Abstract: An apparatus. The apparatus includes a source of radio-frequency energy and a first transformer coil coupled to the source of RF energy. A second transformer coil, the second transformer coil electromagnetically coupled to the first transformer coil. A modulator is coupled to the source of radio frequency energy, wherein the modulator is configured to receive a modulating signal comprising a pseudorandom bit sequence. The apparatus further includes a power receiver coupled to the second transformer coil.

Abstract: A novel scanning method of a mass spectrometer apparatus is introduced so as to relate by simple time shifts, rather than time dilations, the component signal (“peak”) from each ion even to an arbitrary reference signal produced by a desired homogeneous population of ions. Such a method and system, as introduced herein, is enabled in a novel fashion by scanning exponentially the RF and DC voltages on a quadrupole mass filter versus time while maintaining the RF and DC in constant proportion to each other. In such a novel mode of operation, ion intensity as a function of time is the convolution of a fixed peak shape response with the underlying (unknown) distribution of discrete mass-to-charge ratios (mass spectrum). As a result, the mass distribution can be reconstructed by deconvolution, producing a mass spectrum with enhanced sensitivity and mass resolving power.

Abstract: A method and an apparatus are described to improve the separation capacity of an ion analyzer incorporating at least two stages of ion mobility analysis. The new invention utilizes possible use of different mixtures of gases and dopants in each stage, control over different concentrations of gases and dopants in each stage, and allowance of passage of the selected ions from one stage to the next while avoiding the mixing of the gases and dopants among stages. The new invention also includes a method to reduce the time required to identify the physical properties in a set of ion filters where at least one of the filters is a scannable ion mobility analyzer. The present invention also includes how to provide a set of scannable ion mobility analyzers operating in series, wherein each stage can be operated as a filter, or allowing for the passage of all ions.

Abstract: A method and system for acquiring spectral information from an energy sensitive nuclear detector is disclosed. The method includes detecting nuclear radiation at a detection device and generating an electronic input pulse indicative of energy deposited in the detection device. The method further includes integrating the electronic input pulse at an integrating device to produce an integrated output signal and digitally sampling the integrated output signal of the integrating device at intervals to produce a stream of digital samples. The method further includes resetting the integrator synchronously with a sampling clock when a limit condition is reached.

Abstract: Methods and analyzers useful for time of flight mass spectrometry are provided.

Abstract: A hybrid electrostatic lens is used to shape and focus an ion beam. The hybrid electrostatic lens comprises an Einzel lens defined by an elongated tube having a first and second ends and a first electrode disposed at the first end and a second electrode disposed at the second end. The elongated tube is configured to receive a voltage bias to create an electric field within the Einzel lens as the ion beam travels through the hybrid electrostatic lens. The hybrid electrostatic lens further includes a quadrupole lens having a first stage and a second stage, where each of the stages is defined by a plurality of electrodes turned 90° with respect to each other to define a pathway in the Z direction through the elongated tube. The Einzel lens focuses the ion beam and the quadrupole lens shapes the ion beam.

Abstract: The present invention relates to the analytical electronics used to identify compositions and structures of substances, in particular, to the analyzers comprising at least one mass-spectrometer (MS) and may be applied in such fields as medicine, biology, gas and oil industry, metallurgy, energy, geochemistry, hydrology, ecology. Technical result provides the increase in MS resolution, gain in sensitivity, precision and measurement rates of substances compositions and structures concurrently with enhancement of analyzer functional capabilities, downsizing and mass reduction. In claimed invention the ion flux generation and its guiding are performed in off-axis single-flow mode; parallel multi-stage mode; through use of three-dimensional field with mean meridian surface including without limitation three-dimensional reflecting and dual-zoned reflecting modes or by method of multi-reflection arrays. Devices to implement the claimed method are embodied.

Abstract: A hybrid electrostatic lens is used to shape and focus an ion beam. The hybrid electrostatic lens comprises an Einzel lens defined by an elongated tube having a first and second ends and a first electrode disposed at the first end and a second electrode disposed at the second end. The elongated tube is configured to receive a voltage bias to create an electric field within the Einzel lens as the ion beam travels through the hybrid electrostatic lens. The hybrid electrostatic lens further includes a quadrupole lens having a first stage and a second stage, where each of the stages is defined by a plurality of electrodes turned 90° with respect to each other to define a pathway in the Z direction through the elongated tube. The Einzel lens focuses the ion beam and the quadrupole lens shapes the ion beam.

Abstract: The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Abstract: The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Abstract: The invention relates to the measurement of daughter ion spectra of analyte substances that are ionized by means of matrix-assisted laser desorption. The invention shows how to record several daughter ion spectra from several parent ions per single pulse of laser light, that is per desorption event, by spatially splitting the ion beams or by temporally sequencing the spectral measurement; the various parent ions are selected one after another by switching the parent ion selector several times. Summing up corresponding individual daughter ion spectra from many pulses of laser light leads to several sum spectra being recorded practically synchronously with the same series of laser light pulses, with correspondingly reduced sample consumption and shortened data acquisition time.

Abstract: A method for differential mobility separation of ions using digital-drive based high voltage fast switching electronics. The digital waveform delivered to the spectrometer is characterized by at least two substantially rectangular pulses of different amplitude and polarity. The control circuitry allows for waveform frequency, duty cycle and pulse amplitudes to be varied independently. Balanced as well as unbalanced asymmetric waveforms can be designed for optimum differential mobility separation of ions. The digital drive is designed for differential mobility spectrometers including parallel plate and segmented plate multipoles of planar symmetry, as well as multipoles of cylindrical symmetry, which may optionally be arranged in series. The use of the digital drive establishes alternating electric fields during which the displacement as a result of ion oscillation is determined by mobility coefficients.

Abstract: A system and method for detecting an analyte of interest in a sample is provided. The method includes passing a set of ions obtained from the sample through an ion mobility spectrometer to filter out ions that are not ions of interest and to generate an ion mobility spectrum. A mass spectrum of at least some of the ions is generated using a mass spectrometer. The method also includes determining that the analyte of interest is in the sample when peaks of interest are found in one or more of the ion mobility spectrum and the mass spectrum, and the peaks of interest follow a predetermined pattern of peaks associated with the analyte of interest or are confirmed by ion mobility spectrometry.

Abstract: An ion-ion reaction cell is provided comprising a plurality of electrodes (1) forming an ion guide (2). A transient DC voltage wave is applied to the electrodes (2) in order to load reagent anions into the ion guide (2). Analyte cations are then subsequently transmitted through the ion-ion reaction cell by a subsequent transient DC voltage wave. Ion are arranged to undergo ion-ion reactions within the reaction cell and the resulting fragment ions which are formed within the reaction cell are then subsequently translated out of the reaction cell by means of a transient DC voltage wave.

Abstract: A method for differential mobility separation of ions using digital-drive based high voltage fast switching electronics. The digital waveform delivered to the spectrometer is characterized by at least two substantially rectangular pulses of different amplitude and polarity. The control circuitry allows for waveform frequency, duty cycle and pulse amplitudes to be varied independently. Balanced as well as unbalanced asymmetric waveforms can be designed for optimum differential mobility separation of ions. The digital drive is designed for differential mobility spectrometers including parallel plate and segmented plate multipoles of planar symmetry, as well as multipoles of cylindrical symmetry, which may optionally be arranged in series. The use of the digital drive establishes alternating electric fields during which the displacement as a result of ion oscillation is determined by mobility coefficients.

Abstract: The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Abstract: A novel instrument and method for TOF/TOF mass spectrometry is offered. A spiral trajectory time-of-flight mass spectrometer satisfies the spatial focusing conditions for the direction of flight and a direction orthogonal to the direction of flight whenever ions make a turn in the spiral trajectory. An ion gate for selecting precursor ions is placed in the spiral trajectory of the spiral trajectory time-of-flight mass spectrometer. Electric sectors are placed downstream of the ion gate.

Abstract: An electric field source for a mass spectrometer and a mass spectrometer are described.

Abstract: The invention relates generally to ion mobility based systems, methods and devices for analyzing samples and, more particularly, to sample detection using multiple detection and analytical techniques in combination.

Abstract: The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

Abstract: An ion guide or ion trap (1) is disclosed comprising a segmented linear ion guide or ion trap. Ions are confined radially within the ion guide or ion trap (1) by the application of an AC or RF voltage to the electrodes. A static potential well is maintained along at least a portion of the axial length of the ion guide or ion trap (1). A time varying homogeneous electric field is applied along at least a portion of the axial length of the ion guide or ion trap (1). The combination of the static axial potential well and the time varying axial homogeneous electric field causes ions to be ejected from the ion guide or ion trap (1) in a substantially non-resonant manner.

Abstract: A method for controlling charge flux into a charge accumulation device includes determining a charge accumulation time during which charges are to be accumulated in the charge accumulation device, measuring a charge flux of a first ion beam produced from an ion source, determining a target number of charges to be accumulated in the charge accumulation device during the charge accumulation time based on the measured charge flux and, based on the determined target number of charges, modulating a second ion beam produced from the ion source to cause the target number of charges from the second ion beam to be accumulated in the charge accumulation device during the charge accumulation time. An ion processing device is configured for controlling the charge flux. An ion beam modulator modulates the ion beam.

Abstract: The present invention refers to a radiation system (1) comprising an excentric gantry (100) arranged in connection with multiple treatment rooms (61-68) separated by radiation-shielding separating members (71-78). A movable rotation head (120) is connected to the gantry (100) and is able to move between, and direct a radiation beam (110) into, the treatment rooms (61-68). A simulator head (200-1 to 200-8) is preferably arranged together with the radiation system so it can be used in each respective treatment room (61-68). In such a case, while a first subject (40-1) is being irradiated in a first room (61), a treatment set-up procedure, including correct positioning of subjects (40-2 to 40-8) and irradiation simulation, can simultaneously take place for the other subjects (40-2 to 40-8) in the other treatment rooms (62 to 68).

Abstract: A ribbon ion beam system, comprising an ion source configured to generate a ribbon ion beam along a first beam path, wherein the ribbon ion beam enters a mass analysis magnet having a height dimension (h1) and a long dimension (w1) that is perpendicular to an xy plane, wherein the mass analysis magnet is configured with its momentum dispersive xy plane to receive the ribbon ion beam and to provide magnetic fields to transmit the ribbon ion beam along a second beam path, wherein the ribbon ion beam exiting the mass analysis magnet is divergent in the non-dispersive xz plane and convergent in the xy plane, a mass selection slit for receiving the divergent ribbon ion beam and selecting desired ion species of the ribbon ion beam exiting the mass analysis magnet, an angle correction device configured to receive the divergent ribbon ion beam exiting the mass selection slit into a parallel ribbon ion beam in the horizontal xz plane and a diverging ribbon ion beam in an xy plane along a third beam path, and wherein t

Abstract: An improved rotating electric field ion mass spectrometer (REFIMS) provides for a smooth transition of the input ion beam from zero rotation to the desired level of field rotation. The REFIMS grid shape is changed from a fixed-diameter tunnel to that of a horn. The horn shape has a flare end with a larger entrance width that reduces the grid electric field strength to near zero and causes no abrupt deflection of the beam at the entrance, and tapers along the longitudinal z axis to a narrower width so that the field strength applied to the beam increases gradually until the correct field strength is obtained at its exit end for the desired rotation of the beam. Preferably, the horn shape in cross-section is hyperbolic, and the increase in field strength is approximately linear with distance along the z axis. The horn shaped device can provide a 2D spectral readout in which the ions are imaged on the target plane at radial positions increasing linearly with decreasing atomic mass units (amu).

Abstract: Disclosed is an apparatus for separating ions including a plurality of first electrode portions, each first electrode portion of the plurality of first electrode portions having a first length and an outer surface that is at least partially curved in a direction transverse to the first length. The apparatus also includes a plurality of second electrode portions arranged in an alternating sequence with the plurality of first electrode portions, each second electrode portion of the plurality of second electrode portions having a second length and an outer surface that is curved in a direction transverse to the second length, a space between the outer surface of a first electrode portion and the outer surface of an adjacent second electrode portion defining a portion of an analytical gap for separating ions.

Abstract: An electron beam irradiation apparatus includes a turn-transfer mechanism; a turn irradiation chamber; an electron beam irradiation section; a replacement room configured to bring a target into and out of the turn irradiation chamber; an outer irradiation target holding table configured to form a part of the replacement room, and including an X-ray shielding mechanism, an airtightness maintaining mechanism, a target holding mechanism; an inner irradiation target holding table configured to form a part of the replacement room, and including an X-ray shielding mechanism, an airtightness maintaining mechanism, and a target holding mechanism, the inner irradiation target holding table being supported by the turn-transfer mechanism; a turning mechanism configured to drive the turn-transfer mechanism; and an elevator mechanism configured to move the turn-transfer mechanism, which supports the inner irradiation target holding table, up and down.

Abstract: A system and method for separating ions in an ion mixture, such as a plasma in space. The ion mixture enters an electrostatic analyzer, whose ion path has at least two sections. A first section applies a DC voltage to the ions, and a next section applies an RF frequency voltage to the ions. Appropriate DC and RF voltages are applied, such that at least a portion of the lower mass ions are absorbed into the RF section of the analyzer. The heaver ions are transmitted out of the ion path and are readily available for further analysis.

Abstract: A mass spectrometer is provided for identifying mass and velocity distributions in a continuous ion beam is configured with a circular dispersive system creating a rotating electromagnetic field, which is capable of deflecting the ion beam from an initial direction, and a circular position-sensitive detector intercepting the deflected ion beam and providing information from which the ion mass-per-charge ratio is determined

Abstract: A method for filtering ions having a selected mass-to-charge ratio is set forth. In accordance with the method, one or more ions are injected into ion inlets of first and second ion selection chambers in a generally concurrent manner. The first and second ion selection chambers each have a corresponding ion outlet. The first ion selection chamber has a first plurality of electrodes disposed between the respective ion inlet and ion outlet and the said second ion selection chamber has a second plurality of electrodes disposed between its respective ion inlet and ion outlet. One or more RF signals are applied to the first and second plurality of electrodes to generate a rotating electric field respectively in each of the first and second ion selection chambers. Ions exiting the ion outlets of the first and second ion selection chambers, for example, to generate a mass spectrum for the injected ions.

Abstract: A fluorescent trace material is provided within at least a portion of an electrical contact or interrupter assembly component, or a cavity defined therein. At least a portion of the fluorescent trace material is exposed or released from the electrical contact or interrupter assembly component, indicating a degree of component wear.

Abstract: Systems and methods are provided for focusing a scanned ion beam in an ion implanter. A beam focusing system is provided, comprising first and second magnets providing corresponding magnetic fields that cooperatively provide a magnetic focusing field having a time-varying focusing field center generally corresponding to a time-varying beam position of a scanned ion beam along a scan direction. Methods are presented, comprising providing a focusing field having a focusing field center in the scan plane, and dynamically adjusting the focusing field such that the focusing field center is generally coincident with a time-varying beam position of the scanned ion beam along the scan direction.

Abstract: In a TOF-MS according to the present invention, ions fly a round orbit or a reciprocal path once or more than once to be separated by their mass to charge ratios before they are detected by a detector, The detector is movable at least in two positions, where the effective distances from the exit of the round orbit or the reciprocal path to the detector are different. The length of time of flight of ions in each position of detector is measured, and the mass to charge ratio of an ion is calculated based on the difference of the lengths of time of flight in at least two positions. Similarly, the ion source may be movable at least in two positions, and a similar method can be used to calculate or estimate the mass to charge ratio of ions.

Abstract: The invention relates to the construction and operation of a slit diaphragm pulser for a time-of-flight mass spectrometer with orthogonal injection of the ions to be examined. The invention includes switching three diaphragm potentials during a transition from a filling phase to an acceleration phase in order to maintain a potential along the axis of the injected ion beam at a constant level, to prevent any penetration by the accelerating fields during the filling phase and to obtain extremely high mass resolution in the acceleration phase through a lens effect.

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

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

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

Abstract: 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: A rotating field mass and velocity analyzer having a cell with four walls, time dependent RF potentials that are applied to each wall, and a detector. The time dependent RF potentials create an RF field in the cell which effectively rotates within the cell. An ion beam is accelerated into the cell and the rotating RF field disperses the incident ion beam according to the mass-to-charge (m/e) ratio and velocity distribution present in the ion beam. The ions of the beam either collide with the ion detector or deflect away from the ion detector, depending on the m/e, RF amplitude, and RF frequency. The detector counts the incident ions to determine the m/e and velocity distribution in the ion beam.

Abstract: A mass spectrometer includes an inductive coupled plasma source whose flame is near ground potential, an interface, a flight tube, and an analyzer that includes magnetic and electric sectors, and an ion detector, which detector is operated at high voltage for ion acceleration. The magnetic sector includes a magnet and pole pieces that are insulated electrically relative to the flight tube. The pressure within the interface preferably does not exceed 10.sup.-3 mbar. By varying the magnetic field and the acceleration potential, identification of a specified mass over defined time intervals is carried out. The disclosed mass spectrometer provides improved coupling between the plasma ion source and a double-focussing analyzer, while advantageously providing a low voltage regime for the plasma source.

Abstract: A method of mass spectrometry and a mass spectrometer for the analysis of a sample, the mass spectrometer comprising means for producing ions from the sample and a magnetic sector for analyzing the ions, wherein the magnetic field of the magnetic sector is generated by passage of a magnet current controlled by a digital control signal representative of a sequence of integers generated by a computer. According to the invention, means are provided for generating the magnet current in exponential relation to the sequence of integers. In contrast to prior spectrometers, the invention provides peak switching and mass selection across the mass range with a constant number of integer steps per mass peak, thereby facilitating the digital selection of any particular mass peak, particularly those at low mass.

Abstract: A method of selecting the resolution of a charged-particle energy or momentum analyzer wherein an analyzing field disperses the particles in an analyzing plane. An electrostatic field generator is adjusted to cause the dispersed particles leaving the field to pass through either of two apertures formed in a resolving aperture member and disposed at different distances from the plane. Each aperture has a different width, selected to result in a different resolution of the analyzing field. A single means for receiving charged particles (typically an ion or electron detector) is disposed to receive particles which have passed through either aperture. A magnetic sector mass spectrometer incorporating the method is also disclosed.

Abstract: Mass spectrometer having an ion source, acceleration means able to impart to the ions an energy essentially dependent on their electric charge, means for producing in a sector a magnetic field orthogonal to the plane of the trajectory of the ions in order to inwardly curve said trajectory and means for detecting the ions. At the inlet of the magnetic sector are provided electrostatic means able to modify the tangential velocity of the ions and consequently their energy, in such a way that ions with different masses can, at different times, follow the same inwardly curved trajectory in the magnetic sector.

Abstract: Detection of unknown daughter ions using a mass spectrometer in which two mass spectrometric units are coupled together. The spectrometric unit in the front stage has either an electric field or superimposed fields. The spectrometric unit in the rear stage has superimposed fields. The voltage Vdx.sub.2 necessary to produce the electric field in the front stage and the voltage Vdx.sub.1 necessary to produce the electric field of the superimposed fields in the rear stage when daughter ions having known mass and energy are detected are found. Further, the voltage Vdx.sub.2 ' necessary to produce the electric field in the front stage and the voltage Vdx.sub.1 ' necessary to produce the electric field of the superimposed fields in the rear stage when unknown ions are detected are found. Both the mass and the energy of the unknown ions can be determined from these four voltages.

Abstract: A process of obtaining spectra of daughter ions which are produced by collision of sample ions with neutral molecules for dissociating the sample ions in a collision chamber disposed in an ion path to thereby provide a structural analysis of organic compounds. To carry out this process, a mass spectrometer is used which has mass spectrometric units located before and after the collision chamber. The spectrometric unit located behind the chamber has superimposed magnetic field B and electric field E perpendicular to the magnetic field. Daughter ions having a mass m.sub.x produced from parent ions having a mass m.sub.0 inside the chamber are detected and measured by sweeping the voltage Vd.sub.x for producing the electric field or the intensity B.sub.x of the magnetic field singly or sweeping both in an interrelated manner so as to satisfy the relation ##EQU1## where V.sub.00 is the voltage for producing the electric field used to detect the parent ions having infinitely large masses, B.sub.

Abstract: An RF control system suitable for use in a mass spectrometer of the type having an ionization chamber, a mass filter and an ion detector. A constant frequency RF voltage is applied to the filter. The magnitude of the RF signal is varied in response to a DC control signal to permit selected ions having a desired charge-to-mass ratio to pass through the filter and strike the detector. In the control system the generated RF signal is attenuated and added to the DC control signal. The resultant voltage is applied to a comparator-integrator circuit that is arranged to provide a control signal capable of precisely holding the output of the RF generator at a predetermined peak voltage.

Abstract: A mass spectrometer comprising superimposed electric and magnetic fields arranged substantially at right angles. The central orbit of the ion beam produced by an ion source is located on an equipotential surface in the electric field. The ion beam is accelerated by a means for producing a constant accelerating voltage. The electric field is swept by a sweep means. The change of the focal length of the superimposed field when the electric field is swept by said sweep means is compensated by a compensating means, thereby providing a mass spectrometer capable of measuring ions having a wide range of mass to charge ratios and capable of scanning at high speed and having a high accuracy mass marker.

Abstract: The ion beam from a field desorption source in a double focusing magnetic mass spectrometer is monitored by disabling the electric sector of the mass analyzer such that the ion beam is not deflected. An opening is provided in the wall of the electric sector such that the undeflected ion beam may pass therethrough to a detector. This permits the characteristics of the field desorption source to be ascertained more quickly and easily so that a mass analysis may be performed. The monitor may be operated automatically to vary a characteristic of the field desorption source until ions are detected. Thereafter, the electric sector is energized and an analysis performed.