Abstract: The present invention provides a method of calibrating an analytical tool. The method, in a illustrative embodiment, includes preparing a calibration standard having a known concentration of an element and obtaining a portion of the calibration standard with a focused beam, wherein the calibration standard is representative of the concentration. The portion of the calibration standard is then used to calibrate an analytical tool.

Abstract: An electronic ion detection system which may detect low-energy charge particles such as ions from, for example, a mass spectrometer system. The capacitive sensors are located with two plates which are separated by an insulator. The ions which impinge on one of the plates cause charge to be created. That charge may be amplified and then handled by a charge mode amplifier such as a CCD sensor. That CCD sensor may operate using fill and spill operations.

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

Abstract: An ion-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: A mass spectrometer method and apparatus has a mass analyzer and a collision cell. The collision cell is configured to trap ions. Precursor ions are selected in the first mass analyzer and then subject to collision-induced dissociation in the collision cell. The fragment ions are then scanned out axially by application of suitable excitation to the ions. The fragment ions can then be detected by a time of flight (TOF) mass spectrometer. For a TOF spectrometer, trapping fragment ions in the collision cell and scanning them out can give enhanced sensitivity.

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 Faraday collector for measuring ion currents in mass spectrometers, having a cup (11) for capturing the ions, an entrance slit (14) and a secondary electron diaphragm (13) is configured in a special way. The cup (11) consists of two half-shells (18, 19) of solid graphite and his held in a frame (12) with insulators (30).

Abstract: An electronic ion detection system which may detect low-energy charge particles such as ions from, for example, a mass spectrometer system. The capacitive sensors are located with two plates which are separated by an insulator. The ions which impinge on one of the plates cause charge to be created. That charge may be amplified and then handled by a charge mode amplifier such as a CCD sensor. That CCD sensor may operate using fill and spill operations.

Abstract: An ion separation instrument includes an ion source coupled to at least a first ion mobility spectrometer having an ion outlet coupled to a mass spectrometer. In one embodiment, the ion source includes a molecule separation instrument operable to separate ions in time according to a molecular characteristic such as ion retention time. The resultant instrument is thus operable to provide molecular information separated in time as functions of retention time, ion mobility and ion mass/charge. In another embodiment, the ion separation instrument includes first and second ion mobility instruments disposed in a cascade arrangement between the ion source and mass spectrometer, wherein the two ion mobility instruments are operable to separate ions in time each according to different ion mobility functions.

Abstract: An ion transfer assembly for transferring ions from an atmospheric pressure ion source into an ion trap mass spectrometer with reduced random noise during analysis of the transferred ions. A method of reducing noise due to charged particles, undesolvated charged droplets, or ions in an ion trap mass spectrometer connected to an atmospheric pressure ionization source.

Abstract: An electron impact elastic recoil hydrogen atom analyzer includes an electron gun that projects an electron beam on a surface of a specimen for electron bombardment to make hydrogen atoms contained in the specimen elastically recoil, a hydrogen detecting unit that detects hydrogen atoms emitted from the specimen, and a data processing unit that determines a depth-distribution of hydrogen in the specimen on the basis of data provided by the hydrogen detecting unit. The hydrogen detecting unit includes an ionizer for ionizing hydrogen atoms emitted from the specimen, a deflector for energy analysis of hydrogen ions, and an electron multiplying channel plate for detecting the deflected hydrogen ions.

Abstract: An array of ion detectors (30) comprising a plurality of pickup electrodes (20, 34) for receiving ions; a substrate (32); a plurality of insulators (22, 35) positioned respectively between said pickup electrodes (20, 34) and said substrate (32); a plurality of charge storage areas (12, 38) for storing charge received by said pickup electrodes (20, 34), wherein each area (12, 38) is connected to a particular pickup electrode (20, 34) and means (44) for determining the amount of charge collected by each charge storage area.

Abstract: A penning type gauge head with an electrode system comprising an anode and a cathode disposed in the magnetic field of a permanent magnet, including an ignition aid for the electrode system. In order to provide rapid and reliable ignition, the ignition aid consists of a least one metal strip attached on the anode, and the free end of the ignition aid extends in the direction toward the cathode.

Abstract: Improvements for viewing particles, e.g. electrons or ions, in mass spectrometer systems. A special kind of system allows a phosphor to be formed which does not include any kind of conductive layer thereon. The particles impinge directly on the phosphor, and produce light that shines through an ITO layer. This special system enables lower voltage, and smaller systems. Another improvement enables direct viewing of ions from the system.

Abstract: A magnetic field type mass spectrometer having an ion source, an ion accelerator, a mass separation magnet forming an analyzing part which changes the trajectory of ions by a magnetic field of the mass separation magnet, and a current detector, wherein the mass separation magnet is installed so that ions move along a trajectory which turns several times in the analyzing part, and repelling electrodes are installed at turning points of the ions, whereby ions generated from the ion source are caused to move along a trajectory which turns several times in the analyzing part. Mass separation is carried out along each trajectory, which provides high resolution.

Abstract: A multiple charged-particle detector system includes a plurality of charged-particle detector assemblies (10-12) which are each made up of a first arm (19-22) and a second arm (24-27) extending at an angle to each other. Charged particles (4-7) enter an aperture (14-18) at the entrance of the first arm (19-22) of each detector assembly (10-12) and strike a dynode (30-33) positioned at the intersection of the two arms causing electrons to be emitted by the dynode (30-33). Some of the electrons pass into the second arms (24-27) of the detector assemblies (10-12) and are detected by a continuous-dynode electron multiplier (35-38). The first arms (19-22) are narrower than the detectors (35-38), and the detector assemblies (10-12) are arranged in such a way that the minimum separation at which charged-particle beams (4-7) can be detected is determined by the widths of the said first arms (19-22) of the detector assemblies (10-12), and not by the widths of the detectors (35-38) themselves.

Abstract: A negative ion beam source includes a heated refractory metal ribbon which is positioned adjacent a beam forming electrode that is, biased to repel positive ions emitted from the metal ribbon. An extraction electrode is juxtaposed to the beam forming electrode and includes an aperture for passing a beam of positive ions generated by the metal ribbon. The extraction electrode includes a cesium chamber with openings that are directed towards the refractory metal ribbon. A heater heats the cesium chamber and causes it to expel cesium neutrals towards a surface of the refractory metal ribbon where the cesium neutrals are ionized to positively charged cesium ions. A target is displaced to one side of a perpendicular from the surface of the refractory metal ribbon and is positioned adjacent a negative ion beam forming electrode that is biased to attract the cesium ion beam and to repel negative ions produced by cesium ion bombardment of the target.

Abstract: An object of the present invention is to provide a detection system wherein ion counting is performed by varying the quantity of the ions incident on a detector 13 of an inductive plasma mass spectrometer depending on the concentration of the impurities to be measured, thereby extending the life of the detector 13, expanding the range for measurement of impurities in high concentrations, and reducing costs. An assist electrode 30 having a hole for leading the ions which have passed through a mass filter 10 to a detector 30 is disposed between the axis of the mass filter 10 and the detector 13, and a means for applying voltage to a repeller electrode 12 and the assist electrode 30 is provided to vary the difference in voltage between the electrodes 12 and 30 depending on the concentration of impurities to be measured.

Abstract: Compact and economical apparatus for use in accelerator mass spectrometry for mass selection and attenuation of each isotope by a predetermined fraction that is necessary to permit isotope sequencing through the accelerator stage, by a rotating shutter whose attenuation characteristics are defined by its mechanical shape.

Abstract: A focused electron-bombarded (FEB) ion detector comprising an MCP, focusing means, and a collection anode disposed in a detector body. The collection anode includes a diode for receiving the focused output electron beam from the MCP. The gain between the input ion current to the MCP and the detector output signal from the diode is on the order of 1-100 million, depending on the device configuration and applied biasing voltages.

Abstract: A portable mass spectrometer is described having one or more electrostatic focusing sectors and a magnetic focusing sector, all of which are positioned inside a vacuum chamber, and all of which may be adjusted via adjustment means accessible from outside the vacuum chamber. Mounting of the magnetic sector entirely within the vacuum chamber permits smaller magnets to be used, thus permitting reductions in both weight and bulk.

Abstract: A magnetic mass spectrometer having a one or two-dimensional ion detector for simultaneously detecting all ions focused and separated by the magnetic field. An electrostatic or magnetic octupole lens producing an octupole field is disposed in the ion path between the magnetic field and the detector.

Abstract: There is disclosed a mass spectrometer which is equipped with a simultaneous detection-type ion detector including a microchannel plate but provides improved sensitivity. The spectrometer has an ion source, a mass analyzer for dispersing and focusing the ions introduced from the source according to their mass-to-charge ratios, three electrodes each taking the form of a flat plate, as well as the detector. The electrodes are disposed on the ion path between the mass analyzer and the detector. The electrodes produce a focusing action not in the direction in which the ions are dispersed according to their mass-to-charge ratios but in the direction perpendicular to that direction. The electrodes are spaced from each other in the direction in which the ions travel. Each electrode is provided with a rectangular hole to pass the ions. The dimension of this hole taken in the direction in which the ions are dispersed is sufficiently longer than the dimension taken in the direction perpendicular to that direction.

Abstract: A secondary ion mass analyzing apparatus is suitable for a depth directional analysis of a specimen. The apparatus includes means for forming an image of said secondary ions, an aperture disposed on a position in which the secondary ion image is formed, means for detecting the secondary ions which have passed through the aperture and for converting the detected ions into electrical signals, and means for displaying an image of said aperture based on the electrical signals. In such a manner, the aperture is disposed on the secondary ion image forming position. The image of the aperture is displayed on the image displaying apparatus by using the secondary ions which have passed through the aperture. If the ion image is not formed on the position of the aperture, the contour of the aperture image would be unclear while if the ion image is formed on the position of the aperture, the contour of the aperture image would be clear.

Abstract: An improved electro-optical ion detector comprising a channel electron multiplier assembly located at the angled focal plane of the magnetic sector of a scanning mass spectrometer with a twisted fiberoptic window with a means for precisely optically coupling the assembly to the twisted fiberoptic window. Means are provided for precisely spacing the entrance end of said twisted fiberoptic window in the form of a foil of a selected thickness. Also disclosed is a method for making an improved electro-optical ion detector.

Abstract: This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

Abstract: There is disclosed a mass spectrometer capable of multiple simultaneous detection. The operation mode of the instrument can be switched between a mode in which a wide mass range is obtained and another mode in which high resolution is obtained. The spectrometer includes a mass analyzer having at least a sector magnetic field and a two-dimensional ion detector placed along a focal plane of the analyzer. The detector detects simultaneously ions focused and dispersed by the analyzer according to mass-to-charge ratio. A lens means having variable magnitude is disposed in the ion path between the magnetic field and the detector. A position-adjusting means places the detector along the focal plane which differs, depending upon the magnitude of the lens means. There is further disclosed a mass spectrometer which is capable of multiple simultaneous detection and includes said lens means and a lens magnitude-varying means. In this instrument, the lens means consists of two quadrupole lenses arranged in series.

Abstract: A mass spectrometer, including an evacuable vessle, mass separation means provided in the evacuable vessel for separating ions in accordance with the mass thereof, and ion detection means provided in the evacuable vessel for detecting ions emitted from the mass separation means to convert the emitted ions into an electric signal, in which the ion detection means includes an electron-multiplier for detecting positive ions and a photo-multiplier for detecting negative ions. According to this mass spectrometer, positive ions can be detected at high sensitivity, and negative ions are readily detected.

Abstract: A scanning mass spectrometer (10) in combination with an electro-optical detector (100) which enable greatly increased speed of mass determinations by detecting a limited range of masses simultaneously, thus reducing the number of discrete magnetic field adjustments required over a large range of masses. The electro-optical detector (100) includes a channel electron multiplier assembly (94) with the surface of an image plate (80) located along the ion focal plane (44) and at an angle to the exit plate (106) of the magnetic sector (26) and a fiberoptic window (134) of a special shape optically coupled between the angled image plate (80) and a photodiode detector array (140).

Abstract: The invention provides a mass spectrometer comprising an ion source provided with an electron emitting source and magnets which are cooperable to produce a collimated electron beam within the ion source; a mass analyzer; first and second electrodes which cooperate to limit the angular divergence of the ion beam which emerges from the source along the ion beam axis; and magnetic field screens disposed between the first and second electrode means, which reduce the field due to the magnets along the ion beam axis. In this way the mass discrimination introduced by the magnets in prior ion sources is reduced and the accuracy of isotropic ratio measurements is improved.

Abstract: The invention relates to a double focusing mass spectrometer with a combination of an electric and of a magnetic field for directional and velocity focusing. In order to provide a compact and constructionally simple arrangement, it is proposed that a common magnet is used for the Wien filter (10) and the sector magnet (11). Preferably, this double focusing mass spectrometer is used in an MS/MS arrangement.

Abstract: An apparatus for mass-analyzing ions that are generated by bombarding sample components supported by a target by a primary beam. The mass spectrum data thus obtained is preferably as correct as possible. To satisfy this requirement, mass number sweeping is started after the quantity of ions generated from the sample components becomes gets stabilized.

Abstract: A high current (0.2 to at least 2 milliamperes), low-energy (2.2 to 4 MV) ion beam is generated and is utilized to produce clinically significant quantities of medical isotopes useful in applications such as positron emission tomography. For a preferred embodiment, a tandem accelerator is utilized. Negative ions generated by a high current negative-ion source are accelerated by an electrostatic accelerator in which the necessary high voltage is produced by a solid state power supply. The accelerated ions then enter a stripping cell which removes electrons from the ions, converting them into positive ions. The positive ions are then accelerated to a target which is preferably at ground potential.

Abstract: In a mass analyzer, an acceleration voltage is applied to an ionization chamber in which a voltage to be applied to repeller electrodes to repel ions is generated with reference to the acceleration voltage and a repeller voltage source is linked with a controller by use of a photocoupler or the like such that the repeller voltage is adjusted with the repeller voltage source electrically insulated from the controller. The repeller voltage can be easily and automatically adjusted by use of a low-voltage control signal so as to obtain a sensitivity developing the maximum value of the quantity of detected ions and hence a qualitative or quantitative analysis of a sample can be achieved with a high sensitivity. The controller processes digital signals and appropriate parameters are stored in a memory. Each parameter is changed with the center of change set to an appropriate parameter previously used and consequently the automatic control is simplified.

Abstract: The invention provides a mass spectrometer capable of detecting both positive and negative ions. Positive ions emerging from the mass analyzer strike a conversion electrode to release secondary electrons which pass through an annular electrode to strike a phosphor, releasing photons. Negative ions strike the surface of the annular electrode to release secondary electrons which also strike the phosphor, releasing photons. The photons are detected with a conventional photomultiplier. The electrodes are biased and disposed so that both positive ions and negative ions may be detected without changing the potentials applied to them.

Abstract: A secondary ion mass spectrometry system and method is described which operates several orders of magnitude more quickly than previous systems, and captures information that might previously have been missed. A parallel detection approach is used which simultaneously monitors all secondary ion masses of interest, as opposed to prior serial approaches which sense only one ion mass at a time. The secondary ions are spatially separated according to mass and sensed by a detector array. An ion-electron converter and amplifier, implemented as a microchannel plate assembly, is preferably interfaced between the mass separator and detector. The detector preferably uses an array of wires to collect charge emitted by the microchannel plate. The wires are coupled to output lines by an encoding scheme which allows many fewer output lines to be employed than there are wires.

Abstract: An electric beam integrated circuit tester including a source of primary electrons, a support for the integrated circuit, and an electronic column fixed above the support for the integrated circuit for focusing the primary electron beam emitted at the surface of the circuit on the points of the circuit to be tested. It also includes an accelerator of the secondary electrons emitted by the integrated circuit in a direction colinear and opposite that of the primary electron beam, a separator with three pole pieces for directing out of the column the beam of secondary electrons accelerated by the accelerator and an energy spectrometer coupled to the separator and fixed to the outside of the column for analyzing, depending on their energy, the electrons of the beam of secondary electrons emitted separately by the separator.

Abstract: Improved methods and apparatus are disclosed for detecting negative ions and, more particularly, for detecting negative ions produced from a quadrupole mass spectrometer. By modulating the ion beam either at the ion source or within the ion focusing system, the output current from the electron multiplier detector is a pulsating current which is then capacitively or inductively coupled from a high direct current potential to ground level. Electronics operating at ground level are employed to correct the current signal distortion due to the capacitive or inductive coupling of the detector output current. The present invention enables substantially increased detector sensitivity to negative ions compared to prior art equipment, and does not require expensive and complex preamplifier circuitry. The techniques of the present invention allow both positive and negative ions to be detected utilizing the same basic equipment, thereby increasing equipment versatility and reducing costs.

Abstract: The invention relates to a mass spectrometer having a magnetic sector analyzer in which the magnetic field is developed neither by a permanent magnet nor by an electromagnet having the conventional ferromagnetic core. In particular, the spectrometer has a magnetic sector analyzer through which ions of a mass-to-charge ratio selected by said analyzer may travel along a substantially circular trajectory disposed in a first plane, said analyzer comprising at least two electrical conductor portions of substantially circular arcuate form, respectively of greater and smaller radius than said circular trajectory and disposed on radially opposite sides of a curved plane which is aligned with said circular trajectory and perpendicular to said first plane, and wherein substantially all of the magnetic flux generated by the passage of electrical current through said conductor portions passes only through non-ferromagnetic materials.

Abstract: In a mass spectrometer, suitable for use in the determination of isotope ratios, having as a mass selector a sector magnet and detector means for detecting and measuring the intensity of ion beams at two or more positions in the focal plane of said sector magnet, the improvement comprises providing the exit (and optionally also the entrance) pole face of said sector magnet with a curvature such that the focal plane of said sector magnet lies substantially at right angles to the ion optical axis as it passes through said focal plane. With this arrangement, motion of detector means between positions in said focal plane by means of mechanical linkages controlled from outside the vacuum system of the mass spectrometer is facilitated.

Abstract: An apparatus and method for measuring the atomic mass of ion species selected by the analyzing magnet (14) of an ion implanter (10). A signal proportional to the magnetic field of the analyzing magnet is obtained by means of a rotating coil (36), and this signal is used to calculate the atomic mass by means of the equation: Atomic Mass=KB.sup.2 /V where B is the magnetic field, V is the ion beam energy at the analyzing magnet, and K is a proportionality constant. The rotating coil (36) is driven by a synchronous motor (38) powered by A.C. line voltage, and the output voltage is converted to a frequency signal proportional to the magnetic field and the line frequency. The frequency signal is counted over a time corresponding to the period of the line frequency to cancel out the line frequency dependence of the frequency signal. In accordance with one embodiment of the invention, a microprocessor is utilized to evaluate the B and V signals and to calculate the atomic mass.

Abstract: The invention relates to a miniature magnetic spectrometer with a coaxial structure. This spectrometer, associated with a particle generator, comprises a transformer producing a magnetic field for deflecting the charged particles injected at one end of the spectrometer body. The transformer is provided with a secondary circuit, constituting the spectrometer body, formed by an external conductor in short-circuit with an internal conductor and coaxial to the external conductor. These two conductors define an annular space in which can move the charged particles. Means for detecting the deflected particles, disposed at a second end of the spectrometer body, means for selecting the particles in accordance with their injected angle and a converter element for the particles placed in the annular space level with the first end also being provided.

Abstract: In a mass spectrometer of the magnetic field type for analyzing the mass of ions by causing an ion beam to pass through a narrow slit and then through a deflecting magnetic field to be detected by an ion detector where the intensity of the deflecting magnetic field is varied, plural electrostatic quadrupole lenses are provided between the source slit and the deflecting magnetic field so as to give a converging property to an ion beam passing in a direction vertical to the median plane thereof and to give a diverging property to an ion beam passing in the direction of the radius thereof. This minimizes the gap spacing between the magnetic pole pieces which form the deflecting magnetic field, thereby improving sensitivity and detection as well as accuracy and measurement.

Abstract: A neutral particle analyzer has a stripping cell for converting a neutral beam into a charged particle beam, a momentum analyzer for deflecting paths of respective charged particles of the charged particle beam emerging from the stripping cell in correspondence with momenta thereof, and a semiconductor energy analyzer comprising a plurality of semiconductor detectors which are arranged in the paths of deflected charged particle beams emerging from the momentum analyzer. The semiconductor energy analyzer generates pulse signals having pulse heights corresponding to masses of and kinetic energies of the deflected charged particles of the deflected charged particle beams.

Abstract: A mass spectrometer comprises a source for generating ions, a means for separating the ions according to mass, and means for detecting the separated ions. The mass spectrometer is characterized by that means for separating ions comprises a sector type homogenous magnetic field, and that the magnetic field has a deflection angle ranging from 110 to 135 degrees, and incident and exit angles ranging from 40 to 60 degrees.

Abstract: In a mass spectrometer, stabilization control is effected by modulating the unidirectional ion acceleration voltage with a low-amplitude constant-frequency modulation signal, preferably at the frequency of an A.C. source used to energize the instrument, producing an A.C. modulation component in the ion collector output; that modulation component of the output is detected to develop an error signal indicative of the direction of deviation of the acceleration voltage from an optimum condition of maximized output current and the error signal is employed to adjust the acceleration voltage to stabilize operation at the optimum condition. A corresponding control can be effected by modulation of the magnetic field that deflects the ion stream to impinge on the collector.

Abstract: Panoramic detector of ions spatially distributed in different beams, comprising a plane symmetry diaphragm having an opening permitting the passage of the beams and which is brought to earth potential, an electrode for converting ions into electrons having an opening facing the diaphragm opening, the conversion electrode having the same plane of plane symmetry and being brought to a negative potential relative to the earth potential, and a planar electrode facing the conversion electrode and brought to a positive potential relative to the potential of the conversion electrode, the face of the conversion electrode facing the planar electrode having a predetermined shape in such a way that the electron beams formed retain the same spatial distribution as the beams of ion to be detected in the presence of an applied magnetic field.

Abstract: Mass spectrograph comprising an ion source, means for analyzing the ions emitted by this source and a panoramic ion detector, wherein the analysis means are of the type with magnetic separation and measurement of the time of flight and the ion source is a pulsed source.The panoramic ion detector comprises an ion inlet diaphragm, means facing the diaphragm which permit the conversion of ions into electrons, means facing the means for converting the ions into electrons and permitting the conversion of electrons into photons, a photon detector facing the means for converting the electrons into photons and photon guidance means located between the means for converting electrons into photons and the photon detector whereby the photon guidance means have a monoblock structure.

Abstract: .[.A negative ion detector converts negative ions to positive ions by means of a conversion anode which is maintained at a relatively high positive voltage. The resultant positive ions are detected by a standard continuous dynode electron multiplier which has its detection signal output at ground potential..]. .Iadd.Apparatus for detecting the abundance of negative ions from a source of negative ions, having a first conversion dynode and an electron multiplier, the electron multiplier having a second conversion dynode. The first conversion dynode is operated at a high positive potential to attract the negative ions whereby the negative ions impact the first conversion dynode with a substantial portion of the negative ions being converted to secondary positive ions.

Abstract: A high current (0.2 to at least 2 milliamperes), low-energy (2.2 to 4 MV) ion beam is generated and is utilized to produce clinically significant quantities of medical isotopes useful in applications such as positron emission tomography. For a preferred embodiment, a tandem accelerator is utilized. Negative ions generated by a high current negative-ion source are accelerated by an electrostatic accelerator in which the necessary high voltage is produced by a solid state power supply. The accelerated ions then enter a stripping cell which removes electrons from the ions, converting them into positive ions. The positive ions are then accelerated to a target which is preferably at ground potential.