Abstract: A method of mass analysis and a mass spectrometer are provided wherein a batch of ions is accumulated in a mass analyser; the batch of ions accumulated in the mass analyser is detected using image current detection to provide a detected signal; the number of ions in the batch of ions accumulated in the mass analyser is controlled using an algorithm based on a previous detected signal obtained using image current detection from a previous batch of ions accumulated in the mass analyser; wherein one or more parameters of the algorithm are adjusted based on a measurement of ion current or charge obtained using an independent detector located outside of the mass analyser.

Abstract: A method of separating charged particles using an analyzer is provided, the method comprising: causing a beam of charged particles to fly through the analyzer and undergo within the analyzer at least one full oscillation in the direction of an analyzer axis (z) of the analyzer whilst orbiting about the axis (z) along a main flight path; constraining the arcuate divergence of the beam as it flies through the analyzer; and separating the charged particles according to their flight time. An analyzer for performing the method is also provided. At least one arcuate focusing lens is preferably used to constrain the divergence, which may comprise a pair of opposed electrodes located either side of the beam.

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: Ions provided from an ion source are separated ions into a plurality of different ion groups according to at least one ion property. At least some of the different ion groups are stored in an ion storage array, which comprises a plurality of independently operable storage cells, each storage cell being arranged to receive and store a different ion group. A controller is programmed to cause selective switching of each of the storage cells between an ion receiving mode and an ion storage mode, and between the ion storage mode and an ion release mode. In particular, the switching of each storage cell is controllable independently of the switching of any of the other storage cells. Upon release from a respective storage cell of the array, ions are provided to one or more mass analyzers for subsequent analysis.

Abstract: A method of performing imaging mass spectrometry of a sample. The method comprises performing a first mass analysis of the sample using a first mass analyzer comprising a multi-pixel ion detector to obtain first mass spectral data representative of pixels of the sample. The method further comprises identifying clusters of pixels sharing one or more characteristics of first mass spectral data. The method also comprises performing a second mass analysis of the sample using a second mass analyzer to obtain second mass spectral data at at least one location in each cluster, wherein the number of locations is significantly less than the number of pixels in each cluster, said second mass analysis being of higher resolution than said first mass analysis. Also a mass spectrometry apparatus configured for carrying out the method.

Abstract: A charged particle analyzer apparatus comprising two opposing ion mirrors each mirror comprising inner and outer field-defining electrode systems elongated along an axis z, the outer system surrounding the inner, whereby when the electrode systems are electrically biased the mirrors create an electrical field comprising opposing electrical fields along z; and at least one arcuate focusing lens for constraining the arcuate divergence of a beam of charged particles within the analyzer whilst the beam orbits around the axis z, the analyzer further comprising a disc having two faces at least partly spanning the space between the inner and outer field defining electrode systems and lying in a plane perpendicular to the axis z, the disc having resistive coating upon both faces. A mass spectrometer system comprising a plurality of the charged particle analyzers arranged as a parallel array.

Abstract: A mass analyzer 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 analyzer; 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.

Abstract: A method of mass analysis and a mass spectrometer are provided wherein a batch of ions is accumulated in a mass analyzer; the batch of ions accumulated in the mass analyzer is detected using image current detection to provide a detected signal; the number of ions in the batch of ions accumulated in the mass analyzer is controlled using an algorithm based on a previous detected signal obtained using image current detection from a previous batch of ions accumulated in the mass analyzer; wherein one or more parameters of the algorithm are adjusted based on a measurement of ion current or charge obtained using an independent detector located outside of the mass analyzer.

Abstract: A method of reflecting ions in a multireflection time of flight mass spectrometer is disclosed. The method includes guiding ions toward an ion mirror having multiple electrodes, and applying a voltage to the ion mirror electrodes to create an electric field that causes the mean trajectory of the ions to intersect a plane of symmetry of the ion mirror and to exit the ion mirror, wherein the ion are spatially focussed by the mirror to a first location and temporally focused to a second location different from the first location. Apparatus for carrying out the method is also disclosed.

Abstract: A method of ion mobility spectrometry wherein ions undergo multiple stages of ion mobility separation and multiple stages of inertial ion motion wherein the mean free path between ion collisions with gas is significantly longer than in the stages of ion mobility separation, wherein each stage of inertial ion motion lies between successive stages of ion mobility separation.

Abstract: Ions provided from an ion source are separated ions into a plurality of different ion groups according to at least one ion property. At least some of the different ion groups are stored in an ion storage array, which comprises a plurality of independently operable storage cells, each storage cell being arranged to receive and store a different ion group. A controller is programmed to cause selective switching of each of the storage cells between an ion receiving mode and an ion storage mode, and between the ion storage mode and an ion release mode. In particular, the switching of each storage cell is controllable independently of the switching of any of the other storage cells. Upon release from a respective storage cell of the array, ions are provided to one or more mass analyzers for subsequent analysis.

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: A method of performing imaging mass spectrometry of a sample. The method comprises performing a first mass analysis of the sample using a first mass analyzer comprising a multi-pixel ion detector to obtain first mass spectral data representative of pixels of the sample. The method further comprises identifying clusters of pixels sharing one or more characteristics of first mass spectral data. The method also comprises performing a second mass analysis of the sample using a second mass analyzer to obtain second mass spectral data at at least one location in each cluster, wherein the number of locations is significantly less than the number of pixels in each cluster, said second mass analysis being of higher resolution than said first mass analysis. Also a mass spectrometry apparatus configured for carrying out the method.

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 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 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 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: 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 detection system and a method for detecting ions which have been separated in a time-of-flight (TOF) mass analyzer, comprising an amplifying arrangement for converting ions into packets of secondary particles and amplifying the packets of secondary particles, wherein the amplifying arrangement is arranged so that each packet of secondary particles produces at least a first output and a second output separated in time and so that during the delay between producing the first and second output the first output produced by a packet of secondary particles is used for modulating the second output produced by the same packet. An increased dynamic range of detection and protection of the detection system against intense ion pulses is thereby provided.