Mass Analyzers and Mass Spectrometers

Abstract

A mass analyzer and a mass spectrometer. The mass analyzer has: a set of sector-shaped electrodes providing an electrostatic field in a 2D reference plane, which extends along a drift path locally orthogonal to the reference plane to provide a 3D electrostatic field region; and an injection interface for injecting ions into the mass analyzer, so that the injected ions are guided along a 3D reference trajectory through the 3D electrostatic field region, and according to the 3D reference trajectory, the ions rotate multiple times while drifting along the drift path, and each circle corresponds to a completed track in the 2D reference plane. The injection interface includes an injection deflector that deflects the ions along the direction of the drift path. The injection interface preferably allows the ions guided along the 3D reference trajectory to maintain a sufficient distance from the injection port after being injected, so that they are substantially unaffected by the distortion of the electric field around the injection port.

Description

Technical Field

[0001] The present invention relates to mass analysers. Background Art

[0002] A mass analyzer is known which comprises:

[0003] a set of sector electrodes spatially arranged to provide an electrostatic field in a 2D reference plane suitable for directing ions along trajectories in the 2D reference plane, wherein the set of sector electrodes extends along a drift path that is locally orthogonal to the reference plane such that, in use, the set of sector electrodes provides a 3D electrostatic field region; and

[0004] An injection interface is configured to inject ions into the mass analyzer via an injection port, so that the ions injected into the mass analyzer are guided by the 3D electrostatic field region along a 3D reference trajectory, according to which the ions rotate multiple times in the mass analyzer while drifting along a drift path, wherein each rotation corresponds to a completed orbit in a 2D reference plane.

[0005] Such a mass analyzer is disclosed in US9082602B2 (see, for example, FIG. 4 , note that here, the drift path is curved around a reference axis included in the reference plane); “A High Resolution Multi-turn TOF Mass Analyser” published by V.Shchepunov et al. in SHIMADZU REVIEW Vol. 72, No. 3.4 (2015) (see, for example, FIG. 6 , note that here, the drift path is curved); US7504620B2 (see, for example, FIG. 5 , note that here, the drift path is linear); WO2011 / 086430A1 (see, for example, FIG. 11 , note that here, the drift path is linear); and WO2018 / 033494A1 (see, for example, FIG. 6 , note that here, the drift path is linear).

[0006] US9082602B2 suggests (see Figures 15A, 15C, 15D; Column 26, Line 60 to Column 27, Page 36; Column 33, Lines 31 to 46) the use of a "fringe field corrector" in the form of a set of line tracks on a printed circuit board ("PCB") to compensate for the electric field distortion caused by openings in the main sector electrodes, where these openings are present to allow ions to be injected into and extracted from the mass analyzer (these openings are also referred to as "injection holes" and "extraction holes"). However, in smaller sized mass analyzers or in mass analyzers operating with a higher turn density in the direction of the drift path, some or all ions may pass too close to the surface of the PCB fringe field corrector, where the electric field may be distorted. During injection, this distortion may deteriorate the beam timing characteristics and reduce the mass resolution and analyzer transmission efficiency. The extraction efficiency may also be reduced due to additional losses at the extraction port caused by the effects of both the injection PCB fringe field corrector and the extraction PCB fringe field corrector. Additionally, imperfect alignment and / or manufacturing accuracy of the PCB corrector may result in similar degradation of transmission and resolution.

[0007] The present invention is designed based on the above considerations. Summary of the invention

[0008] A first aspect of the present invention provides:

[0009] A mass analyzer, used in a mass spectrometer, comprising:

[0010] a set of sectorized electrodes spatially arranged to provide an electrostatic field in a 2D reference plane, the electrostatic field being suitable for directing ions along trajectories in the 2D reference plane, wherein the set of sectorized electrodes extends along a drift path that is locally orthogonal to the reference plane such that, in use, the set of sectorized electrodes provides a 3D electrostatic field region; and

[0011] an injection interface configured to inject ions into the mass analyzer via an injection port, such that the ions injected into the mass analyzer are guided by the 3D electrostatic field region along a 3D reference trajectory, according to which the ions rotate a plurality of times within the mass analyzer while drifting along the drift path, wherein each rotation corresponds to a completed orbit in the 2D reference plane;

[0012] Wherein, the injection interface includes at least one injection deflector located in the mass analyzer, and the at least one injection deflector is configured to deflect ions injected into the mass analyzer along the direction of the drift path, wherein the injection interface is preferably configured so that the ions guided along the 3D reference trajectory maintain a sufficient distance from the injection port after being injected into the mass analyzer so that they are substantially unaffected by the electric field distortion around the injection port.

[0013] In this way, at least one deflector of the injection interface can help prevent ions from being too close to the injection port after being injected into the mass analyzer (e.g., when the first turn in the mass analyzer is completed), and thus can help avoid the ions from being affected by electric field distortions around the injection port (e.g., caused by the injection port or a fringe field corrector located near the injection port). For example, this can help improve beam timing characteristics, mass resolution and / or transmission efficiency.

[0014] Note here that the above definition refers to the ions maintaining a sufficient distance from the injection port after they are injected into the mass analyzer (i.e., after the ions have been introduced into the mass analyzer and preferably after completing the first half turn in the mass analyzer). This is because it is obvious that when the ions are introduced into the mass analyzer through the injection port, they will be very close to the injection port.

[0015] For the avoidance of any doubt, when it is described herein that ions are deflected "in the direction of a drift path", the ions may be deflected forwards or backwards in the direction of the drift path.

[0016] For a typical mass analyzer, in order for ions guided along the 3D reference trajectory to be substantially unaffected by the electric field distortions around the injection port after being injected into the mass analyzer, the injection interface is preferably configured so that the 3D reference trajectory (e.g., at the completion of the first turn in the mass analyzer, and preferably at all positions on the 3D reference trajectory corresponding to the ion after the ion has completed the first half turn in the mass analyzer) is no closer to the injection port than one "electrode gap" (more preferably at least two electrode gaps, more preferably at least three electrode gaps). Here, the "electrode gap" can be defined as the distance between the inner and outer electrodes, which defines the gap reached by the ion when it completes its first turn in the mass analyzer. These inner and outer electrodes can, for example, be sector electrodes defining an electrostatic sector region, or can be electrodes defining a field-free region.

[0017] For a typical instrument, the electrode gap may be, for example, 20 mm. Thus, in some embodiments, the injection interface is preferably configured such that the 3D reference trajectory (e.g., when the first lap in the mass analyzer is completed) is no closer than 20 mm to the injection port (preferably 40 mm), but of course, this distance will vary from instrument to instrument.

[0018] If a fringe field corrector is used, this distance can be smaller, for example the injection interface can be configured so that the 3D reference trajectory is no closer than 10 mm to the injection port (and preferably also to the fringe field corrector) when the first revolution in the mass analyser is completed, but of course this distance will vary from instrument to instrument, for example depending on the configuration of the fringe field corrector, the size of the electrode gap, etc.

[0019] Of course, in addition to the sector electrodes mentioned above, the mass analyzer will usually also include lenses and other auxiliary electrodes.

[0020] Preferably, the injection deflector is configured to deflect the ions injected into the mass analyzer in the direction of the drift path so that the distance between the 3D reference trajectory and the injection port is increased, that is, so that the ions guided along the 3D reference trajectory after the ions are injected into the mass analyzer (for example, when the first loop in the mass analyzer is completed) pass closer to the injection port than when at least one injection deflector is missing. That is, the closest distance from the 3D reference trajectory to the injection port (except during injection) should be larger than when at least one injection deflector is missing. This is one way in which the injection interface can be configured so that ions guided along the 3D reference trajectory maintain a sufficient distance from the injection port after injection into the mass analyzer so that they are substantially unaffected by the electric field distortion around the injection port.

[0021] Optionally, the injection interface can be configured to inject ions into the mass analyzer with an initial trajectory such that the ions are substantially unaffected by electric field distortions around the injection port (e.g., with relatively large distances between adjacent turns), wherein at least one injection deflector is configured to cause subsequent turns within the mass analyzer to be closer together (compared to a situation where at least one injection deflector is absent) (e.g., see Figure 7 ). This is another way in which the injection interface can be configured so that ions guided along the 3D reference trajectory remain a sufficient distance from the injection port after injection into the mass analyser so that they are substantially unaffected by the electric field distortions surrounding the injection port.

[0022] Note that while each "circle" corresponds to a completed orbit in the 2D reference frame, in reality the ions do not actually complete an orbit in the 2D reference plane, as they are drifting along a drift path and therefore following an open 3D reference trajectory. For example, if the completed orbit in the 2D reference frame corresponds to a circle and the drift path is linear, then the 3D reference trajectory will have a spiral shape (rather than a 2D circle).

[0023] Note also that the deflector shown in FIG. 16A of US9082602B2 is an external deflector located outside the mass analyser and therefore cannot be used as an injection deflector according to the first aspect of the present invention.

[0024] Also note that although Figure 16B of US9082602B2 and Figure 6 of "A High Resolution Multi-turn TOF Mass Analyser" published by V. Shchepunov et al. in SHIMADZU REVIEW Vol. 72 No. 3.4 (2015) both disclose the use of reverse deflectors located within the mass analyzer, these reverse deflectors are not used to increase the distance between the 3D reference trajectory and the injection port (because the ions have already passed close to the injection port before being reversed by these reverse deflectors), and therefore these reverse deflectors are clearly not configured to be used as injection deflectors according to the first aspect of the present invention.

[0025] As is known in the art, a sector electrode can be understood as at least two electrodes to which different potentials are applied to generate an electrostatic field therebetween (usually, the electrostatic field is locally perpendicular to the predetermined reference trajectory followed by the ions), thereby guiding the ions along a curved predetermined reference trajectory between the at least two sector electrodes of different potentials. At least two sector electrodes arranged in this manner can be referred to as an "electrostatic sector region". Typically, the predetermined reference trajectory is a 2D trajectory, but according to the present invention, the sector electrodes extend along a drift path, and the predetermined trajectory is a 3D reference trajectory of the ions drifting along the drift path. Mass analyzers that guide ions along such a 3D reference trajectory are disclosed in US9082602B2 (see, for example, FIG. 4 , note that here, the drift path is curved around a reference axis included in the reference plane), US7504620B2 (see, for example, FIG. 5 , note that here, the drift path is linear), WO2011 / 086430A1 (see, for example, FIG. 11 , note that here, the drift path is linear), and WO2018 / 033494A1 (see, for example, FIG. 6 , note that here, the drift path is linear).

[0026] Preferably, at least one injection deflector is configured to deflect the ions along the direction of the drift path before the ions injected into the mass analyser have completed their first three revolutions within the mass analyser, more preferably before the ions have completed their first two revolutions within the mass analyser, more preferably before the ions have completed their first revolution within the mass analyser, and more preferably before the ions have completed their first half revolution within the mass analyser.

[0027] This is important because the injection deflector needs to be used early enough in the flight path of ions injected into the mass analyser to keep the ions at a sufficient distance from the injection port so that they are substantially unaffected by electric field distortions surrounding the injection port, whilst allowing adjacent turns of the 3D reference trajectory to be packed closely together for most flight paths.

[0028] Here, "first turn" refers to the first turn that the ion completes when traveling along the 3D reference trajectory after being injected into the mass analyzer. Similarly, "first two turns" refers to the first two turns that the ion completes when traveling along the 3D reference trajectory after being injected into the mass analyzer. And so on.

[0029] Most preferably, at least one injection deflector is configured to deflect the ions injected into the mass analyser in the direction of the drift path before they have completed their first turn in the mass analyser (e.g. at a position within the first half turn or within the second half turn), preferably increasing the distance between the deflected ions that have completed the first turn and the injection port. This is the most convenient way to increase the distance between the 3D reference trajectory and the injection port. However, at least one injection deflector may, for example, be located within the second turn or the third turn - for example, with a drift angle (pitch) that is larger before the injection deflector (allowing for bypassing electric field distortions near the injection port within the first turn) and smaller after the injection deflector, such as, for example Figure 7 As shown in . Those skilled in the art may conceive of various configurations in light of the disclosure herein.

[0030] Preferably, the drift path is curved. More preferably, the drift path is curved around a reference axis located in a 2D reference plane. For example, a mass analyzer implementing such a drift path is disclosed in US9082602B2 (see FIG. 4 ).

[0031] In other embodiments, the drift path may be linear, i.e., extending along a straight line. In this case, for an ion of a given m / z value, the 2D reference plane will move along a straight line (and thus along the direction of the drift path) as the ion moves along the 3D reference trajectory. For example, a mass analyzer implementing such a drift path is disclosed in US7504620B2 (see FIG5 ).

[0032] Other drifting paths are conceivable but may be challenging to implement.

[0033] The set of sector electrodes can be spatially arranged to provide an electrostatic field in a 2D reference plane that is suitable for directing ions along a track in the 2D reference plane that may have a variety of shapes. For example, the track can be, for example, O-shaped (e.g., circular, elliptical), figure 8-shaped, or other paths corresponding to periodic motion in the 2D reference plane.

[0034] For the avoidance of any doubt, the injection interface may comprise only one injection deflector (see, for example, Figure 2A ). However, for more complex 3D reference trajectories, e.g. including reverse deflectors (see e.g. Figure 4A ), multiple injection deflectors can be used.

[0035] The mass analyser may comprise an extraction interface configured to extract ions from the mass analyser via an extraction outlet, the extraction being performed after the ions being extracted from the mass analyser have been guided along a 3D reference trajectory by the 3D electrostatic field region.

[0036] Preferably, the extraction interface includes at least one extraction deflector located within the mass analyzer, the at least one extraction deflector being configured to deflect ions following a 3D reference trajectory along a direction of a drift path, wherein the extraction interface is preferably configured such that: the ions guided along the 3D reference trajectory maintain a sufficient distance from the extraction outlet before being extracted from the mass analyzer so that they are substantially unaffected by electric field distortion surrounding the extraction outlet.

[0037] More preferably, the extraction deflector is configured to deflect ions following the 3D reference trajectory in the mass analyzer in the direction of the drift path so that the distance between the 3D reference trajectory and the extraction outlet is increased, that is, the ions guided along the 3D reference trajectory before the ions are extracted from the mass analyzer (for example, when the last turn in the mass analyzer is started) pass in a manner that is closer to the extraction outlet than when at least one extraction deflector is missing. That is, the closest distance of the 3D reference trajectory to the extraction outlet (except during extraction) should be larger than when at least one extraction deflector is missing. This is a preferred way in which the extraction interface can be configured so that the ions guided along the 3D reference trajectory maintain a sufficient distance from the extraction outlet before being extracted from the mass analyzer so that they are substantially unaffected by the electric field distortion around the extraction outlet.

[0038] In this way, at least one extraction deflector can help prevent ions from being too close to the extraction port before being extracted from the mass analyzer (e.g., when starting its last turn), and can therefore help avoid the ions being affected by electric field distortions around the extraction port (e.g., caused by the extraction port or a fringe field corrector located near the extraction port). This can help improve beam timing characteristics, mass resolution, and extraction efficiency.

[0039] Note here that the above definition refers to the ions maintaining a sufficient distance from the extraction port before they are extracted from the mass analyzer (i.e., before the ions are extracted from the mass analyzer, and preferably when the ions start their last loop in the mass analyzer). This is because it is obvious that when the ions are extracted from the mass analyzer through the extraction port, they will be very close to the injection port.

[0040] For a typical mass analyzer, in order to make the ions guided along the 3D reference trajectory substantially unaffected by the electric field distortion around the extraction port before being extracted from the mass analyzer, the extraction interface is preferably configured so that the 3D reference trajectory (e.g., at the start of the last turn in the mass analyzer, and preferably at all positions corresponding to the ion on the 3D reference trajectory before the ion starts the last half turn in the mass analyzer) is no closer to the extraction port than one "electrode gap" (more preferably at least two electrode gaps, more preferably at least three electrode gaps). Here, the "electrode gap" can be defined as the distance between the inner electrode and the outer electrode, which defines the gap reached by the ion when it starts its last turn in the mass analyzer. These inner and outer electrodes can, for example, be sector electrodes defining an electrostatic sector region, or can be electrodes defining a field-free region.

[0041] For a typical instrument, the electrode gap may be, for example, 20 mm. Thus, in some embodiments, the extraction interface is preferably configured such that the 3D reference trajectory (e.g., when starting the last turn in the mass analyzer) is no closer than 20 mm to the extraction port (preferably 40 mm), but of course, this distance will vary from instrument to instrument.

[0042] If an edge field corrector is used, this distance can be smaller, for example, the lead-out interface can be configured so that the 3D reference trajectory, for example when starting the last revolution in the mass analyser, is no closer than 10 mm to the lead-out port (and preferably also to the edge field corrector), but of course, this distance will vary from instrument to instrument, for example depending on the configuration of the edge field corrector, the size of the electrode gap, etc.

[0043] An extraction interface is not a necessary feature of this aspect of the invention, since the ion detector (for detecting ions travelling along the 3D reference trajectory) may in some embodiments be located within the mass analyser.

[0044] For the avoidance of any doubt, the output interface may only include one output deflector (see, for example Figure 2A ). However, for more complex 3D reference trajectories, e.g. including reverse deflectors (see e.g. Figure 4A ), multiple extraction deflectors can be used.

[0045] Preferably, at least one extraction deflector is configured to deflect the ions to be extracted from the mass analyzer in the direction of a drift path after the ions have begun their last three turns within the mass analyzer, more preferably after the ions have begun their last two turns within the mass analyzer, more preferably after the ions have begun their last turn within the mass analyzer, and more preferably after the ions have begun their last turn within the mass analyzer.

[0046] This is important because the extraction deflector needs to be used late enough in the flight path of ions injected into the mass analyser to keep the ions at a sufficient distance from the extraction outlet so that they are substantially unaffected by electric field distortions surrounding the extraction outlet, whilst allowing adjacent turns of the 3D reference trajectory to be packed closely together for most flight paths.

[0047] Here, "last turn" refers to the last (final) turn that the ion completes while traveling along the 3D reference trajectory before extraction from the mass analyzer. Similarly, "last two turns" refers to the last two turns that the ion completes while traveling along the 3D reference trajectory before extraction from the mass analyzer. And so on.

[0048] Most preferably, at least one extraction deflector is configured to deflect the ions to be extracted from the mass analyzer in the direction of the drift path after they have begun their last turn in the mass analyzer (e.g., at a position within the last half turn or the second-to-last half turn), preferably increasing the distance between the deflected ions entering their last turn and the extraction outlet. This is the most convenient way to increase the distance between the 3D reference trajectory and the extraction outlet. However, at least one extraction deflector may be located, for example, within the second-to-last turn or the third-to-last turn - for example, its drift angle (pitch) is large after the extraction deflector (allowing the electric field distortion near the extraction outlet to be bypassed in the last turn) and small before the extraction deflector. Various configurations can be envisioned by those skilled in the art in view of the disclosure herein.

[0049] The injection port and the withdrawal port may be the same opening (although this is not shown in the figure).

[0050] Preferably, at least one injection deflector is used as at least one extraction deflector (see for example Figure 4A), in which case the at least one injection deflector may be referred to as at least one injection / extraction deflector. Such an arrangement may include a set of reverse deflectors (as discussed below, e.g., see Figure 4A ) is implemented as a mass analyzer. In this arrangement, the same deflector(s) used as both the at least one injection deflector and the at least one extraction deflector can also be used as the second set of reverse deflectors (see Figure 4A ).

[0051] If the drift path is curved about the reference axis, then preferably the 3D reference trajectory comprises at least one pair of adjacent turns for which the angle measured using a straight line extending from the reference axis to the respective vertices of the adjacent turns projected by the 3D reference trajectory in a plane perpendicular to the reference axis is less than 10°, more preferably 7° or less, more preferably 6° or less, or in some cases 5° or less, 4° or less, or even 3° or less. For a given pair of adjacent turns, this angle may be referred to as the "drift angle" or "pitch" between the adjacent turns. Preferably, there are at least two pairs, more preferably at least five pairs, more preferably at least ten pairs, more preferably at least twenty pairs of adjacent turns that meet this criterion. For the avoidance of any doubt, the adjacent turns included in each pair need not be exclusively a pair. The turns (one or more pairs) that meet this criterion may be located after the injection interface and / or before the extraction interface on the 3D reference trajectory.

[0052] Here, the “vertex” of the projection of the 3D reference trajectory in the plane may be understood as the extreme point of the projection, for example, a minimum value or a maximum value.

[0053] If the drift path is linear, then preferably the 3D reference trajectory comprises at least one circle for which the angle measured using a straight line extending between three consecutive (following each other along the 3D reference trajectory) vertices projected in a plane perpendicular to the 2D reference plane is less than 5°, more preferably 3.5° or less, more preferably 3° or less, or in some cases 2.5° or less, 2° or less, or even 1.5° or less. This angle for a given circle may be referred to as the "drift angle" or "pitch" of that circle. Note that the values ​​given here are reduced by half compared to the values ​​given for the case of a curved drift path, because here the drift angle is defined by a single circle, not between two adjacent circles. Note also that there are many possible planes perpendicular to the 2D reference plane, and any one of these possible planes (preferably a predetermined one of these planes) may be selected according to the above definition. Preferably, there are at least two, more preferably at least five, more preferably at least ten, more preferably at least twenty circles that meet this criterion. The circle(s) that meet this criterion may be located after the injection interface and / or before the extraction interface on the 3D reference trajectory.

[0054] The mass analyzer may include a reverse deflector set, wherein the reverse deflector set includes one or more reverse deflectors, which are configured to reverse the direction of drift of ions along the drift path so that ions drifting toward the reverse deflector set drift back toward the injection interface.

[0055] In this way, the ions can be made to complete two "passes" through the mass analyser, with each "pass" completing a predetermined 3D reference trajectory in either a "forward" direction (according to which the ions drift toward the reverse deflector set) or a "backward" direction (according to which the ions drift away from the reverse deflector set).

[0056] If the mass analyser comprises a set of reverse deflectors, then conveniently at least one injection deflector may additionally be configured to function as at least one extraction deflector (by applying different voltages to the at least one injection / extraction deflector at appropriate times), such as Figure 4A As is the case with the example shown.

[0057] The mass analyzer may include a second reverse deflector set (in which case the reverse deflector set described in the previous paragraph may be referred to as the "first" reverse deflector set), wherein the second reverse deflector set includes one or more reverse deflectors, which are configured to reverse the direction in which ions drift along a drift path so that ions drifting toward the second reverse deflector set drift back toward the first reverse deflector set.

[0058] In this way, ions can be made to complete more than two "passes" through the mass analyser.

[0059] Conveniently, at least one injection deflector may be configured to additionally function as a second set of reverse deflectors (by applying different voltages to at least one injection deflector at appropriate times). In other words, one or more deflectors may function as at least one injection deflector and as a second set of reverse deflectors. This helps to reduce the number of deflectors included in the mass analyser.

[0060] Conveniently, at least one extraction deflector (if present) may be configured to be used additionally as a set of reverse deflectors (by applying different voltages to at least one extraction deflector at appropriate times). In other words, one or more deflectors may be used as at least one extraction deflector and as a set of reverse deflectors. This helps to reduce the number of deflectors included in the mass analyser. Preferably, at least one extraction deflector is configured to be used additionally as a second set of reverse deflectors, but alternatively, at least one extraction deflector may alternatively be used additionally as a first set of reverse deflectors.

[0061] In a preferred arrangement, at least one injection deflector is configured to additionally function as at least one extraction deflector and as a reverse deflector set (by applying different voltages to at least one injection / extraction deflector at appropriate times), such as Figure 4A As is the case with the example shown. In other words, one or more deflectors can be used as at least one injection deflector, at least one extraction deflector and a second set of reverse deflectors. This helps to reduce the number of deflectors included in the mass analyzer. Preferably, at least one injection / extraction deflector is configured to be additionally used as a second set of reverse deflectors, but optionally, at least one injection / extraction deflector can alternatively be additionally used as a first set of reverse deflectors.

[0062] Each set of reverse deflectors may optionally change the speed at which ions drift along the drift path, but preferably only changes the direction in which ions drift along the drift path (so that the packing of the 3D reference trajectory in the drift direction remains the same).

[0063] Any of the above deflectors may typically comprise at least one (preferably two) electrodes configured to deflect ions in the direction of a drift path.

[0064] Any of the above deflectors (optionally, the / each of the above deflectors) may include an additional electrode configured to deflect ions along a transverse direction (herein referred to as the "transverse direction") that is locally perpendicular to the reference trajectory and the direction of the drift path (herein referred to as the "drift direction"). Being able to deflect ions along the transverse direction may be useful for guiding ions to compensate for alignment errors in sector electrode sets, or for embedding the deflector in a focusing lens electrode. Of course, both the transverse direction and the drift direction are transverse to the reference trajectory.

[0065] Deflectors capable of deflecting ions in a predetermined direction are well known, and the exact form of the / each deflector is not considered to be particularly important to the present invention.

[0066] By way of example, any of the above-mentioned deflectors (optionally, the / each of the above-mentioned deflectors) may include a pair of parallel plates configured to deflect ions along the direction of the drift path (by application of appropriate voltages), and may optionally include an additional pair of parallel plates configured to deflect ions along a lateral direction.

[0067] By way of example, any of the above-mentioned deflectors (optionally, the / each of the above-mentioned deflectors) may be a multipole configured to deflect ions along the direction of a drift path (by application of appropriate voltages), and may optionally also be configured to deflect ions along a transverse direction (by application of appropriate voltages).

[0068] The 3D reference trajectory preferably includes a field region and a field-free region, wherein along the field region, the 3D reference trajectory is surrounded by the sector electrodes included in the sector electrode set, and along the field-free region, the 3D reference trajectory is not surrounded by the sector electrodes included in the sector electrode set. The field region can be a region where the projection of the 3D reference trajectory onto the 2D reference plane is curved, because the sector electrodes are usually required to change the direction of the ions in the 2D reference plane.

[0069] Of course, in general, a "field-free" region will only be relatively free of electric fields, since electric fields generated elsewhere will generally leak into the field-free region (this leakage field is called the so-called "fringe field" - it's an established term).

[0070] Preferably, any of the above-mentioned deflectors (optionally, the / each of the above-mentioned deflectors) is (respectively) located at a position along the 3D reference trajectory at which the 3D reference trajectory is not surrounded by the sector-shaped electrodes (i.e., in a field-free region of the 3D reference trajectory), because it is practically difficult to position the deflector between the sector-shaped electrodes surrounding the 3D reference trajectory.

[0071] The mass analyser may comprise one or more focusing lens electrodes configured to focus ions towards a 3D reference trajectory.Any (optionally, the / each) above-mentioned deflector may be located within a (respective) focusing lens electrode.

[0072] Any of the above deflectors (optionally, the / each of the above deflectors) may be configured to guide ions to compensate for alignment errors in the set of sector electrodes. In this case, the / each deflector configured to guide ions to compensate for alignment errors in the set of sector electrodes preferably includes at least two (preferably four) electrodes configured to deflect ions along the direction of the drift path, and at least two (preferably four) additional electrodes configured to deflect ions along a transverse direction that is locally perpendicular to the reference trajectory and the drift path.

[0073] The 3D reference trajectory is preferably a single 3D reference trajectory that is the same for ions of all m / z values.

[0074] Here, it should be understood that although ions with different initial coordinates and velocities are preferably all guided along a single predetermined 3D reference trajectory, the ions may actually deviate slightly from this trajectory, for example due to small changes in their initial positions or velocities.

[0075] The 3D reference trajectory can be defined as extending between a starting point and an end point. The starting point of the 3D reference trajectory can be defined as a position outside or inside the ion source. This point will generally be outside the ion source (if present) and outside the mass analyzer. The end point of the 3D reference trajectory can be defined as a position at or near an ion detector for detecting ions guided along the predetermined 3D reference trajectory. This point may be outside or inside the mass analyzer.

[0076] Preferably, the electrode set includes a drift focusing electrode configured to provide drift focusing, such as to focus the ions in the direction of the drift path at one or more positions along a predetermined 3D reference trajectory. Preferably, the drift focusing electrode focuses the ions toward the 3D reference trajectory at one or more positions along the 3D reference trajectory. (For example, as discussed in detail in US9082602B2) This can help keep the ions close to the predetermined 3D reference trajectory (see Figure 14B), and can help achieve isochronism.

[0077] Preferably, the drift focusing electrode is configured to provide drift focusing by generating an electrostatic field whose potential has a non-zero second-order derivative and / or higher-order derivative, thereby generating focusing in the direction of the drift path. For example, an example form of a drift focusing electrode is described in US9082602B2.

[0078] The 3D reference trajectory can be an open trajectory or a closed trajectory. In this context, a "closed" 3D reference trajectory preferably refers to a trajectory along which reference ions moving along the 3D reference trajectory return to substantially the same point at substantially the same speed. In contrast, an "open" 3D reference trajectory preferably refers to a trajectory along which reference ions moving along the 3D reference trajectory do not return to substantially the same point at substantially the same speed.

[0079] The mass analyzer can be configured as a TOF mass analyzer and / or an E-Trap mass analyzer. A TOF mass analyzer can be considered as a mass analyzer that separates ions according to their mass-to-charge ratio because the flight time of ions through the mass analyzer depends on their mass-to-charge ratio. An E-Trap mass analyzer can be considered as a mass analyzer for trapping ions in one or more tracks. In an E-Trap mass spectrometer, the mass-to-charge ratio of ions can be measured using an image current detection technique.

[0080] In case the mass analyser is configured as a TOF mass analyser, the predetermined 3D reference trajectory may be open or closed.Having a closed predetermined reference trajectory may be advantageous for extending the path length travelled by ions in a TOF mass analyser.

[0081] The mass analyzer can be configured to have a "multi-pass" operating mode in which ions are guided along a predetermined 3D reference trajectory having a closed portion, wherein the ions repeat the closed portion of the predetermined 3D reference trajectory multiple times, thereby increasing the overall flight time. Here, each repeated closed portion of the 3D reference trajectory can be considered a "one pass". For example, the multi-pass operating mode can be implemented using a reverse deflector as described above.

[0082] The first aspect of the present invention may also provide a mass spectrometer having:

[0083] an ion source for generating ions with different initial coordinates and velocities;

[0084] The mass analyzer according to the first aspect of the present invention, wherein the injection interface is configured to inject ions generated by the ion source into the mass analyzer via an injection port so that the ions are guided along a 3D reference trajectory;

[0085] An ion detector is used to detect ions generated by the ion source after they have been directed along the 3D reference trajectory.

[0086] If the mass analyser comprises an extraction interface (see above), the ion detector may be used to detect ions after they have been extracted from the mass analyser via the extraction outlet by the extraction interface.Alternatively, the ion detector may be located within the mass analyser.

[0087] The mass spectrometer may have a processing device for acquiring mass spectral data representing the mass-to-charge ratio of ions generated by the ion source based on the output of the ion detector.

[0088] The ion source may include a vacuum ionization source or an atmospheric pressure ion source.

[0089] Preferably, the ion source is configured to generate ions with different initial coordinates and velocities in short beams, for example, each ion beam is generated in a short period of time, for example, in a period of 1 nanosecond (or less). Such beams can be generated using a pulsed ion source (e.g., a MALDI ion source, or an orthogonal TOF ion source, a 2D or 3D ion trapping device, etc.).

[0090] The ion beam can be selected using any of the following: orthogonal gate, MALDI ion source, RF ion guide, RF ion trap.

[0091] The ion detector may include a time-of-flight ion detector for producing an output representing the flight time of ions generated by the ion source (through the mass analyzer), and / or an image charge / current ion detector for producing an output representing the image current caused by ions generated by the ion source.

[0092] If the mass analyser is configured as a TOF mass analyser (see above), the processing apparatus is preferably used to acquire mass spectral data representing the mass-to-charge ratio of ions produced by the ion source based on the output of the TOF ion detector. Methods for acquiring data in this way are well known in the art.

[0093] If the mass analyser is configured as an E-Trap mass analyser (see above), the processing device is preferably used to acquire mass spectral data representing the mass-to-charge ratio of ions produced by the ion source based on converting the time domain image charge / current signal obtained by the image charge / current detector into the frequency domain using, for example, Fourier analysis. Methods for acquiring data in this manner are well known in the art.

[0094] A second aspect of the present invention provides:

[0095] A mass analyzer, used in a mass spectrometer, comprising:

[0096] a set of sectorized electrodes spatially arranged to provide an electrostatic field in a 2D reference plane, the electrostatic field being suitable for directing ions along trajectories in the 2D reference plane, wherein the set of sectorized electrodes extends along a drift path that is locally orthogonal to the reference plane such that, in use, the set of sectorized electrodes provides a 3D electrostatic field region; and

[0097] an extraction interface configured to extract ions from the mass analyzer via an extraction port, the extraction being performed after the ions extracted from the mass analyzer have been guided by the 3D electrostatic field region along a 3D reference trajectory, according to which the ions make a plurality of turns within the mass analyzer while drifting along the drift path, wherein each turn corresponds to a completed orbit in the 2D reference plane;

[0098] Wherein, the extraction interface comprises at least one extraction deflector located within the mass analyzer, and the at least one extraction deflector is configured to deflect ions following the 3D reference trajectory along the direction of the drift path, wherein the extraction interface is preferably configured so that: the ions guided along the 3D reference trajectory maintain a sufficient distance from the extraction outlet before being extracted from the mass analyzer so that they are substantially unaffected by the electric field distortion around the extraction outlet.

[0099] Preferably, the extraction deflector is configured to deflect ions following the 3D reference trajectory in the direction of the drift path so that the distance between the 3D reference trajectory and the extraction outlet is increased, i.e., so that the ions guided along the 3D reference trajectory before extraction from the mass analyzer pass in a manner not close to the extraction outlet (e.g., when starting the last turn in the mass analyzer) compared to the case where at least one extraction deflector is missing. This is a preferred way in which the extraction interface can be configured so that ions guided along the 3D reference trajectory before extraction from the mass analyzer maintain a sufficient distance from the extraction outlet so that they are substantially unaffected by the electric field distortion around the extraction outlet.

[0100] In this way, at least one extraction deflector can help prevent ions from getting too close to the extraction outlet before they are extracted from the mass analyzer (e.g., when starting their last pass), and thereby can help avoid the ions being affected by electric field distortions surrounding the extraction outlet (e.g., caused by the extraction outlet or a fringe field corrector located near the extraction outlet).

[0101] The mass analyser according to the second aspect of the invention may have any of the features described in conjunction with the first aspect of the invention.

[0102] The mass analyser according to the second aspect of the invention may have an injection interface according to the first aspect of the invention, but such an interface is optional for this second aspect of the invention as the ion source may be located within the mass analyser.

[0103] If the mass analyser comprises an injection interface (see above), the injection interface may be configured to inject ions produced by the ion source into the mass analyser via the injection port such that the ions are directed along the 3D reference trajectory. Alternatively, the ion source may be located within the mass analyser.

[0104] The second aspect of the present invention can also provide a mass spectrometer, which has:

[0105] an ion source for generating ions with different initial coordinates and velocities;

[0106] The mass analyzer according to the second aspect of the present invention, wherein the mass analyzer is configured to guide ions generated by the ion source along a 3D reference trajectory;

[0107] An ion detector is used to detect ions after the ions generated by the ion source have traveled along the 3D reference trajectory and have been extracted from the mass analyzer via an extraction outlet through an extraction interface.

[0108] The mass spectrometer according to the second aspect of the invention may have any of the features described in conjunction with the mass spectrometer according to the first aspect of the invention, except that the mass analyser is not required to have the injection interface described in relation to the first aspect of the invention.

[0109] The invention may include a method of operating a mass analyser or mass spectrometer as disclosed herein. The method may include any method steps implementing or corresponding to any apparatus features described in connection with any of the above aspects of the invention.

[0110] The invention may include a method of configuring a mass analyzer to provide a mass analyzer as disclosed herein. The method may include configuring one or more deflectors of the mass analyzer to compensate for alignment errors in the set of sector electrodes of the mass analyzer. The invention includes combinations of the described aspects and preferred features except where such combinations are expressly not permitted or expressly avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0111] Embodiments and experiments illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings, in which:

[0112] Figure 1A and Figure 1B A mass analyser implementing the disclosure of US9082602B2 is shown.

[0113] Figure 2A and Figure 2B A mass analyser embodying the present invention is shown.

[0114] Figure 3 Another mass analyzer embodying the present invention is shown.

[0115] Figure 4A and Figure 4B Another mass analyzer embodying the present invention is shown.

[0116] FIG. 5A to FIG. 5C Another mass analyzer embodying the present invention is shown.

[0117] Fig. 6A and Figure 6B Another mass analyzer embodying the present invention is shown.

[0118] Figure 7 Another mass analyzer embodying the present invention is shown.

[0119] Fig. 8A and Figure 8B Another mass analyzer embodying the present invention is shown.

[0120] Fig. 9 Another mass analyzer embodying the present invention is shown.

[0121] Fig.10 Alternative positioning of the deflectors for the injection and exit interfaces are shown.

[0122] FIG. 11A to FIG. 11C An exemplary parallel plate deflector is shown.

[0123] FIG. 12A to FIG. 12C An exemplary combined parallel plate and multipole deflector is shown.

[0124] Fig.13A and Fig. 13B Shown is an example of a deflector embedded in a conical lens electrode. DETAILED DESCRIPTION

[0125] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Other aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated herein by reference.

[0126] In the following example, additional deflectors within the mass analyzer are used to direct ions further away from the injection and extraction ports that cause large electric field distortions. This helps to improve the mass resolution of the analyzer.

[0127] Additionally, this allows the ions to rotate an increased number of "turns" within the mass analyzer, which also helps improve mass resolution.

[0128] Finally, the injection deflector and the extraction deflector can be used for additional guidance to compensate for possible alignment errors of the main electrodes, for example to reduce the loss of ions over the reverse deflector and / or the small extraction port. This can help to improve the transfer efficiency.

[0129] In the examples shown, in addition to the sector electrodes of the mass analyzer, a small additional deflector is also included. In these examples, the purpose of the deflector is to deflect the ions along the drift direction so that the distance from the injection port to the first circle of ion trajectories and from the extraction port to the last circle of ion trajectories increases. This means that the influence of field distortion at the injection port / extraction port on mass resolution and transmission efficiency is significantly reduced. At least one injection deflector is required to deflect the ions away from the injection port (if present). At least one extraction deflector is required to deflect the ions away from the extraction port (if present). The same (one or more) deflectors can be used as both injection deflectors and extraction deflectors. The deflectors are located inside the mass analyzer, preferably in a field-free region. Optionally, they can be embedded in the internal focusing lens electrodes. In addition to the main purpose of bypassing areas with poor field quality, the injection deflector / extraction deflector can also be used for additional guidance in two lateral directions to compensate for possible alignment errors of the main electrode.

[0130] Figure 1A and Figure 1B A mass analyser implementing the disclosure of US9082602B2 is shown.

[0131] This mass analyzer includes:

[0132] a set of sector electrodes spatially arranged to provide an electrostatic field in a reference plane suitable for directing ions along trajectories in the 2D reference plane, wherein the set of sector electrodes extends along a drift path D that is locally orthogonal to the reference plane such that, in use, the set of sector electrodes provides a 3D electrostatic field region; and

[0133] An injection interface is configured to inject ions into the mass analyzer via an injection port, so that the ions injected into the mass analyzer are guided by the 3D electrostatic field region along a 3D reference trajectory, according to which the ions rotate multiple times in the mass analyzer while drifting along a drift path, wherein each rotation corresponds to a completed orbit in a 2D reference plane.

[0134] As depicted, the reference plane is shown Figure 1A and 1B The page is vertical.

[0135] exist Figure 1A and Figure 1B , a mass analyzer 1 is shown, in which ions 10 are injected from an external ion source (not shown) via an injection port 3 a at a distal end of an injection tube 3 .

[0136] At the end of the first cycle, the ions pass through the area near the injection port 3 a of the injection tube 3 , where the electrostatic field generated by the sector electrodes of the mass analyzer is distorted by the presence of the injection tube 3 .

[0137] Therefore, according to the teaching of US9082602B2, a PCB fringe field corrector 5 is used to compensate for the electric field distortion at the injection hole 3a. In US9082602B2, the PCB fringe field corrector 5 is described in detail with reference to FIG. 15D of US9082602B2. A similar PCB fringe field corrector can also be used at the outlet (not shown) of the mass analyzer.

[0138] Figure 1A and Figure 1B A disadvantage of the PCB fringe field corrector 5 shown is that ions may pass too close to the corrector 5. This problem is exacerbated at small analyzer sizes or small drift angles (i.e., large number of turns). In this case, both the mass resolving power and the transmission efficiency of the analyzer may be reduced. In addition, misalignment of the corrector or its poor manufacturing quality may lead to degradation of the same key parameters.

[0139] Figure 2A and Figure 2B A mass analyser 101 embodying the present invention is shown.

[0140] In this example, the injection interface includes a single injection deflector 107 located within the mass analyzer, and the injection deflector 107 is configured to deflect the ions injected into the mass analyzer before they have completed a first turn within the mass analyzer along the direction of the drift path D, so that the distance between the deflected ions that have completed the first turn and the injection port 103a increases. Note that due to the inclusion of the injection deflector 107, the distance between the 3D reference trajectory and the injection port 103a is significantly increased, that is, the ions following the 3D reference trajectory pass in a manner that is closer to the injection port 103a than when the injection deflector 107 is missing.

[0141] Thus, the injection deflector 107 is used to increase the distance from ions moving within the mass analyzer to the injection tube 103 (rather than ions entering the mass analyzer through the injection tube), and therefore to the injection port 103a. This distance is preferably large enough so that the field distortion of the tube 103 has a negligible effect on the ion optics of the mass analyzer and so that the PCB fringe field corrector 105 is not required.

[0142] like Figure 2A and Figure 2B As depicted in FIG. 1 , the PCB fringe field corrector 5 is not used. However, in other examples (not shown), the PCB fringe field corrector 5 may be used, but its effect on the ion beam will be greatly reduced due to the main deflector 107.

[0143] In this example, the main deflector 107 is located in the field-free region of the 3D reference trajectory, approximately halfway through the first closed orbit ("turn") completed by the ions.

[0144] Figure 3 Another mass analyser 101' embodying the present invention is shown.

[0145] In this example, the extraction interface includes a single extraction deflector 109' located within the mass analyzer, which is configured to deflect the ions following the 3D reference trajectory in the direction of the drift path D after the ions have begun their last turn within the mass analyzer, so that the distance between the deflected ions entering their last turn and the extraction outlet 104a' at the far end of the extraction tube 104' is increased. The extracted ions 111' can then be detected by a suitable detector (e.g., a TOF detector). Note that due to the inclusion of the injection deflector 107, the distance between the 3D reference trajectory and the extraction outlet 104a' is significantly increased, that is, the ions following the 3D reference trajectory pass in a manner that is closer to the extraction outlet 104a' than when the extraction deflector 109' is missing.

[0146] exist Figure 2A and Figure 2BIn the example of , only a single injection deflector 107 is used. The inventors have noticed that it is possible (by appropriately positioning the deflector 107 and setting the deflection it provides accordingly, and by appropriately setting the injection tube 103) to ensure that ions completing their first turn are well spaced from the injection port 103a, while also achieving a small angle (in the drift direction D) between adjacent turns of the 3D reference trajectory.

[0147] Similarly, in Figure 3 In the example of , only a single extraction deflector 109' is used. The inventors note that it is possible (by appropriately positioning the deflector 109' and setting the deflection it provides accordingly, and appropriately setting the extraction tube 104') to ensure that ions entering their last turn are sufficiently spaced from the extraction outlet 104a', while also achieving a small angle (in the drift direction D) between adjacent turns of the 3D reference trajectory.

[0148] However, as we now Figure 4A and Figure 4B As described, if counter-deflectors are used, the considerations are more complex, and it is generally preferred to use more than one injection deflector and more than one extraction deflector, and preferably also to use the same injection deflector as the extraction deflector, to avoid ions striking these deflectors.

[0149] Figure 4A and Figure 4B Another mass analyser 201 embodying the present invention is shown.

[0150] In this example, the injection interface including the injection tube 203 also includes injection deflectors 207a, 207b.

[0151] The injection deflectors 207a, 207b are configured to deflect ions injected into the mass analyzer via the injection port 203a of the injection tube 203 along the direction of the drift path before the ions have completed a first turn in the mass analyzer, so as to increase the distance between the deflected ions that have completed the first turn and the injection port.

[0152] In this example, the mass analyser comprises a reverse deflector set comprising two reverse deflectors 215a, 215b, wherein the reverse deflectors 215a, 215b are configured to reverse the direction in which ions drift along the drift path such that the ions drift back towards the injection interface.

[0153] Thus, in this example, the ions "pass" through the instrument twice before being extracted. The reason for including two injection deflectors 207a, 207b can be seen from the following: Figure 5BThe reason for including two reverse deflectors 215a, 215b here is to improve the isochronous characteristics in the drift direction, and because it is technically difficult to position a single reverse deflector within the main sector S2.

[0154] In this example, the injection pipe 203 and the outlet pipe 204 are positioned one above the other (see Figure 4B ) and (by applying appropriate voltages at appropriate times) the injection deflectors 207a, 207b also serve as extraction deflectors and are therefore referred to as injection / extraction deflectors 207a, 207b.

[0155] The injection / extraction deflectors 207a, 207b are configured to deflect ions following the 3D reference trajectory along the direction of the drift path after they have started their last turn in the mass analyzer when used as extraction deflectors, so that the distance between the deflected ions entering their last turn and the extraction outlet increases.

[0156] In this example, like the injection tube 203 and the extraction tube 204, the injection / extraction deflectors 207a, 207b are positioned one above the other in the field-free region of the 3D reference trajectory, so that the azimuthal positions of the injection tube 203 and the extraction tube 204 coincide (see Figure 4B ). This arrangement helps to provide the maximum flight path length and therefore the maximum resolution capability m / dm.

[0157] for Figure 4A and Figure 4B In the arrangement shown, deflectors 207a and 207b are used both for injection (where ions are deflected by both deflectors 207a and 207b in the first half turn) and for extraction (where ions pass through and are deflected by both deflectors 207a and 207b in the last half turn before extraction).

[0158] In this example, it is envisaged that each deflector 207a, 207b takes the form of parallel plates separated along the direction of the drift path, where the potentials on the two plates are not equal even under equal geometrical parameters to provide the deflection.

[0159] Since the same deflectors 207a, 207b are used for injection and extraction, the potentials applied to these deflectors 207a, 207b are preferably switchable so that before extraction begins, the potentials applied to the deflectors 207a, 207b for injection are exchanged to the potentials applied to the deflectors 207a, 207b for extraction.

[0160] By lengthening the flight path, the mass resolving power m / dm can be increased.

[0161] exist Figure 4Aand Figure 4B The example shown (preferably also Figure 2A , Figure 2B and Figure 3 In the example shown), the deflectors of the injection interface and the extraction interface are preferably located in the field-free region of the 3D reference trajectory, in the upper (polar) region and the lower (polar) region of the mass analyser.

[0162] FIG. 5A to FIG. 5C Another mass analyser 301 embodying the present invention is shown.

[0163] In this example, ions "pass" the instrument twice before extraction, and there is only one injection deflector 307 and only one extraction deflector 309.

[0164] from Figure 5B As can be seen in FIG. 1 , in order to use only one injection deflector 307 and only one extraction deflector 309, the 3D reference trajectory is very close to the injection deflector 307 and the extraction deflector 309. There is little space between adjacent turns for mounting these deflectors 307, 309. For this reason, having FIG. 5A to FIG. 5C The analyzer 301 of the form shown cannot be too small. In addition, there will be additional losses of ions (oscillations around the reference trajectory) on the deflectors 307, 309, and higher tolerance requirements will be required for the azimuthal positioning of the deflectors. These problems can be avoided by using two deflectors for injection and two deflectors for extraction (e.g. Figure 4A and Figure 4B ), but FIG. 5A to FIG. 5C At least it is shown that only one injection deflector 307 and only one extraction deflector 309 can be used.

[0165] Fig. 6A and Figure 6B Another mass analyser 401 embodying the present invention is shown.

[0166] Here, the drift path is linear, ie extends along a straight line, with only one injection deflector 407 located in the first half turn after injection and one extraction deflector 409 located in the last half turn before extraction. No injection / extraction PCB corrector is used.

[0167] from Figure 6B The positioning of the deflectors 407, 409 can be seen from the side view.

[0168] Figure 7 Shown with Fig. 6A and Figure 6B A similar modified mass analyser 401' is shown, except here the injection deflector 407' is located in the second turn after injection. Similarly, the extraction deflector 409' is located in the second to last turn.

[0169] Here, the injection deflector 407' is configured to increase the distance between the 3D reference trajectory and the injection port by being mutually configured with the introduction tube 403' so that the injection interface injects ions into the mass analyzer with an initial trajectory, so that the ions are substantially unaffected by the electric field distortion surrounding the injection port, wherein the injection deflector is configured to bring subsequent turns within the mass analyzer closer together.

[0170] Fig. 8A and Figure 8B Another mass analyser 501 embodying the present invention is shown.

[0171] Here, the drift path is linear, i.e. extends along a straight line, with only one injection deflector 507 located in the first half turn after ions 510 are injected through injection port 503, and one extraction deflector 509 located in the last half turn before ions 511 are extracted through extraction port 504. No injection / extraction PCB corrector is used.

[0172] In this example, reverse deflectors 515a, 515b (upper and lower) are used to allow ions to pass through the mass analyzer 501 twice.

[0173] Fig. 9 Shown with Fig. 8A and Figure 8B A similar modified mass analyser 501' is shown, except here the injection deflector 507' and extraction deflector 509' act as a second set of reverse deflectors so that ions can complete more than two "passes" through the mass analyser.

[0174] Fig.10 Alternative positioning of the deflectors for the injection and exit interfaces are shown.

[0175] exist Fig.10 In the example shown, the deflectors 607a, 607b of the injection and extraction interfaces are positioned within focusing lens electrodes L1, L2 which are configured to focus ions towards a 3D reference trajectory.

[0176] Note that the separation in the direction of the drift paths of adjacent turns within lenses L1, L2 is much larger than at the poles, and therefore, compared to the positioning of the deflector in the poles (which may be difficult to position in a small analyzer), the deflector embedded in the focusing electrode can be advantageous for analyzers of very small size.

[0177] A potential problem with positioning the deflectors within the focusing lens electrodes is that the inventors have deduced from simulations that such deflectors need to be able to deflect ions both along the direction of the drift path and in a lateral direction that is locally perpendicular to the reference trajectory and the drift path.

[0178] However, the inventors have observed that positioning the deflectors in the polar regions can only be achieved using deflectors that are able to deflect the ions in the direction of the drift path (but some additional deflection in the transverse direction may still be required to correct for misalignment, even if the deflectors are located in the polar regions). The inventors have also observed that embedding the deflectors in the focusing lens electrodes is generally more difficult in terms of manufacturing and assembly than electrodes located in the field-free region.

[0179] Figure 2B and Figure 7 Based on the definitions already provided above, the drift angles 115, 415 are labeled for the curved drift path example and the linear drift path example (the straight lines referenced in these earlier definitions are shown here as dashed lines).

[0180] By way of comparison, in the analyzer shown in Figure 1, the drift angle (the angle between adjacent turns) cannot be too small (typically at least 5-6° is required), because at small drift angles, the ions pass too close to the injection / extraction PCB corrector. However, the use of an injection / extraction deflector according to the present invention allows the drift angle to be made smaller on the portion of the 3D reference trajectory after the injection deflector and before the extraction deflector, and in fact, it is preferred to make the drift angle as small as possible, down to a minimum drift angle that depends on the deflector size and the spacing of adjacent turns at the deflector position. (As shown below in Fig.10 Positioning within the conical focusing lens electrodes F1, F2 (as discussed in ) may allow the use of drift angles of 3° or even less, resulting in an increase in the number of turns, respectively.

[0181] Fig.11A (i) to (iii) in FIG. 5 schematically illustrate a parallel plate deflector for generating a deflection electric field in a drift direction by applying a positive potential +V and a negative potential −V to the plates.

[0182] Fig. 11B A 3D model of another parallel plate deflector is shown.

[0183] Fig. 11C A 3D model of another parallel plate deflector is shown.

[0184] Fig. 12A (i) and (ii) in the figure schematically show a combined parallel plate deflector for generating a deflection electric field in the drift direction and (other) lateral direction by applying potentials +V1, +V2, -V1 and -V2 to the plates respectively.

[0185] Fig. 12B A multipole deflector (with twelve poles) is shown, which is used to generate a deflection electric field in the drift direction and in (other) lateral directions by applying a plurality of potentials distributed over the poles.

[0186] Fig. 12C (i) to (ii) in FIG. 5 show the 3D models of (i) a combined parallel plate deflector and (ii) a multi-pole deflector, respectively.

[0187] Fig.13A and Fig. 13B shown embedded in (e.g., as in Fig.10 An example of a deflector in a conical lens electrode that can be used in the example shown, which is used to generate an electric field to deflect ions along the drift direction. In addition to the main deflector electrodes with potentials +V1, -V1, there are auxiliary inner electrodes (lower electrodes in the figure) and outer electrodes (upper electrodes in the figure) with potentials +0.742V1, -0.742V1 and +0.25V1, -0.25V1, which are dedicated to improving the uniformity of the electric field in the (other) lateral directions.

[0188] The features disclosed in the preceding description or the following claims or drawings, expressed in a specific form or in the form of means for performing the disclosed functions or methods or processes for obtaining the disclosed results, may, where appropriate, be used alone or in any combination of these features to realize the invention in various forms.

[0189] Although the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art when the present invention is given. Therefore, the exemplary embodiments of the present invention set forth above are considered to be illustrative rather than restrictive. Various changes may be made to the described embodiments without departing from the spirit and scope of the present invention.

[0190] For the avoidance of any doubt, any theoretical explanations provided herein are provided to enhance the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.

[0191] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0192] Throughout this specification, including the following claims, unless the context requires otherwise, the words "comprise" and "comprising" and variations such as "including", "comprising" and "comprising", will be understood to mean the inclusion of stated integers or steps or groups of integers or steps but not the exclusion of any other integers or steps or groups of integers or steps.

[0193] It must be noted that, as used in this specification and the appended claims, the singular forms "it," "the," and "said" include plural references unless the context clearly indicates otherwise. Here, ranges may be expressed as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when a value is expressed as an approximation by using the antecedent "about," it should be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and, for example, means + / - 10%.

[0194] References

[0195] Many publications are cited above to more fully describe and disclose the present invention and the prior art to which the present invention relates. The full citations of these references are provided below. Each of these references is incorporated herein in its entirety.

[0196] V. Shchepunov et al., “A High Resolution Multi-turn TOF Mass Analyser”, SHIMADZU REVIEW, Vol. 72, No. 3.4 (2015)

[0197] ·US9082602B2

[0198] ·US7504620B2

[0199] WO2011 / 086430A1

[0200] WO2018 / 033494A1

Claims

1. A mass analyzer for use in a mass spectrometer, the mass analyzer comprising: a set of sector-shaped electrodes spatially arranged to provide an electrostatic field in a 2D reference plane, the electrostatic field being suitable for directing ions along trajectories in the 2D reference plane, wherein, The set of sector-shaped electrodes extends along a drift path that is locally orthogonal to the reference plane, such that, in use, the set of sector-shaped electrodes provides a 3D electrostatic field region; as well as an injection interface configured to inject ions into the mass analyzer via an injection port, such that the ions injected into the mass analyzer are guided by the 3D electrostatic field region along a 3D reference trajectory, according to which the ions rotate a plurality of times within the mass analyzer while drifting along the drift path, wherein each rotation corresponds to a completed orbit in the 2D reference plane; Wherein, the injection interface includes at least one injection deflector located in the mass analyzer, and the at least one injection deflector is configured to deflect the ions injected into the mass analyzer along the direction of the drift path so as to increase the distance between the 3D reference trajectory and the injection port, so that compared with the case where the at least one injection deflector is missing, the closest distance from the 3D reference trajectory to the injection port is larger when the first circle in the mass analyzer is completed, so that the ions guided along the 3D reference trajectory are deflected by the injection deflector to maintain a sufficient distance from the injection port after being injected into the mass analyzer, so that they are basically not affected by the electric field distortion around the injection port.

2. The mass analyzer according to claim 1, wherein The at least one injection deflector is configured to deflect an ion injected into the mass analyser in the direction of the drift path before the ion has completed a first half revolution of the ion within the mass analyser.

3. The mass analyzer according to any one of claims 1 to 2, wherein: The mass analyzer comprises an extraction interface, the extraction interface being configured to extract ions from the mass analyzer via an extraction port, the extraction being performed after the ions to be extracted from the mass analyzer have been guided along the 3D reference trajectory by the 3D electrostatic field region; as well as The extraction deflector is configured to deflect ions injected into the mass analyzer along the direction of the drift path so that the distance between the 3D reference trajectory and the extraction outlet increases.

4. The mass analyzer according to claim 3, wherein: At least one of the extraction deflectors is configured to deflect an ion injected into the mass analyser in the direction of the drift path after the ion has begun its last three turns within the mass analyser.

5. The mass analyzer according to claim 3, wherein: The at least one injection deflector serves as at least one of the extraction deflectors.

6. The mass analyzer according to any one of claims 1 to 2, wherein: The drift path is bent around a reference axis, and the 3D reference trajectory includes at least five pairs of adjacent circles, for which the angle measured using a straight line extending from the reference axis to the corresponding vertices of the adjacent circles projected by the 3D reference trajectory in a plane perpendicular to the reference axis is 6° or less.

7. The mass analyzer according to any one of claims 1 to 2, wherein: The drift path is linear, and the 3D reference trajectory includes at least five turns, for which the angle measured using a straight line extending between three consecutive vertices of the 3D reference trajectory projected in a plane perpendicular to the 2D reference plane is 3° or less.

8. The mass analyzer according to any one of claims 1 to 2, wherein: The mass analyzer includes a reverse deflector set, wherein the reverse deflector set includes one or more reverse deflectors, and the one or more reverse deflectors are configured to reverse the direction of drift of ions along the drift path so that ions drifting toward the reverse deflector set drift back toward the injection interface.

9. The mass analyzer according to claim 8, wherein: The reverse deflector set includes a first reverse deflector set, and the mass analyzer also includes a second reverse deflector set, wherein the second reverse deflector set includes one or more reverse deflectors, and the one or more reverse deflectors are configured to reverse the direction of drift of ions along the drift path, so that ions drifting toward the second reverse deflector set drift back toward the first reverse deflector set.

10. The mass analyzer according to claim 9, wherein The at least one injection deflector is configured to additionally function as the second set of reverse deflectors.

11. The mass analyzer according to claim 8, wherein At least one of the extraction deflectors is configured to additionally function as a reverse deflector set.

12. The mass analyzer according to claim 9, wherein The at least one injection deflector is configured to additionally function as at least one extraction deflector and as the second set of reverse deflectors.

13. The mass analyzer according to any one of claims 1 to 2, wherein: At least one of the injection deflector, the extraction deflector included in the mass analyzer, and the reverse deflector included in the mass analyzer is positioned at a position along the 3D reference trajectory at which the 3D reference trajectory is not surrounded by the sector electrodes.

14. The mass analyzer according to any one of claims 1 to 2, wherein: The mass analyzer includes one or more focusing lens electrodes, which are configured to focus ions toward the 3D reference trajectory, wherein at least one of the injection deflector, the extraction deflector included in the mass analyzer, and the reverse deflector included in the mass analyzer is located within the focusing lens electrode.

15. A mass spectrometer comprising: an ion source for generating ions with different initial coordinates and velocities; The mass analyzer according to any one of claims 1 to 14, wherein the injection interface is configured to inject ions generated by the ion source into the mass analyzer via the injection port so that the ions are guided along the 3D reference trajectory; An ion detector is used to detect ions generated by the ion source after they have been directed along the 3D reference trajectory.

16. A mass analyzer for use in a mass spectrometer, the mass analyzer comprising: a set of sector-shaped electrodes spatially arranged to provide an electrostatic field in a 2D reference plane, the electrostatic field being suitable for directing ions along trajectories in the 2D reference plane, wherein, The set of sector-shaped electrodes extends along a drift path that is locally orthogonal to the reference plane, such that, in use, the set of sector-shaped electrodes provides a 3D electrostatic field region; as well as an extraction interface configured to extract ions from the mass analyzer via an extraction port, the extraction being performed after the ions extracted from the mass analyzer have been guided by the 3D electrostatic field region along a 3D reference trajectory, wherein according to the 3D reference trajectory, the ions make a plurality of turns within the mass analyzer while drifting along the drift path, wherein each turn corresponds to a completed orbit in the 2D reference plane; Wherein, the extraction interface includes at least one extraction deflector located in the mass analyzer, and the at least one extraction deflector is configured to deflect ions following the 3D reference trajectory along the direction of the drift path, wherein the extraction deflector is configured to deflect ions following the 3D reference trajectory along the direction of the drift path to increase the distance between the 3D reference trajectory and the extraction outlet, so that compared with the case where the at least one extraction deflector is missing, the closest distance from the 3D reference trajectory to the extraction outlet is larger when the last circle in the mass analyzer starts, so that the ions guided along the 3D reference trajectory are deflected by the extraction deflector to maintain a sufficient distance from the extraction outlet before being extracted from the mass analyzer, so that they are substantially unaffected by the electric field distortion around the extraction outlet.

17. A mass spectrometer comprising: an ion source for generating ions with different initial coordinates and velocities; The mass analyzer according to claim 16, wherein The mass analyzer is configured to direct ions generated by the ion source along the 3D reference trajectory; An ion detector is used to detect ions generated by the ion source after the ions have traveled along the 3D reference trajectory and have been extracted from the mass analyzer via an extraction outlet through an extraction interface.

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