency cavity excited by at least one high frequency electromagnetic field which is associated with a magnetic field, whose amplitude is selected in such a way that the electronic cyclotron frequency associated with said magnetic field is equal to the frequency of the electromagnetic field also established in the cavity, the latter being provided with an opening for the extraction of ions by means of appropriate electrodes, wherein the said magnetic field is constituted by superimposing of a multipole radial magnetic field having a minimum amplitude in the central part of the cavity and a rotationally symmetrical axial magnetic field having a gradient along said axis, the resulting magnetic field being regulated in such a way that in the cavity there is at least one completely closed magnetic layer having no contact with the cavity walls, whereby on s

Abstract: An electron bombardment ion source of the Freeman type incorporates an electrode having multiple segments which are electrically connected in parallel to provide increased surface area for constant cross section.

Abstract: An ionizer adapted to be placed in a vacuum envelope for providing ions of a sample to be analyzed is disclosed herein and includes an electron source, ion accelerating and focusing electrodes and an interchangeable ionization chamber including a first opening for allowing electrons to enter the chamber and an exit opening to allow ions to exit said chamber. The ionization chamber is supported in cooperative relationship with the electron source and accelerating and focusing electrodes whereby electrons enter the chamber through the first opening and form sample ions in the chamber which then exit the chamber through the exit opening toward said accelerating and focusing electrodes.

Abstract: A plurality of magnetic pole pieces are arranged around the external wall of a high temperature plasma confining structure. The pole pieces are positioned between permanent magnets spaced from one another and the confining structure by distances calculated to produce a minimum field toward the center of the structure with an effective containing field around the periphery of the structure. The magnets and the pole pieces are cooled. An odd number of poles are employed such that the missing pole appears as a virtual pole at the extraction slit used for forming an ion beam for ion implantation. The resulting small package multipole plasma containment functions to provide higher beam current, longer source lifetime, higher voltage stability and reduces maintenance and cleaning operations, with the permanent magnets protected from high temperature and corrosive gases.

Abstract: The ion accelerator comprises an arrangement consisting of getter pumps and gas storages. This makes for a possibility of gas pressure and gas phase composition control in the device after its being unsoldered from the vacuum installation. The device is equipped with an evaporator and an additional gas storage which permit renovating the target surface as required. Proposed herein is a method ensuring higher efficiency of the device operation.

Abstract: Molecules are tritiated by depositing molecules of a substance to be tritiated on a supporting substrate in a vacuum chamber, and then subjecting the substance to low pressures of tritium gas. In a second embodiment of the invention, a substance is tritiated by placing the same near, but not in the path of, an electron beam which traverses a chamber; admitting tritium gas into the chamber; and subjecting the tritium to the electron beam thereby generating vibrationally excited tritium gas molecules which collide and react with the substance thus incorporating tritium atoms into the substance.

Abstract: A source for a high density electrically neutral beam of combined positive and negative particles suitable for bombardment and heating of a pellet of nuclear fusion material to fusion temperature. A source mounted in a housing with a spherical substrate and providing free elements at the surface thereof, an electron beam for ionizing the free elements to produce positive ions, first, second and third grids spaced from each other along beam paths, and electron emitters, all for providing positive ion beams and electron beams at the same velocity for mixing to provide an overall neutral electrical charge. A porous substrate for passing a gas under pressure to the surface for ionizing. A porous substrate charged with solids, and a heater for vaporizing the solids for passing to the surface for ionizing.

Abstract: A direct heated rod-shaped cathode for an ion source is provided with a region of reduced cross-section adjacent its negative end to maximize the path length of electron movement within the discharge chamber and to provide effective control of the cathode resistance in a region that is relatively free of sputtering erosion during use.

Abstract: A field emission cathode affording multiple emitting points, formed by a tiplicity of carbon fibers mounted on a conductive base, preferably in spaced clusters of about one thousand or more fibers, and projecting from the base to afford a multiplicity of emission points at the fiber tips. The fibers are in a range of diameters of about two to ten microns. As applied to an electron impact ion source for an instrument such as a mass spectrometer or molecular beam detector, the cathode is of annular configuration, incorporated in an electrode assembly comprising, radially inwardly of the assembly, the cathode, an extraction grid, a retardation grid and an ionization cage.

Abstract: A cryogenic collimator apparatus and method for collimating pyrolysis fragments produced by a pyrolysis unit. The apparatus includes a cryogenic plate having an aperture therein, the plate being adapted to be interposed between the pyrolysis unit and an ionization center so that the aperture is in a direct line between the pyrolysis unit and the ionization center. The method includes using the cryogenic plate for trapping pyrolysis fragments not passing through the aperture directly from the pyrolysis unit.

Abstract: Ionization chamber for the chemical ionization of vapors of substances in ion-molecule reactions by means of ionizing primary particles and a reactance gas, having at least one inlet opening for feeding the reaction partners and at least one outlet opening for the reaction products formed in the chamber. As shown, the ionization chamber has an elongated shape. The inlet opening for the ionizing primary particles on the one hand, and the outlet opening for the reaction products on the other hand, are arranged in alignment in opposite end walls of the ionization chamber.

Abstract: A plasma isotope separation process and apparatus. The plasma must be generated and moved into an excitation region for the differential heating of a selected isotope. This motion is accomplished by a crossed magnetic and electric field whereby charged particles move normal to the direction of both fields. The plasma is generated by electrons liberated from hot filaments and the electric field is generated by a plurality of electrodes forming an anode for providing an electric field in a desired direction. An alternating electric voltage may additionally be imparted to the anode to generate an alternating electric field, thereby to differentially excite the isotope of the plasma.

Abstract: Apparatus to reduce pyrophoricity in deposits collected upon collection plates within a chamber employed for vapor deposition. The apparatus is preferably employed in a chamber utilized for isotopically selective photoexcitation, ionization and separation of metallic uranium vapor. The uranium vapor which collects on all surfaces exposed to it within the chamber is caused to collect in a relatively dense, non-porous body by maintaining a suitably elevated temperature for those surfaces while at the same time keeping the chamber itself cooled. The elevated temperature is achieved by baffles shielding the collection plates from the cooler chamber walls to reduce thermal radiation thereto and/or by applying additional thermal energy to the plates.

Abstract: An ion source using the cyclotron resonance principle is provided using a miniaturized ion source device in an air gap of a small permanent magnet with a substantially uniform field in the air gap of about 0.5 inch. The device and permanent magnet are placed in an enclosure which is maintained at a high vacuum (typically 10.sup.-7 torr) into which a sample gas can be introduced. The ion-beam end of the device is placed very close to an aperture through which an ion beam can exit into apparatus for an experiment.

Abstract: An extended range static eliminator for impinging a stream of ionized air upon light-sensitive articles to be neutralized includes a housing for directing air through an opening therein toward the articles and a plurality of pointed discharge electrodes supported in the housing across the opening and facing opposite the air stream. The electrodes are preferably capacitively coupled to the high side of an A.C. power source to reduce likelihood of arcing while a conductive casing connected to the other side of the power source partially encircles the discharge electrodes to shield the high voltage field at the base of the electrodes from the ions emitted from the points thereof and further shield the sensitive articles from corona developed around the points.

Abstract: An apparatus for ionizing and vaporizing non-volatile or thermally labile molecules of a sample for introduction into a mass spectrometer analyzer which comprises a housing containing an ionization chamber; an ion exit port for the introduction of gaseous ions from said ionization chamber into a mass spectrometer analyzer on the portion of the housing attached to said mass spectrometer analyzer; inlet means for introducing a gaseous reactant into said ionization chamber within said housing; inlet means for admitting high energy radiation into said ionization chamber within said housing to at least partially ionize the molecules of said gaseous reactant; aperture means open into said ionization chamber of said housing for admitting a conductive emitter characterized by having a conductive element of a highly irregular surface upon which is deposited said sample for analysis into said mass spectrometer analyzer; and a vacuum exit aperture in said housing by which the pressure within said ionization chamber can

Abstract: A method has been devised whereby material is removed from a solid surface and ionized to produce singly charged monatomic ions representative of the surface. A sample of the material (or surface) is mounted in place of the repeller electrode of an ion source, biased negatively with respect to the source's block and sputtered with argon ions. Some of the sputtered sample material is ionized by charge exchange with the argon ions near the ion source's exit slit and accelerated into a mass analyzer. An electron beam is used to ionize the argon sputtering gas. This method provides an advantage in that the initial kinetic energy spread of the monatomic ions is much lower than with other methods.To perform this method, the solid sample is mounted upon a removable probe which is introduced into the ion source or ion chamber of a mass spectrometer. More specifically, the sample is placed in a recessed cavity in the end of the probe located opposite the exit slit of the ion chamber.

Abstract: A chemical ionization ion source comprising a firt electrode disposed in a discharge region, a counter electrode disposed to confront the first electrode and having at least one space for introducing electrons generated in the discharge region into an ionization region and means for maintaining the counter electrode at a potential higher than that of the first electrode and applying a direct current voltage between the two electrodes, wherein the discharge region and the ionization region are maintained under substantially the same pressures.

Abstract: A reduced size ion source for on-line use with a cyclotron heavy-ion beam is provided. A sixfold reduction in source volume while operating with similar input power levels results in a 2000.degree. C. operating temperature. A combined target/window normally provides the reaction products for ionization while isolating the ion source plasma from the cyclotron beam line vacuum. A graphite felt catcher stops the recoiling reaction products and releases them into the plasma through diffusion and evaporation. Other target arrangements are also possible. A twenty-four hour lifetime of unattended operation is achieved, and a wider range of elements can be studied than was heretofore possible.

Abstract: A long life, high emission electron source for a plasma environment. The plasma environment is made up of corrosive particles having a lower work function than the exposed material of the electron source. The electron source is operated at an elevated temperature not only to provide free electrons but also to establish and maintain a thin partial monolayer coating of the source's emissive surface with plasma particles in an equilibrium between condensation and evaporation. The equilibrium coating increases the emissivity of the surface without permitting substantial corrosion of the surface or structure from the particles of the plasma environment. The cooler regions of the electron source are shielded from the plasma particles to prevent a build-up of corrosive particles.

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

Abstract: A power supply for the cathode of an electron beam gun disposed in a vacuum chamber comprises a transformer for frequencies above about 20 kHz and having a primary winding and a secondary winding connected to the cathode. The transformer is mounted so as to integrate same into the vacuum chamber to dispose the primary winding in communication with the atmosphere and the secondary winding in communication with the vacuum chamber. A partition is disposed between the primary winding and the secondary winding to seal the primary winding from the vacuum and the seondary winding from the atmosphere. A control circuit receptive of a direct current supply has the output thereof connected to the primary winding of the transformer and has pulse width controlled transistors for the chopping of the direct current at a frequency above about 20 kHz.

Abstract: An ion source is described in which a compound of the material of a desired ion is dissociated in a plasma discharge process to provide a beam of charged particles including the desired ions. The proportion of the desired ion in the particle beam is selected by adjustment of the temperature of the plasma, and, for increasing the range of selection of obtainable proportions, various means are described for increasing the plasma temperature beyond that which was previously attainable in ion sources of this type.

Abstract: Ion sources which become coated with insulative materials are rejuvenated by forming the repeller electrode in the ion source of gold and bombarding such repeller electrode with ions to sputter the gold onto the coated surfaces to render them conductive again. Gold sputtering is accomplished by bombarding the gold repeller electrode with inert argon ions.To perform this method, the slit of the extractor plate on the ion source is greatly reduced in cross-sectional area such that the normally higher sputtering pressures may be maintained within the ion source itself. If a direct sample probe is used, it too may be formed of gold and used to provide the gold sputtering source.

Abstract: A source of a tubular beam of ions comprising a cylindrical shell with one butt end having an axial hole in it and the other butt end solid. It is provided with a rod having one end fixed to the solid butt end of the cylindrical shell and arranged coaxially to the latter. The free end of the rod carries a disc placed in the axial hole of the butt end of the cylindrical shell so as to obtain a circular gap confined by the side wall of the hole. A hollow annular shell is arranged coaxially within the cylindrical shell so that a circular gap made in the butt end of the annular shell faces the circular gap in the butt end of the cylindrical shell. An annular cathode and an anode are arranged coaxially inside the annular shell. A thermoelectronic cathode is placed outside the cylindrical shell near to its butt end with the circular gap. An electromagnet coil is arranged coaxially inside the cylindrical shell. A device for ion acceleration is placed on the path of emission of the ions.

Abstract: The invention provides a method and apparatus for generating large quantities of singlet oxygen and/or ozone at unexpectedly high efficiencies. An electron beam generated by a hollow cathode plasma discharge device (HCD) is spread by disclosed means over an electron-transmissive window past which is flowing an oxygen-containing atmosphere at a high velocity.

Abstract: Finely divided borides, carbides, and nitrides of metals of Groups III-VI of the Periodic Table, formed by reacting vaporous metal halide and a boron, carbon, or nitrogen source reactant at high temperatures, e.g., 1500.degree. C., are separated from gaseous reactor effluent stream at temperatures between about 200.degree. C. and 1500.degree. C. with the use of a porous sintered filter. By separating the finely divided product from the effluent stream before the stream cools to below about 200.degree. C., adsorption of impurities, e.g., unreacted metal halide or metal subhalides, on the product is reduced. The use of a filter, e.g., a porous sintered filter, avoids the size classification of product which may result when cyclones and a bag filter are used to collect product.

Abstract: Apparatus and a method for electrically sweeping particles from a gaseous effluent are disclosed which are particularly efficient in removing small as well as large particles. A voltage is applied across two electrodes in such a way that a strong electric field can be generated between them. A source of ions is provided by bombardment of the effluent gas stream with electrons. A strong electric field established between the electrodes creates at least one region of ions having only one polarity and moves these ions towards the oppositely charged electrode. In the region having ions of one sign, these ions rapidly charge the particles, especially small sized particles because of the strong electric field. The charged particles are moved by the field and deposited on the oppositely charged collection electrode where they agglomerate in preparation for collection and disposal.

Abstract: In a quadrupole mass spectrometer enclosed by a high vacuum container and including an ionization chamber, a molecular beam radiator passing through the container and having an output opening for supplying the gas to be analyzed, and a cryopump arranged for receiving the molecular beam exiting from the output opening and serving as a radiation trap, the output opening of the radiator and the cryopump are disposed at the periphery of the ionization chamber preferably diametrically opposite one another.

Abstract: A combined ion source capable of operating either in an electron-impact-ionization mode or in a chemical ionization mode and being quickly shiftable from one mode to the other, consists of a cavity into which either a sample gas can be introduced to be ionized alone or together with a reaction gas introduced into the cavity, the cavity having at least one opening for the introduction of ionizing particles, or radiation, into the cavity and another opening for the discharge of ions, with a flexible band covering the exterior surface of the cavity between the openings, the band having suitable patterns of openings, each of which patterns cooperates with the various openings to provide a specific combination of openings and at the same time adjusting the width of each opening used in each combination.

Abstract: A beam of positive or negative primary ions of at least one compound of a chemical element is accelerated in order to pass through collision boxes placed in series. As a result of inelastic collisions of the ions with the molecules of a neutral target gas within each collision box, a given percentage of primary ions is dissociated into at least two fragments, one of which is a secondary ion in the form of at least two isotopic species. The collision boxes are brought to a potential V.sub.2 so as to trap preferentially one isotopic species which is condensed within each box.

Abstract: A beam-plasma type ion source comprises a first section for generating an electron beam, a cylindrical second section for ionizing a gas by virtue of electron bombardment caused by the electron beam generated from the first section, a microwave energy transmission circuit disposed in the second section and connected to receive microwave energy in order to cause plasma ionization, and a third section for collecting the electron beam. The gas introduced into the third section is ionized at the second section and extracted by and accelerated in the first section in the opposite direction to the electron beam way. The first section functions to converge an ion beam to generate a well-focused ion beam toward a desired target by means of ions trapped into a negative-potential well due to the electron beam.

Abstract: This is an ion-producing source having a distinct chemical ionization configuration and a distinct electron impact configuration. In this source, a hollow chamber including an ion source and a source of sample molecules receives a hollow, slidable cylindrical member having a chemical ionization chamber within it. Orifices in the chamber and the cylindrical member connect the chemical ionization source chamber to the electron source and to the sample molecule source when the cylindrical member is pulled to one position. When the cylindrical member is pulled to another position, the slidable cylindrical member and the inside walls of the chamber define the ionization region to which the electron source and the sample molecule source are directly connected. By moving the cylindrical member, the ionization source can be changed from a chemical ionization source to an electron impact source.

Abstract: A multipurpose apparatus is useful in either prefiltering ions or in forming ions from residual gases, prior to the analysis of the prefiltered or formed ions in a quadrupole type mass spectrometer. The apparatus includes a cylindrical grid, an annular entrance aperture wherein a center circular baffle has a unidimensional electrode extending along the axis of the grid, and a circular exit aperture, the axis of the grid being in line with the axis of a quadrupole type mass analyzer. The application of appropriate potentials to these members allows only low energy ions to pass therethrough and into the quadrupole analyzer. High energy ions or neutral particles having an axial trajectory are blocked by the baffle, while divergent high energy charged particles are insufficiently deflected and hence do not pass through the exit aperture. The apparatus further includes a filament positioned outside the grid, which, when energized, emits electrons.

Abstract: This is an ion-producing source having a distinct chemical ionization configuration and a distinct electron impact configuration. In this source, a hollow chamber including an ion source and a source of sample molecules receives a hollow, slidable cylindrical member having a chemical ionization chamber within it. Orifices in the chamber and the cylindrical member connect the chemical ionization source chamber to the electron source and to the sample molecule source when the cylindrical member is pulled to one position. When the cylindrical member is pulled to another position, the slidable cylindrical member and the inside walls of the chamber define the ionization region to which the electron source and the sample molecule source are directly connected. By moving the cylindrical member, the ionization source can be changed from a chemical ionization source to an electron impact source.