Device and method for controlling kinetic energy dispersion of static trap ions

Abstract

The invention provides a device and a method for controlling kinetic energy dispersion of static trap ions, the device for controlling kinetic energy dispersion of static trap ions comprises a power supply, and a first vacuum cavity and a second vacuum cavity which are communicated, the first vacuum cavity is internally provided with a first lens group for ion compression, and the second vacuum cavity is internally provided with a detector; the electrostatic trap comprises a second lens group, the second lens group is arranged in the second vacuum cavity and comprises a plurality of electrodes which are arranged in sequence, and each electrode is provided with a channel allowing ions to pass through; the power supply supplies power to the second lens group; the ion detection unit is used for detecting whether ions pass through the second lens group; and the controller adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the preorder ions in the ion sequence entering the second lens group are decelerated, and the subsequent ions are accelerated. The device has the advantages of simple structure and the like.

Description

Technical Field

[0001] The invention relates to mass spectrometry technology, and in particular to a device and method for controlling kinetic energy dispersion of electrostatic trap ions. Background Art

[0002] Ion traps, including RF ion traps, are existing devices that allow for the storage of ions and the ejection of the stored ions into a mass analyser such as an ion cyclotron resonance (ICR) analyser.

[0003] Makarov et al. provided a curved linear trap, namely C-trap, in patent US8017909B2, which is specifically a storage trap that stores ions and can quickly inject the ions into an Orbitrap detector. Ions enter the gas-filled curved linear trap (C-Trap) through the gate electrode of the C-trap. The C-trap quadrupole applies an RF potential (500-1500Vpp, 3Mhz) to radially capture the ions. The entering ions are reflected by the trap electrode at the other end of the C-trap and begin to lose energy (~1mTorr) in the collision with the nitrogen gas and cool in the C-trap. The ions form a long arc along the curved axis of the C-trap and are axially confined by simultaneously applying a potential to the gate electrode and trap electrode of the C-trap (raised to 200V and with a limit on the raising rate). 1200, 1000 and 1100 volt DC pulses are applied to the push electrode (the electrode farthest from the center of curvature of the C-trap), the pull-out electrode (the electrode closest to the center of curvature of the C-trap) and the upper and lower electrodes, respectively, to focus the ions into a compact ion cloud.

[0004] The above technical solution has the following technical problems: 1. The collision of ions of different sizes with the gas causes the loss of kinetic energy, which then causes kinetic energy dispersion.

[0005] 2. Collisions cause ions to disperse. Through simulation, it is found that ions at the edge of the ion packet have difficulty passing through the slit, resulting in ion wall loss.

[0006] 3. Due to the inhomogeneity of the gas, the distribution of ions in the trap is uncontrollable, and the flow rate and position of gas injection are very demanding. Summary of the invention

[0007] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a device for controlling the kinetic energy dispersion of electrostatically trapped ions.

[0008] The objective of the present invention is achieved through the following technical solutions: A device for controlling kinetic energy dispersion of electrostatically trapped ions, the device comprising a power supply and a first vacuum chamber and a second vacuum chamber connected to each other, a first lens group for ion compression being arranged in the first vacuum chamber, and a detector being arranged in the second vacuum chamber; the device for controlling kinetic energy dispersion of electrostatically trapped ions further comprising: an electrostatic trap, wherein the electrostatic trap comprises a second lens group, the second lens group is arranged in the second vacuum chamber, and comprises a plurality of electrodes arranged in sequence, each electrode having a channel allowing ions to pass through; the power supply supplies power to the second lens group; An ion detection unit, the ion detection unit is used to detect whether ions pass through the second lens group; A controller is provided, wherein the controller adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the leading ions in the ion sequence entering the second lens group are decelerated and the subsequent ions are accelerated.

[0009] The present invention also aims to provide a method for controlling the kinetic energy dispersion of electrostatically trapped ions, which is achieved by the following technical solutions: A method for controlling the kinetic energy dispersion of electrostatically trapped ions, the method for controlling the kinetic energy dispersion of electrostatically trapped ions comprising the steps of: (S1) The ions enter the first lens group in the first vacuum chamber, the ions are compressed in the transmission direction, and then the ions enter the second vacuum chamber; (S2) ions enter the electrostatic trap in different orders, and an ion detection unit detects whether ions reach the electrode in the second lens group in the electrostatic trap; When the electrode detects the preceding ion, the controller controls the power supply to apply a voltage to the electrode downstream of the preceding ion, so that the preceding ion is decelerated; When the electrode detects the subsequent ion, the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion, so that the subsequent ion is accelerated, the distance between the ions becomes smaller, and the kinetic energy dispersion of the ions is reduced; (S3) The ions are received by the detector.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. Small ion kinetic energy dispersion; In the second vacuum chamber, multiple electrodes (ion lens group structure) can be applied with program-controlled voltage. The voltage program can be automatically adjusted according to the ion mass range, slowing down the faster-flying small ions and accelerating the slower-flying large ions, thereby reducing the kinetic energy dispersion and flight time difference between large-mass ions and small-mass ions; In the first vacuum chamber, the ions are not disturbed by collision gas before ejection, which reduces the loss of ion collision with the wall and reduces the dispersion of kinetic energy of ions with different mass-to-charge ratios; 2. Vacuum is easy to achieve; After being deflected, the ions pass through multiple vacuum chambers in sequence, which avoids the ion path and the pumping path being on the same path, reducing the difficulty of achieving vacuum. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings: Figure 1 is a schematic structural diagram of a device for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of a first lens group in a device for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention; Figure 3 It is a schematic flow chart of a method for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention. DETAILED DESCRIPTION

[0012] Figure 1-Figure 3 The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents. Example 1

[0013] A device for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention, such as Figure 1 As shown, the device for controlling the kinetic energy dispersion of electrostatically trapped ions comprises: A power supply and a first vacuum chamber and a second vacuum chamber connected to each other, wherein a first lens group for ion compression is arranged in the first vacuum chamber, and a detector is arranged in the second vacuum chamber; an electrostatic trap, wherein the electrostatic trap comprises a second lens group, the second lens group is arranged in the second vacuum chamber, and comprises a plurality of electrodes arranged in sequence, each electrode having a channel allowing ions to pass through; the power supply supplies power to the second lens group; An ion detection unit, the ion detection unit is used to detect whether ions pass through the second lens group; A controller is provided, wherein the controller adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the leading ions in the ion sequence entering the second lens group are decelerated and the subsequent ions are accelerated, so that the distance between the ions becomes smaller and the kinetic energy dispersion of the ions is reduced.

[0014] In order to reduce the kinetic energy dispersion of the ions, further, when the electrode detects the preceding ion, the controller controls the power supply to apply a voltage to the electrode downstream of the preceding ion, so that the preceding ion is decelerated; When the electrode detects the subsequent ion, the controller controls the power supply to apply a voltage to the electrode located upstream of the subsequent ion, so that the subsequent ion is accelerated.

[0015] In order to focus ions and realize gradient vacuum, the device for controlling kinetic energy dispersion of electrostatically trapped ions further comprises: a third vacuum chamber, wherein the first vacuum chamber, the third vacuum chamber and the second vacuum chamber are connected in sequence; The third lens group is used for ion focusing and deflection.

[0016] In order to compress ions in the ion transmission direction and reduce the ion kinetic energy dispersion, further, as Figure 2 As shown, the first lens group includes: A plurality of groups of electrodes, the plurality of groups of electrodes comprising a central group of electrodes and a peripheral group of electrodes, the central group of electrodes having an ion exit hole, the peripheral group of electrodes being symmetrically arranged about the central group of electrodes; each group of electrodes encloses an ion channel, the plurality of groups of electrodes arranged in sequence form a linear ion channel, the power supply applies a radio frequency voltage and a direct current voltage to each group of electrodes; From the central group of electrodes toward the peripheral group of electrodes, the RF voltage V on the nth group of electrodes n satisfy: , (m / z) max is the highest mass-to-charge ratio of the ion packet, (m / z) min is the minimum mass-to-charge ratio of the ion packet; K is the reference voltage, which is generally set to 2000V according to the structure of the trap.

[0017] From the central group of electrodes toward the peripheral group of electrodes, the gap J between the nth group of electrodes and the (n+1)th group of electrodes n satisfy: , a is the minimum distance between the inner surfaces of the electrodes arranged opposite to each other in the first lens group, b is the total length of the first lens group, and c is the length of the nth group of electrodes in a direction parallel to the central axis of the ion channel.

[0018] In order to reduce the complexity of the structure, further, each group of electrodes is composed of two pairs of electrodes arranged opposite to each other, and the inner surfaces of the electrodes are plane.

[0019] In order to reduce the complexity of the structure, further, from the central group of electrodes toward the peripheral group of electrodes, the length of each group of electrodes in the direction parallel to the central axis of the ion channel is equal or increases.

[0020] A method for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention is as follows: Figure 3 As shown, the method for controlling the kinetic energy dispersion of electrostatically trapped ions comprises the steps of: (S1) The ions enter the first lens group in the first vacuum chamber, the ions are compressed in the transmission direction, and then the ions enter the second vacuum chamber; (S2) ions enter the electrostatic trap in different orders, and an ion detection unit detects whether ions reach the electrode in the second lens group in the electrostatic trap; When the electrode detects the preceding ion, the controller controls the power supply to apply a voltage to the electrode downstream of the preceding ion, so that the preceding ion is decelerated; When the electrode detects the subsequent ion, the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion, so that the subsequent ion is accelerated, the distance between the ions becomes smaller, and the kinetic energy dispersion of the ions is reduced; (S3) The ions are received by the detector.

[0021] In order to focus ions and achieve gradient vacuum, further, in step (S1), ions emitted from the first vacuum chamber enter into a third vacuum chamber; The ions are focused and deflected in the third lens group of the third vacuum chamber, and then enter the second vacuum chamber.

[0022] In order to achieve ion compression, further, step (S1) includes: (S11) a power source applies a radio frequency voltage to the first lens group, and ions are stored in an ion channel formed by the first lens group; like Figure 2 As shown, the first lens group includes a central group electrode and a peripheral group electrode, the central group electrode has an ion exit hole, and the peripheral group electrodes are symmetrically arranged about the central group electrode; each group of electrodes surrounds an ion channel, and multiple groups of electrodes arranged in sequence form a linear ion channel, and the power supply applies a radio frequency voltage and a direct current voltage to each group of electrodes; From the central group of electrodes toward the peripheral group of electrodes, the RF voltage V on the nth group of electrodes n satisfy: , (m / z) max is the highest mass-to-charge ratio of the ion packet, (m / z) min is the minimum mass-to-charge ratio of the ion packet; K is the reference voltage, which is generally set to 2000V according to the structure of the trap.

[0023] From the central group of electrodes toward the peripheral group of electrodes, the gap J between the nth group of electrodes and the (n+1)th group of electrodes n satisfy: , a is the minimum distance between the inner surfaces of the electrodes arranged opposite to each other in the first lens group, b is the total length of the first lens group, and c is the length of the nth group of electrodes in a direction parallel to the central axis of the ion channel; (S22) adjusting the DC voltage on the first lens group so that the ions in the ion channel of the peripheral group electrode enter the ion channel of the central group electrode along the linear ion channel; (S13) Changing the voltage of the central group electrode to eject ions in the ion channel of the central group electrode, and the ions are ejected from the ion ejection hole.

[0024] In order to achieve a gradient vacuum, further, the central axis of the ion exit hole is perpendicular to the central axis of the linear ion channel. Example 2

[0025] An application example of a device and method for controlling kinetic energy dispersion of electrostatically trapped ions according to embodiment 1 of the present invention.

[0026] In this application example, Figure 1 As shown, a first vacuum chamber, a third vacuum chamber and a second vacuum chamber are arranged in sequence, and the vacuum degree is increased in sequence; a third lens group is arranged in the third vacuum chamber to realize ion focusing and deflection, and the structure and working mode of the third lens group are the prior art in this field.

[0027] like Figure 2 As shown, in the first vacuum chamber, the first lens group includes 15 groups of electrodes arranged in sequence, that is, 7 peripheral groups of electrodes (from the second group of electrodes P2 to the eighth group of electrodes P8) are arranged on both sides of the central group of electrodes (i.e., the first group of electrodes P1), and the 14 peripheral groups of electrodes are arranged symmetrically about the central group of electrodes; each group of electrodes includes two pairs of relatively parallel (and mutually perpendicular) flat plate electrodes to form a prismatic ion channel, and the 15 groups of electrodes form a linear ion channel; the electrodes of the central group of electrodes have ion exit holes, and the central axis of the exit holes is perpendicular to the central axis of the ion channel. Ions enter the first group of electrodes in the first vacuum chamber along the central axis of the linear ion channel, and then exit from the ion exit hole, which is equivalent to a 90-degree deflection of the ions. Accordingly, the central axis of the ion inlet on the first vacuum chamber is perpendicular to the central axis of the ion outlet, that is, the ions are deflected 90 degrees in the first vacuum chamber.

[0028] The length of the flat electrode in the direction parallel to the central axis of the ion channel is c=4 mm, the minimum distance between the inner surfaces of the oppositely arranged flat electrodes is a=12 mm, and the total length of the first group of electrodes is b=60 mm; The gap between the nth electrode and the (n+1)th electrode in the first electrode group is full J n satisfy: It can be seen that the gap J1 between the first group of electrodes (P1) and the second group of electrodes (P2) is 1.160 mm, and the gap J2 between the second group of electrodes (P2) and the third group of electrodes (P3) is 1.877 mm….

[0029] The power supply applies radio frequency voltages of different amplitudes to each set of electrodes to achieve ion trapping and transmission. , ion packet (m / z) max =500, (m / z) min =200, the reference voltage K is 2000V. It can be seen that, The radio frequency voltage V1 on the first group of electrodes (P1) is 1665V, the radio frequency voltage V2 on the second group of electrodes (P2) is 1685V, V3 is 1720V..., and the radio frequency voltage frequency is 3MHz.

[0030] In the third vacuum chamber, the second set of electrodes of the electrostatic trap includes 9 electrodes (in the direction of ion transmission, electrodes Q1, Q2...Q9 in sequence), the apertures of the electrodes are the same, all 0.78mm, and the spacing between adjacent electrodes is h=2mm. Each electrode is equipped with a charge monitoring unit for ion detection, and a signal can be detected when an ion passes through the electrode. When a leading ion is detected, the controller controls the power supply to apply a voltage to the electrode downstream of the leading ion, and the leading ion decelerates, and the voltage application time t<2∆T / 3, ∆T is the time for the ion to pass through two adjacent electrodes; when the electrode detects a subsequent ion, the controller controls the power supply to apply a voltage to the electrode upstream of the subsequent ion, and the subsequent ion is accelerated, so that the distance between the ions becomes smaller, thereby reducing the kinetic energy dispersion of the ions.

[0031] A method for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention is as follows: Figure 3 As shown, the method for controlling the kinetic energy dispersion of electrostatically trapped ions comprises the steps of: (S1) The ions enter the first lens group in the first vacuum chamber, and are compressed in the transmission direction in the following manner: (S11) A power source applies a radio frequency voltage to the first lens group, The RF voltage V1=1665V on the first set of electrodes (P1), V2=1685V, V3=1720V… on the second set of electrodes (P2), the RF voltage frequency is 3MHz, and ions are stored in a linear ion channel formed by multiple sets of electrodes; (S12) applying a direct current voltage to each group of electrodes step by step from outside to inside (i.e., from the eighth group of electrodes to the first group of electrodes), so that ions in the ion channels of the peripheral group of electrodes enter the ion channels of the central group of electrodes along the linear ion channels; (S13) changing the voltage of the central group electrode, ejecting ions (ion groups of two ions with mass-to-charge ratios of 200 and 1500, and the kinetic energy of the ion packets is 1000 eV) in the ion channel of the central group electrode, and the ions are ejected from the ion exit hole and then enter the third vacuum chamber; The ions are focused and deflected 60 degrees in the third lens group, and then enter the second vacuum chamber; (S2) ions enter the electrostatic trap in different orders, and an ion detection unit detects whether ions reach the electrode in the second lens group in the electrostatic trap; When the electrode detects the leading ion (i.e., the ion with m / z=200), the controller controls the power supply to apply voltage to the electrode downstream of the leading ion, and the leading ion slows down. When the overcharge monitoring device detects that the smaller mass ion (m / z=200) in the ion packet has flown to the electrode Q1, the speed v of the ion 200 =3.16m / s, the time taken to pass through the adjacent electrodes ∆T=h / v 200 =0.000633s=0.633ms, according to the pressurization time t<2∆T / 3, t is taken as 0.3ms, so a voltage of 500V is applied to electrode Q2 for a duration of 300μs, which reduces the flight speed of small ions, making the time taken for ions to pass through adjacent electrodes longer and longer, and the voltage loading time on the electrode upstream of the ion longer and longer. Then the ion packet continues to fly forward, and when the (m / z=200) ion flies to electrode Q2, according to the above calculation method of pressurization time, a voltage of 500V is applied to electrode Q3 for a duration of 400μs; when the (m / z=200) ion flies to Q3, a voltage of 500V is applied to Q4 for a duration of 500μs, and so on to other downstream electrodes until electrode Q9; When the electrode detects a subsequent ion (i.e., an ion with an m / z of 500), the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion, and the pressurization time is calculated in the above manner, so that the subsequent ion is accelerated, so that the time taken for the ion to pass through the adjacent electrode becomes shorter and shorter, and the voltage loading time on the electrode upstream of the ion becomes shorter and shorter, so that the distance between the ions becomes shorter, and the spatial distance of the ions is reduced from the original 50mm level to 10mm, thereby reducing the kinetic energy dispersion of the ions; (S3) The ions are received by the detector.

[0032] The benefits achieved according to the embodiments of the present invention are: 1. Simple structure; By setting the RF voltage on the multiple groups of electrodes in the first group of lenses and the gap between the multiple groups of electrodes, the same RF field effect as that of a complex structure can be achieved with simple linear electrodes, thereby achieving ion cooling and trapping (i.e., storage); the compression of the axial field can be achieved without the gate electrodes on both sides in the prior art; 2. No need for complex ion collection and compression devices; 3. A program-controlled voltage can be applied to the electrode, and the voltage program can be better tuned and modulated according to the instrument status, so that the trap has better transmission efficiency, better compression focusing, and better injection effect; 4. Through low processing precision and simpler structure, combined with more controllable voltage parameters, better focusing effect can be achieved than complex curved arc trap. Example 3

[0033] An application example of a device for controlling kinetic energy dispersion of electrostatically trapped ions and a working method thereof according to embodiment 1 of the present invention.

[0034] In this application example, Figure 1 As shown, a first vacuum chamber, a third vacuum chamber and a second vacuum chamber are arranged in sequence, and the vacuum degree is increased in sequence; a third lens group is arranged in the third vacuum chamber to realize ion focusing and deflection, and the structure and working mode of the third lens group are the prior art in this field.

[0035] like Figure 2 As shown, in the first vacuum chamber, the first group of lenses includes 9 groups of electrodes arranged in sequence, that is, 4 groups of peripheral electrodes (from the second group of electrodes P2 to the fifth group of electrodes P5) are respectively arranged on both sides of the central group electrode (i.e., the first group of electrodes P1), and the 8 groups of peripheral electrodes are symmetrically arranged about the central group electrode; each group of electrodes includes two pairs of electrodes arranged oppositely (and perpendicular to each other), and the inner surfaces of the electrodes are curved surfaces to form a linear ion channel; the electrodes of the central group of electrodes are provided with ion exit holes, and the central axis of the exit holes is perpendicular to the central axis of the ion channel.

[0036] The lengths of the flat electrodes in the direction parallel to the central axis of the ion channel are different, wherein the length of the first group of electrodes is c1=2.5 mm, the length of the second group of electrodes is c2=2.8 mm, the length of the third group of electrodes is c3=3.15 mm, the length of the fourth group of electrodes is c4=3.5 mm, the length of the fifth group of electrodes is c5=4.0 mm, the minimum distance between the inner surfaces of the electrodes arranged oppositely is a=10 mm, and the total length of the electrostatic trap is b=29.4 mm; use It was found that the gap J1 between the first group of electrodes (P1) and the second group of electrodes (P2) was 0.977 mm, the gap J2 between the second group of electrodes (P2) and the third group of electrodes (P3) was 1.392 mm, the gap J3 between the third group of electrodes (P3) and the fourth group of electrodes (P4) was 1.676 mm, and the gap J4 between the fourth group of electrodes (P4) and the fifth group of electrodes (P5) was 1.900 mm.

[0037] The power supply applies radio frequency voltages of different amplitudes to each set of electrodes to achieve ion trapping and transmission. , ion packet (m / z) min =150, (m / z) max =1000, reference voltage K=2000 V. It can be seen that the RF voltage V1=1691 V on the first set of electrodes (P1), the RF voltage V2=1828 V, V3=2072 V, V4=2423 V… on the second set of electrodes (P2), and the RF voltage frequency is 3 MHz.

[0038] In the third vacuum chamber, the second set of electrodes of the electrostatic trap includes 7 electrodes (in the direction of ion transmission, electrodes Q1, Q2...Q7 in sequence). In the direction of ion transmission, the aperture of the electrodes decreases from 1mm to 0.5mm, and the spacing between adjacent electrodes is h=2mm. Each electrode is equipped with a charge monitoring unit for ion detection, and a signal can be detected when an ion passes through the electrode. When a leading ion is detected, the controller controls the power supply to apply a voltage to the electrode downstream of the leading ion, and the leading ion decelerates. The voltage application time t<2∆T / 3, ∆T is the time for the ion to pass through two adjacent electrodes; when the electrode detects a subsequent ion, the controller controls the power supply to apply a voltage to the electrode upstream of the subsequent ion, and the subsequent ion is accelerated, so that the distance between the ions becomes smaller, thereby reducing the kinetic energy dispersion of the ions.

[0039] The working method of the device for controlling kinetic energy dispersion of electrostatically trapped ions according to an embodiment of the present invention is as follows: Figure 3 As shown, the working method of the device for controlling the kinetic energy dispersion of electrostatically trapped ions comprises the steps of: (S1) The ions enter the first lens group in the first vacuum chamber, and are compressed in the transmission direction in the following manner: (S11) The power supply applies radio frequency voltage to the nine groups of electrodes in the first group of lenses, wherein the radio frequency voltage V1 on the first group of electrodes (P1) is 1691V, the radio frequency voltage V2 on the second group of electrodes (P2) is 1828V, V3 is 2072V, V4 is 2423V…, the radio frequency voltage frequency is 3MHz, and the ions are stored in a linear ion channel formed by the multiple groups of electrodes; (S12) applying a DC voltage to each group of electrodes step by step from outside to inside (i.e., from the fifth group of electrodes to the first group of electrodes), so that ions in the ion channels of the peripheral group of electrodes enter the ion channels of the central group of electrodes along the linear ion channels; (S13) changing the voltage of the central group electrode to eject ions (ion clusters with a mass-to-charge ratio of 100-2000) in the ion channel of the central group electrode, the ions are ejected from the ion ejection hole, and then enter the third vacuum chamber; The ions are focused and deflected in the third lens group and then enter the second vacuum chamber; (S2) ions enter the electrostatic trap in different orders, and an ion detection unit detects whether ions reach the electrode in the second lens group in the electrostatic trap; When the electrode detects the leading ion (e.g., ion with m / z=100), the controller controls the power supply to apply voltage to the electrode downstream of the leading ion, and the leading ion slows down. When the overcharge monitoring device detects that the smaller mass ion (e.g., m / z=100) in the ion packet has flown to electrode Q1, the time it takes to pass through the adjacent electrode is ∆T=h / v 100 , according to the pressurization time t<2∆T / 3, a voltage of 500V is applied to electrode Q2 for 50μs, which reduces the flight speed of small ions, making the time taken for ions to pass through adjacent electrodes longer and longer, and the voltage loading time on the electrode upstream of the ion longer and longer. Then the ion packet continues to fly forward. When the (m / z=100) ion flies to electrode Q2, according to the above calculation method of pressurization time, a voltage of 500V is applied to electrode Q3 for 60μs, and the same is true for other downstream electrodes until electrode Q7; When the electrode detects a subsequent ion (such as an ion with an m / z of 2000), the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion, and the pressurization time is calculated in the above manner, so that the subsequent ion is accelerated, so that the time taken for the ion to pass through the adjacent electrode becomes shorter and shorter, and the voltage loading time on the electrode upstream of the ion becomes shorter and shorter, so that the distance between the ions becomes smaller, and the flight time difference before the ions with different mass-to-charge ratios arrive at the detector is reduced from 2μs to 0.9μs, thereby reducing the ion kinetic energy dispersion; (S3) The ions are received by the detector.

Claims

1. A device for controlling kinetic energy dispersion of electrostatically trapped ions, the device comprising a power supply and a first vacuum chamber and a second vacuum chamber connected to each other, a first lens group for ion compression being arranged in the first vacuum chamber, and a detector being arranged in the second vacuum chamber; characterized in that: The device for controlling the kinetic energy dispersion of electrostatically trapped ions also includes: an electrostatic trap, wherein the electrostatic trap comprises a second lens group, the second lens group is arranged in the second vacuum chamber, and comprises a plurality of electrodes arranged in sequence, each electrode having a channel allowing ions to pass through; the power supply supplies power to the second lens group; An ion detection unit, the ion detection unit is used to detect whether ions pass through the second lens group; A controller is provided, wherein the controller adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the leading ions in the ion sequence entering the second lens group are decelerated and the subsequent ions are accelerated.

2. The device for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 1, characterized in that: When the electrode detects the preceding ion, the controller controls the power supply to apply a voltage to the electrode downstream of the preceding ion, so that the preceding ion is decelerated; When the electrode detects the subsequent ion, the controller controls the power supply to apply a voltage to the electrode located upstream of the subsequent ion, so that the subsequent ion is accelerated.

3. The device for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 1, characterized in that: The device for controlling the kinetic energy dispersion of electrostatically trapped ions also includes: a third vacuum chamber, wherein the first vacuum chamber, the third vacuum chamber and the second vacuum chamber are connected in sequence; The third lens group is used for ion focusing and deflection.

4. The device for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 1, characterized in that: The first lens group includes a central group electrode and a peripheral group electrode, the central group electrode has an ion exit hole, and the peripheral group electrodes are symmetrically arranged about the central group electrode; each group of electrodes surrounds an ion channel, and multiple groups of electrodes arranged in sequence form a linear ion channel, and the power supply applies a radio frequency voltage and a direct current voltage to each group of electrodes; From the central group of electrodes toward the peripheral group of electrodes, the RF voltage V on the nth group of electrodes n satisfy: , (m / z) max is the highest mass-to-charge ratio of the ion packet, (m / z) min is the minimum mass-to-charge ratio of the ion packet; K is the reference voltage; From the central group of electrodes toward the peripheral group of electrodes, the gap J between the nth group of electrodes and the (n+1)th group of electrodes n satisfy: , a is the minimum distance between the inner surfaces of the electrodes arranged opposite to each other in the multiple groups of electrodes, b is the total length of the first lens group, and c is the length of the nth group of electrodes in a direction parallel to the central axis of the ion channel.

5. The device for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 4, characterized in that: The central axis of the ion exit hole is perpendicular to the central axis of the linear ion channel.

6. The device for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 4, characterized in that: The central electrode group or the peripheral electrode group is composed of two pairs of electrodes arranged opposite to each other, and the inner surfaces of the electrodes are flat or curved.

7. A method for controlling the kinetic energy dispersion of electrostatically trapped ions, the method for controlling the kinetic energy dispersion of electrostatically trapped ions comprising the steps of: (S1) The ions enter the first lens group in the first vacuum chamber, the ions are compressed in the transmission direction, and then the ions enter the second vacuum chamber; (S2) ions enter the electrostatic trap in different orders, and an ion detection unit detects whether ions reach the electrode in the second lens group in the electrostatic trap; When the electrode detects the preceding ion, the controller controls the power supply to apply a voltage to the electrode downstream of the preceding ion, so that the preceding ion is decelerated; When the electrode detects the subsequent ion, the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion, so that the subsequent ion is accelerated, the distance between the ions becomes smaller, and the kinetic energy dispersion of the ions is reduced; (S3) The ions are received by the detector.

8. The method for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 7, characterized in that: In step (S1), ions emitted from the first vacuum chamber enter into a third vacuum chamber; The ions are focused and deflected in the third lens group of the third vacuum chamber, and then enter the second vacuum chamber.

9. The method for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 7, characterized in that: Step (S1) comprises: (S11) The power supply applies a radio frequency voltage to the first lens group, and the ions are stored in an ion channel formed by the first lens group; The first lens group includes a central group electrode and a peripheral group electrode, the central group electrode has an ion exit hole, and the peripheral group electrodes are symmetrically arranged about the central group electrode; each group of electrodes surrounds an ion channel, and multiple groups of electrodes arranged in sequence form a linear ion channel, and the power supply applies a radio frequency voltage and a direct current voltage to each group of electrodes; From the central group of electrodes toward the peripheral group of electrodes, the RF voltage V on the nth group of electrodes n satisfy: , (m / z) max is the highest mass-to-charge ratio of the ion packet, (m / z) min is the minimum mass-to-charge ratio of the ion packet; K is the reference voltage; From the central group of electrodes toward the peripheral group of electrodes, the gap J between the nth group of electrodes and the (n+1)th group of electrodes n satisfy: , a is the minimum distance between the inner surfaces of the electrodes arranged opposite to each other in the first lens group, b is the total length of the first lens group, and c is the length of the nth group of electrodes in a direction parallel to the central axis of the ion channel; (S22) adjusting the DC voltage on the first lens group so that the ions in the ion channel of the peripheral group electrode enter the ion channel of the central group electrode along the linear ion channel; (S13) Changing the voltage of the central group electrode to eject ions in the ion channel of the central group electrode, and the ions are ejected from the ion ejection hole.

10. The method for controlling kinetic energy dispersion of electrostatically trapped ions according to claim 9, characterized in that: In step (S2), the time t for which the voltage is applied to the electrodes is less than 2∆T / 3, where ∆T is the time taken for ions to pass through two adjacent electrodes.

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