Electrostatic trap ion implantation device and working method thereof

Abstract

The invention provides an electrostatic trap ion implantation device and method, the electrostatic trap ion implantation device comprises a power supply and a multi-pole rod, and the power supply applies a radio frequency voltage to the multi-pole rod; the plurality of annular electrodes are arranged on the outer side of the multi-pole rod and are sequentially arranged in the direction parallel to the ion transmission direction in the multi-pole rod; the part on the inner side of the annular electrode enters the area between the adjacent electrode rods; the inlet electrode and the outlet electrode are respectively arranged at an ion inlet and an ion outlet of the multi-pole rod, and the power supply applies voltage to the inlet electrode, the outlet electrode and the annular electrode. The method has the advantages of good ion focusing effect and the like.

Description

Technical Field

[0001] The invention relates to mass spectrometry technology, and in particular to an electrostatic trap ion implantation device and a working method thereof. 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] In patent US7425699B2, an ion trap is used as an injection device. The kinetic energy and spatial scale of the ions are dispersed, and the injection time requires hundreds or even thousands of microseconds, which is difficult to match with the downstream detector. In patent US8017909B2, C-trap is used as an ion implantation device. This method solves the problem of ion dispersion in space and time scales. However, the voltage on the electrode needs to be switched repeatedly and without delay between RF and DC, which increases the difficulty and complexity of circuit design. In addition, the time scale for ion enrichment is small, and ion enrichment on a larger time scale cannot be achieved. Summary of the invention

[0004] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides an electrostatic trap ion implantation device.

[0005] The objective of the present invention is achieved through the following technical solutions: An electrostatic trap ion implantation device, the electrostatic trap ion implantation device comprising a power supply and a multipole, the power supply applying a radio frequency voltage to the multipole; the electrostatic trap ion implantation device further comprising: A plurality of annular electrodes, the plurality of annular electrodes are arranged outside the multipole and are arranged in sequence parallel to the ion transmission direction in the multipole; the inner part of the annular electrodes enters the area between adjacent poles; An inlet electrode and an outlet electrode are respectively arranged at the ion inlet and the ion outlet of the multipole, and the power supply applies voltage to the inlet electrode, the outlet electrode and the annular electrode.

[0006] The present invention also aims to provide a working method of an electrostatic trap ion implantation device, and the present invention aims to be achieved through the following technical solutions: The working method of the electrostatic trap ion implantation device is as follows: (S1) applying voltage to the inlet electrode and the outlet electrode, and not applying voltage to the annular electrode; The ions enter the multipole, collide with the bath gas and gradually cool down; (S2) applying voltages to the entrance electrode and the annular electrode in sequence, so that the ions are transported toward the exit electrode and enter between the exit electrode and the annular electrode adjacent thereto; (S3) reducing the voltage of the exit electrode and its adjacent annular electrode, so that the ions are trapped between the exit electrode and its adjacent annular electrode, and turning off the voltage of other annular electrodes; (S4) repeating steps (S1) to (S3) multiple times, wherein the adjacent annular electrodes maintain an ion trapping voltage; (S5) increasing the voltage of the exit electrode and its adjacent annular electrode, so that the trapped ions are compressed in the axial direction; (S6) reducing the voltage of the exit electrode to allow the trapped ions to be ejected; In the above steps, a radio frequency voltage is applied to the multipole rods.

[0007] Compared with the prior art, the present invention has the following beneficial effects: Through the design of the annular electrode, multipole, entrance electrode and exit electrode, the dispersion of ions in time and space is small, and their kinetic energy can be well coupled with the downstream detector; The DC voltage and RF voltage are controlled and applied separately, which reduces the difficulty of circuit design and the complexity of implementation, and enhances the reliability of ion confinement; Through the device structure and voltage control method, it is possible to continue to accept ions after a single enrichment, thus achieving enrichment on a large time scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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 an electrostatic trap ion implantation device according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of an annular electrode according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of an annular electrode according to an embodiment of the present invention. DETAILED DESCRIPTION

[0009] Figure 1-Figure 3The 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

[0010] The electrostatic trap ion implantation device of the embodiment of the present invention is as follows: Figure 1 As shown, the electrostatic trap ion implantation device comprises: A power source and a multipole 21, wherein the power source applies a radio frequency voltage to the multipole 21; A plurality of annular electrodes 31, wherein the plurality of annular electrodes 31 are arranged outside the multipole 21 and are arranged in sequence parallel to the ion transmission direction in the multipole 21; the inner part of the annular electrode 31 enters the area between adjacent poles 21; The inlet electrode 11 and the outlet electrode 12 are respectively arranged at the ion inlet and the ion outlet of the multipole 21 , and the power supply applies voltage to the inlet electrode 11 , the outlet electrode 12 and the annular electrode 31 .

[0011] In order to realize ion ejection in the multipole 21, further, the side of the exit electrode 12 facing the detector is a concave spherical surface or a concave parabola, and the focus is at the entrance of the detector.

[0012] In order to improve the ion stability, the length of the multipole 21 is 20 mm to 40 mm, and the radius R of the inscribed circle of the multipole 21 in the cross section perpendicular to the central axis is 0 Between 1mm and 5mm.

[0013] In order to take into account both the multiple accumulation function and controllability of ions, further, the number of the annular electrodes 31 is 3-6.

[0014] The working method of the electrostatic trap ion implantation device according to the embodiment of the present invention comprises the following steps: (S1) applying voltage to the inlet electrode 11 and the outlet electrode 12, and no voltage is applied to the annular electrode 31; The ions enter the multipole 21, collide with the bath gas and gradually cool down; (S2) applying voltages to the entrance electrode 11 and the annular electrode 31 in sequence, so that the ions are transported toward the exit electrode 12 and enter between the exit electrode 12 and the annular electrode 31 adjacent thereto; (S3) reducing the voltage of the outlet electrode 12 and its adjacent annular electrode 31, so that the ions are trapped between the outlet electrode 21 and its adjacent annular electrode 31, and turning off the voltage of other annular electrodes 31; (S4) repeating steps (S1) to (S3) for multiple times, wherein the adjacent annular electrodes 31 maintain an ion trapping voltage; (S5) increasing the voltage of the outlet electrode 12 and the adjacent annular electrode 31, so that the trapped ions are compressed in the axial direction; (S6) reducing the voltage of the exit electrode 12 so that the trapped ions are ejected; In the above steps, a radio frequency voltage is applied to the multipole rods 21 .

[0015] In order to realize ion ejection, further, in step ( S5 ), after the ions are ejected from the outlet electrode 12 , the voltage of the outlet electrode 12 is increased.

[0016] In order to significantly cool the ions, further, when the ions enter the multipole 21, the bath gas pressure P and the ion travel distance L satisfy: 0.2mm·Torr <P·L<0.5mm·Torr。

[0017] In order to achieve ion cooling and maintain a good operating state, further, 0.1Torr <P <10Torr。

[0018] In order to prevent the stability of the ions with poor stability from being significantly lost, the bath gas pressure P and the radius R of the inscribed circle of the multipole 21 in the cross section perpendicular to the central axis of the multipole 21 are further 0 satisfy: P.R 0 <0.01mm·Torr. Example 2

[0019] An application example of the electrostatic trap ion implantation device and the working method thereof according to embodiment 1 of the present invention.

[0020] In this application example, Figure 1 As shown, the multipole 21 is a quadrupole, 26 mm long and 6 mm in diameter, and the diameter of the inscribed circle of the multipole 21 on the cross section perpendicular to its central axis is R 0 =6mm; The entrance electrode 12 is in the shape of a ring, with an outer diameter of 14 mm, an inner diameter of 3 mm, a thickness (axial length) of 0.6 mm, and is 0.5 mm away from the end of the quadrupole 21 .

[0021] The side of the exit electrode 12 facing the annular electrode 31 (or quadrupole 21) is a plane, 0.68 mm away from the end of the quadrupole 21, and the side facing the detector is a concave spherical surface; the exit electrode 12 is 2.6 mm thick, 13 mm in outer diameter, and has a minimum inner diameter of 2.5 mm. This part is 0.68 mm deep and has a spherical diameter of 20 mm.

[0022] Four annular electrodes P1, P2, P3, and P4 are arranged in sequence, located outside the multipole 21, and arranged in sequence along the axial direction; the outer diameter is 24 mm, the thickness (axial length) is 2 mm, and the spacing is 4 mm; Figure 2 As shown, the inner side of the annular electrode 31 has four evenly distributed cutouts with a diameter of 8 mm, and the distances from the centers of the four cutouts to the center of the annular electrode 31 are the same; the portion 32 between adjacent cutouts of the annular electrode 31 enters the area between adjacent poles 31; the four poles 31 pass through the circular cutouts of each annular electrode respectively, and the distance from the inner side of the annular electrode 31 is 1 mm, the poles 31 and the annular electrode 32 are not in contact, and the distances between the annular electrodes P1 and P4 and the ends of the quadrupole are 3 mm respectively.

[0023] The bath gas is nitrogen, the pressure P is 1mTorr, P·R 0 =0.006 mm·Torr <0.01mm·Torr.

[0024] The working method of the electrostatic trap ion implantation device according to the embodiment of the present invention is as follows: (S1) The power supply applies a DC voltage of 6V to the inlet electrode 11 and the outlet electrode 12, and the voltage rise rate is 1V / ms, and no voltage is applied to the annular electrode 31; The ions enter the multipole 21, and return between the entrance electrode 11 and the exit electrode 12. The ions collide with the bath gas and gradually cool down. The ion travel distance L and the bath gas pressure P satisfy: 0.2mm·Torr <P·L<0.5mm·Torr; (S2) the voltage of the entrance electrode 11 is increased to 10V at a rate of 1V / ms, and after 100μs of the voltage increase, the voltage of the annular electrode 31 is increased by 20μs at a time, and the voltage is increased to 100V at a rate of 10V / ms, and the ions are transmitted toward the exit electrode 12 and enter between the exit electrode 12 and the adjacent annular electrode P4; (S3) When ions enter between the exit electrode 12 and the annular electrode P4, the voltages of the exit electrode 12 and the annular electrode P4 are reduced. The voltage of the exit electrode 12 is 6V, and the voltage of the annular electrode P4 is 60V. The ions are trapped between the exit electrode 12 and its adjacent annular electrode P4, and the voltages of other annular electrodes 31 are turned off. (S4) repeating steps (S1) to (S3) multiple times, except that during the multiple cycles, the annular electrode P4 maintains a voltage to achieve an ion trapping function; (S5) increasing the voltage of the outlet electrode 12 to 30 V at 1 V / ms and increasing the voltage of the annular electrode P4 to 500 V at 10 V / ms, the trapped ions are compressed in the axial direction; (S5) Rapidly reducing the voltage of the exit electrode 12 to 6 V, and the trapped ions are ejected; After a delay of 100ms, the ions have been ejected from the exit electrode 12, and the voltage of the exit electrode 12 is rapidly increased to 1200V, and the ions are ejected and enter the downstream detector; In the above steps, a radio frequency voltage is applied to the multipole 21, with an amplitude of 1500 Vp-p and a frequency of 3 MHz. Example 3

[0025] The application example of the electrostatic trap ion implantation device and the working method thereof according to the first embodiment of the present invention is different from the second embodiment in that: 1. The side of the exit electrode facing the detector is a concave parabola.

[0026] 2. Use 6 ring electrodes.

[0027] The above embodiments are only examples of some parameters, such as bath gas pressure, multipole length, inscribed circle radius R 0 Of course, it can also be other values ​​within the range, and the technical effect achieved is similar to that of the above embodiment. Example 4

[0028] The application example of the electrostatic trap ion implantation device and the working method thereof according to the first embodiment of the present invention is different from the second embodiment in that: For ions with larger m / z, such as those with m / z of 800 or above, the initial momentum of the ion (m×v, where v is the initial velocity) is greater than its cross section (roughly the same as m 2 / 3 The ratio of m / z to m / z is higher, so the "braking distance" for ions to lose energy through collisions in the ion trap is much longer than for ions with smaller m / z. Since the pseudopotential well depth is inversely proportional to the m / z of the ion, heavy ions are less focused by the RF field than light ions. Therefore, when heavy ions return to the lens with less energy loss, the electric field strength needs to be relatively increased to prevent ions from settling or escaping.

[0029] like Figure 3 As shown, the end of the portion 32 between adjacent cutouts has an inward extension 33, such as an extension length of 1 mm, which increases the effective area of ​​the propulsion electrode, forms a stronger confinement field, and reduces the escape of heavy ions.

Claims

1. An electrostatic trap ion implantation device, comprising a power supply and a multipole, wherein the power supply applies a radio frequency voltage to the multipole; characterized in that: The electrostatic trap ion implantation device further comprises: A plurality of annular electrodes, the plurality of annular electrodes are arranged outside the multipole and are arranged in sequence parallel to the ion transmission direction in the multipole; the inner part of the annular electrodes enters the area between adjacent poles; An inlet electrode and an outlet electrode are respectively arranged at the ion inlet and the ion outlet of the multipole, and the power supply applies voltage to the inlet electrode, the outlet electrode and the annular electrode.

2. The electrostatic trap ion implantation device according to claim 1, characterized in that: The side of the exit electrode facing the detector is a concave spherical surface or a concave parabola, with the focus at the entrance of the detector.

3. The electrostatic trap ion implantation device according to claim 2, characterized in that: The side of the exit electrode facing the multipole rod is a plane.

4. The electrostatic trap ion implantation device according to claim 1, characterized in that: The length of the multipole is 20 mm-40 mm, and the radius R0 of the inscribed circle of the multipole in a cross section perpendicular to the central axis thereof is 1 mm-5 mm.

5. The electrostatic trap ion implantation device according to claim 1, characterized in that: The number of the annular electrodes is 3-6.

6. The working method of the electrostatic trap ion implantation device according to any one of claims 1 to 5, comprising the following steps: (S1) applying voltage to the inlet electrode and the outlet electrode, and not applying voltage to the annular electrode; The ions enter the multipole, collide with the bath gas and gradually cool down; (S2) applying voltages to the entrance electrode and the annular electrode in sequence, so that the ions are transported toward the exit electrode and enter between the exit electrode and the annular electrode adjacent thereto; (S3) reducing the voltage of the exit electrode and its adjacent annular electrode, so that the ions are trapped between the exit electrode and its adjacent annular electrode, and turning off the voltage of other annular electrodes; (S4) repeating steps (S1) to (S3) multiple times, wherein the adjacent annular electrodes maintain an ion trapping voltage; (S5) increasing the voltage of the exit electrode and its adjacent annular electrode, so that the trapped ions are compressed in the axial direction; (S6) reducing the voltage of the exit electrode to allow the trapped ions to be ejected; In the above steps, a radio frequency voltage is applied to the multipole rods.

7. The working method of the electrostatic trap ion implantation device according to claim 6, characterized in that: In step ( S5 ), when the ions reach the concave hollow region of the outlet electrode, the voltage of the outlet electrode is increased.

8. The working method of the electrostatic trap ion implantation device according to claim 6, characterized in that: When ions enter the multipole, the bath gas pressure P and the ion travel distance L satisfy: 0.2mm·Torr <P·L<0.5mm·Torr。 9. The working method of the electrostatic trap ion implantation device according to claim 8, characterized in that: 0.1Torr <P <10Torr。 10. The working method of the electrostatic trap ion implantation device according to claim 6, characterized in that: The bath gas pressure P and the radius R0 of the inscribed circle of the multipole in the cross section perpendicular to its central axis satisfy: P·R0<0.01mm·Torr.

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