Abstract: An electron beam tester (11) utilizes a source (13) of stored electrons to produce a probing beam (14) of short pulses and high intensity. The high intensity improves the signal-to-noise ratio of the potential being measured and is especially suited for measuring potentials in high speed integrated circuits (19) while they are operating. The cyclotron principle is adapted for storing the electrons in an orbital configuration wherein the electrons are clustered in bunches having substantially the same energy level. These characteristics of the electrons in a beam facilitate its operation and control in an electron beam tester for contactless monitoring of voltage potentials in an operating high speed integrated circuit.

Abstract: An apparatus for forming a beam includes a housing, electromagnetic coils and/or electrostatic devices for combining a plurality of individual beams into a single beam. Deflection mirrors can be used to deflect the combined beam in a predetermined direction. The beams so combined can include beams of a constant wave or beams in pulse formation. The electromagnetic energy may include visible and non-visible rays, infrared rays, as well as particles. Laser beams can be used employing CO2 X-rays, and Argon, among others. The application has navigational, medicinal, and military uses, among other such as total disruption of enemy's guidance, communication and detection devices employing radar. Also, total incapability of "heat-seeking" aircraft destruction devices to be effective against aircraft fitted with this invention.

Abstract: A charge forming system and apparatus for introducing ion source materials into the ion source vaporizer of an ion implant instrument is disclosed.

Abstract: There is provided a mass spectrometer adapted for the elemental analysis of a sample, especially a solid sample, comprising a glow discharge ion source which yields ions characteristic of the elements in the sample. The background spectrum produced by such a mass spectrometer is substantially reduced by cooling the ion source below 20.degree. C., and preferably below -100.degree. C., thereby increasing the sensitivity and the accuracy of the spectrometer. The cooling of the ion source is preferably accomplished by flowing liquid nitrogen through a heat exchanger disposed in good thermal contact with it.

Abstract: An ion source application device comprising a gas tight plasma formation chamber sustaining a plasma produced by high frequency discharge, a high frequency coil producing the high frequency discharge, and means for extracting an ion beam from the plasma thus produced, characterized in that it comprises further an electron beam generator or a laser light generator as means for obtaining electrons serving as seeds for starting the high frequency discharge.

Abstract: An improved liquid chromatography/mass spectrometer apparatus is disclosed of the type wherein the liquid eluent from a chromatograph column is injected as a heated spray into an ionization chamber located between the chromatograph and the mass spectrometer to form ionized adducts containing solvent and the molecule to be analyzed which are then passed into the mass spectrometer through an exit port in the sidewall of the ionization chamber. The improvement comprises an acceleration electrode located in the sidewall of the ionization chamber at a position opposite the exit port into the mass spectrometer, an electron emission source located between the acceleration electrode and the point of injection of the heated spray into the chamber, and means for providing a positive voltage on the acceleration electrode with respect to the electron emission source in the ionization chamber.

Abstract: An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases.

Abstract: A sputtering type of a metal ion source includes a microwave radiation means and a pair of magnetic poles to which a negative electric potential is applied. The magnetic pole acts as an electrode for retarding electrons when a sputtering target is placed at the pointed end of the magnetic pole, high density ions generated by the operation of PIG (Penning Ionization Guage) discharge and a magnetic field efficiently bombard and sputter a target, and a microwave discharge acts as an electron supplying source so that a stable discharge is maintained.

Abstract: A system for implanting ions into a target element including a source arrangement for producing an ion beam; a beam analyzing arrangement for receiving the ion beam and selectively separating various ion species in the beam on the basis of mass to produce an analyzed beam; and a beam resolving arrangement disposed in the path of the analyzed beam for permitting a preselected ion species to pass to the target element. The analyzing arrangement has an ion dispersion plane associated therewith. The source arrangement has an associated ion emitting envelope including an area of substantial extension in a plane parallel to the ion dispersion plane and producing ions entering said analyzing arrangement which are travelling substantially either toward or from a common apparent line object lying in a plane perpendicular to the ion dispersion plane.

Abstract: An ion source device comprises a plasma generating vessel for generating plasma therein, a plurality of magnets arranged on an outer periphery of the plasma generating vessel to establish a cusp field in the plasma generating vessel, means for supplying a power to generate the plasma in the plasma generating vessel, and an anode electrode arranged on an inner wall of the plasma generating vessel and adapted to be heated by electrons emitted from the plasma and maintain the heat.

Abstract: An improved ion source for characterization of a surface of a sample including a housing oriented about a central axis, Z; a magnet cooperatively disposed within the housing for producing a magnetic field along the Z axis direction an anode radially disposed within the housing and within the magnetic field of the magnet that defines an annular ionization chamber having an open annular space and further forming a central tubular space about the Z axis; a cathode cooperatively disposed at the anode and within the annular ionization chamber; an extractor grids means cooperatively disposed within the housing so as to form a boundary of the ionization chamber; annular focusing rings disposed on the housing and externally to the extractor grids for focusing ions emerging therefrom; neutralizer filament cooperatively disposed with focusing rings; a central lens cooperatively disposed about the central axis Z in the central tubular space formed by the anode and adapted to accept ions and neutrals emanating from a sam

Abstract: A method and apparatus for producing ions by surface ionization by increasing the molecular energy of the substance to be ionized to the hyperthermal energy range, and directing a beam of the substance to impinge against a solid surface disposed in a vacuum chamber. The solid surface is one e.g., clean diamond or dirty molybdenum, which is capable of inducing from the substance, e.g., an organic halide, molecular ionization or dissociative ionization of the substance, and one which does not react with the molecules or tend to neutralize the produced ions. The molecular energy includes kinetic energy gained in aerodynamic acceleration by seeding a light gas, e.g., hydrogen or helium, with molecules of the substance to be ionized, thereby producing a hyperthermal beam of 0.5-20 electron volts of the substance to be ionized.

Abstract: Ion source including an electric discharge chamber body divided by a partition, having an anode electrode therein, into a main discharge chamber and a subsidiary discharge chamber. The subsidiary discharge chamber has a filament mounted therein aligned with at least one small opening through the partition wall and the anode electrode. An inert gas opening is provided into the subsidiary discharge chamber. An electric discharge gas opening and an ion outlet opening are provided to the main discharge chamber. Magnets are provided outside of the chamber body for creating a magnetic field extending nearly along an axis of the at least one small opening in the anode electrode.

Abstract: A source of clusters of atoms is provided, wherein the clusters are thermally conditioned after their formation so that the clusters are in the liquid state. A beam of clusters is first formed during the mixing of a stream of atoms and a carrier gas. The beam of clusters mixed with carrier gas is passed through a conditioner, preferably including a heated drift tube, to bring the clusters to a temperature whereat the clusters are in a condensed state without crystalline order, comparable to the liquid state. The conditioned cluster beam passes to vacuum, with separation and removal of a large portion of the carrier gas mixed therewith, so that cooling of the clusters in the cluster beam is minimized during their flight to the cluster target.

Abstract: A diode flood gun for introducing an amplified current of low energy electrons into an ion beam for neutralizing charge build up on a target such as a semiconductor wafer during irradiation by the beam. The low energy, amplified current is effected by introducing an inert gas into the flood gun.

Abstract: A scanned electron beam system employs an electron beam source using an NEA activated photo-emitter as the cathode. The activated photo-emitter cathode produces a pre-shaped electron beam having a relatively small spot focussed on a target plane. The beam is selectively deflected to scan the beam spot along the target plane to expose desired patterns on that plane. The distance between the cathode and anode can be made large enough to accommodate in situ replenishment of cathode material, such as Cesium, without obstructing the electron optical path. The system includes two vacuum chambers which are differentially pumped through respective ports. The first chamber, in which the anode and cathode are located, is utilized for establishing the required electrostatic field. The second chamber is employed to produce the necessary focussing and selective beam deflection.

Abstract: An ion source for use in a mass spectrometer comprises a porous member arranged in the ionization chamber and bearing against the inlet tube so as to obstruct the open end of the inlet tube. A particle beam is directed to the effluent which exudes from the surface of the porous member after passing through the porous member. A cover shields a portion of the surface of the porous member from the particle beam so as only the most recently exuded effluent is irradiated. The effluent supplied into the porous member by the inlet tube is allowed to exude from surfaces of the porous member other than the surface bombarded with the particle beam so as to carry away stale effluents.

Abstract: The invention relates to high-powered negative ion generator in a gaseous medium with a high-strength electric field configuration. This high-powered negative ion generator in a gaseous medium with a high-strength electric field configuration comprising two self-contained subsystems:a source of very high negative dc voltage (THT) which is capable of supplying the current required for the second subsystem;an electron optics unit comprising the points emitting electrons (Pte) and the various components (S1, P1, P2, P3) which cannot be separated and which create the configuration of the electric field required for the result it is desired to achieve.

Abstract: This disclosure is concerned with method and apparatus for vaporizing liquid solutions in order to detect, quantitate, and/or determine physical or chemical properties of samples present in liquid solution. Mixtures may be separated by an on-line liquid chromatographic column and the methods used for detection, quantitation, identification, and/or determination of chemical and physical properties include mass spectrometry, photoionization, flame ionization, electron capture, optical photometry, including UV, visible, and IR regions of the spectrum, light scattering, light emission, atomic absorption, and any other technique suitable for detecting or analyzing molecules or particles in a gaseous or vacuum environment. The method and apparatus involves controlled partial vaporization of the solution.

Abstract: Sample material is sputtered from an orifice in a disc mounted in a hollow cathode. A plasma plume is ejected from the orifice and the material sputtered from the smaple is transported directly into the base of the plasma plume. Collisions with particles in the plasma plume excite the sputtered material. Light emission and absorption from the plume are measured and ions in the plume are measured. A chamber surrounding the plasma plume is maintained at about 1 torr. About 15 cc's per minute of argon are supplied to the hollow cathode at 2 torr. The power supply supplies about 200 volts at about 0.10 amps. Low energy argon ions strick the disc at the end of the cathode tube and sputter atoms off the aperture. Atoms collide with particles in the plasma causing excitation, photon emission and ionization of atoms which are measured by optical and mass spectrometers.

Abstract: There is disclosed an ion source for use in a mass spectrometer. The front end of an inlet tube carrying liquid sample reaches into the ionization chamber of the ion source, and is obstructed by a porous member. Sample injected into the porous member from the inlet tube passes through the porous member and exudes from its surface. Then, the sample evaporates into the ionization chamber. The vaporized sample is ionized by electron-impact ionization or chemical ionization.

Abstract: A gas chromatography plus mass spectrometer (GC/MS) system includes a gas chromatograph, a mass spectrometer, and a computer interface to both of them. The mass spectrometer includes an ion source with an electron emission filament which can be damaged if on during the time a solvent peak is eluting from the chromatography. The filament is regulated to provide a constant emission rate by feedback which causes a current source to compensate deviations from a desired emission level. When a solvent peak begins to elute, the concomitant sudden cooling of the filament is sensitively reflected in the feedback to the current source. a comparator AC-coupled to the current source input can be used in shutting off the current source when the emission current abruptly drops. A computer controller can reactivate the filament in response to a decrease in ambient pressure or elapse of a predetermined duration so that component peaks following the solvent peak can be analyzed.

Abstract: An apparatus utilizing charged particles comprises a means for generating charged particles which are irradiated on the surface of a material and a means for generating plasma in the neighborhood of the surface of the material. The plasma generated by the plasma generating means can neutralize incident charge, to prevent an accumulation of the charge on the surface of the material.

Abstract: An inductively-coupled radio frequency plasma mass spectrometer comprises an induction coil for generating a high frequency magnetic field, a plasma torch for causing a plasma by introducing an aerosol therein, and an electrostatic shield, interposed between the induction coil and the plasma torch, for shielding off the plasma from the electric field by the induction coil.

Abstract: An ion source is described, including a source of neutral particles which arrive at an ionization support positioned inside a chamber which is closed by a cap and which includes lateral walls. The cap includes an outlet orifice opposite which a plate defines a main ionization active surface. An electric field is applied between said device and by an electrode place downstream from the orifice in the direction of ion emission and fitted with a corresponding opening. Overall, the ionization support defines, by virtue of its active surface, and by virtue of holes surrounding said central active surface, a baffle assembly which prevents neutral atoms from passing directly to the outlet orifice, and which contributes to a high degree of ionization.

Abstract: A compact, quick-igniting, and high-efficiency Penning-discharge type plasma source which comprises a cathode means for thermionically emitting electrons; an electron emission means disposed inside the cathode; anode means defining a discharge space, for accelerating electrons emitted by said cathode means and said emission means into the discharge space; means for supplying gas to be ionized to the discharge space; and heating means for initially heating the emission means. In a preferred embodiment, the anode means is a planar anode. Initial heating of the emission means by the heater causes electrons to be emitted therefrom. These electrons are accelerated by the planar anode to ionize the gas in the discharge space. An axial magnetic field with axial maximum near the exit aperture in the planar anode optimizes ionization and causes most of the plasma production to occur near the exit aperture, thereby enhancing efficiency of the source. Most of the ions produced exit the source before recombination.

Abstract: A self-cleaning rotating anode x-ray source comprising an evacuable housing, a rotatable cylindrical anode within the housing, a source of electrons within the housing which electrons are caused to impinge upon the anode to produce x-rays, and means for ionizing residual particles within the housing and accelerating such ions so as to impinge upon the anode to sputter impurities from the surface thereof.

Abstract: A microwave ion source is disclosed and includes a plain rectangular waveguide having a first section to which a microwave generator is coupled, a second section defining a discharge chamber and an intervening transformer section dimensioned to provide for transmission of microwaves between the first section and the second section substantially without impedance losses. The first and second sections have uniform rectangular internal cross-sectional shapes defined by a first dimension which, for both sections equals one half of the wavelength of the microwaves, and a second, smaller dimension which is less than the second section of the waveguide than in the first section.

Abstract: Specially shaped filaments improve the performance of Freeman ion sources. There are many different filament shapes covered by this invention. These shapes have two features in common--they have flat surfaces or facets, and two of these facets must join to form a knife edge. It is the purpose of these facets to direct negative ions away from the extraction slit. These negative ions are emitted from the filament normal to the surface. If the knife edge is directed toward the slit, very little of the negative ion flux can enter the extraction slit. In effect, the filament becomes invisible at the slit as far as negative ion flux is concerned. A converse application in which a large negative ion flux is desirable, requires shaping of the filament with a smooth concave surface in order to maximize the cathode surface normal to the extraction slit.

Abstract: A plasma generating device comprises:a rectangular wave guide for transmitting microwaves, wherein the width of the plasma generating device is decreased in the direction of an electrical field of the microwaves; a plasma generating chamber wherein plasma is generated by absorbing, in a gas, microwave energy transmitted by the rectangular wave guide, and a part of the plasma generating chamber has a rectangular cross-section taken along the plane perpendicular to the microwave propagation direction. A magnetic field generating device is provided having the same axial direction as the direction of propagation of the microwaves and applies a magnetic field having an Electron Cyclotron Resonance intensity to the plasma generating chamber.

Abstract: A source (100, 101, 200, 300, 400) of a beam of positive ions or atoms comprises an ion-emission pellet (1, 401) consisting essentially of a solid electrolyte. Preferred solid electrolytes for the pellet (10, 49) are alkali or alkali-earth mordenites. A pellet heater is capable of heating the pellet (1, 401) to an ion-emission temperature at which ions are emitted from the pellet. A beam-forming electrode (2, 4, 31, 60) contacts an ion-emission surface (22) of the pellet (1, 401). The beat-forming electrode (2, 4,31, 60) has at least one passageway extending through it into which ions from the ion-emission surface (22) can pass. Ions emitted into the passageway are discharged from the source as unneutralized ions or neutralized atoms.

Abstract: A system for post analysis acceleration of an ion beam to a selected energy without beam blow-up. A group of electrodes extablish a non-linear voltage gradient along the beam axis for accelerating and then decelerating the beam to the selected energy level with focusing.

Abstract: The ion source comprises a cathode, an intermediate electrode and an anode with two ionization chambers between these electrodes, means for producing an axial magnetic field, means for applying a DC voltage between an intermediate electrode and the anode, ion extraction means and an alternating voltage generator between the cathode and the intermediate electrode.

Abstract: An electron cyclotron resonance (ECR) plasma source for generating a plasma for etching, deposition, pre-deposition and material property modification processes. The plasma source includes two magnetic field sources. The first magnetic field source provides a magnetic field of sufficient intensity to achieve an ECR condition for a given microwave frequency input beam. The second magnetic field source enhances the uniformity of the plasma formed and the uniformity of the output by creating a uniform field region in the plasma generating chamber. The second magnetic field source also reduces the magnetic field so that the plasma near the extraction system and the output extracted are less magnetized. The magnetic field intensity, longitudinal position, radial position and pole orientation are design variables for adjusting the second magnetic field source to enhance uniformity and reduce the magnetization of the output.

Abstract: The electron gun comprises an ionization chamber, adjacent to a high voltage chamber. In the wall common the both chambers provision is made for an extraction grid. On the opposite side, the ionization chamber comprises an outlet window for the electrons similar in shape to the extraction grid, and accompanied by a fine metallic foil. The high voltage chamber comprises a cathode brought to a high negative voltage. By giving the two grids the shape of similar parallel strips, a masking effect and a focusing effect are obtained at one and the same time which allows the efficiency of the electron gun to be increased.

Abstract: A mixture of an alkali metal compound and its reducing agent is heated by a heating means, whereby alkali metal vapors are generated and stored in a vapor reserver. The thus stored vapors permeate through a porous member heated by another heating means and are ionized. The thus formed ions are withdrawn by an ion withdrawal means.

Abstract: An ion emmisive head for fusing a metal to emit ion beam is disclosed, wherein a fused metal is designed to infiltrate through a porous portion for flow control and to reach an extremely sharpened needle which is provided after infiltration and wherefrom the fused metal is converted to ion beam by electrical action. Thus, ionized metallic beam is rendered to have smaller width or more focused ray. Submicron technology used in the IC industry, for instance, desires far thinner, finer beam line to attain more compact circuits, which need will be responded in the present invention by disposing a tipping needle to extend out of a porous tip portion which receives the fused metal from melting zone. Appropriate combination of sharpness at the needle point and provision of a beam guiding electrode in neighborhood of an emitting needle point enable to produce about 0.1 micron beam width by prevention of plasma ball which will otherwise diffuse the emitted beam.

Abstract: This invention relates to a liquid metal ion source which melts a source material and extracts ions. Stable extraction of ions of at least one element selected from among As, P and B for a long period of time can be attained by using as a source material an alloy having a composition represented by the formula L.sub.X R.sub.Y M.sub.A wherein X, Y and A each stands for atomic percentage; L at least one element selected from among Pt, Pd and Ag; R at least one element selected from among As, P and B; M at least one element selected from among Ge, Si and Sb; 5<A<50; 40<X<70; and X+Y+A=100.

Abstract: A thin film manufacturing and processing apparatus by using an ion beam comprises a plasma producing vessel for producing therein a plasma by ionizing a neutral gas, an electrode assembly for extracting ions in the form of an ion beam from the plasma, a vacuum container accomodating therein a target to be worked through irradiation of the ion beam, and permanent magnets disposed on the outer periphery of the plasma generating vessel which is formed of a nonmagnetic material and serves as an anode electrode. An ion beam of high uniformity and a large diameter can be obtained to allow manufacture and processing of large scale magnetic thin films and semiconductors with high precision.

Abstract: Metal tetrafluoroborates, alkali and alkaline earth tetrafluoroborates in particular, and preferably lithium tetrafluoroborate are used as ion source materials in ion implantation of semiconductor materials with boron.

Abstract: An ion source (10) of the side-extraction hot cathode type in which the inherent drift of electrons toward the positive side of the cathode is minimized by the addition of auxiliary electrodes (31, 32) which surround the cathode (14) at the ends of the anode (12). The electrodes are electrically isolated from the cathode and anode, and various means are provided to apply a potentials to the electrodes, including interconnecting the electrodes, cross-connecting the electrodes to opposite ends of the cathode, and biasing the electrodes at fixed potentials with respect to the cathode, anode or ground.

Abstract: An electron cyclotron resonance negative ion source comprises an enclosure containing a gas or vapor of a material for forming a plasma, means for injecting into the enclosure a high frequency electromagnetic field forming electrons by ionizing the gas or vapor, means for producing within the enclosure an axially symmetric magnetic field whose amplitude increases along the axis of symmetry, whereby said amplitude, which is at a maximum in the vicinity of and upstream of the negative ion extraction zone, having in the central region of the enclosure a value for which the electron cyclotron resonance condition is satisfied, as well as means for extracting the negative ions formed, brought to a positive potential compared with the enclosure.

Abstract: A corrosion-resistant, long-life, high-capacity, power-efficient source substructure for a source of liquid-metal ions useable in focused-ion-beam apparatus. The substructure takes the form of an elongate carbon needle, pointed at one end, structurally supported entirely within the turns of an electrical heating coil having end leads which are conductively connected to, and structurally supported by, a pair of larger cross section electrical feeder legs.

Abstract: A method and apparatus for the production of cluster ions, and preferably isotopic hydrogen cluster ions is disclosed. A gas, preferably comprising a carrier gas and a substrate gas, is cooled to about its boiling point and expanded through a supersonic nozzle into a region maintained at a low pressure. Means are provided for the generation of a plasma in the gas before or just as it enters the nozzle.

Abstract: A method for operating an ion source having a filament-cathode and an anode. The method includes supplying direct current electrical power between the anode and the filament-cathode characterized by substantially constant arc current there between and varying arc voltage on the filament-cathode. Direct current electrical power is also supplied across the filament-cathode. The value of the arc voltage is monitored and the magnitude of electrical power supplied to the filament-cathode is altered in response to detected changes in the arc voltage to return the arc voltage to substantially a preset reference value. The monitoring step and the altering step are carried out at regular preset intervals. The altering step includes deriving an filament power error signal as a prearranged function which includes the difference in values between the monitored arc voltage and the preset reference value multiplied by a predefined integral gain value.

Abstract: U-shaped billet (52) has a slot (54) cut therein for receipt of a slip of insulator material (56). This body is machined on its front end (64) to produce a narrow bridge (66) of controlled cross-sectional area. Emitter needle (78) is positioned in a bore through the bridge to be heated by current through the bridge. The ion emitter body is rigid and strong to hold the emitter needle in the proper location.

Abstract: An ion plasma electron gun for the generation of large area electron beams with uniform electron distribution. Positive ions generated by a wire in a plasma discharge chamber are accelerated through an extraction grid into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam. After passage through an extraction grid and plasma discharge chamber, the electron beam exits from the gun by way of a second grid and a foil window supported on the second grid. The gun is constructed so that the electron beam passing through the foil window has a relatively large area and uniform electron distribution which is substantially the same as the ion distribution of the ion beam impinging upon the cathode.

Abstract: An electron beam-excited ion beam source having a plasma region, an accelerating cathode, an electron beam accelerating region, an accelerating anode, an ion producing region and a target cathode in this order, and further comprising means for applying a negative electric potential to the target cathode as against the accelerating cathode and an ion extracting electrode for extracting positive ions or negative ions produced in the ion producing region whereby a high current ion beam can be obtained in a low input power.

Abstract: An ion-producing apparatus comprises an electron-producing vessel having an electron-producing chamber, an ion-producing vessel having an ion-producing chamber communicating with the electron-producing chamber, a cathode provided at one end of the electron-producing vessel, an accelerating electrode provided within the ion-producing chamber, for allowing passage of electrons, an anode provided between the cathode and the accelerating electrode, and a power supply circuit for providing a potential difference between the cathode and the anode, thereby to produce electrons in the gap between the cathode and the anode. A vacuum pump is provided for evacuating gas from the ion-producing chamber. A partition is provided within the electron-producing vessel, between the cathode and the anode to divide the electron-producing vessel into a cathode-side chamber and an anode-side chamber, and hinders a gas flow from the cathode-side chamber to the anode-side chamber to apply a pressure difference between both chambers.

Abstract: A compact radiation source is obtainable by cascade ionization of a high pressure gas jet as it emerges into a vacuum. The high frequency electric field causing the ionization can be supplied by either microwave or infra-red means. The radiation produced includes ions, atoms, plasma or light, in particular, vacuum ultraviolet radiation.