Abstract: A system and method of mass spectrometry is provided. Ions from an ion source are stored in a first ion storage device and in a second ion storage device. Ions are ejected from the first ion storage device to a first mass analysis device during a first ejection time period, for analysis during a first analysis time period. Ions are ejected from the second ion storage device to a second mass analysis device during a second ejection time period. The ion storage devices are connected in series such that an ion transport aperture of the first ion storage device is in communication with an ion transport aperture of the second ion storage device. The first analysis time period and the second ejection time period at least partly overlap.

Abstract: A method of switching between two modes of power supply to a mass analyzer is provided. In a first mode of operation, operated for a first predefined time duration, a first power supply, coupled to the mass analyzer, generates a first nonzero potential, while a second power supply, disconnected from the mass analyzer, generates a second non-zero potential. In a second mode of operation, operated for a second predefined time duration, the second potential is coupled to the mass analyzer, while the first power supply, disconnected from the mass analyzer, generates the first potential. These predefined time durations are selected such that only one of: the first potential; and the second potential is coupled to the mass analyzer at any time, and such that the first and second modes of operation are carried out at least once within a predetermined length of time.

Abstract: A tandem mass spectrometer and method are described. Precursor ions are generated in an ion source and an ion injector injects ions towards a downstream ion guide via a single or multi reflection TOF device that separates ions into packets in accordance with their m/z. A single pass ion page in the path of the precursor ions between the ion injector and the ion guide is controlled so that (only a subset of precursor ion packets, containing precursor ions of interest, is allowed onward transmission to the ion guide. A high resolution mass spectrometer is provided for analysis of those ions, or their fragments, which have been allowed passage through the ion gate. The technique permits multiple m/z ranges to be selected from a wise mass range of precursors, with optional fragmentation of one or more of the chosen ion species.

Abstract: An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U?(r, ?, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U?(r, ?, z) is the result of a perturbation W to an ideal field U(r, ?, z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, ?, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2 ? radians over an ion detection period Tm.

Abstract: The present invention provides a radio frequency (RF) power supply in a mass spectrometer. The power supply provides an RF signal to electrodes of a storage device to create a trapping field. The RF field is usually collapsed prior to ion ejection. In an illustrative embodiment the RF power supply includes a RF signal supply; a coil arranged to receive the signal provided by the RF signal supply and to provide an output RF signal for supply to electrodes of an ion storage device; and a shunt including a switch operative to switch between a first open position and a second closed position in which the shunt shorts the coil output.

Abstract: A vacuum pump system for evacuating at least five volumes comprising a turbomolecular pump and a forevacuum pump arranged to pump an output of the turbomolecular pump arrangement to atmosphere. The turbomolecular pump has at least five pumping stages separated by rotor blades. Not more than three pumping stages have pumping speeds in excess of ? of the highest pumping speed when under vacuum and/or a pumping port cross section in excess of ? of the highest pumping port cross section, and at least two pumping stages have pumping speeds less than ¼ of the highest pumping speed when under vacuum and/or a pumping port cross section of less than ¼ of the biggest pumping port cross section. The ratio of pressures between the pumping stage with the highest pressure and the pumping stage with the lowest pressure is at least 100000:1 when under vacuum.

Abstract: A method of operating a gas-filled collision cell in a mass spectrometer is provided. The collision cell has a longitudinal axis. Ions are caused to enter the collision cell. A trapping field is generated within the collision cell so as to trap the ions within a trapping volume of the collision cell, the trapping volume being defined by the trapping field and extending along the longitudinal axis. Trapped ions are processed in the collision cell and a DC potential gradient is provided, using an electrode arrangement, resulting in a non-zero electric field at all points along the axial length of the trapping volume so as to cause processed ions to exit the collision cell. The electric field along the axial length of the trapping volume has a standard deviation that is no greater than its mean value.

Abstract: A tandem mass spectrometer and method are described. Precursor ions are generated in an ion source (10) and an ion injector (21, 23) injects ions towards a downstream ion guide (50, 60) via a single or multi reflection TOF device (30) that separates ions into packets in accordance with their m/z. A single pass ion gate (40) in the path of the precursor ions between the ion injector (21, 23) and the ion guide (50, 60) is controlled so that only a subset of precursor ion packets, containing precursor ions of interest, is allowed onward transmission to the ion guide (50, 60). A high resolution mass spectrometer (70) is provided for analysis of those ions, or their fragments, which have been allowed passage through the ion gate (40). The technique permits multiple m/z ranges to be selected from a wise mass range of precursors, with optional fragmentation of one or more of the chosen ion species.

Abstract: A multi-reflection mass spectrometer is provided comprising two ion-optical mirrors, each mirror elongated generally along a drift direction (Y), each mirror opposing the other in an X direction, the X direction being orthogonal to Y, characterized in that the mirrors are not a constant distance from each other in the X direction along at least a portion of their lengths in the drift direction. In use, ions are reflected from one opposing mirror to the other a plurality of times while drifting along the drift direction so as to follow a generally zigzag path within the mass spectrometer. The motion of ions along the drift direction is opposed by an electric field resulting from the non-constant distance of the mirrors from each other along at least a portion of their lengths in the drift direction that causes the ions to reverse their direction.

Abstract: A multi-reflection mass spectrometer comprising two ion-optical mirrors, each mirror elongated generally along a drift direction (Y), each mirror opposing the other in an X direction and having a space therebetween, the X direction being orthogonal to Y; the mass spectrometer further comprising one or more compensation electrodes each electrode being located in or adjacent the space extending between the opposing mirrors; the compensation electrodes being configured and electrically biased in use so as to produce, in at least a portion of the space extending between the mirrors, an electrical potential offset which: (i) varies as a function of the distance along the drift length, and/or; (ii) has a different extent in the X direction as a function of the distance along the drift length. In a preferred embodiment the period of ion oscillation between the mirrors is not substantially constant along the whole of the drift length.

Abstract: A method of ion mobility spectrometry comprising: (i) introducing a packet of ions into a drift space; (ii) passing the ions through the drift space wherein the ions separate according to their ion mobility; and (iii) reflecting or deflecting the ions that have passed through the drift space back into the drift space wherein the ions can further separate according to their ion mobility. The reflecting or deflecting takes place in a region at lower pressure than the drift space. The drift space may be re-used multiple times to extend the separation path length. The regions of low pressure preferably allow inertial ion motion wherein the mean free path between ion collisions with gas is significantly longer than in the stages of ion mobility separation. The low pressure reflecting or deflecting region enables a time of flight focusing of ions to be provided without ion mobility separation occurring therein.

Abstract: A method of increasing ion throughput within an accumulator, an energy lift and a pulsed ion extractor, operated in that order upon a batch of ions, comprising the steps of: firstly loading a batch of ions into the accumulator; secondly changing the electrical potential of the energy lift to raise the energy of the batch of ions contained therein; and thirdly ejecting the batch of ions from the pulsed ion extractor; and wherein: the energy lift is a separate device from the accumulator and the pulsed ion extractor, and whilst changing the electrical potential in the second step a fresh batch of ions is loaded into the accumulator and/or a previous batch of ions is prepared for ejection in the pulsed ion extractor; or the energy lift is incorporated into the pulsed ion extractor and whilst changing the electrical potential in the second step a fresh batch of ions is loaded into the accumulator; or the energy lift is incorporated into the accumulator and whilst changing the electrical potential in the second st

Abstract: A method of operating a gas-filled collision cell in a mass spectrometer is provided. The collision cell has a longitudinal axis. Ions are caused to enter the collision cell. A trapping field is generated within the collision cell so as to trap the ions within a trapping volume of the collision cell, the trapping volume being defined by the trapping field and extending along the longitudinal axis. Trapped ions are processed in the collision cell and a DC potential gradient is provided, using an electrode arrangement, resulting in a non-zero electric field at all points along the axial length of the trapping volume so as to cause processed ions to exit the collision cell. The electric field along the axial length of the trapping volume has a standard deviation that is no greater than its mean value.

Abstract: The invention relates to a vacuum pump or vacuum apparatus having a vacuum pump for the evacuation of one or a plurality of volumes, the vacuum pump having a plurality of pressure stages and at least two suction inlets. According to the invention, an outer suction inlet for a first pressure stage spatially encompasses an inner suction inlet for a second pressure stage such that the inner suction inlet seals only against pressure within the outer suction inlet, not against external pressure.

Abstract: An ion transfer tube for a mass spectrometer comprises a core member and a first jacket tube member at least partially enclosing the core member and providing one or more channels therethrough. A method of forming an ion transfer tube, comprises: providing a first jacket tube member having a length and an internal bore, the internal bore passing along the length and defining an interior surface of circular cross section; removing at least one portion of the first jacket tube member adjacent to the interior surface so as to form at least one groove, channel, slot, recess or embayment of or in the interior surface; and providing a core member within the bore of the jacket tube member such that remnant portions of the interior surface of circular cross section mate against portions of an exterior surface of the core member.

Abstract: A mass analyzer comprises: an electrical field generator, providing a time-varying electric field for injection of ions to be analyzed, excitation of ions to be analyzed or both; first and second detection electrodes, each of which receives a respective voltage pickup due to the time-varying electric field and provides a respective detection signal based on a respective image current at the detection electrode; and a differential amplifier, providing an output based on the difference between the detection signal for the first detection electrode and the detection signal for the second detection electrode. It may also be provided that the electrical field generator comprises at least one field generating electrode without a spatially symmetrical counterpart and the capacitance between each field generating electrode and the first detection electrode is substantially the same as the capacitance between that field generating electrode and the second detection electrode.

Abstract: A method of improving the detection limits of a mass spectrometer by: generating sample ions from an ion source; storing the sample ions in a first ion storage device; ejecting the stored ions into an ion selection device; selecting and ejecting ions of a chosen mass to charge ratio out of the ion selection device; storing the ions ejected from the ion selection device in a second ion storage device without passing them back through the ion selection device; repeating the preceding steps so as to augment the ions of the said chosen mass to charge ratio stored in the second ion storage device; and transferring the augmented ions of the said chosen mass to charge ratio back to the first ion storage device for subsequent analysis.

Abstract: An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U?(r, ?, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U?(r, ?, z) is the result of a perturbation W to an ideal field U(r, ?, z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, ?, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2? radians over an ion detection period Tm.

Abstract: A mass analyser in which ions form packets that oscillate with a period has an ion detector comprising: a detection arrangement; and compensation circuitry. The detection arrangement may comprise: a plurality of detection electrodes detecting image current signals from ions in the mass analyser; and a preamplifier, providing an output based on the image current signals. The compensation circuitry provides a compensation signal to a respective compensatory part of the detection arrangement, based on one or more of the image current signals. A capacitance between each of the compensatory parts of the detection arrangement and a signal-carrying part of the detection arrangement affects the signal-to-noise ratio of the preamplifier output. A generator may provide a trapping field defining an ion trapping volume and a shielding conductor may be positioned between two detection electrodes, with a controller applying a voltage to the shielding conductor based on a detected image current.

Abstract: A method of operating a gas-filled collision cell in a mass spectrometer is provided. The collision cell has a longitudinal axis. Ions are caused to enter the collision cell. A trapping field is generated within the collision cell so as to trap the ions within a trapping volume of the collision cell, the trapping volume being defined by the trapping field and extending along the longitudinal axis. Trapped ions are processed in the collision cell and a DC potential gradient is provided, using an electrode arrangement, resulting in a non-zero electric field at all points along the axial length of the trapping volume so as to cause processed ions to exit the collision cell. The electric field along the axial length of the trapping volume has a standard deviation that is no greater than its mean value.