Apparatus and method for controlling kinetic energy dispersion of ions in an electrostatic trap

Abstract

The application provides a device and method for controlling kinetic energy dispersion of ions in an electrostatic trap, which comprises a power supply, a first vacuum chamber and a second vacuum chamber connected to each other, a first lens group for ion compression arranged in the first vacuum chamber, and a detector arranged in the second vacuum chamber; the electrostatic trap comprises a second lens group arranged in the second vacuum chamber, which comprises a plurality of electrodes arranged in sequence, each electrode having a passage allowing ions to pass through; the power supply supplies power to the second lens group; an ion detection unit is used for detecting whether ions pass through the second lens group; and a controller adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the front sequence ions in the ion sequence entering the second lens group are decelerated and the subsequent ions are accelerated. The application has the advantages of simple structure and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to mass spectrometry, in particular to a device and method for controlling kinetic energy dispersion of ions in an electrostatic trap. BACKGROUND

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

[0003] Makarov et al. in US8017909B2 provides a curved linear trap, C-trap, which is a storage trap that stores ions and can rapidly inject ions into an Orbitrap detector. Ions enter the curved linear trap (C-Trap) filled with gas through the gate electrode of the C-trap, the C-trap quadrupole applies an RF potential (500-1500Vpp, 3Mhz) to radially trap the ions, the entering ions are reflected by the trap electrode at the other end of the C-trap, and start to lose energy in collisions with nitrogen gas (~1mTorr) and cool in the C-trap. The ions form a long arc along the curved axis of the C-trap, and the ions are axially confined by simultaneously applying potentials (raised to 200V and the rate of raising is increased) on the gate electrode and the trap electrode of the C-trap, and 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 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 tight ion cloud.

[0004] The above technical solution has the following technical problems:

[0005] 1. Different size ions collide with gas to cause loss of kinetic energy, and then cause kinetic energy dispersion.

[0006] 2. Collision causes dispersion of ions, and simulation shows that edge ions of the ion packet are difficult to pass through the slit, causing ion loss by wall collision.

[0007] 3. Non-uniformity of the gas causes uncontrollable distribution of ions in the trap, and the flow rate and position of gas injection are demanding. SUMMARY

[0008] To solve the above problems in the prior art, the present application provides a device for controlling kinetic energy dispersion of ions in an electrostatic trap.

[0009] The purpose of the present application is achieved by the following technical solution:

[0010] The application discloses a device for controlling kinetic energy dispersion of ions in an electrostatic trap, which comprises a power supply, a first vacuum chamber and a second vacuum chamber connected to each other, a first lens group for ion compression arranged in the first vacuum chamber, and a detector arranged in the second vacuum chamber.

[0011] The electrostatic trap comprises a second lens group arranged in the second vacuum chamber, which comprises a plurality of electrodes arranged in sequence, each of which has a channel allowing ions to pass through; and the power supply supplies power to the second lens group.

[0012] An ion detection unit is arranged for detecting whether ions pass through the second lens group.

[0013] A controller is arranged for adjusting the voltage on the second lens group according to the output of the ion detection unit, so that the front sequence ions in the ion sequence entering the second lens group are decelerated, and the subsequent ions are accelerated.

[0014] The application also provides a method for controlling kinetic energy dispersion of ions in an electrostatic trap.

[0015] The method for controlling kinetic energy dispersion of ions in an electrostatic trap comprises the following steps:

[0016] (S1) Ions enter the first lens group in the first vacuum chamber, and the ions are compressed in the transmission direction, and then the ions enter the second vacuum chamber.

[0017] (S2) Ions enter the electrostatic trap in different sequences, and an ion detection unit detects whether ions reach the electrodes in the second lens group in the electrostatic trap.

[0018] When the electrodes detect the front sequence ions, a controller controls a power supply to apply voltage to the electrodes downstream of the front sequence ions, and the front sequence ions are decelerated.

[0019] When the electrodes detect the subsequent ions, the controller controls the power supply to apply voltage to the electrodes upstream of the subsequent ions, and the subsequent ions are accelerated, so that the distance between the ions is reduced, thereby reducing the kinetic energy dispersion of the ions.

[0020] (S3) The ions are received by the detector.

[0021] Compared with the prior art, the application has the following beneficial effects:

[0022] 1. The kinetic energy dispersion of ions is small.

[0023] In the second vacuum cavity, a plurality of electrodes (ion lens group structure) with program-controlled voltage can be applied, and the voltage program can be automatically adjusted according to the ion mass range, so that the small ions with fast flight speed are slowed down, the large ions with slow flight speed are accelerated, and the kinetic energy dispersion and flight time difference between the large mass ions and the small mass ions are reduced.

[0024] In the first vacuum cavity, the ions are not disturbed by collision gas before ejection, the ion loss caused by wall collision is reduced, and the kinetic energy dispersion of ions with different mass-to-charge ratios is reduced.

[0025] 2. The vacuum is easy to achieve.

[0026] The ions pass through a plurality of vacuum cavities in turn after deflection, avoiding the ion path and the pumping path on the same path, and reducing the difficulty of vacuum realization. BRIEF DESCRIPTION OF DRAWINGS

[0027] The disclosure of the present application will become more apparent with reference to the drawings. It is easy for those skilled in the art to understand that the drawings are only used to illustrate the technical solutions of the present application, and are not intended to limit the protection scope of the present application. In the drawings:

[0028] Figure 1 is a structural schematic diagram of a device for controlling kinetic energy dispersion of ions in an electrostatic trap according to an embodiment of the present application;

[0029] Figure 2 is a structural schematic diagram of a first lens group in a device for controlling kinetic energy dispersion of ions in an electrostatic trap according to an embodiment of the present application;

[0030] Figure 3 is a flowchart of a method for controlling kinetic energy dispersion of ions in an electrostatic trap according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] Figures 1-3 The optional specific embodiments of the present application described in the following description and the accompanying drawings are presented to teach those skilled in the art how to make and use the present application. Some conventional aspects have been simplified or omitted in order to teach the present application. Those skilled in the art should understand that variations or substitutions of the embodiments derived from these embodiments will be within the scope of the present application. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the present application. Therefore, the present application is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents. Example 1

[0032] A device for controlling kinetic energy dispersion of ions in an electrostatic trap according to an embodiment of the present application, as shown in Figure 1 The device for controlling kinetic energy dispersion of ions in an electrostatic trap comprises:

[0033] a power supply and a first vacuum chamber and a second vacuum chamber connected in series, a first lens group for ion compression is arranged in the first vacuum chamber, and a detector is arranged in the second vacuum chamber;

[0034] an electrostatic trap, 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 series, each electrode has a passage allowing ions to pass through; the power supply supplies power to the second lens group;

[0035] an ion detection unit for detecting whether ions pass through the second lens group;

[0036] a controller, which adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the front sequence 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 is reduced, and the ion kinetic energy dispersion is reduced.

[0037] In order to reduce the ion kinetic energy dispersion, further, when the electrode detects the front sequence ion, the controller controls the power supply to apply voltage to the electrode downstream of the front sequence ion, and the front sequence ion is decelerated;

[0038] When the electrode detects the subsequent ion, the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion, and the subsequent ion is accelerated.

[0039] In order to focus ions and realize gradient vacuum, further, the device for controlling the ion kinetic energy dispersion of the electrostatic trap further comprises:

[0040] a third vacuum chamber, the first vacuum chamber, the third vacuum chamber and the second vacuum chamber are connected in series;

[0041] a third lens group for ion focusing and deflection.

[0042] In order to compress ions in the ion transmission direction and reduce ion kinetic energy dispersion, further, as shown in Figure 2 the first lens group comprises:

[0043] a plurality of groups of electrodes, the plurality of groups of electrodes comprises a center group of electrodes and a peripheral group of electrodes, the center group of electrodes has an ion exit hole, and the peripheral group of electrodes is symmetrically arranged about the center group of electrodes; each group of electrodes surrounds an ion passage, and the plurality of groups of electrodes arranged in series form a linear ion passage; the power supply applies radio frequency voltage and direct current voltage to each group of electrodes;

[0044] The radio frequency voltage V n satisfies:

[0045] (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 a reference voltage, which is generally set to 2000 V according to the structure of the trap.

[0046] The gap J between the nth electrode group and the (n+1)th electrode group is arranged from the center electrode group to the peripheral electrode group. n satisfies:

[0047] a is the minimum distance between the inner surfaces of the oppositely arranged electrodes in the first lens group, b is the total length of the first lens group, and c is the length of the nth electrode group in the direction parallel to the central axis of the ion channel.

[0048] To reduce the structural complexity, further, each electrode group is composed of two pairs of oppositely arranged electrodes, and the inner surfaces of the electrodes are flat.

[0049] To reduce the structural complexity, further, the length of each electrode group in the direction parallel to the central axis of the ion channel is equal or increases from the center electrode group to the peripheral electrode group.

[0050] A method for controlling the kinetic energy dispersion of ions in an electrostatic trap according to an embodiment of the present application is shown in FIG. 1. Figure 3 The method for controlling the kinetic energy dispersion of ions in an electrostatic trap includes the following steps:

[0051] (S1) Ions enter the first lens group in the first vacuum chamber, and the ions are compressed in the transmission direction, and then the ions enter the second vacuum chamber;

[0052] (S2) Ions enter the electrostatic trap in different orders, and the ion detection unit detects whether ions reach the electrodes in the second lens group in the electrostatic trap;

[0053] When the electrodes detect the preceding ions, the controller controls the power supply to apply voltage to the electrodes downstream of the preceding ions, and the preceding ions are decelerated;

[0054] When the electrodes detect the subsequent ions, the controller controls the power supply to apply voltage to the electrodes upstream of the subsequent ions, and the subsequent ions are accelerated, so that the distance between the ions is reduced, thereby reducing the kinetic energy dispersion of the ions;

[0055] (S3) The ions are received by the detector.

[0056] To focus the ions and achieve gradient vacuum, further, in step (S1), the ions exiting from the first vacuum chamber enter the third vacuum chamber;

[0057] Ions are focused and deflected in the third lens group of the third vacuum chamber, and then enter the second vacuum chamber.

[0058] To achieve ion compression, step (S1) further includes:

[0059] (S11) The power supply applies a radio frequency voltage to the first lens group, and ions are stored in the ion channel formed by the first lens group;

[0060] like Figure 2 As shown, the first lens group includes a central electrode group and a peripheral electrode group. The central electrode group has an ion emission port, and the peripheral electrode group is symmetrically arranged about the central electrode group. Each electrode group surrounds an ion channel, and multiple electrode groups arranged in sequence form a linear ion channel. The power supply applies radio frequency voltage and DC voltage to each electrode group.

[0061] From the central group of electrodes toward the peripheral group of electrodes, the radio frequency voltage V on the nth group of electrodes n satisfy:

[0062] (m / z) max The highest mass-to-charge ratio of the ion pack is given by (m / z). min is the minimum mass-to-charge ratio of the ion pack; K is the reference voltage, which is generally set to 2000V depending on the structure of the trap.

[0063] The gap J between the nth group of electrodes and the (n+1)th group of electrodes is as follows: From the central group of electrodes towards the peripheral group of electrodes... n satisfy:

[0064] , a is the minimum distance between the inner surfaces of the electrodes in the first lens group, b is the total length of the first lens group, and c is the length of the nth electrode along the direction parallel to the central axis of the ion channel;

[0065] (S22) Adjust the DC voltage on the first lens group so that ions in the peripheral electrode ion channel enter the central electrode ion channel along the linear ion channel;

[0066] (S13) Change the voltage of the central electrode group to eject ions in the ion channel of the central electrode group, and the ions are ejected from the ion emission hole.

[0067] To achieve a gradient vacuum, the central axis of the ion exit aperture is further perpendicular to the central axis of the linear ion channel. Example 2

[0068] An application example of a device and method for controlling the kinetic energy dispersion of ions in an electrostatic trap according to Embodiment 1 of the present invention.

[0069] In this application example, such as Figure 1 As shown, a first vacuum chamber, a third vacuum chamber, and a second vacuum chamber are arranged sequentially, with the vacuum level increasing sequentially. A third lens group is arranged in the third vacuum chamber to realize ion focusing and deflection. The structure and operation of the third lens group are existing technologies in this field.

[0070] like Figure 2 As shown, within the first vacuum chamber, the first lens group includes 15 sets of electrodes arranged sequentially. Specifically, seven peripheral electrodes (from the second set of electrodes P2 to the eighth set of electrodes P8) are arranged on either side of the central electrode set (i.e., the first set of electrodes P1), and 14 of the peripheral electrodes are symmetrically arranged about the central electrode set. Each set of electrodes includes two pairs of relatively parallel (and mutually perpendicular) flat plates forming a prismatic ion channel. The 15 sets of electrodes form a linear ion channel. The central electrode set has an ion exit hole, the central axis of which is perpendicular to the central axis of the ion channel. Ions enter the first set of electrodes within the first vacuum chamber along the central axis of the linear ion channel and then exit through the ion exit hole, effectively deflecting the ions by 90 degrees. Correspondingly, the central axis of the ion inlet in the first vacuum chamber is perpendicular to the central axis of the ion outlet, meaning the ions are deflected by 90 degrees within the first vacuum chamber.

[0071] The length of the plate electrodes along the direction parallel to the central axis of the ion channel is c=4mm, the minimum distance between the inner surfaces of the relatively arranged plate electrodes is a=12mm, and the total length of the first group of electrodes is b=60mm.

[0072] The gap between the nth electrode and the (n+1)th electrode in the first group of electrodes is J n satisfy:

[0073] 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...

[0074] The power supply applies radio frequency voltages of different amplitudes to each group of electrodes to achieve ion trapping and transport. Among these methods, the use of… In the ion package (m / z) max =500, (m / z) min =200, and the reference voltage K is taken as 2000V. Therefore,

[0075] The radio frequency voltage V1 on the first set of electrodes (P1) is 1665V, the radio frequency voltage V2 on the second set of electrodes (P2) is 1685V, V3 is 1720V, and so on. The radio frequency voltage frequency is 3MHz.

[0076] Inside the third vacuum chamber, the second set of electrodes in the electrostatic trap comprises nine electrodes (Q1, Q2…Q9 in sequence along the ion transport direction). All electrodes have the same aperture of 0.78 mm, and the spacing between adjacent electrodes is h = 2 mm. Each electrode is equipped with a charge monitoring unit for ion detection; a signal is detected when an ion passes through that electrode. When a preceding ion is detected, the controller applies a voltage to the electrode downstream of the preceding ion, causing the preceding ion to decelerate. The voltage application time t < 2∆T / 3, where ∆T is the time it takes for an ion to pass between two adjacent electrodes. When a subsequent ion is detected, the controller applies a voltage to the electrode upstream of the subsequent ion, causing the subsequent ion to accelerate. This reduces the distance between ions, thereby decreasing ion kinetic energy dispersion.

[0077] An embodiment of the present invention provides a method for controlling the kinetic energy dispersion of ions in an electrostatic trap, such as... Figure 3 As shown, the method for controlling the kinetic energy dispersion of electrostatic trap ions includes the following steps:

[0078] (S1) Ions enter the first lens group inside the first vacuum cavity, and are compressed in the transport direction, specifically in the following manner:

[0079] (S11) The power supply applies a radio frequency voltage to the first lens group.

[0080] The radio frequency voltage V1 on the first set of electrodes (P1) is 1665V, the radio frequency voltage V2 on the second set of electrodes (P2) is 1685V, V3 is 1720V, and so on. The radio frequency voltage frequency is 3MHz. Ions are stored in a linear ion channel formed by multiple sets of electrodes.

[0081] (S12) Apply DC voltage to each group of electrodes gradually from the outside to the inside (i.e. from the eighth group of electrodes to the first group of electrodes), so that ions in the ion channels of the outer group of electrodes enter the ion channels of the central group of electrodes along the linear ion channels.

[0082] (S13) Change the voltage of the central electrode group to eject ions (ion clusters of two types of ions with mass-to-charge ratios of 200 and 1500, with a kinetic energy of 1000eV) in the ion channel of the central electrode group. The ions are ejected from the ion emission hole and then enter the third vacuum chamber.

[0083] The ions are focused and deflected by 60 degrees in the third lens group before entering the second vacuum chamber;

[0084] (S2) Ions enter the electrostatic trap in different orders, and the ion detection unit detects whether any ions reach the electrodes in the second lens group inside the electrostatic trap.

[0085] When the electrode detects a preceding ion (i.e., an ion with m / z of 200), the controller controls the power supply to apply voltage to the electrode downstream of the preceding ion, causing the preceding ion to decelerate. When the overcharge monitoring device detects that a smaller mass ion (m / z = 200) in the ion packet has flown to electrode Q1, the velocity v of this ion... 200 =3.16 m / s, the time taken to pass through the adjacent electrode ∆T = h / v 200 =0.000633s=0.633ms. Based on the pressure application time t < 2∆T / 3, t is taken as 0.3ms. Therefore, a voltage of 500V is applied to electrode Q2 for 300μs, reducing the velocity of the small ions and increasing the time it takes for the ions to pass through adjacent electrodes. This results in an increasingly longer voltage application time on the electrodes upstream of the ion. The ion packet then continues its flight. When an ion (m / z=200) reaches electrode Q2, a voltage of 500V is applied to electrode Q3 for 400μs, based on the above calculation method for pressure application time. When an ion (m / z=200) reaches Q3, a voltage of 500V is applied to Q4 for 500μs, and so on down to the other downstream electrodes, up to electrode Q9.

[0086] When the electrode detects a subsequent ion (i.e., an ion with m / z of 500), the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion. The pressurization time is calculated in the above manner. The subsequent ion is accelerated, so that the time it takes for the ion to pass through the adjacent electrode becomes shorter and shorter. The voltage loading time on the electrode upstream of the ion becomes shorter and shorter, so that the distance between the ions becomes smaller. The spatial distance between the ions is reduced from the original 50mm level to 10mm, thereby reducing the ion kinetic energy dispersion.

[0087] (S3) Ions are received by the detector.

[0088] The benefits achieved by the embodiments of the present invention are as follows:

[0089] 1. Simple structure;

[0090] By setting the radio frequency voltage on multiple electrodes in the first set of lenses and setting the gap between the multiple sets of electrodes, the same radio frequency field effect as the complex structure can be achieved with simple straight electrodes, realizing the cooling and trapping (i.e. storage) of ions; axial field compression can be achieved without the gate electrodes on both sides as in the prior art.

[0091] 2. No complex ion collection and compression devices are required;

[0092] 3. A programmable voltage can be applied to the electrodes. 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 jetting effect.

[0093] 4. By using lower processing precision and a simpler structure, combined with more controllable voltage parameters, it achieves better focusing effect than complex curved arc traps. Example 3

[0094] An application example of a device and its working method for controlling the kinetic energy dispersion of ions in an electrostatic trap according to Embodiment 1 of the present invention.

[0095] In this application example, such as Figure 1 As shown, a first vacuum chamber, a third vacuum chamber, and a second vacuum chamber are arranged sequentially, with the vacuum level increasing sequentially. A third lens group is arranged in the third vacuum chamber to realize ion focusing and deflection. The structure and operation of the third lens group are existing technologies in this field.

[0096] like Figure 2 As shown, in the first vacuum chamber, the first set of lenses includes nine sets of electrodes arranged sequentially, namely, four sets of peripheral electrodes (from the second set of electrodes P2 to the fifth set of electrodes P5) are arranged on both sides of the central set of electrodes (i.e., the first set of electrodes P1), and the eight sets of peripheral electrodes are symmetrically arranged about the central set of electrodes; each set of electrodes includes two pairs of electrodes arranged opposite to each other (and perpendicular to each other), the inner surface of the electrodes is curved, forming a straight ion channel; the electrodes of the central set of electrodes have ion emission holes, and the central axis of the emission holes is perpendicular to the central axis of the ion channel.

[0097] The planar electrodes have different lengths along the direction parallel to the central axis of the ion channel. The lengths of the first group of electrodes are c1=2.5mm, the second group of electrodes are c2=2.8mm, the third group of electrodes are c3=3.15mm, the fourth group of electrodes are c4=3.5mm, and the fifth group of electrodes are c5=4.0mm. The minimum distance between the inner surfaces of the electrodes is a=10mm, and the total length of the electrostatic trap is b=29.4mm.

[0098] use The results show that the gap between the first group of electrodes (P1) and the second group of electrodes (P2) is J1=0.977mm, the gap between the second group of electrodes (P2) and the third group of electrodes (P3) is J2=1.392mm, the gap between the third group of electrodes (P3) and the fourth group of electrodes (P4) is J3=1.676mm, and the gap between the fourth group of electrodes (P4) and the fifth group of electrodes (P5) is J4=1.900mm.

[0099] The power supply applies radio frequency voltages of different amplitudes to each group of electrodes to achieve ion trapping and transport. Among these methods, the use of… In the ion package (m / z) min =150, (m / z) max=1000, reference voltage K=2000V. It can be seen that 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..., and the radio frequency voltage frequency is 3MHz.

[0100] Inside the third vacuum chamber, the second set of electrodes in the electrostatic trap comprises seven electrodes (Q1, Q2…Q7 in sequence along the ion transport direction). The aperture of the electrodes decreases from 1 mm to 0.5 mm along the ion transport direction, and the spacing between adjacent electrodes is h = 2 mm. Each electrode is equipped with a charge monitoring unit for ion detection; a signal is detected when an ion passes through that electrode. When a preceding ion is detected, the controller controls the power supply to apply voltage to the electrode downstream of the preceding ion. The preceding ion decelerates, and the voltage application time t < 2∆T / 3, where ∆T is the time it takes for an ion to pass between two adjacent electrodes. When a subsequent ion is detected, the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion. The subsequent ion accelerates, reducing the distance between ions and thus decreasing ion kinetic energy dispersion.

[0101] The operating method of the device for controlling the kinetic energy dispersion of electrostatic trap ions according to embodiments of the present invention is as follows: Figure 3 As shown, the operating method of the device for controlling the kinetic energy dispersion of electrostatic trap ions includes the following steps:

[0102] (S1) Ions enter the first lens group inside the first vacuum cavity, and the ions are compressed in the transport direction, specifically in the following manner:

[0103] (S11) The power supply applies radio frequency voltage to the nine electrodes in the first group of lenses. The radio frequency voltage on the first group of electrodes (P1) is V1=1691V, the radio frequency voltage on the second group of electrodes (P2) is V2=1828V, V3=2072V, V4=2423V..., and the radio frequency voltage frequency is 3MHz. Ions are stored in the linear ion channel formed by multiple groups of electrodes.

[0104] (S12) Apply DC voltage to each group of electrodes gradually from the outside to the inside (i.e. from the fifth group of electrodes to the first group of electrodes), so that ions in the ion channels of the outer group of electrodes enter the ion channels of the central group of electrodes along the linear ion channels.

[0105] (S13) Change the voltage of the central electrode group to eject ions (ion clusters with a mass-to-charge ratio of 100-2000) in the ion channel of the central electrode group. The ions are ejected from the ion emission hole and then enter the third vacuum chamber.

[0106] The ions are focused and deflected in the third lens group, and then enter the second vacuum chamber;

[0107] (S2) Ions enter the electrostatic trap in different orders, and the ion detection unit detects whether any ions reach the electrodes in the second lens group inside the electrostatic trap.

[0108] When an electrode detects a preceding ion (e.g., an ion with m / z = 100), the controller controls the power supply to apply voltage to the electrode downstream of the preceding ion, causing the preceding ion to decelerate. When the overcharge monitoring device detects that a smaller mass ion (e.g., m / z = 100) in the ion packet has flown to electrode Q1, the time ∆T taken to pass through the adjacent electrode is ΔT = h / v. 100 Based on the pressure application time t < 2∆T / 3, a voltage of 500V is applied to electrode Q2 for 50μs to reduce the velocity of the small ions. This results in the ions taking increasingly longer to pass through adjacent electrodes, and thus, the voltage application time on the electrodes upstream of the ion increases. The ion packet then continues to fly forward. When the ion (m / z = 100) reaches electrode Q2, a voltage of 500V is applied to electrode Q3 for 60μs, based on the aforementioned calculation method for pressure application time. This process is repeated for other downstream electrodes until electrode Q7.

[0109] When the electrode detects a subsequent ion (such as an ion with m / z of 2000), the controller controls the power supply to apply voltage to the electrode upstream of the subsequent ion. The pressurization time is calculated in the above manner. The subsequent ion is accelerated, so that the time it takes for the ion to pass through the adjacent electrode becomes shorter and shorter. The voltage loading time on the electrode upstream of the ion becomes shorter and shorter, so that the distance between the ions becomes smaller. The time difference of flight before the ions with different mass-to-charge ratios reach the detector is reduced from 2 μs to 0.9 μs, thereby reducing the ion kinetic energy dispersion.

[0110] (S3) Ions are received by the detector.

Claims

1. An apparatus for controlling kinetic energy dispersion of ions in an electrostatic trap, the apparatus comprising a power supply and first and second vacuum chambers in communication, a first lens group for ion compression disposed within the first vacuum chamber, and a detector disposed within the second vacuum chamber; wherein, The device for controlling kinetic energy dispersion of ions in an electrostatic trap further comprises: an electrostatic trap, which comprises a second lens group arranged in the second vacuum chamber, and comprises a plurality of electrodes arranged in sequence, each electrode having a passage allowing ions to pass through; the power supply supplies power to the second lens group; an ion detection unit for detecting whether ions pass through the second lens group; a controller adjusts the voltage on the second lens group according to the output of the ion detection unit, so that the front sequence ions in the ion sequence entering the second lens group are decelerated, and the subsequent ions are accelerated; when the electrode detects the front sequence ions, the controller controls the power supply to apply voltage to the electrodes downstream of the front sequence ions, and the front sequence ions are decelerated; when the electrode detects the subsequent ions, the controller controls the power supply to apply voltage to the electrodes upstream of the subsequent ions, and the subsequent ions are accelerated; 2. A device for controlling the kinetic energy dispersion of ions in an electrostatic trap as defined in claim 1, characterized in that the first lens group comprises central group electrodes and peripheral group electrodes, the central group electrodes have ion exit holes, and the peripheral group electrodes are symmetrically arranged about the central group electrodes; each group of electrodes encloses an ion passage, and a plurality of electrodes arranged in sequence form a linear ion passage. The device for controlling kinetic energy dispersion of ions in an electrostatic trap further comprises: a third vacuum chamber, the first vacuum chamber, the third vacuum chamber and the second vacuum chamber are sequentially connected; 3. The apparatus of claim 1, wherein the apparatus is configured to control the kinetic energy dispersion of ions in the electrostatic trap by applying a time-varying electric field to the ions in the electrostatic trap. a third lens group for ion focusing and deflection. RF voltage Vn on the nth set of electrodes, as a function of the radial position r, is given by: n satisfies: , (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 a reference voltage; gap J between the n-th electrode group and the (n+1)-th electrode group in a direction from the center electrode group toward the outer electrode group n satisfies: a is the minimum distance between the inner surfaces of oppositely disposed electrodes in a group 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.

4. A device for controlling the kinetic energy dispersion of ions in an electrostatic trap as defined in claim 3, characterized in that the power supply applies radio frequency voltage and direct current voltage to each group of electrodes; 5. The apparatus for controlling the kinetic energy dispersion of ions in an electrostatic trap as defined in claim 3, wherein, the central axis of the ion exit hole is perpendicular to the central axis of the linear ion passage. The central group electrodes or the peripheral group electrodes are composed of two pairs of oppositely arranged electrodes, and the inner surfaces of the electrodes are planar or curved.

6. A method for controlling kinetic energy dispersion of ions in an electrostatic trap, the method comprising the steps of: (S1) ions enter a first lens group in a first vacuum chamber, and the ions are compressed in the transmission direction, and then the ions enter a second vacuum chamber; the first lens group comprises central group electrodes and peripheral group electrodes, the central group electrodes have ion exit holes, and the peripheral group electrodes are symmetrically arranged about the central group electrodes; each group of electrodes encloses an ion passage, and a plurality of electrodes arranged in sequence form a linear ion passage; (S2) ions enter the electrostatic trap in different sequences, and an ion detection unit detects whether ions reach the electrodes in the second lens group in the electrostatic trap; when the electrode detects the front sequence ions, the controller controls the power supply to apply voltage to the electrodes downstream of the front sequence ions, and the front sequence ions are decelerated; when the electrode detects the subsequent ions, the controller controls the power supply to apply voltage to the electrodes upstream of the subsequent ions, and the subsequent ions are accelerated, so that the distance between the ions is reduced, thereby reducing the kinetic energy dispersion of the ions; 7. A method of controlling kinetic energy dispersion of ions in an electrostatic trap as claimed in claim 6, wherein, (S3) the ions are received by a detector. In step (S1), the ions exiting from the first vacuum chamber enter a third vacuum chamber; 8. The method of claim 6, wherein the method further comprises: the ions are focused and deflected in the third lens group of the third vacuum chamber, and then enter the second vacuum chamber. Step (S1) comprises: (S11) The power supply applies a radio frequency voltage to the first lens group, and ions are stored in the ion channel formed by the first lens group; The power supply applies a radio frequency voltage and a direct current voltage to each electrode group; RF voltage Vn on the nth set of electrodes, as a function of the radial position r, is given by: n satisfies: , (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 a reference voltage; gap J between the n-th electrode group and the (n+1)-th electrode group in a direction from the center electrode group toward the outer electrode group n satisfies: a is the minimum distance between the inner surfaces of the oppositely disposed electrodes in the first lens group, b is the total length of the first lens group, and c is the length of the nth electrode group in the direction parallel to the central axis of the ion channel. (S22) The direct current voltage on the first lens group is adjusted so that the ions in the ion channel of the peripheral electrode group enter the ion channel of the central electrode group along the linear ion channel; (S13) The voltage of the central electrode group is changed, and the ions in the ion channel of the central electrode group are ejected, and the ions are ejected from the ion exit hole.

9. A method of controlling the kinetic energy dispersion of ions in an electrostatic trap as claimed in claim 8, characterised in that, In step (S2), the time t at which the voltage is applied to the electrodes is < 2∆T / 3, and ∆T is the time taken by the ions to pass through two adjacent electrodes.

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