Mass analyser having extended flight path

Information

  • Patent Grant
  • 10950425
  • Patent Number
    10,950,425
  • Date Filed
    Friday, August 11, 2017
    6 years ago
  • Date Issued
    Tuesday, March 16, 2021
    3 years ago
Abstract
A time-of-flight or electrostatic trap mass analyzer is disclosed comprising: an ion flight region comprising a plurality of ion-optical elements (30-35) for guiding ions through the flight region in a deflection (x-y) plane. The ion-optical elements are arranged so as to define a plurality of identical ion-optical cells, wherein the ion-optical elements in each ion-optical cell are arranged and configured so as to generate electric fields for either focusing ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or for focusing ions diverging from a point at the ion entrance location to travel parallel at the ion exit location. Each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii for bending the flight path of the ions in the deflection (x-y) plane. The ion-optical elements in each cell are configured to generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell. The ion-optical elements are arranged and configured such that, in the frame of reference of the ions, the ions are guided through the deflection plane in the ion-optical cells along mean flight paths that are of the same shape and length in each ion-optical cell.
Description
CROSS-REFERENCE TO RELATED APPLICATION

This application is a national phase filing claiming the benefit of and priority to International Patent Application No. PCT/EP2017/070508, filed on Aug. 11, 2017, which claims priority from and the benefit of United Kingdom patent application No. 1613988.3 filed on Aug. 16, 2016. The entire contents of these applications are incorporated herein by reference.


FIELD OF THE INVENTION

The present invention relates generally to mass spectrometers and in particular to folded flight path (FFP) spectrometers comprising electrostatic sectors.


BACKGROUND

Time-of-flight (TOF) mass spectrometers having a folded flight path (FFP) for the ions are known. These are promising instruments for achieving high mass resolution at high sensitivity and high speed of analysis. There are two main types of folded flight path TOF mass spectrometers. One type comprises two opposing ion mirrors and reflects the ions between the ion mirrors multiple times so as to provide a relatively long flight path length for the ions in a relatively small size instrument. GB 2080021 and SU 1725289 disclose examples of such instruments.


Another type of folded flight path TOF mass spectrometer comprises electrostatic sectors for bending the flight path of the ions so that a relatively long flight path can be provided in a relatively small instrument. Sakurai et al (Nucl. Instrum. Meth. A427, 1999, 182-186) and Toyoda et al (J. Mass Spectrom. 38, 2003, 1125-1142) disclose examples of such instruments.


It may be preferred to use sector-based folded flight path TOF mass spectrometers rather than ion mirror based instruments, because sector-based instruments need not have ion reflecting regions and thus may provide an order of magnitude higher space-charge tolerance. Also, sector-based instruments are able to use fewer power supplies.


On the other hand, it may be preferred to use ion mirror based folded flight path TOF mass spectrometers rather than sector-based instruments, because ion mirrors provide relatively high order time per energy focusing and thus provide the instrument with a relatively high energy acceptance. This may be important, for example, when analyzing ions from some pulsed ion sources. In contrast, conventional sector-based instruments possess only first order time per energy focusing, thus inhibiting use of sector-based analyzers in combination with some ion sources and high-field pulsed ion converters.


Another drawback of conventional sector-based folded flight path TOF mass spectrometers is that they have a relatively small spatial acceptance, i.e. the product of the accepted packet size and divergence angle is relatively small. This is especially restrictive for some instruments, for example, when used in combination with pulsed linear ion trap converters in which the phase space of the ion beam may reach 10 mm×mrad or more, even after accelerating the ions to relatively high energy.


Also, conventional sector-based folded flight path TOF mass spectrometers possess only first order time of flight focusing with respect to the spatial spread in the plane of ion deflection. In other words, the term ‘isochronous ion transport’ typically used when describing ion-optical properties of sector-based folded flight path TOF mass spectrometers, in practice, always means first order isochronous ion transport, e.g., as described by Sakurai et al (Int. J. Mass Spectrom. Ion Proc., 63, 1985, 273-287).


Another drawback of sector-based folded flight path TOF mass spectrometers is that they require relatively complex devices for ion confinement in the direction orthogonal to the plane of the curved mean ion trajectory. Conventional systems employ either toroidal sector fields or complex quadrupolar lenses. In addition to these devices being complex, they prevent operation of the instrument in many useful modes that would increase sensitivity and mass resolving power. For example, such sectors prevent the operation in an ‘open trap’ mode as described in US 2013/056627 or with reversing direction of drift in the direction perpendicular to deflection plane, similar to that disclosed in U.S. Pat. No. 5,017,780 for mirror-type sector-based folded flight path TOF mass spectrometers.


Thus, there is a need for development of simpler and less expensive sector-based folded flight path TOF mass spectrometers with increased spatial and energy acceptance and improved mass resolving power.


The present invention provides an improved mass analyser and an improved method of mass spectrometry.


SUMMARY

The present invention provides a time-of-flight or electrostatic trap mass analyzer comprising:


an ion flight region comprising a plurality of ion-optical elements for guiding ions through the flight region in a deflection (x-y) plane;


wherein said ion-optical elements are arranged so as to define a plurality of identical ion-optical cells;


wherein the ion-optical elements in each ion-optical cell are arranged and configured so as to generate electric fields for either focusing ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or for focusing ions diverging from a point at the ion entrance location to travel parallel at the ion exit location;


wherein each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii for bending the flight path of the ions in the deflection (x-y) plane;


wherein the ion-optical elements in each cell are configured to generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell; and


wherein the ion-optical elements are arranged and configured such that, in the frame of reference of the ions, the ions are guided through the deflection plane in the ion-optical cells along mean flight paths that are of the same shape and length in each ion-optical cell.


The inventors have recognized that using a novel combination of ion-optical symmetry, focusing conditions and electrostatic sectors having different deflection radii provides the analyzer with second order spatial isochronicity, thus providing the instrument with a relatively high spatial acceptance (i.e. the product of the accepted packet size and divergence angle is relatively large). The inventors have also realized that this provides second order energy isochronicity, thus considerably increasing their energy acceptance of the instrument. This allows the instrument to use, for example, pulsed ion sources and high-field pulsed ion converters. Embodiments provide instruments with full second order time of flight focusing with respect to the spatial spread in the deflection plane.


Sakurai et al (Nucl. Instrum. Meth. A427, 1999, 182-186) disclose a folded flight path TOF mass spectrometer comprising ion-optical elements, including electrostatic sectors. However, the ion-optical elements are not arranged in ion-optical cells, wherein each cell is capable of parallel-to-point or point-to-parallel focussing. Also, the electrostatic sectors do not have different deflection radii. As such, the analyser of Sakurai et al cannot provide the advantages of the present invention.


The skilled person will appreciate that the geometry of the ion-optical elements in the embodiments of the electrostatic sector analyser described herein defines the operating characteristics of the analyser, i.e. to achieve at least first order isochronicity in any given embodiment of the analyser, a unique set of electrical potentials must be applied to the analyser (i.e. there is single operational voltage set, rather than a plurality of sets). The geometry thus automatically defines the functions described above (e.g. repetitive cells, symmetry of the cells, and point-to-parallel and parallel-to-point focussing). For example, the deflection radii of the sectors, the angle through which each ion-optical element deflects ions, and the free flight path between adjacent ion-optical elements defines the operating characteristics of the analyser and also the voltages that must be applied to the ion-optical elements to achieve the functions described herein. The same deterministic principle linking the geometry, the voltages and the properties of sector analysers provides sufficient information for synthesis of the isochronous sector analyser based on the herein described ion optical principles. Thus, a person skilled in ion optics is capable of synthesising the proper sector system with second order isochronicity based on the principles described herein of repetitive ion cells, ion cell symmetry, parallel-to-point focusing, while using sectors with different radii. Since the principle allows synthesising a multiplicity of second order isochronous systems, we consider the set of ion optical principles as the only correct way for describing ion optics of the second order isochronous analyser.


According to the embodiments of the present invention, the ion-optical elements comprise voltage supplies and are connected to a controller. The controller and voltage supplies are set up and configured to apply voltages to the ion-optical elements so as to perform the functions described herein.


The ions may be deflected by the ion-optical elements in a substantially circular or oval loop in the deflection (x-y) plane.


The ions may be deflected by the ion-optical elements in a closed loop in the deflection (x-y) plane.


The parallel-to-point focusing, or point-to-parallel focusing, may be focusing to the first order approximation.


The analyser may be arranged and configured such that ions enter a first of the ion-optical cells as a parallel beam at the ion entrance location, or diverging from a point at the ion entrance location (to a first order approximation).


It will be appreciated that the ion entrance location and/or ion exit location of any given ion-optical cell need not correspond to a physical aperture or other physical structure, but is/are location(s) defined by the focusing of the ion optical elements in that cell (i.e. the point-to parallel or parallel-to-point focusing).


The ion-optical elements may be arranged and configured such that the ions are transmitted directly from one ion-optical cell to the next ion-optical cell. In other words, the ion exit location of any given ion-optical cell corresponds to the ion entrance location of the adjacent downstream ion-optical cell. The exit location of that downstream ion-optical cell may correspond to the ion entrance location of an ion-optical cell arranged adjacent and downstream thereof.


The analyzer may comprise only two of said ion-optical cells. Ions may be transmitted between and through these ion-optical cells only once, or a plurality of times. Alternatively, the analyzer may comprise more than two of said ion-optical cells. Ions may be transmitted between and through these ion-optical cells only once, or a plurality of times.


The ion-optical elements may be arranged and configured such that said ions travel through said ion-optical cells such that they are subjected to one or more cycle, wherein each cycle comprises either: (i) said parallel-to-point focusing by one of said cells and then said point-to-parallel focusing by another successive one of said cells; or (ii) said point-to-parallel focusing by one of said cells and then said parallel-to-point focusing by another successive one of said cells.


The ion-optical elements may be arranged and configured such that said ions are subjected to an even, integer number of said cycles.


The ion-optical elements may be arranged and configured such that, in use, said ions pass through each of said ion-optical cells in a spatially achromatic and/or energy isochronous mode to a first order approximation.


Each of said ion-optical cells may comprise at least three electrostatic sectors having at least two different deflection radii.


The mean ion path through a sector forms part of a circumference of a circle and the deflection radius of a sector is the radius defined by that circle.


The ion-optical elements may be arranged and configured in any given ion-optical cell such that for ions entering the cell as a parallel beam, the flight time of these ions through the cell is independent, to the second order approximation, of the distance of the ions from a beam ion-optic axis on entering the cell, at least in the deflection (x-y) plane.


The ion-optical elements may be arranged and configured in any given ion-optical cell so as to provide second order focusing of ion flight time with respect to energy spread in ion bunches passing through the cell.


More specifically, the ratios of sector deflection radii, sector deflection angles and sector focusing fields may be tuned to provide second order focusing of the flight time with respect to energy spread in ion bunches passing through the cell.


The electrostatic sectors may be configured to generate two-dimensional electrostatic fields for deflecting the ions in the deflection plane, wherein the fields generated by the sectors are independent of any electric fields in the direction perpendicular to the deflection plane.


The electrostatic sectors may be cylindrical sectors.


The analyser may comprise an ion accelerator for accelerating ions into the flight region and/or an ion detector for detecting ions exiting the flight region.


The analyser may comprise a drift electrode arranged and configured to cause ions to drift through the analyzer in a drift (z−) dimension perpendicular to the deflection (x-y) plane as the ions travel through the ion-optical elements.


The drift electrode may pulse ions into said flight region. The drift electrode may form at least part of an ion accelerator that accelerates ions into the flight region.


The inventors have realized that due to the significant reduction of flight time aberrations provided by the embodiments described herein, the time spread of the ion source may become a major limiting factor in the resolving power of the instrument. A relatively long flight path may be used, together with a device to avoid ion packet spreading, to overcome this.


The ion-optical elements may be arranged and configured to cause the ions to have a looped flight path in the deflection plane and to perform a plurality of loops in the deflection plane; and the analyzer may comprise one or more drift lens arranged in the flight region so that the ions pass through the one or more drift lens as the ions loop around the deflection plane, and the one or more drift lens may be configured to focus the ions in the drift (z−) dimension so as to limit the divergence of the ions in said drift dimension as they drift along the drift dimension.


The analyser may comprise a plurality of said drift lenses spaced along said drift dimension.


The plurality of said drift lenses may be arranged in a periodic array in the drift dimension.


Each of the drift lenses may be an electrostatic lens and/or may be a 2D lens.


Each of the drift lenses may focus the ions in the drift dimension in a manner that is independent of ion focusing in the deflection plane or may be configured to generate electric fields that are quadrupolar in the plane orthogonal to the deflection plane.


Each of the drift lenses may be one of: (i) a 2D lens arranged and configured so that to perform no focusing in the deflection (x-y) plane; (ii) a quadrupole lens; (iii) a combination of 2D and quadrupole lenses.


The drift lenses may be coaxial in the deflection plane.


The drift lens(es) may be arranged between sectors or may be a locally z-focusing field within at least one of the sectors.


The drift electrode may cause the ions to drift in a linear (z−) drift direction.


Alternatively, the analyzer may be arranged and configured such that the drift electrode pulses the ions to drift along a curved, e.g. circular, drift path.


The drift electrode may be arranged on a first side, in the drift (z−) dimension, of the ion-optical elements and the ion detector may be arranged on a second opposite side, in said drift dimension, of the ion-optical elements.


Alternatively, the drift electrode and ion detector may be arranged on a first side, in the drift dimension, of the ion-optical elements and one or more reflector electrode may be arranged on a second opposite side, in said drift dimension, of the ion-optical elements; wherein said reflector electrode is configured to reflect ions back in the drift dimension towards the detector.


One or more reflector electrode may be arranged on each side, in the drift dimension, of the ion-optical elements and may be configured to reflect the ions along the drift dimension as the ions pass through the ion-optical elements.


The reflector electrode(s) described herein enable ions to travel multiple times along the drift dimension, thus increasing the flight path of the ions in the analyzer and enabling higher resolving powers. The reflector electrode(s) may be supplied by a continuous or pulsed power supply.


The reflector electrode(s) described herein may be arranged and configured so as not to change the spatial focusing properties of the analyzer in the deflection (x-y) plane. However, the z-fields may affect the flight time of the ions and thus allow tuning the position of the time focus of the analyzer, i.e. may provide additional flexibility in tuning of the sector fields in the x-y deflection plane.


The drift lens(es) and reflector electrode(s) described herein do not significantly limit the resolving power of the instrument but provide significant ion flight path extension, thus compensating for higher turn-around times in an ion source, at limited energy acceptance of the analyzer.


The analyser may comprise a pulsed ion source or pulsed ion accelerator for pulsing ions into the ion-optical elements.


The relatively high spatial acceptance of the instrument enables it to be used with pulsed ion sources or pulsed ion accelerators. The pulsed ion source or ion accelerator may be any one of: a MALDI ion source; a DE MALDI ion source; a SIMS ion source; a radiofrequency axial or linear ion trap; or an orthogonal ion accelerator for accelerating ions orthogonally. For example, MALDI, SIMS, or radio frequency linear ion traps (LITs) produce ion packets with relatively low energy spreads (e.g., from 10 to 100 eV) which are particularly suitable for sector-based folded flight path TOF mass spectrometers at high transport energies, e.g., above 10 keV.


The ion accelerator may pulse ions towards a detector in a series of ion accelerator pulses, wherein the timings of the pulses are determined by an encoding sequence that varies the duration of the time interval between adjacent pulses as the series of pulses progresses; and wherein the analyser comprises a processor configured to use the timings of the pulses in the encoding sequence to determine which ion data detected at the detector relate to which ion accelerator pulse so as to resolve spectral data obtained from the different ion accelerator pulses. The ion accelerator may be configured to pulse ions towards the detector at a rate such that some of the ions pulsed towards the detector in any given pulse arrive at the detector after some of the ions that are pulsed towards the detector in a subsequent pulse. The use of the encoding sequence (i.e. an encoded frequency pulsing method) enables ions to be injected into the flight region of the analyser at time intervals that are shorter than the ion separation time in the flight region and so enables the duty cycle of the analyser to be increased.


Each of the electrostatic sectors may be a cylindrical sector having its axis of cylindrical rotation aligned in the dimension orthogonal to the deflection (x-y) plane.


The analyser may be one of:


(i) a time-of-flight mass analyzer comprising an ion accelerator for pulsing ions into said flight region and an ion detector, wherein said flight region is arranged between said ion accelerator and detector such that ions separate according to mass to charge ratio in the flight region;


(ii) an open trap mass analyzer configured such that ions enter a first end of the flight region and exit the flight region at a second, opposite end;


(iii) an electrostatic trap mass analyzer having an image current detector for detecting ions; or


(iv) an electrostatic trap mass analyzer having an ion detector arranged for detecting only a portion of the ions passing the detector.


For example, the analyzer may be an open trap mass analyser (e.g. of the type described ion WO 2011/107836) that injects ions into the analyser at one end such that the ions drift through the analyser in a z-direction orthogonal to the deflection (x-y) plane and exit the analyzer at the other end (in the z-direction) onto an ion detector. The analyser may not include drift lenses that focus the ions in the drift z-dimension (for limiting the divergence of the ions in said drift z-dimension) as they drift along the drift z-dimension. The ions may diverge in the z-dimension as they travel through the analyzer in the deflection (x-y) plane and towards the detector, and so ions may have performed different numbers of loops around the deflection (x-y) plane by the time that they reach the detector. The detector may therefore see several signals at different times for ions of the same mass to charge ratio from the same ion packet. The spectra may be interpreted using a Fourier transform technique or a multi-start encoded frequency pulsing technique (e.g. as described in WO 2011/135477).


It is also contemplated that the analyser may be an electrostatic trap mass analyzer having an image current detector for detecting ions (e.g. of the type disclosed in WO 2011/086430). The image current detector comprises at least one detection electrode and detection electronics configured to detect a current induced in the detection electrode due to ions passing proximate the detection electrode. For example, the detection electrode may be a plate electrode, or may be a tubular electrode through which the ions pass. The analyser is configured such that the ions repeatedly pass the detection electrode. The image current detector may determine, from the current induced in the detection electrode, the frequency with which ions pass the detection electrode. The analyser may then determine the mass to charge ratio of ions from the determined frequency that the ions pass the detection electrode. If ions of different mass to charge ratios are present, the different ions will pass the detection electrode with different frequencies and will induce time varying currents in the detection electrode that have different periodic frequencies. The mass to charge ratios of the different ions can be determined by determining the different periodic frequencies of the currents. As described in the above embodiments, ions may be confined and reflected in the z-direction of the analyser and so may be trapped indefinitely.


It is also contemplated that the analyser may be an electrostatic trap mass analyzer having an ion detector arranged for detecting only a portion of the ions passing the detector. The detector comprises at least one detection electrode and detection electronics configured to detect ions striking the detection electrode. The analyser is configured such that ions are repeatedly directed passed or through the detection electrode, but such that during each pass some of the ions strike the detector electrode. For example, the detection electrode may comprise a mesh or a plurality of wires through which the ions are repeatedly directed. On each pass some of the ions strike the detector electrode and the detector may determine, from the current generated in the detection electrode due to the ions striking it, the frequency with which ions pass the detection electrode. The analyser may then determine the mass to charge ratio of these ions from the determined frequency that the ions pass the detection electrode. If ions of different mass to charge ratios are present, the different ions will pass the detection electrode with different frequencies and will cause time varying currents in the detection electrode that have different periodic frequencies. The mass to charge ratios of the different ions can be determined by determining the different periodic frequencies of the currents. As described in the above embodiments, ions may be confined and reflected in the z-direction of the analyser and so may be trapped indefinitely (other than striking the detection electrode).


The present invention also provides a mass spectrometer comprising an analyzer as described herein.


The present invention also provides a method of time of flight or electrostatic trap mass analysis comprising:


transmitting ions through a flight region comprising a plurality of ion-optical elements that guide the ions in a deflection (x-y) plane;


wherein said ion-optical elements are arranged so as to define a plurality of identical ion-optical cells;


wherein the ion-optical elements in each ion-optical cell generate electric fields that either focus ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or focus ions diverging from a point at the ion entrance location to travel parallel at the ion exit location;


wherein each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii that bend the flight path of the ions in the deflection (x-y) plane;


wherein the ion-optical elements in each cell generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell; and wherein the ion-optical elements guide the ions through the deflection plane in the ion-optical cells along mean flight paths that, in the frame of reference of the ions, are of the same shape and length in each ion-optical cell.


The method comprises applying voltages to the ion-optical elements so as to perform the functions described herein.


The method may comprise deflecting the ions, using the ion-optical elements, in a substantially circular or oval loop in the deflection (x-y) plane.


The ions may be deflected by the ion-optical elements in a closed loop in the deflection (x-y) plane.


Each of the ion-optical cells performs said parallel-to-point focusing, or point-to-parallel focusing, in the deflection plane. The parallel-to-point focusing, or point-to-parallel focusing, may be to the first order approximation.


The ions may enter a first of the ion-optical cells in the analyser as a parallel beam at the ion entrance location, or diverge from a point at the ion entrance location (to a first order approximation).


It will be appreciated that the ion entrance location and/or ion exit location of any given ion-optical cell need not correspond to a physical aperture or other physical structure, but is/are location(s) defined by the focusing of the ion optical elements in that cell (i.e. the point-to parallel or parallel-to-point focusing).


Ions may be transmitted directly from one ion-optical cell to the next ion-optical cell. In other words, the ion exit location of any given ion-optical cell may correspond to the ion entrance location of the adjacent downstream ion-optical cell. The exit location of that downstream ion-optical cell may correspond to the ion entrance location of an ion-optical cell arranged adjacent and downstream thereof.


The analyzer may comprise only two of said ion-optical cells. Ions may be transmitted between and through these ion-optical cells only once, or a plurality of times. Alternatively, the analyzer may comprise more than two of said ion-optical cells. Ions may be transmitted between and through these ion-optical cells only once, or a plurality of times.


The ions may be subjected to one or more cycle as they travel through said ion-optical cells, wherein each cycle comprises either: (i) said parallel-to-point focusing by one of said cells and then said point-to-parallel focusing by another successive one of said cells; or (ii) said point-to-parallel focusing by one of said cells and then said parallel-to-point focusing by another successive one of said cells.


The ions may be subjected to an even, integer number of said cycles.


The ions may pass through each of said ion-optical cells in a spatially achromatic and/or energy isochronous mode to a first order approximation.


Each of said ion-optical cells may comprise at least three electrostatic sectors having at least two different deflection radii.


The mean ion path through a sector forms part of a circumference of a circle and the deflection radius of a sector is the radius defined by that circle.


In any given ion-optical cell, the flight time of ions entering the cell as a parallel beam may be independent, to the second order approximation, of the distance of the ions from a beam ion-optic axis on entering the cell (at least in the deflection (x-y) plane).


Any given ion-optical cell may provide second order focusing of ion flight time with respect to energy spread in ion bunches passing through the cell. More specifically, the ratios of sector deflection radii, sector deflection angles and sector focusing fields may be tuned to provide second order focusing of the flight time with respect to energy spread in ion bunches passing through the cell.


The electrostatic sectors may generate two-dimensional electrostatic fields that deflect the ions in the deflection plane, wherein the fields generated by the sectors are independent of any electric fields in the direction perpendicular to the deflection plane.


The electrostatic sectors may be cylindrical sectors.


The method may comprise accelerating ions into the flight region using an ion accelerator and/or detecting ions exiting the flight region using an ion detector.


The method may comprise directing or deflecting ions into the flight region with a drift electrode so as to cause the ions to drift through the analyzer in a drift (z−) dimension perpendicular to the deflection (x-y) plane as the ions travel through the ion-optical elements.


The method may comprise applying a voltage pulse to the drift electrode so as to pulse ions into said flight region. The drift electrode may form at least part of an ion accelerator that accelerates ions into the flight region.


The method may comprise guiding ions in a looped flight path in the deflection plane, optionally so as to perform a plurality of loops in the deflection plane.


The method may comprise providing one or more drift lens in the flight region so that the ions pass through the one or more drift lens as the ions loop around the deflection plane.


The method may comprise applying one or more voltages to the one or more drift lens so as to focus the ions in the drift (z−) dimension, so as to limit the divergence of the ions in said drift dimension as they drift along the drift dimension.


The method may comprise providing a plurality of said drift lenses spaced along said drift dimension.


The plurality of said drift lenses may be arranged in a periodic array in the drift dimension.


Each of the drift lenses may be an electrostatic lens and/or may be a 2D lens.


Each of the drift lenses may focus the ions in the drift dimension in a manner that is independent of ion focusing in the deflection plane or may be configured to generate electric fields that are quadrupolar in the plane orthogonal to the deflection plane.


The drift lenses may be coaxial in the deflection plane.


The drift lens(es) may be arranged between sectors or may be a locally z-focusing field within at least one of the sectors.


The drift electrode may cause the ions to drift in a linear (z−) drift direction. Alternatively, the analyzer may be arranged and configured such that the drift electrode pulses the ions to drift along a curved, e.g. circular, drift path.


The drift electrode may be arranged on a first side, in the drift (z−) dimension, of the ion-optical elements and the ion detector may be arranged on a second opposite side, in said drift dimension, of the ion-optical elements.


Alternatively, the drift electrode and ion detector may be arranged on a first side, in the drift dimension, of the ion-optical elements and one or more reflector electrode may be arranged on a second opposite side, in said drift dimension, of the ion-optical elements. The method may comprise applying one or more voltages to the drift electrode (e.g. ion accelerator) so as to cause ions to drift in the drift dimension towards the reflector electrode and then applying one or more voltage to the reflector electrode so as to reflect ions back in the drift dimension towards the detector. The ions may then be detected at the deflector.


One or more reflector electrode may be arranged on each side, in the drift dimension, of the ion-optical elements. Voltages may be applied to these reflector electrodes so as to reflect the ions along the drift dimension multiple times as the ions pass through the ion-optical elements. The ions may be detected at a detector, which may be arranged on either side of the ion-optical elements.


The reflector electrode(s) described herein enable ions to travel multiple times along the drift dimension, thus increasing the flight path of the ions in the analyzer and enabling higher resolving powers. The reflector electrode(s) may be supplied by a continuous or pulsed power supply.


The reflector electrode(s) described herein may not change the spatial focusing properties of the analyzer in the deflection (x-y) plane. However, the z-fields may affect the flight time of the ions and thus allow tuning the position of the time focus of the analyzer, i.e. may provide additional flexibility in tuning of the sector fields in the x-y deflection plane.


The method may comprise pulsing ions into the ion-optical elements of the flight region using a pulsed ion source or pulsed ion accelerator.


The pulsed ion source or ion accelerator may be one of: a MALDI ion source; a DE MALDI ion source; a SIMS ion source; a radiofrequency axial or linear ion trap; or an orthogonal ion accelerator for accelerating ions orthogonally. For example, MALDI, SIMS, or radio frequency linear ion traps (LITs) produce ion packets with relatively low energy spreads (e.g., from 10 to 100 eV) which are particularly suitable for sector-based folded flight path TOF mass spectrometers at high transport energies, e.g., above 10 keV.


The ion accelerator may pulse ions towards a detector in a series of ion accelerator pulses, wherein the timings of the pulses are determined by an encoding sequence that varies the duration of the time interval between adjacent pulses as the series of pulses progresses; and a processor may use the timings of the pulses in the encoding sequence to determine which ion data detected at the detector relate to which ion accelerator pulse so as to resolve spectral data obtained from the different ion accelerator pulses. The ion accelerator may pulse ions towards the detector at a rate such that some of the ions pulsed towards the detector in any given pulse arrive at the detector after some of the ions that are pulsed towards the detector in a subsequent pulse. The use of the encoding sequence (i.e. an encoded frequency pulsing method) enables ions to be injected into the flight region of the analyser at time intervals that are shorter than the ion separation time in the flight region and so enables the duty cycle of the analyser to be increased.


The method may be a method of time-of-flight mass spectrometry comprising pulsing ions into said flight region and detecting ions leaving the flight region with an ion detector. The flight region may be arranged between the ion accelerator and detector such that ions separate according to mass to charge ratio in the flight region. The pulse time of the ion accelerator and the detection time at the ion detector, for any given ion, may be used to determine the mass to charge ratio of the ion.


The present invention also provides a method of mass spectrometry comprising a method as described herein.


The mass analysers and methods described herein are not necessarily limited to time of flight and/or electrostatic trap mass analysers.


Accordingly, the present invention also provides a mass analyzer comprising:


an ion flight region comprising a plurality of ion-optical elements for guiding ions through the flight region in a deflection (x-y) plane;


wherein said ion-optical elements are arranged so as to define a plurality of identical ion-optical cells;


wherein the ion-optical elements in each ion-optical cell are arranged and configured so as to generate electric fields for either focusing ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or for focusing ions diverging from a point at the ion entrance location to travel parallel at the ion exit location;


wherein each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii for bending the flight path of the ions in the deflection (x-y) plane;


wherein the ion-optical elements in each cell are configured to generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell; and


wherein the ion-optical elements are arranged and configured such that, in the frame of reference of the ions, the ions are guided through the deflection plane in the ion-optical cells along mean flight paths that are of the same shape and length in each ion-optical cell.


The present invention also provides a corresponding method of mass analysis.


The spectrometer described herein may comprise an ion source selected from the group consisting of: (i) an Electrospray ionisation (“ESI”) ion source; (ii) an Atmospheric Pressure Photo Ionisation (“APPI”) ion source; (iii) an Atmospheric Pressure Chemical Ionisation (“APCI”) ion source; (iv) a Matrix Assisted Laser Desorption Ionisation (“MALDI”) ion source; (v) a Laser Desorption Ionisation (“LDI”) ion source; (vi) an Atmospheric Pressure Ionisation (“API”) ion source; (vii) a Desorption Ionisation on Silicon (“DIOS”) ion source; (viii) an Electron Impact (“EI”) ion source; (ix) a Chemical Ionisation (“CI”) ion source; (x) a Field Ionisation (“FI”) ion source; (xi) a Field Desorption (“FD”) ion source; (xii) an Inductively Coupled Plasma (“ICP”) ion source; (xiii) a Fast Atom Bombardment (“FAB”) ion source; (xiv) a Liquid Secondary Ion Mass Spectrometry (“LSIMS”) ion source; (xv) a Desorption Electrospray Ionisation (“DESI”) ion source; (xvi) a Nickel-63 radioactive ion source; (xvii) an Atmospheric Pressure Matrix Assisted Laser Desorption Ionisation ion source; (xviii) a Thermospray ion source; (xix) an Atmospheric Sampling Glow Discharge Ionisation (“ASGDI”) ion source; (xx) a Glow Discharge (“GD”) ion source; (xxi) an Impactor ion source; (xxii) a Direct Analysis in Real Time (“DART”) ion source; (xxiii) a Laserspray Ionisation (“LSI”) ion source; (xxiv) a Sonicspray Ionisation (“SSI”) ion source; (xxv) a Matrix Assisted Inlet Ionisation (“MAII”) ion source; (xxvi) a Solvent Assisted Inlet Ionisation (“SAII”) ion source; (xxvii) a Desorption Electrospray Ionisation (“DESI”) ion source; (xxviii) a Laser Ablation Electrospray Ionisation (“LAESI”) ion source; and (xxix) Surface Assisted Laser Desorption Ionisation (“SALDI”).


The spectrometer may comprise one or more ion traps or one or more ion trapping regions.


The spectrometer may comprise one or more collision, fragmentation or reaction cells.


The spectrometer may comprise a device or ion gate for pulsing ions into the flight region and/or a device for converting a substantially continuous ion beam into a pulsed ion beam for pulsing ions into the flight region.





BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will now be described, by way of example only, and with reference to the accompanying drawings in which:



FIG. 1 shows an ion-optical scheme of a prior art sector based instrument in which the ions travel a substantially oval path;



FIG. 2 shows an ion-optical scheme of another prior art sector based instrument in which the ions travel a figure-of-eight path;



FIG. 3 shows a typical ion flight time dependence on the initial y-coordinate of the ions for the analyser of FIG. 2;



FIGS. 4A and 4B show ion-optical schemes of sector based instruments according to embodiments of the present invention having second order focusing of the flight time with respect to spatial ion spread in the deflection plane;



FIGS. 5A and 5B show simulated dependencies of the flight time on the initial y-coordinate of the ions and the angle b, respectively, for the analyser of FIG. 4A;



FIG. 6A shows an ion-optical scheme of a sector based instruments according to an embodiment of the present invention having cylindrical sectors and periodic lenses for confining ions in the z-direction, and FIG. 6B shows an embodiment having an end deflector for reversing the direction of the ions in the z-direction;



FIG. 7 shows a simulated time peak for an analyser according to FIG. 4A; and



FIG. 8 shows an ion-optical scheme of an embodiment of the present invention having five sectors per cell; and



FIG. 9 shows an ion-optical scheme of an embodiment of the present invention having three sectors and two lenses in each cell.





DETAILED DESCRIPTION

As described above, folded flight path time of flight (TOF) mass spectrometers are known in which electrostatic sectors are used to bend the flight paths of the ions so that a relatively long TOF flight path can be provided in a relatively small instrument.


Various instrument geometries and ion flight paths of folded flight path TOF mass spectrometers will be described herein using Cartesian coordinates. The Cartesian coordinates are described herein such that the plane in which the electrostatic sectors bend the ion path are defined as the x-y plane, where x is the position along the ion optic axis (i.e. along the mean flight path of the ions), and y is perpendicular to this ion optic axis. The z-dimension is orthogonal to the x-y plane.



FIG. 1 shows a schematic of the ion-optical scheme of part of a prior art folded flight path TOF mass spectrometer according to Sakurai et al (Nucl. Instrum. Meth. A427, 1999, 182-186). The spectrometer comprises ion-optical elements arranged so as to bend the ion path. The ion-optical elements comprise six electrostatic sectors 2-10 arranged so as to bend the ion path so that the ions are guided in a closed loop. A drift region is provided between each pair of adjacent sectors. Each sector is torroidal and the sectors have the same deflection radius. Electrostatic potentials are applied to the electrodes of each of the sectors so as to bend the flight paths of the ions so that the ions travel into the downstream electrostatic sector and continue around the closed path.


As can be seen from FIG. 1, ions pass into the first electrostatic sector 2 along the ion optical axis x. The ions diverge in the y-direction as they travel towards the first sector 2. The first sector 2 bends the ion path and directs the ions into the second sector 4. The second sector bends the ion path and directs the ions into the third sector 6. The ions emerge from the third sector 6 and are focused in the y-direction to a point 14 before diverging again in the y-direction and entering the fourth sector 8. The fourth sector 8 bends the ion path and directs the ions into the fifth sector 10. The fifth sector 10 bends the ion path and directs the ions into the sixth sector 12. The ions emerge from the sixth sector 12 and are focused in the y-direction to a point 16 before diverging again in the y-direction and re-entering the first sector 2. It can therefore be seen that the use of sectors 2-12 enables the TOF path length to be relatively long within a relatively small instrument.


However, as described in the Background section, conventional sector field folded flight path TOF mass spectrometers, such as that shown in FIG. 1, have limited spatial acceptance since they possess only first order TOF focusing with respect to the spatial spread of the ions in the plane that the sectors deflect the ions (i.e. the x-y plane). When such conventional instruments are described as having ‘isochronous ion transport’ this actually means, in practice, first order isochronous ion transport at small spatial acceptance, as described by Sakurai et al (Int. J. Mass Spectrom. Ion Proc., 63, 1985, 273-287). This is because, unlike ion mirror-based folded flight path TOF mass spectrometers, sector field based instruments have a curved ion optic axis and so multiple geometrical conditions are required to be satisfied to reach first order isochronicity. The number of second order aberrations is even larger, when accounting for mixed geometrical-chromatic TOF aberrations, and ion optical designers have conventionally been unable to compensate for these aberrations.


The analysis of aberrations can be assisted by considering the closed loop motion of the ions as periodic motion of the ions through a sequence of identical ion-optical cells, wherein each cell is considered to comprise a set of sector fields (and may optionally also comprise other ion optical elements such as ion lenses for focusing ions). For example, in FIG. 1 the three sectors 2-6 on the right side may be considered to form a first ion-optical cell and the three sectors 8-12 on the left side may be considered to form a second ion-optical cell. Each cell also has mirror symmetry about a line that is perpendicular to the mean ion path through the cell at the point half way along the mean ion path through the cell (in the x-y plane of deflection).


Ion trajectory projections in the x-y deflection plane can be described at each coordinate x along the ion optic axis by position vectors {y, b, τ, δ}, where: b=dyldx=tan β, β being the inclination angle of ion trajectory projection to the ion optic axis; δ=(K−K0)/K0, wherein δ is the relative deviation of the ion kinetic energy K component in the x-y deflection plane and the kinetic energy K0 component in the deflection plane for ions moving along the ion optic axis; and τ=t−t0, where r is the difference between the flight time t of the considered ion and the flight time t0 of an ion moving along the optic axis or ‘mean trajectory’.


The transformation between the position vectors performed by one cell extending from the point x=x0 and x=x1 can be described by a transfer matrix M(1): {y1, b1, τ1, δ1}=M(1){y0, b0, τ0, δ0}, where the components with the subscript 1 correspond to position x=x1 and the components with the subscript 0 correspond to position x=x0. In this case, the transport of ions through N cells is described by a product of cell transfer matrices, i.e. as follows:

M(N)=[M(1)]N  (1)


It is important to emphasize that equation 1 above requires that all cells have identical electric field distributions to each other, as viewed by the ions. This requires that the mean path of the ions be bent in the same manner by each cell, as viewed from the frame of reference of the ions. For example, in FIG. 1 the first cell formed of sectors 2-6 causes the mean path of the ions to be bent to the right as the ions travel through the first cell (from the ions' frame of reference), and the second cell formed by sectors 8-12 also causes the mean path of the ions to be bent in the same manner to the right as the ions travel through the second cell (from the ions' frame of reference).


The transformation of components of the position vector by one cell can be represented by aberration expansions, as follows:

y1=Yyy0+Ybba0+Ybδ0+Yyyy02+Yyby0b0+Ybbb02+Yy0δ0+Yb0δ0+Yδδδ02+ . . . , b=Byy0+Bbb0+Bδδ0+Byyy02+Byby0b0+Bbbb02+By0δ0+Bb0δ0+Bδδδ02+ . . . , τ1=Tyy0+Tbb0+Tδδ0+Tyyy02+Tyby0b0+Tbbb02+Ty0δ0+Tb0δ0+Tδδδ02+ . . . , δ10.


The transformation up to a particular order of aberration expansion can be expressed by the transfer matrix of this order, which is expressed through the aberration coefficients up to the same order. The general form of the second order transfer matrix is presented in the book ‘Optics of charged particles’ by H. Wollnik (Acad. Press, Orlando, 1987).


It is relatively easy to select the combination of sector fields and the drift intervals between them so as to eliminate the first order dependence of time of flight on ion energy (i.e. Tδ=0). In order to make a cell first order isochronous (Ty=Tb=0) it is also required to make the cell symmetric, either by mirror symmetry or point symmetry. The above-mentioned three conditions for first order focusing are satisfied in prior art sector based instruments. Note that due to the so-called symplectic conditions, a first order isochronous cell is always first order spatially achromatic: Yδ=Bδ=0, and vice versa.


Referring back to the prior art instrument of FIG. 1, the arrangement shows sector fields and sample ion trajectories with different initial y-coordinates and different energies. The ions follow a closed oval path in the analyzer by passing through identical 180-degree deflecting cells. The geometric condition after each cell is Yb=0, but the flight time focusing is performed only in the first order approximation and the aberration coefficients Tyy and Tbb remain.



FIG. 2 shows a schematic of the ion-optical scheme of a prior art folded flight path TOF mass spectrometer according to ‘MULTUM II’ by Toyoda et al (J. Mass Spectrom. 38, 2003, 1125-1142). The instrument comprises ion-optical elements arranged so as to guide ions in a figure-of-eight flight path. More specifically, the instrument comprises four electrostatic sectors 22-28 and drift regions between adjacent pairs of sectors, arranged so as to guide ions in a figure-of-eight flight path. Each sector has a 157-degree deflecting toroidal sector field. The arrangement of sector fields and sample ion trajectories for ions having different initial y-coordinates and different energies are shown. The motion of the ions will now be described in ions' frame of reference. As can be seen from FIG. 2, ions pass into the first electrostatic sector 22 along the ion optical axis x. The ions travel parallel, rather than diverging in the y-direction, as they travel towards the first sector 22. The first sector 22 bends the ion path to the right and directs the ions into the second sector 24. The second sector 24 bends the ion path to the left and directs the ions into the third sector 26. The ions emerge from the second sector 24 and are focused in the y-direction to a point 23 before diverging again in the y-direction and entering the third sector 26. The third sector 26 bends the ion path to the left and directs the ions into the fourth sector 28. The fourth sector 28 bends the ion path to the right. The ions emerge from the fourth sector 28 travelling parallel to each other, rather than diverging or converging in the y-direction, and then re-enter the first sector 22.


As will be described in more detail below, the inventors have recognized that it is necessary for each cell to perform parallel-to-point (or point-to-parallel) of the ion beam in order to avoid certain aberrations. Accordingly, the first sector 22 and second sector 24 may be considered to form a first ion-optical cell that provides parallel-to-point focusing of the ions in the x-y deflection plane, thus eliminating aberration coefficients Yy=Bb=0. The third sector 26 and fourth sector 28 may be considered to form a second ion-optical cell that provides point-to-parallel divergence of the ion beam in the x-y deflection plane. However, as described above, equation 1 requires that all ion-optical cells have identical electric field distributions to each other, as viewed by the ions. In the analyzer of FIG. 2, the ions cannot be considered as passing through consecutive identical cells that meet the requirements of equation 1 above (and each having point-to-parallel or parallel-to-point focusing), because the orientation of the coordinate frame reverses after each cell. That is, in the frame of reference of the ions, the first cell consisting of sectors 22 and 24 causes the mean path of the ions to be bent firstly to the right and then to the left; whereas in contrast the second cell consisting of sectors 26 and 28 causes the mean path of the ions to be bent firstly to the left and then to the right. The ions are therefore guided in different manners by the first and second cells. Therefore, the cell symmetry condition described above in relation to equation 1 is violated and the second order flight time aberrations cannot be eliminated, even if ions are passed along the full figure-of-eight like path once or several times. Furthermore, in each zigzag cell (i.e. the combination of sectors 22 and 24, or the combination of sectors 26 and 28) the second order flight time aberrations Tyy and Tbb are not eliminated.



FIG. 3 is a graph showing a typical time dependence on the initial y-coordinate of the ion for the prior art analyzer of FIG. 2, as simulated by the computer program SIMION 8.0. The calculated value of the second order coefficient is (T|yy)/t0=−29.6 m−2 which is in reasonable agreement with the data given by Toyoda et al (J. Mass Spectrom. 38, 2003, 1125-1142). This shows that the prior art arrangement of FIG. 2 does not suffers from higher order aberrations.


Therefore, it will be appreciated that the prior art instruments provide first order focusing only and that second order aberration coefficients are not able to be fully eliminated.


The inventors have recognized that using a special combination of symmetry and focusing conditions in sector field based folded flight path TOF mass spectrometers, and simultaneously using electrostatic sectors with different radii, allows the ion flight time to be independent of spatial coordinates as well as independent of mixed spatial-chromatic terms in the sector field deflection plane (i.e. the x-y plane) in the second order approximation, thus considerably increasing spatial acceptance of the instrument in this plane.


Various embodiments of the present invention will now be described, which allow full independence of ion flight time from spatial coordinates in the x-y deflection plane, i.e. to eliminate all second order coefficients for the flight time expansion except for Tδδ.


As in the prior art instruments described above, it remains important for the analyzers according to the embodiments of the present invention to fulfill first order isochronicity. As described above in relation to equation 1, the sectors of the analyzers according to the embodiments of the present invention are arranged such that the motion of the ions in the x-y deflection plane can be considered to be a motion through a sequence of identical ion-optical cells.


Each cell is symmetric with respect to its middle, and the symmetry may be mirror symmetry such that the transfer matrix M(1) obeys the relationship:

M(1)=P[M(1)]−1P  (2a)

where P is the reversing operator: P{y, b, τ, δ}={y, −b, −τ, δ}.


Alternatively, the symmetry may be point symmetry such that the transfer matrix M(1) obeys the relationship:

M(1)=RP[M(1)]−1PR  (2b)

where R is the rotating operator: R{y, b, τ, δ}={−y, −b, τ, δ}.


The sectors are arranged and configured such that each cell is first order isochronous, as in prior art instruments, such that:

Tδ=Ty=Tb=0  (3)


The electrostatic fields in each cell are tuned such that, in the first order approximation, ions entering the cell as a parallel beam will be focused to a point at the exit (i.e. parallel-to-point focusing). As a result of the cell symmetry given by equations 2a or 2b above, this also means that the electrostatic fields in each cell are tuned such that, in the first order approximation, ions entering the cell that diverge from a point will be focused to a parallel beam at the exit (i.e. point-to-parallel focusing).


As each cell provides parallel-to-point focusing in the first order approximation (for ions entering the cell as a parallel beam), this leads to:

Yy=0  (4)


As each cell provides point-to-parallel focusing in the first order approximation (for ions diverging from a point and entering the cell), this leads to:

Bb=0  (5)


The condition of equation 4 also leads to stable, indefinite ion confinement of ions in the x-y plane, since it satisfies the stability condition −1<Yy<1. Note that some prior art sector systems such as that of FIG. 1 violate the stability condition since Yy=1.


The inventors have recognized that in sector based instruments the compensation of at least one second order aberration (e.g. fulfilling the condition Tyy=0) can be reached by adding another degree of flexibility, such as by using a cell in which there are sector fields with two different deflection radii. As it is required for each cell to be symmetric, a cell having sectors of two different deflection radii must comprise at least three sectors.



FIGS. 4A and 4B show ion-optical schemes of embodiments of the present invention with second order focusing of the flight time with respect to spatial ion spread in the x-y deflection plane. These instruments are capable of compensating for the second order time-of-flight aberration Tyy such that:

Tyy=0  (6)


The ion-optical elements in the analyzer of FIG. 4A comprise six electrostatic sectors 30-35 arranged so as to bend the ion path so that the ions are guided in a substantially oval closed loop. A drift region is provided between each pair of adjacent sectors. Electrostatic potentials are applied to the electrodes of each of the sectors so as to bend the flight paths of the ions so that the ions travel into the downstream electrostatic sector and continue around the closed path. The motion of the ions will now be described in the frame of reference of the ions. As can be seen from FIG. 4A, ions pass as a parallel ion beam into the first electrostatic sector 30 along the ion optical axis x. The first sector 30 bends the ion path to the right and directs the ions into the second sector 31. The second sector 31 bends the ion path to the right and directs the ions into the third sector 32. The ions emerge from the third sector 32 and are focused in the y-direction to a point 36 before diverging again in the y-direction and entering the fourth sector 33. The fourth sector 33 bends the ion path to the right and directs the ions into the fifth sector 34. The fifth sector 34 bends the ion path to the right and directs the ions into the sixth sector 35. The ions emerge from the sixth sector 35 as a parallel beam and re-enter the first sector 30. It can therefore be seen that the use of sectors 30-35 enables the TOF path length to be relatively long within a relatively small instrument.


The projection of the ion optic axis to the xy-plane forms a closed substantially oval path. Ion motion through the analyzer can be considered as the transport of ions through a sequence of identical cells, each cell deflecting the mean ion path by 180 degrees. More specifically, sectors 30-32 can be considered to form a first cell and sectors 33-35 can be considered to form a second cell. The sectors in each cell are arranged and configured to perform parallel-to-point focusing of the ions (or point-to-parallel focusing). Each cell also has mirror symmetry about a line that is perpendicular to the mean ion path through the cell at the point half way along the mean ion path through the cell (in the x-y plane of deflection).


In order to compensate for at least one second order aberration, each cell comprises sectors having different deflection radii. Considering the first cell, the radius of the optic axis in the second sector 31 is 1.55 times larger than the radius of the optic axis in each of the first and third sectors 30,32. The ion deflecting angle of each of the first and third sectors 30,32 is 49 degrees. The ion deflecting angle of the second sector 31 is 82 degrees. Similarly, in the second cell, the radius of the optic axis in the fifth sector 34 is 1.55 times larger than the radius of the optic axis in each of the fourth and sixth sectors 33,35. The ion deflecting angle of each of the fourth and sixth sectors 33,35 is 49 degrees. The ion deflecting angle of the fifth sector 34 is 82 degrees. The ion deflecting angles, deflection radii, and lengths of drift spaces between the sectors are chosen such that in each cell the ion-optical conditions of equations 3-5 above are satisfied, i.e. Yy=Bb=0 and Ty=Tb=T6=0. Additionally, the use of sectors having different deflection radii in each cell enables the system to compensate for the second order aberration of equation 6 above, i.e. Tyy=0.



FIG. 4B shows an embodiment that substantially corresponds to that of FIG. 4A, except that the sectors in FIG. 4B have different lengths, deflection radii and deflection angles. Like elements have been given the same reference numbers in FIGS. 4A and 4B. Considering the first cell in FIG. 4B, the radius of the optic axis in each of the first and third sectors 30,32 is 2.4 times larger than the radius of the optic axis the second sector 31. The ion deflecting angle of each of the first and third sectors 30,32 is 25 degrees. The ion deflecting angle of the second sector 31 is 130 degrees. Similarly, in the second cell, the radius of the optic axis in each of the fourth and sixth sectors 33,35 is 2.4 times larger than the radius of the optic axis in the fifth sector 34. The ion deflecting angle of each of the fourth and sixth sectors 33,35 is 25 degrees. The ion deflecting angle of the fifth sector 34 is 130 degrees. The ion deflecting angles, deflection radii, and lengths of drift spaces between the sectors are chosen such that in each cell the ion-optical conditions of equations 3-5 above are satisfied, i.e. Yy=Bb=0 and Ty=Tb=T6=0. Additionally, the use of sectors having different deflection radii in each cell enables the system to compensate for the second order aberration of equation 6 above, i.e. Tyy=0.


Although two specific examples have been described in relation to FIGS. 4A and 4B, it will be appreciated that embodiments of the present invention may have other values of deflection radii ratio and/or deflection angles.


The inventors have realized that the parallel-to-point (and point-to-parallel) geometric focusing described above in relation to equations 4 and 5 within a symmetric cell according to equations 2a or 2b has the important consequence that two second order aberration coefficients for the flight time expansion are proportional to each other, i.e. that:

Tyy=By2Tbb  (7)

Thus, the compensation of one second order aberration Tyy=0 as described in relation to equation 6 automatically compensates for another proportional second order aberration such that:

Tbb=0  (8)


Accordingly, it has been recognized that each identical cell of the system is now able to be first order isochronous in accordance with equation 3, provide parallel-to-point focusing (or point-to-parallel focusing) according to equations 4 and 5, and is able to compensate for two second order aberrations according to equations 6 and 8.


The inventors have also recognized that fulfilling the above three conditions automatically allows the elimination of the rest of the second order time of flight aberrations (except for Tδδ) after passing the ions through a number of the cells. This can be shown by calculating geometric and time of flight coefficients of aberration expansions after several cells by using multiplication of the cell transfer matrices. Indeed, considering equations 4 and 5 for a single cell, the multiplication of transfer matrices as in equation 1 above gives the following first order geometric transfer matrix coefficients after two cells:

Yy(2)=Bb(2)=−1,By(2)=Yb(2)=0  (9)


The same multiplication for the time of flight coefficients shows that all of the elimination conditions of equations 3, 6 and 8 above, which are achieved for a single cell, also remain valid after two cells, i.e.:

Tδ(2)=Ty(2)=Tb(2)=Tyy(2)=Tbb(2)=0  (10)


Also, due to the conditions of equations 4 and 5 above, the mixed geometric aberration coefficient Tyb is eliminated after the ions pass through two identical cells. i.e.:

Tyb(2)=0


By multiplying two identical second order transfer matrices for two cells, it is also apparent that all time of flight coefficients that are eliminated after the ions pas through two cells (see equations 10 and 11) remain eliminated after the ions pass through four cells, i.e.:

Tδ(4)=Ty(4)=Tb(4)=Tyy(4)=Tbb(4)=Tyb(4)=0  (12)


Also, due to the conditions in equation 9, the mixed geometric-chromatic aberration coefficients are also eliminated after the ions pass through each 4 cells, i.e.:

T(4)=T(4)=0.  (13)


Thus, it is clear from equations 12 and 13 that after ions pass through four successive cells all second order aberration coefficients for the flight time expansion, except for Tδδ, are eliminated.


In order to illustrate the ability of an embodiment of the present invention to compensate for aberrations, Table 1 below is presented. Table 1 shows the aberration coefficients after the ions pass through one, two and four cells in the instrument of FIG. 4A. The passage of ions through two sectors is one loop around the instrument shown in FIG. 4A. The unit for the coordinate y is metres and the flight path length per loop is 1.95 m.












TABLE 1





Coefficient
1 cell (half loop)
2 cells (one loop)
4 cells (two loops)


















Yy
0
−1
1


Yb
0.091
0
0


By
−11.0
−1
1


Bb
0
0
0


Ty/t0
0
0
0


Tb/t0
0
0
0


Tδ/t0
0
0
0


Tyy/t0
0
0
0


Tyb/t0
−4.60
0
0


Tbb/t0
0
0
0


T/t0
4.82
0.025
0


T/t0
0.434
0.436
0


Tδδ/t0
0.084
0.084
0.084









It can be seen from Table 1 that the only non-vanishing second order aberration after the ions pass through four successive cells is Tδδ/t0, and even then the value of this aberration is about 3 times smaller than in the prior art analyzer of FIG. 2.


The system of FIG. 4B is also first order isochronous and second order spatially isochronous, meaning that all of the aberration coefficients listed in Table 1 are zero, except Tδδ/t0, which is 0.276.



FIG. 5A is a graph showing the simulated flight time dependence on the initial y-coordinate of the ion for the analyzer of FIG. 4A. The relative time deviation τ/t0 is within 10−6 in the intervals Δy=3.5 mm. The dependence t(y) is dominated by a 4th order term. It can be seen by comparing FIG. 5A to FIG. 3 that the flight time dependence on the initial y-coordinate is improved for the analyzer of FIG. 4A over the analyzer of FIG. 2.



FIG. 5B is a graph showing the simulated flight time dependence on the angle β=arctan (b) for the analyzer of FIG. 4A. The relative time deviation τ/t0 is within Δβ≈2 degrees. The dependence t(b) is dominated by a 3rd order term.


In the embodiments described above, the ions may be pulsed into the analyzer and guided along a flight path defined by the sectors. The sectors bend the flight path and hence allow a relatively long flight path to be provided in a relatively small space. When the ions have travelled a desired flight path length, e.g. when the ions have travelled through a desired number of cells of the analyzer, the ions are directed onto a detector. The duration of time between an ion being pulsed into the analyzer and the ion being detected at the detector can be used to determine the mass to charge ratio of that ion, as in conventional TOF mass analyzers. As the instruments of the present invention have a relatively long flight path length, the mass resolution of the instrument may be relatively high. The configuration of the sectors increases the flight path length per unit size of the instrument, whilst eliminating second order aberrations that would otherwise deteriorate mass analysis.


The motion of the ions around the analyzer has only been described in the x-y deflection plane. When the ions have travelled the desired flight path length they may be deflected, e.g. in a direction perpendicular to the mean flight path, onto the detector. Alternatively, the ions may be caused to drift in a direction perpendicular to the x-y plane (i.e. the z-direction) as they pass around the analyzer in the x-y plane. The ion detector may be arranged at a position in the z-direction such that after a predetermined flight path (e.g., after a predetermined number of loops in the x-y place) the ions have travelled a distance in the z-direction such that the ions impact on the ion detector.



FIG. 6A shows a perspective view of a schematic in which ions travel in the x-y plane and also travel in the z-direction. The analyser is of substantially the same form as that described in relation to FIGS. 4A-4B and like elements have been given like reference numbers. However, FIG. 6A also illustrates that the ions may drift in the z-direction as they loop around the analyser through the cylindrical sectors. Ions are pulsed into the first sector 30 along axis 60. Ions may be pulsed into the sector 30 at an angle such that they drift in the z-direction, or a drift electrode may be provided that urges the ions in the z-direction. The first sector 30, second sector 31 and third sector 32 form a first cell that bends the flight path of the ions, in the same manner described in relation to FIGS. 4A-4B. The fourth sector 33, fifth sector 34 and sixth sector 35 form a second cell that bends the flight path of the ions, in the same manner described in relation to FIGS. 4A-4B. The ions then re-enter the first sector 30 and continue around the analyser in the x-y plane for another loop. This looping in the x-y plane is repeated as the ions drift along the z-direction until the ions exit the fifth sector 35 along exit axis 62 and impact on ion detector 64.


The analyser may also comprise periodic drift lenses 66 for confining ions in the z-direction. The drift lenses 66 focus ions in the z-direction and thus maintain the ion packets at a desired x-position as they loop around the analyzer in the x-y plane. The electric fields of the periodic lenses 64 may not focus or disperse the ions in the x-y plane but, e.g. by inducing an accelerating or retarding field, allow tuning a position of the final time focus at the detector 64. Note that in contrast to periodic lenses used in ion mirror based multi-reflecting time of flight mass spectrometers, in sector field instruments ions can pass through periodic lenses only once per loop. Although z-direction periodic lenses 66 are only shown between sectors 32 and 33 it is contemplates that these lenses, or additional such lenses, may be arranged between any other pair of sectors such as between sectors 30 and 35. Periodic lenses may be arranged between more than one pair of sectors so as to provide for tighter ion confinement in the z-direction. The periodic lenses may produce a two-dimensional focusing field, may be coaxial lenses, or may have an adjustable quadrupolar field component for adjustments of ion trajectories in the x-y plane.



FIG. 6B shows an embodiment that is substantially the same as that shown in FIG. 6A, except that it additionally has a reflecting electrode 68 for reflecting the ions back in the z-direction. The ions are pulsed into the analyser along path 60, travel around the x-y plane and along the z-direction in the same manner as described in relation to FIG. 6A. However, rather than striking ion detector 64 at the z-end of the device, the ions are reflected back in the z-direction by reflecting electrode 68. As the ions drift back along the device in the x-direction they continue to loop around the x-y plane until they exit the analyser along path 62 and impact on ion detector 64. It will be appreciated that this embodiment doubles the ion flight path length as compared to the embodiment of 6A, without increasing the physical dimensions of the instrument or restricting mass range.



FIG. 7 shows a simulated time peak after 20 loops of ions in an analyser of FIG. 4A having a 1.95 m long path per loop, i.e. a full path length of 39 m. The ion packet was simulated as a Gaussian profile having a 2 ns initial time FWHM width, Δy=2 mm, Δb=1 deg, a 35 mm×mrad phase space in the X-Y deflection plane, a m/z=1000 amu, a mean kinetic energy of K=6 keV, and an energy spread ΔK=30 eV. After passing 20 loops the packet time width increases from 2 ns to 2.75 ns, i.e. a mass resolving power R=200 000 is achieved. Comparative simulation shows that achieving the same resolving power in prior art sector-based spiral flight path instruments would require reducing the phase space in the x-y plane by an order of magnitude. Thus, embodiments of the present invention are able to provide at least an order of magnitude improved product of phase space acceptance and resolving power. Also, an order of magnitude higher spatial acceptance means at least an order of magnitude higher space charge tolerance of the analyzer, since ion packets are known to expand spatially under own space charge.


At a simulated resolving power of R=200,000, embodiments of the present invention have an acceptance over 30 mm x mrad, while prior art sector based instruments have an acceptance of less than 3 mm x mrad. The embodiments of the present invention therefore accommodate ion sources having relatively great emittances, such as SIMS and DE MALDI sources, which tend to have emittances between 3 and 10 mm x mrad. The embodiments are also able to accommodate radio-frequency linear ion traps well, which tend to have larger emittances, e.g., emittances of at least 10 mm x mrad. The embodiments also have a relatively high tolerance to space charge effects (the analyzer tolerates ion packets spatial expansion), and an ability to reach higher resolving powers for ion sources with limited emittance. Compact analyzers or ion guides may also be used to match an ion sources emittance with the analyzer acceptance.



FIG. 8 shows an ion-optical scheme according to an embodiment of the present invention with second order focusing of the flight time with respect to both energy and spatial ion spread in the x-y deflection plane. The analyser is substantially the same as that shown and described in relation to FIG. 4A, except that the ion-optical elements in the first cell comprise five cylindrical sectors 80-84 rather than three sectors, and the ion-optical elements in the second cell comprise five cylindrical sectors 85-89 rather than three sectors. The deflection angle of each of sectors 82 and 87 is 64 degrees, and the deflection angle of each of the other sectors is 29 degrees. The deflection radius of each of sectors 82,87 is 1.9 times larger than the deflection radius of each of sectors 80,84,85,89. The deflection radius of each of sectors 81,83,86,88 is 2.1 times larger than of each of sectors 80,84,85,89.



FIG. 9 shows another ion-optical schemes according to an embodiment of the present invention with second order focusing of the flight time with respect to both energy and spatial ion spread in the x-y deflection plane. The analyser is substantially the same as that shown and described in relation to FIG. 4A, except that the ion-optical elements comprise sectors and 2D lenses. In each cell the three sectors are arranged between a pair of 2D lenses for focussing the ions in the x-y plane. More specifically, in the first cell the three sectors 91-93 are arranged between 2D lenses 90 and 94, and in the second cell the three sectors 96-98 are arranged between 2D lenses 95 and 99. In this embodiment, the angle of deflection of each of the sectors 91, 93, 96 and 98 is 50 degrees, and the angle of deflection of each of sectors 92,97 is 80 degrees. The deflection radius of each of sectors 92,97 is 1.2 times larger than the deflection radius of each of sectors 91, 93, 96 and 98.


Although the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the accompanying claims.

Claims
  • 1. A time-of-flight or electrostatic trap mass analyzer comprising: an ion flight region comprising a plurality of ion-optical elements for guiding ions through the flight region in a deflection (x-y) plane;wherein said ion-optical elements are arranged so as to define a plurality of identical ion-optical cells;wherein the ion-optical elements in each ion-optical cell are arranged and configured so as to generate electric fields for either focusing ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or for focusing ions diverging from a point at the ion entrance location to travel parallel at the ion exit location;wherein each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii for bending the flight path of the ions in the deflection (x-y) plane;wherein the ion-optical elements in each cell are configured to generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell; andwherein the ion-optical elements are arranged and configured such that, in the frame of reference of the ions, the ions are guided through the deflection plane in the ion-optical cells along mean flight paths that are of the same shape and length in each ion-optical cell.
  • 2. The analyser of claim 1, wherein the parallel-to-point focusing, or point-to-parallel focusing, is focusing to the first order approximation.
  • 3. The analyser of claim 1, wherein said ion-optical elements are arranged and configured such that said ions travel through said ion-optical cells such that they are subjected to one or more cycle, wherein each cycle comprises either: (i) said parallel-to-point focusing by one of said cells and then said point-to-parallel focusing by another successive one of said cells; or (ii) said point-to-parallel focusing by one of said cells and then said parallel-to-point focusing by another successive one of said cells.
  • 4. The analyzer of claim 3, wherein said ion-optical elements are arranged and configured such that said ions are subjected to an even, integer number of said cycles.
  • 5. The analyzer of claim 1, wherein said ion-optical elements are arranged and configured such that, in use, said ions pass through each of said ion-optical cells in a spatially achromatic and/or energy isochronous mode to a first order approximation.
  • 6. The analyzer of claim 1, wherein each of said ion-optical cells comprises at least three electrostatic sectors having at least two different deflection radii.
  • 7. The analyzer of claim 1, wherein the ion-optical elements are arranged and configured in any given ion-optical cell such that for ions entering the cell as a parallel beam, the flight time of these ions through the cell is independent, to the second order approximation, of the distance of the ions from a beam ion-optic axis on entering the cell, at least in the deflection (x-y) plane.
  • 8. The analyzer of claim 1, wherein the ion-optical elements are arranged and configured in any given ion-optical cell so as to provide second order focusing of ion flight time with respect to energy spread in ion bunches passing through the cell.
  • 9. The analyzer of claim 1, comprising an ion accelerator for accelerating ions into the flight region and/or an ion detector for detecting ions exiting the flight region.
  • 10. The analyzer of claim 1, comprising a drift electrode arranged and configured to cause ions to drift through the analyzer in a drift (z−) dimension perpendicular to the deflection (x-y) plane as the ions travel through the ion-optical elements.
  • 11. The analyzer of claim 10, wherein the ion-optical elements are arranged and configured to cause the ions to have a looped flight path in the deflection plane and to perform a plurality of loops in the deflection plane; and wherein the analyzer comprises one or more drift lens arranged in the flight region so that the ions pass through the one or more drift lens as the ions loop around the deflection plane, and wherein the one or more drift lens is configured to focus the ions in the drift (z−) dimension so as to limit the divergence of the ions in said drift dimension as they drift along the drift dimension.
  • 12. The analyzer of claim 11, wherein the analyzer comprises a plurality of said drift lenses spaced along said drift dimension.
  • 13. The analyzer of claim 10, wherein said drift electrode is arranged on a first side, in the drift (z−) dimension, of the ion-optical elements and the ion detector is arranged on a second opposite side, in said drift dimension, of the ion-optical elements.
  • 14. The analyzer of claim 10, wherein said drift electrode and ion detector are arranged on a first side, in the drift dimension, of the ion-optical elements and one or more reflector electrode is arranged on a second opposite side, in said drift dimension, of the ion-optical elements; wherein said reflector electrode is configured to reflect ions back in the drift dimension towards the detector.
  • 15. The analyzer of claim 13, wherein one or more reflector electrode is arranged on each side, in the drift dimension, of the ion-optical elements and are configured to reflect the ions along the drift dimension as the ions pass through the ion-optical elements.
  • 16. The analyzer of claim 1, wherein each of the electrostatic sectors is a cylindrical sector having its axis of cylindrical rotation aligned in the dimension orthogonal to the deflection (x-y) plane.
  • 17. The analyzer of claim 1, wherein said analyzer is one of: (i) a time-of-flight mass analyzer comprising an ion accelerator for pulsing ions into said flight region and an ion detector, wherein said flight region is arranged between said ion accelerator and detector such that ions separate according to mass to charge ratio in the flight region;(ii) an open trap mass analyzer configured such that ions enter a first end of the flight region and exit the flight region at a second, opposite end;(iii) an electrostatic trap mass analyzer having an image current detector for detecting ions; or(iv) an electrostatic trap mass analyzer having an ion detector arranged for detecting only a portion of the ions passing the detector.
  • 18. A mass spectrometer comprising an analyzer as claimed in claim 1.
  • 19. A method of time of flight or electrostatic trap mass analysis comprising: transmitting ions through a flight region comprising a plurality of ion-optical elements that guide the ions in a deflection (x-y) plane;wherein said ion-optical elements are arranged so as to define a plurality of identical ion-optical cells;wherein the ion-optical elements in each ion-optical cell generate electric fields that either focus ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or focus ions diverging from a point at the ion entrance location to travel parallel at the ion exit location;wherein each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii that bend the flight path of the ions in the deflection (x-y) plane;wherein the ion-optical elements in each cell generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell; andwherein the ion-optical elements guide the ions through the deflection plane in the ion-optical cells along mean flight paths that, in the frame of reference of the ions, are of the same shape and length in each ion-optical cell.
  • 20. A mass analyzer comprising: an ion flight region comprising a plurality of ion-optical elements for guiding ions through the flight region in a deflection (x-y) plane;wherein said ion-optical elements are arranged so as to define a plurality of identical ion-optical cells;wherein the ion-optical elements in each ion-optical cell are arranged and configured so as to generate electric fields for either focusing ions travelling in parallel at an ion entrance location of the cell to a point at an ion exit location of the cell, or for focusing ions diverging from a point at the ion entrance location to travel parallel at the ion exit location;wherein each ion-optical cell comprises a plurality of electrostatic sectors having different deflection radii for bending the flight path of the ions in the deflection (x-y) plane;wherein the ion-optical elements in each cell are configured to generate electric fields that either (i) have mirror symmetry in the deflection plane about a line in the deflection plane that is perpendicular to a mean ion path through the cell at a point half way along the mean ion path through the cell, or (ii) have point symmetry in the deflection plane about a point in the deflection plane that is half way along the mean ion path through the cell; andwherein the ion-optical elements are arranged and configured such that, in the frame of reference of the ions, the ions are guided through the deflection plane in the ion-optical cells along mean flight paths that are of the same shape and length in each ion-optical cell.
Priority Claims (1)
Number Date Country Kind
1613988 Aug 2016 GB national
PCT Information
Filing Document Filing Date Country Kind
PCT/EP2017/070508 8/11/2017 WO 00
Publishing Document Publishing Date Country Kind
WO2018/033494 2/22/2018 WO A
US Referenced Citations (307)
Number Name Date Kind
3898452 Hertel Aug 1975 A
4390784 Browning et al. Jun 1983 A
4691160 Ino Sep 1987 A
4731532 Frey et al. Mar 1988 A
4855595 Blanchard Aug 1989 A
5017780 Kutscher et al. May 1991 A
5107109 Stafford, Jr. et al. Apr 1992 A
5128543 Reed et al. Jul 1992 A
5202563 Cotter et al. Apr 1993 A
5331158 Dowell Jul 1994 A
5367162 Holland et al. Nov 1994 A
5396065 Myerholtz et al. Mar 1995 A
5435309 Thomas et al. Jul 1995 A
5464985 Cornish et al. Nov 1995 A
5619034 Reed et al. Apr 1997 A
5654544 Dresch Aug 1997 A
5689111 Dresch et al. Nov 1997 A
5696375 Park et al. Dec 1997 A
5719392 Franzen Feb 1998 A
5763878 Franzen Jun 1998 A
5777326 Rockwood et al. Jul 1998 A
5834771 Yoon et al. Nov 1998 A
5955730 Kerley et al. Sep 1999 A
5994695 Young Nov 1999 A
6002122 Wolf Dec 1999 A
6013913 Hanson Jan 2000 A
6020586 Dresch et al. Feb 2000 A
6080985 Welkie et al. Jun 2000 A
6107625 Park Aug 2000 A
6160256 Ishihara Dec 2000 A
6198096 Le Cocq Mar 2001 B1
6229142 Bateman et al. May 2001 B1
6271917 Hagler Aug 2001 B1
6300626 Brock et al. Oct 2001 B1
6316768 Rockwood et al. Nov 2001 B1
6337482 Francke Jan 2002 B1
6384410 Kawato May 2002 B1
6393367 Tang et al. May 2002 B1
6437325 Reilly et al. Aug 2002 B1
6455845 Li et al. Sep 2002 B1
6469295 Park Oct 2002 B1
6489610 Barofsky et al. Dec 2002 B1
6504148 Hager Jan 2003 B1
6504150 Verentchikov et al. Jan 2003 B1
6534764 Verentchikov et al. Mar 2003 B1
6545268 Verentchikov et al. Apr 2003 B1
6570152 Hoyes May 2003 B1
6576895 Park Jun 2003 B1
6580070 Cornish et al. Jun 2003 B2
6591121 Madarasz et al. Jul 2003 B1
6614020 Cornish Sep 2003 B2
6627877 Davis et al. Sep 2003 B1
6646252 Gonin Nov 2003 B1
6647347 Roushall et al. Nov 2003 B1
6664545 Kimmel et al. Dec 2003 B2
6683299 Fuhrer et al. Jan 2004 B2
6694284 Nikoonahad et al. Feb 2004 B1
6717132 Franzen Apr 2004 B2
6734968 Wang et al. May 2004 B1
6737642 Syage et al. May 2004 B2
6744040 Park Jun 2004 B2
6744042 Zajfman et al. Jun 2004 B2
6747271 Gonin et al. Jun 2004 B2
6770870 Vestal Aug 2004 B2
6782342 LeGore et al. Aug 2004 B2
6787760 Belov et al. Sep 2004 B2
6794643 Russ, IV et al. Sep 2004 B2
6804003 Wang et al. Oct 2004 B1
6815673 Plomley et al. Nov 2004 B2
6833544 Campbell et al. Dec 2004 B1
6836742 Brekenfeld Dec 2004 B2
6841936 Keller et al. Jan 2005 B2
6861645 Franzen Mar 2005 B2
6864479 Davis et al. Mar 2005 B1
6870156 Rather Mar 2005 B2
6870157 Zare Mar 2005 B1
6872938 Makarov et al. Mar 2005 B2
6888130 Gonin May 2005 B1
6900431 Belov et al. May 2005 B2
6906320 Sachs et al. Jun 2005 B2
6940066 Makarov et al. Sep 2005 B2
6949736 Ishihara Sep 2005 B2
7034292 Whitehouse et al. Apr 2006 B1
7071464 Reinhold Jul 2006 B2
7084393 Fuhrer et al. Aug 2006 B2
7091479 Hayek Aug 2006 B2
7126114 Chernushevich Oct 2006 B2
7196324 Verentchikov Mar 2007 B2
7217919 Boyle et al. May 2007 B2
7221251 Menegoli et al. May 2007 B2
7326925 Verentchikov et al. Feb 2008 B2
7351958 Vestal Apr 2008 B2
7365313 Fuhrer et al. Apr 2008 B2
7385187 Verentchikov et al. Jun 2008 B2
7388197 McLean et al. Jun 2008 B2
7399957 Parker et al. Jul 2008 B2
7423259 Hidalgo et al. Sep 2008 B2
7498569 Ding Mar 2009 B2
7501621 Willis et al. Mar 2009 B2
7504620 Sato et al. Mar 2009 B2
7521671 Kirihara et al. Apr 2009 B2
7541576 Belov et al. Jun 2009 B2
7582864 Verentchikov Sep 2009 B2
7608817 Flory Oct 2009 B2
7663100 Vestal Feb 2010 B2
7675031 Konicek et al. Mar 2010 B2
7709789 Vestal et al. May 2010 B2
7728289 Naya et al. Jun 2010 B2
7745780 McLean et al. Jun 2010 B2
7755036 Satoh Jul 2010 B2
7772547 Verentchikov Aug 2010 B2
7800054 Fuhrer et al. Sep 2010 B2
7825373 Willis et al. Nov 2010 B2
7863557 Brown Jan 2011 B2
7884319 Willis et al. Feb 2011 B2
7932491 Vestal Apr 2011 B2
7982184 Sudakov Jul 2011 B2
7985950 Makarov et al. Jul 2011 B2
7989759 Holle Aug 2011 B2
7999223 Makarov et al. Aug 2011 B2
8017907 Willis et al. Sep 2011 B2
8063360 Willis et al. Nov 2011 B2
8080782 Hidalgo et al. Dec 2011 B2
8093554 Makarov Jan 2012 B2
8237111 Golikov et al. Aug 2012 B2
8354634 Green et al. Jan 2013 B2
8395115 Makarov et al. Mar 2013 B2
8492710 Fuhrer et al. Jul 2013 B2
8513594 Makarov Aug 2013 B2
8633436 Ugarov Jan 2014 B2
8637815 Makarov et al. Jan 2014 B2
8642948 Makarov et al. Feb 2014 B2
8642951 Li Feb 2014 B2
8648294 Prather et al. Feb 2014 B2
8653446 Mordehai et al. Feb 2014 B1
8658984 Makarov et al. Feb 2014 B2
8680481 Giannakopulos et al. Mar 2014 B2
8723108 Ugarov May 2014 B1
8735818 Kovtoun et al. May 2014 B2
8772708 Kinugawa et al. Jul 2014 B2
8785845 Loboda Jul 2014 B2
8847155 Vestal Sep 2014 B2
8853623 Verenchikov Oct 2014 B2
8884220 Hoyes et al. Nov 2014 B2
8921772 Verenchikov Dec 2014 B2
8952325 Giles et al. Feb 2015 B2
8957369 Makarov Feb 2015 B2
8975592 Kobayashi et al. Mar 2015 B2
9048080 Verenchikov et al. Jun 2015 B2
9082597 Willis et al. Jul 2015 B2
9082604 Verenchikov Jul 2015 B2
9099287 Giannakopulos Aug 2015 B2
9136101 Grinfeld et al. Sep 2015 B2
9147563 Makarov Sep 2015 B2
9196469 Makarov Nov 2015 B2
9207206 Makarov Dec 2015 B2
9214322 Kholomeev et al. Dec 2015 B2
9214328 Hoyes et al. Dec 2015 B2
9281175 Haufler et al. Mar 2016 B2
9312119 Verenchikov Apr 2016 B2
9324544 Rather Apr 2016 B2
9373490 Nishiguchi et al. Jun 2016 B1
9396922 Verenchikov et al. Jul 2016 B2
9417211 Verenchikov Aug 2016 B2
9425034 Verentchikov et al. Aug 2016 B2
9472390 Verenchikov et al. Oct 2016 B2
9514922 Watanabe et al. Dec 2016 B2
9576778 Wang Feb 2017 B2
9595431 Verenchikov Mar 2017 B2
9673033 Grinfeld et al. Jun 2017 B2
9679758 Grinfeld et al. Jun 2017 B2
9683963 Verenchikov Jun 2017 B2
9728384 Verenchikov Aug 2017 B2
9779923 Verenchikov Oct 2017 B2
9786484 Willis et al. Oct 2017 B2
9786485 Ding et al. Oct 2017 B2
9865441 Damoc et al. Jan 2018 B2
9865445 Verenchikov et al. Jan 2018 B2
9870903 Richardson et al. Jan 2018 B2
9870906 Quarmby et al. Jan 2018 B1
9881780 Verenchikov et al. Jan 2018 B2
9899201 Park Feb 2018 B1
9922812 Makarov Mar 2018 B2
9941107 Verenchikov Apr 2018 B2
9972483 Makarov May 2018 B2
10006892 Verenchikov Jun 2018 B2
10037873 Wang et al. Jul 2018 B2
10141175 Verentchikov et al. Nov 2018 B2
10141176 Stewart et al. Nov 2018 B2
10163616 Verenchikov et al. Dec 2018 B2
10186411 Makarov Jan 2019 B2
10192723 Verenchikov et al. Jan 2019 B2
10290480 Crowell et al. May 2019 B2
10373815 Crowell et al. Aug 2019 B2
10388503 Brown et al. Aug 2019 B2
10593525 Hock et al. Mar 2020 B2
10593533 Hoyes et al. Mar 2020 B2
10622203 Veryovkin et al. Apr 2020 B2
10629425 Hoyes et al. Apr 2020 B2
10636646 Hoyes et al. Apr 2020 B2
20010011703 Franzen Aug 2001 A1
20010030284 Dresch et al. Oct 2001 A1
20020030159 Chernushevich et al. Mar 2002 A1
20020107660 Nikoonahad et al. Aug 2002 A1
20020190199 Li Dec 2002 A1
20030010907 Hayek et al. Jan 2003 A1
20030111597 Gonin et al. Jun 2003 A1
20030232445 Fulghum Dec 2003 A1
20040084613 Bateman et al. May 2004 A1
20040108453 Kobayashi et al. Jun 2004 A1
20040119012 Vestal Jun 2004 A1
20040144918 Zare et al. Jul 2004 A1
20040155187 Axelsson Aug 2004 A1
20040159782 Park Aug 2004 A1
20040183007 Belov et al. Sep 2004 A1
20050006577 Fuhrer et al. Jan 2005 A1
20050040326 Enke Feb 2005 A1
20050103992 Yamaguchi et al. May 2005 A1
20050133712 Belov et al. Jun 2005 A1
20050151075 Brown et al. Jul 2005 A1
20050194528 Yamaguchi et al. Sep 2005 A1
20050242279 Verentchikov Nov 2005 A1
20050258364 Whitehouse et al. Nov 2005 A1
20060169882 Pau et al. Aug 2006 A1
20060214100 Verentchikov et al. Sep 2006 A1
20060289746 Raznikov et al. Dec 2006 A1
20070023645 Chernushevich Feb 2007 A1
20070029473 Verentchikov Feb 2007 A1
20070176090 Verentchikov Aug 2007 A1
20070187614 Schneider et al. Aug 2007 A1
20070194223 Sato et al. Aug 2007 A1
20080049402 Han et al. Feb 2008 A1
20080197276 Nishiguchi et al. Aug 2008 A1
20080203288 Makarov et al. Aug 2008 A1
20080290269 Saito et al. Nov 2008 A1
20090090861 Willis et al. Apr 2009 A1
20090114808 Bateman et al. May 2009 A1
20090206250 Wollnik Aug 2009 A1
20090250607 Staats et al. Oct 2009 A1
20090272890 Ogawa et al. Nov 2009 A1
20100001180 Bateman et al. Jan 2010 A1
20100044558 Sudakov Feb 2010 A1
20100072363 Giles et al. Mar 2010 A1
20100078551 Loboda Apr 2010 A1
20100140469 Nishiguchi Jun 2010 A1
20100193682 Golikov et al. Aug 2010 A1
20100301202 Vestal Dec 2010 A1
20110133073 Sato et al. Jun 2011 A1
20110168880 Ristroph et al. Jul 2011 A1
20110180702 Flory et al. Jul 2011 A1
20110180705 Yamaguchi Jul 2011 A1
20110186729 Verentchikov et al. Aug 2011 A1
20120168618 Vestal Jul 2012 A1
20120261570 Shvartsburg et al. Oct 2012 A1
20130048852 Verenchikov Feb 2013 A1
20130056627 Verenchikov Mar 2013 A1
20130068942 Verenchikov Mar 2013 A1
20130187044 Ding et al. Jul 2013 A1
20130240725 Makarov Sep 2013 A1
20130248702 Makarov Sep 2013 A1
20130256524 Brown et al. Oct 2013 A1
20130313424 Makarov et al. Nov 2013 A1
20130327935 Wiedenbeck Dec 2013 A1
20140054456 Kinugawa et al. Feb 2014 A1
20140084156 Ristroph et al. Mar 2014 A1
20140117226 Giannakopulos May 2014 A1
20140138538 Hieftje et al. May 2014 A1
20140183354 Moon et al. Jul 2014 A1
20140191123 Wildgoose et al. Jul 2014 A1
20140239172 Makarov Aug 2014 A1
20140291503 Shchepunov et al. Oct 2014 A1
20140312221 Verenchikov et al. Oct 2014 A1
20140361162 Murray et al. Dec 2014 A1
20150028197 Grinfeld et al. Jan 2015 A1
20150028198 Grinfeld et al. Jan 2015 A1
20150034814 Brown et al. Feb 2015 A1
20150048245 Vestal et al. Feb 2015 A1
20150060656 Ugarov Mar 2015 A1
20150122986 Haase May 2015 A1
20150194296 Verenchikov et al. Jul 2015 A1
20150228467 Grinfeld et al. Aug 2015 A1
20150279650 Verenchikov Oct 2015 A1
20150294849 Makarov et al. Oct 2015 A1
20150318156 Loyd et al. Nov 2015 A1
20150364309 Welkie Dec 2015 A1
20150380233 Verenchikov Dec 2015 A1
20160005587 Verenchikov Jan 2016 A1
20160035558 Verenchikov et al. Feb 2016 A1
20160079052 Makarov Mar 2016 A1
20160225598 Ristroph Aug 2016 A1
20160225602 Ristroph et al. Aug 2016 A1
20160240363 Verenchikov Aug 2016 A1
20170016863 Verenchikov Jan 2017 A1
20170025265 Verenchikov et al. Jan 2017 A1
20170032952 Verenchikov Feb 2017 A1
20170098533 Stewart et al. Apr 2017 A1
20170229297 Green et al. Aug 2017 A1
20170338094 Verenchikov et al. Nov 2017 A1
20180144921 Hoyes et al. May 2018 A1
20180315589 Oshiro Nov 2018 A1
20180366312 Hamish et al. Dec 2018 A1
20190237318 Brown Aug 2019 A1
20200083034 Hoyes et al. Mar 2020 A1
20200126781 Kovtoun Apr 2020 A1
20200152440 Hoyes et al. May 2020 A1
20200168447 Verenchikov May 2020 A1
20200168448 Verenchikov et al. May 2020 A1
Foreign Referenced Citations (130)
Number Date Country
2412657 May 2003 CA
101369510 Feb 2009 CN
102131563 Jul 2011 CN
201946564 Aug 2011 CN
4310106 Oct 1994 DE
10116536 Oct 2002 DE
102015121830 Jun 2017 DE
102019129108 Jun 2020 DE
112015001542 Jul 2020 DE
0237259 Sep 1987 EP
1137044 Sep 2001 EP
1566828 Aug 2005 EP
1901332 Mar 2008 EP
2068346 Jun 2009 EP
1665326 Apr 2010 EP
1789987 Sep 2010 EP
1522087 Mar 2011 EP
2599104 Jun 2013 EP
1743354 Aug 2019 EP
3662501 Jun 2020 EP
3662502 Jun 2020 EP
3662503 Jun 2020 EP
2080021 Jan 1982 GB
2217907 Nov 1989 GB
2300296 Oct 1996 GB
2390935 Jan 2004 GB
2396742 Jun 2004 GB
2403063 Dec 2004 GB
2396742 Dec 2005 GB
2455977 Jul 2009 GB
2476964 Jul 2011 GB
2478300 Sep 2011 GB
2484361 May 2012 GB
2484429 Jun 2012 GB
2489094 Sep 2012 GB
2490571 Nov 2012 GB
2562990 Dec 2012 GB
2495127 Apr 2013 GB
2495221 Apr 2013 GB
2496991 May 2013 GB
2496994 May 2013 GB
2500743 Oct 2013 GB
2501332 Oct 2013 GB
2506362 Apr 2014 GB
2528875 Feb 2016 GB
2555609 May 2018 GB
2556451 May 2018 GB
2556830 Jun 2018 GB
2575157 Jan 2020 GB
2575339 Jan 2020 GB
S6229049 Feb 1987 JP
2000036285 Feb 2000 JP
2000048764 Feb 2000 JP
2003031178 Jan 2003 JP
3571546 Sep 2004 JP
2005538346 Dec 2005 JP
2006049273 Feb 2006 JP
2007227042 Sep 2007 JP
2010062152 Mar 2010 JP
4649234 Mar 2011 JP
2011119279 Jun 2011 JP
4806214 Nov 2011 JP
2013539590 Oct 2013 JP
5555582 Jul 2014 JP
2015506567 Mar 2015 JP
2015185306 Oct 2015 JP
2564443 Oct 2015 RU
2015148627 May 2017 RU
2660655 Jul 2018 RU
198034 Sep 1991 SU
1681340 Sep 1991 SU
1725289 Apr 1992 SU
9103071 Mar 1991 WO
9801218 Jan 1998 WO
98008244 Feb 1998 WO
0077823 Dec 2000 WO
2005001878 Jan 2005 WO
2006049623 May 2006 WO
2006102430 Sep 2006 WO
2007044696 Apr 2007 WO
2007104992 Sep 2007 WO
2007136373 Nov 2007 WO
2008046594 Apr 2008 WO
2008087389 Jul 2008 WO
2010008386 Jan 2010 WO
2010138781 Dec 2010 WO
2011086430 Jul 2011 WO
2011107836 Sep 2011 WO
2011135477 Nov 2011 WO
2012010894 Jan 2012 WO
2012023031 Feb 2012 WO
2012024468 Feb 2012 WO
2012024570 Feb 2012 WO
2012116765 Sep 2012 WO
2013045428 Apr 2013 WO
2013063587 May 2013 WO
2013067366 May 2013 WO
2013093587 Jun 2013 WO
2013098612 Jul 2013 WO
2013110587 Aug 2013 WO
2013110588 Aug 2013 WO
2013124207 Aug 2013 WO
2014021960 Feb 2014 WO
2014074822 May 2014 WO
2014110697 Jul 2014 WO
2014142897 Sep 2014 WO
2015142897 Sep 2015 WO
2015152968 Oct 2015 WO
2015153622 Oct 2015 WO
2015153630 Oct 2015 WO
2015153644 Oct 2015 WO
2015175988 Nov 2015 WO
2016064398 Apr 2016 WO
2016174462 Nov 2016 WO
2018073589 Apr 2018 WO
2018109920 Jun 2018 WO
2018124861 Jul 2018 WO
2019030472 Feb 2019 WO
2019030475 Feb 2019 WO
2019030476 Feb 2019 WO
2019030477 Feb 2019 WO
2019058226 Mar 2019 WO
2019162687 Aug 2019 WO
2019202338 Oct 2019 WO
2019229599 Dec 2019 WO
2020002940 Jan 2020 WO
2020021255 Jan 2020 WO
2019030474 Jun 2020 WO
2020121167 Jun 2020 WO
2020121168 Jun 2020 WO
Non-Patent Literature Citations (79)
Entry
Sakurai (Sakurai et al, “A New Multi-Passage Time-of-Flight Mass Spectrometer at JAIST” Nuclear Instruments & Methods in Physics Research A 427 (1999) 182-186) (Year: 1999).
oyoda (Toyoda et al, “Multi-Turn Time-of-Flight Mass Spectrometers with Electrostatic Sectors”, J. Mass Spectrom; 2003; 38, 1125-1142) (Year: 2003).
Sakurai et al, “A New Multi-Passage Time of Flight Mass Spectonneter at JAIST” Nuclear Instruments and Methods in Physics Research A 427 (1999), 182-186 (Year: 1999).
Toyoda et al., “Multi-Turn Time of Flight Mass Spectrometers with Electrostatic Sectors”, J. Mass Spectrom; 2003, 38, 1125-1142 (Year: 2003).
International Search Report and Written Opinion for International Application No. PCT/EP2017/070508 dated Oct. 16, 2017, 18 pages.
Search Report for United Kingdom Application No. GB1613988.3 dated Jan. 5, 2017, 5 pages.
Sakurai et al., “A New Multi-Passage Time-of-Flight Mass Spectrometer at JAIST”, Nuclear Instruments & Methods in Physics Research, Section A, Elsevier, 427(1-2): 182-186, May 11, 1999.
Toyoda et al., “Multi-Turn-Time-of-Flight Mass Spectometers with Electrostatic Sectors”, Journal of Mass Spectrometry, 38: 1125-1142, Jan. 1, 2003.
Nouters et al., “Optical Design of the TOFI (Time-of-Flight Isochronous) Spectrometer for Mass Measurements of Exotic Nuclei”, Nuclear Instruments and Methods in Physics Research, Section A, 240(1): 77-90, Oct. 1, 1985.
International Search Report and Written Opinion for International Application No. PCT/US2016/062174 dated Mar. 6, 2017, 8 pages.
IPRP PCT/US2016/062174 dated May 22, 2018, 6 pages.
Search Report for GB Application No. GB1520130.4 dated May 25, 2016.
International Search Report and Written Opinion for International Application No. PCT/US2016/062203 dated Mar. 6, 2017, 8 pages.
Search Report for GB Application No. GB1520134.6 dated May 26, 2016.
IPRP PCT/US2016/062203, dated May 22, 2018, 6 pages.
Search Report Under Section 17(5) for Application No. GB1507363.8 dated Nov. 9, 2015.
International Search Report and Written Opinion of the International Search Authority for Application No. PCT/GB2016/051238 dated Jul. 12, 2016, 16 pages.
IPRP for application PCT/GB2016/051238 dated Oct. 31, 2017, 13 pages.
International Search Report and Written Opinion for International Application No. PCT/US2016/063076 dated Mar. 30, 2017, 9 pages.
Search Report for GB Application No. 1520540.4 dated May 24, 2016.
IPRP for application PCT/US2016/063076, dated May 29, 2018, 7 pages.
IPRP PCT/GB17/51981 dated Jan. 8, 2019, 7 pages.
International Search Report and Written Opinion for International Application No. PCT/GB2018/051206, dated Jul. 12, 2018, 9 pages.
Author unknown, “Electrostatic lens,” Wikipedia, Mar. 31, 2017 (Mar. 31, 2017), XP055518392, Retrieved from the Internet URL https://en.wikipedia.org/w/index.phptitle=Electrostaticlens oldid=773161674[retrieved on Oct. 24, 2018].
Hussein, O.A. et al., “Study the most favorable shapes of electrostatic quadrupole doublet lenses”, AIP Conference Proceedings, vol. 1815, Feb. 17, 2017 (Feb. 17, 2017), p. 110003.
Guan S., et al., “Stacked-ring electrostatic ion guide”, Journal of the American Society for Mass Spectrometry, Elsevier Science Inc, 7(1)101-106 (1996).
Scherer, S., et al., “A novel principle for an ion mirror design in time-of-flight mass spectrometry”, International Journal of Mass Spectrometry, Elsevier Science Publishers, Amsterdam, NL, vol. 251, No. 1, Mar. 15, 2006.
International Search Report and Written Opinion for application No. PCT/GB2018/052104, dated Oct. 31, 2018, 14 pages.
International Search Report and Written Opinion for application No. PCT/GB2018/052105, dated Oct. 15, 2018, 18 pages.
International Search Report and Written Opinion for application PCT/GB2018/052100, dated Oct. 19, 2018, 19 pages.
International Search Report and Written Opinion for application PCT/GB2018/052102, dated Oct. 25, 2018, 14 pages.
International Search Report and Written Opinion for application No. PCT/GB2018/052099, dated Oct. 10, 2018, 16 pages.
International Search Report and Written Opinion for application No. PCT/GB2018/052101, dated Oct. 19, 2018, 15 pages.
Combined Search and Examination Report under Sections 17 and 18(3) for application GB1807605.9, dated Oct. 29, 2018, 6 pages.
Combined Search and Examination Report under Sections 17 and 18(3) for application GB1807626.5, dated Oct. 29, 2018, 8 pages.
Yavor, M.I., et al., “High performance gridless ion mirrors for multi-reflection time-of-flight and electrostatic trap mass analyzers”, International Journal of Mass Spectrometry, vol. 426, Mar. 2018, pp. 1-11.
Search Report under Section 17(5) for application GB1707208.3, dated Oct. 12. 2017, 6 pages.
Communication Relating to the Results of the Partial International Search for International Application No. PCT/GB2019/01118, dated Jul. 19, 2019, 25 pages.
Doroshenko, V.M., and Cotter, R.J., “Ideal velocity focusing in a reflectron time-of-flight mass spectrometer”, American Society for Mass Spectrometry, 10(10):992-999 (1999).
Kozlov, B. et al. “Enhanced Mass Accuracy in Multi-Reflecting Tof MS” www.Waters.Com/Posters, ASMS Conference (2017).
Kozlov, B. et al. “Multiplexed Operation of an Orthogonal Multi-Reflecting TOF Instrument to Increase Duty Cycle by Two Orders” ASMS Conference, San Diego, CA, Jun. 6, 2018.
Kozlov, B. et al. “High accuracy self-calibration method for high resolution mass spectra” ASMS Conference Abstract, 2019.
Kozlov, B. et al. “Fast Ion Mobility Spectrometry and High Resolution TOF MS” ASMS Conference Poster (2014).
Verenchicov, A. N. “Parallel MS-MS Analysis in a Time-Flight Tandem. Problem Statement, Method, and Instrumental Schemes” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2004).
Yavor, M. I. “Planar Multireflection Time-of-Flight Mass Analyzer with Unlimited Mass Range” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2004).
Khasin, Y. I. et al., “Initial Experimental Studies of a Planar Multireflection Time-of-Flight Mass Spectrometer” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2004).
Verenchicov, A. N. et al. “Stability of Ion Motion in Periodic Electrostatic Fields” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2004).
Verenchicov, A. N. “The Concept of Multireflecting Mass Spectrometer for Continuous Ion Sources” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2006).
Verenchicov, A. N., et al. “Accurate Mass Measurements for Interpreting Spectra of atmospheric Pressure Ionization” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2006).
Kozlov, B. N. et al., “Experimental Studies of Space Charge Effects in Multireflecting Time-of-Flight Mass Spectrometes” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2006).
Kozlov, B. N. et al., “Multireflecting Time-of-Flight Mass Spectrometer With an Ion Trap Source” Institute for Analytica nstrumentation RAS, Saint-Petersburg, (2006).
Hasin, Y. I., et al., “ Planar Time-of-Flight Multireflecting Mass Spectrometer with an Orthogonal Ion Injection Out of Continuous Ion Sources” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2006).
Lutvinsky, Y. I., et al., “Estimation of Capacity of High Resolution Mass Spectra for Analysis of Complex Mixtures” Institute for Analytical Instrumentation RAS, Saint-Petersburg, (2006).
Wikipedia “Reflectron”, Oct. 9, 2015, Retrieved from the Internet URL https://en.wikipedia.org/w/index.php?title=Reflectron&oldid=684843442 [retrieved on May 29, 2019].
Verenchicov., A. N. et al. “Multiplexing in Multi-Reflecting TOF MS” Journal of Applied Solution Chemistry and Modeling, 6:1-22 (2017).
Supplementary Partial EP Search Report for EP Application No. 16869126.9, dated Jun. 13, 2019.
Supplementary Partial EP Search Report for EP Application No. 16866997.6, dated Jun. 7, 2019.
Extended European Search Report for EP Patent Application No. 16866997.6 dated Oct. 16, 2019.
International Search Report and Written Opinion for International Application No. PCT/GB2019/051234 dated Jul. 29, 2019.
International Search Report and Written Opinion for International Application No. PCT/GB2019/051839 dated Sep. 18, 2019.
International Search Report and Written Opinion for International Application No. PCT/GB20180051320 dated Aug. 1, 2018.
Stresau, D., et al., “Ion Counting Beyond 10ghz Using a New Detector and Conventional Electronics”, European Winter Conference on Plasma Spectrochemistry, Feb. 4-8, 2001, Lillehammer, Norway, Retrieved from the Internet URL htps://www.etp-ms.com/file-repository/21 [retrieved on Jul. 31, 2019].
Kaufmann, R., et. al., “Sequencing of peptides in a time-of-flight mass spectrometer: evaluation of postsource decay following matrix-assisted laser desorption ionisation (MALDI)”, International Journal of Mass Spectrometry and Ion Processes, Elsevier Scientific Publishing CO. Amsterdam, NL, 131:355-385, Feb. 24, 1994.
Shaulis, Barry, et al., “Signal linearity of an extended range pulse counting detector: Applications to accurate and precise U-Pb dating of zircon by laser ablation quadrupole ICP-MS”, G3: Geochemistry, Geophysics, Geosystems, 11(11):1-12, Nov. 20, 2010.
Search Report for United Kingdom Application No. GB1708430.2 dated Nov. 28, 2017.
International Search Report and Written Opinion for International application No. PCT/GB2020/050209, dated Apr. 28, 2020, 12 pages.
Search Report under Section 17(5) for GB1916445.8, dated Jun. 15, 2020.
Author unknown, “Einzel Lens”, Wikipedia [online]Nov. 2020 [retrieved on Nov. 3, 2020]. Retrieved from Internet URL: https://en.wikipedia.org/wiki/Einzel_lens, 2 pages.
Combined Search and Examination Report for United Kingdom Application No. GB1901411.7 dated Jul. 31, 2019.
Examination Report for United Kingdom Application No. GB1618980.5 dated Jul. 25, 2019.
Combined Search and Examination Report for GB 1906258.7, dated Oct. 25, 2019.
Combined Search and Examination Report for GB1906251.8, dated Oct. 30, 2019.
IPRP for International application No. PCT/GB2018/051206, dated Nov. 5, 2019, 7 pages.
International Search Report and Written Opinion for lntemational application No. PCT/GB2019/051235, dated Sep. 25, 2019, 22 pages.
International Search Report and Written Opinion for International application No. PCT/GB2019/051416, dated Oct. 10, 2019, 22 pages.
Search and Examination Report under Sections 17 and 18(3) for Application No. GB1906258.7, dated Dec. 11, 2020, 7 pages.
Wollnik, H., and Casares, A., “An energy-isochronous multi-pass time-of-flight mass spectrometer consisting of two coaxial electrostatic mirrors”, International Journal of Mass Spectrometry, 227(2):217-222 (2003).
Carey, D.C., “Why a second-order magnetic optical achromat works”, Nucl. Instrum. Meth., 189(2-3):365-367 (1981).
Sakurai, et al., “Ion optics for time-of-flight mass spectrometers with multiple symmetry”, Int J Mass Spectrom Ion Proc 63(2-3):273-287 (1985).
Related Publications (1)
Number Date Country
20190206669 A1 Jul 2019 US