A multi-pulse field ion implantation compression ion transfer tube

Abstract

The application relates to a multi-pulse field ion implantation compression ion transfer tube in an analysis instrument, which comprises an insulating inner cylinder, a BN ion gate and a Faraday disc; the BN ion gate divides the insulating inner cylinder into two areas, namely an ionization reaction area and a transfer area; a gas inlet is arranged at the position close to the Faraday disc in the transfer area, a gas outlet is arranged at the position far from the BN ion gate in the ionization reaction area, and a sample inlet is arranged at the position close to the BN ion gate; an electric potential U1 is applied to the BN ion gate when the BN ion gate is opened, the electric field intensity of the ionization reaction area is E1, and the electric field intensity of the transfer area is E2; a metal grid net which is perpendicular to the axis direction of the ion transfer tube is arranged at the position with a distance L1 (the distance in the axis direction of the ion transfer tube) from the BN ion gate in the ionization reaction area and is used as a pulse ion implantation grid net; an electric potential U1+El*L1+P1 is applied to the pulse ion implantation grid net; a pulse compression metal grid net which is perpendicular to the axis direction of the ion transfer tube is arranged at the distance L2 (the distance in the axis direction of the ion transfer tube) from the BN ion gate in a transfer area; and an electric potential U1-E2*L2+P2 is applied to the pulse compression metal grid net.

Description

TECHNICAL FIELD

[0001] The present invention relates to a multi-pulsed field ion implantation compression ion transfer tube in an analytical instrument, in particular, by adding a grid in different regions in the transfer tube and applying a pulsed voltage at a specific time, the ion implantation amount and spatial compression are improved, thereby improving the sensitivity and resolution. BACKGROUND

[0002] In recent years, portable detection instruments have received widespread attention and have been applied in fields such as public safety and environmental pollution monitoring. Ion mobility spectrometry (IMS) is characterized by high sensitivity, fast detection speed, and portability, making it one of the most widely used technologies. However, due to its relatively low resolution, IMS often produces false alarms in complex environments. Furthermore, to achieve very early warning, it is necessary to further improve detection sensitivity. Although ionization reactions can be controlled by manipulating reacting ions, this is limited to specific systems and lacks universality. Therefore, improving the resolution of IMS itself has always been a key research focus. For example, Du Yongzhai et al. invented a spatial focusing ion gate assembly and a spatial focusing ion migration tube (patent number CN201110226912). The spatial focusing ion gate assembly includes an ion gate, characterized in that: a focusing grid (3) parallel to the ion gate is provided on one side of the ion gate (2), and the ion gate (2) and the focusing grid (3) are combined to form a spatial focusing ion gate assembly (1); the ion gate (2) used is a Bradbury-Nielsen type ion gate, which is composed of two sets of metal wires arranged in parallel, coplanar but mutually insulated. A constant voltage equivalent to the potential of the position in the migration tube is applied to the first set of metal wires of the ion gate, and a periodic high voltage is applied to the second set of metal wires, the absolute value of which is higher than the absolute value of the constant voltage on the first set of metal wires, and is within the range of ≥ 100% and ≤ 300% of the absolute value of the voltage on the first set of metal wires; the high voltage forms a control electric field that blocks ions between the first set of metal wires and the second set of metal wires, realizing the function of the ion gate, and periodically injecting ions into the migration region (6). In the middle; another constant voltage is applied to the focusing grid (3), the absolute value of which is less than the absolute value of the constant voltage on the first metal wire, and the potential at its position in the migration tube is >0 and ≤200%; the high voltage on the second group of metal wires forms a focusing electric field between it and the focusing grid (3), realizing the focusing function and compressing the injected ions. A spatial focusing ion gate assembly and a spatial focusing ion migration tube invented by Wang Weiguo et al. (patent number CN201210394772), a spatial focusing ion gate assembly, characterized in that: the ion gate is composed of a high-voltage metal wire group and a low-voltage metal wire group, the high-voltage metal wire group and the low-voltage metal wire group are respectively located in two mutually parallel planes, and the metal wires in the high-voltage metal wire group and the metal wires in the low-voltage metal wire group are mutually intersected by the projections on a plane parallel to the planes in which they are located; the metal wires in the high-voltage metal wire group are arranged in parallel to each other, and the metal wires in the low-voltage metal wire group are arranged in parallel to each other.

[0003] The aforementioned method of improving resolution by increasing the ion gate voltage has a limited effect. Furthermore, when the pulse width decreases, the ion implantation amount becomes too low, severely impacting sensitivity. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a multi-pulse field ion implantation compressed ion migration tube, which significantly improves mass spectrometry sensitivity and resolution.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A multi-pulse field ion implantation compressed ion migration tube,

[0007] It includes an insulating inner cylinder, a BN ion gate, and a Faraday disk. The BN ion gate divides the insulating inner cylinder into two regions: an ionization reaction zone and a migration zone. A drift gas inlet is located in the migration zone near the Faraday disk, and a gas outlet is located in the ionization reaction zone on the side away from the BN ion gate and a sample inlet is located on the side near the BN ion gate.

[0008] When the gate of the BN ion is opened, the electric potential U1 is applied, the electric field strength in the ionization reaction region is E1, and the electric field strength in the migration region is E2.

[0009] A metal grid perpendicular to the ion migration tube axis is installed at a distance L1 from the BN ion gate within the ionization reaction zone as a pulsed ion implantation grid. The potential applied to the pulsed ion implantation grid is U1 + El × L1 + P1, where P1 is the required pulsed square wave voltage applied to the pulsed ion implantation grid. El is in V / cm, L1 is in cm, and U1 and P1 are in V.

[0010] A pulse-compression metal grid is installed in the migration region at a distance (distance from the axis of the ion migration tube) of L2 from the BN ion gate, perpendicular to the axis of the ion migration tube. The potential applied to the pulse-compression metal grid is U1-E2×L2+P2, where P2 is the pulse square wave voltage required to be applied to the pulse-compression metal grid, E2 is in V / cm, L2 is in cm, and U1 and P2 are in V.

[0011] The ion migration tube, wherein the BN ion gate is composed of two sets of alternating resistance wires; when the gate is open, the potential difference between the two sets of metal wires is zero; when the gate is closed, there is a potential difference between the two sets of metal wires; within 200-500 microseconds after the gate is closed, the potential difference on the two sets of metal wires remains unchanged; however, the potentials applied to the two sets of metal wires are switched or exchanged, and the switching or exchange frequency is not less than 50kHz, preferably 100kHz.

[0012] The ion migration tube has at least one pulse-compressed metal grid or two or more arranged in parallel intervals; the pulse square wave voltage on it is at least 50V, preferably 300V; the pulse width is less than or equal to 200us, preferably 100us; the pulse square wave is turned on for L2 / KE2 after the BN ion gate is turned off.

[0013] The ion migration tube has at least one pulsed ion implantation grid or two or more arranged in parallel intervals; the pulsed square wave voltage on it is at least 50V, preferably 300V; the pulse width is less than or equal to 200us, preferably 50us; and the pulsed square wave opening time is synchronized with the ion gate opening time.

[0014] The advantages of this invention are: This invention provides an ion migration tube that utilizes multi-pulse field injection and ion compression, which can significantly improve sensitivity and resolution, thereby broadening the application range. Attached Figure Description

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0016] Figure 1 This is a schematic diagram of a multi-pulse field ion implantation compression ion migration tube. The tube consists of an insulating inner cylinder (11), a BN ion gate (1), a pulsed ion implantation grid (2), a pulsed compression metal grid (3), a pulsed compression metal grid (4), a shielding metal grid (5), a Faraday disk (6), a drift gas inlet (7), a sample inlet (8), a gas outlet (9), a metal ring electrode (10), and an insulating inner cylinder (11).

[0017] Figure 2 These are migration spectra before and after compression using multi-pulse field ion implantation. Detailed Implementation

[0018] This invention develops a multi-pulse field ion implantation compressed ion migration tube.

[0019] A multi-pulse field ion implantation compressed ion migration tube,

[0020] It includes an insulating inner cylinder 11, a BN ion gate 1, and a Faraday disk 6; the BN ion gate 1 divides the insulating inner cylinder 11 into two regions: an ionization reaction zone and a migration zone; a drift gas inlet 7 is provided in the migration zone near the Faraday disk 6, a gas outlet 9 is provided on the side of the ionization reaction zone away from the BN ion gate 1, and a sample inlet 8 is provided on the side near the BN ion gate 1; the reaction zone is 3 cm long and the migration zone is 8 cm long.

[0021] When the gate 1 of the BN ion is opened, the electric field strength E1 in the ionization reaction region is 300 V / cm, and the electric field strength E2 in the migration region is 350 V / cm.

[0022] A metal grid perpendicular to the axis of the ion migration tube is installed at a distance L1 from the BN ion gate 1 within the ionization reaction zone, serving as a pulsed ion implantation grid 2. L1 is 3 mm. The potential applied to the pulsed ion implantation grid is U1 + El × L1 + P1, where P1 is the pulsed square wave voltage required to be applied to the pulsed ion implantation grid. El is in V / cm, L1 is in cm, and U1 and P1 are in V. U1 and P1 are 3500V and 500V, respectively.

[0023] A pulse-compression metal grid 3 is installed at a distance L2 from the BN ion gate 1 within the migration region, perpendicular to the ion migration tube axis. The potential applied to the pulse-compression metal grid 3 is U1 - E2 × L2 + P2, where P2 is the pulse square wave voltage required to be applied to the pulse-compression metal grid, E2 is in V / cm, L2 is in cm, and U1 and P2 are in V. U1 and P2 are 3500V and 500V respectively, and L2 is 4cm.

[0024] BN ion gate 1 is composed of two sets of alternating resistance wires. When the gate is open, the potential difference between the two sets of wires is zero. When the gate is closed, there is a potential difference between the two sets of wires. Within 200 microseconds after the gate is closed, the potential difference between the two sets of wires remains unchanged. However, the potentials applied to the two sets of wires are switched or exchanged with each other at a frequency of 100 kHz.

[0025] There is one pulse-compressed metal grid; the pulse square wave voltage on it is 300V; the pulse width is selected as 100us; the pulse square wave is turned on at L2 / KE2 after BN ion gate 1 is turned off.

[0026] There is one pulsed ion implantation grid; the pulsed square wave voltage on it is 300V; the pulse width is 50us; the pulse square wave opening time is synchronized with the ion gate opening time.

[0027] Example 1

[0028] E1 is 300V / cm, E2 is 250V / cm, L1 is 0.5cm long, and L2 is 5cm long; the ion gate opening time is 50µs; the pulsed ion implantation grid applies a square wave voltage with an amplitude of 500V and a pulse width of 5µs; the pulsed ion compression grid applies a square wave voltage with an amplitude of 800V and a pulse width of 10µs. The total length of the migration tube is 10cm. The ionization source is a VUV photoionization source.

[0029] The sample detection process is as follows: Sample ions are generated by ionization under VUV light. These ions move towards the ion gate under the influence of an electric field E1. When the gate opens, a large number of ions between the ion gate and the pulse injection grid are injected into the migration region. Within the migration region, after passing through the pulse compression grid, the ions are compressed by applying a pulse to the grid, thus increasing sensitivity.

[0030] Figure 2 The migration spectra of formaldehyde from a VUV photoionization source are presented. The experimental conditions for these spectra were as follows: migration tube length 8 cm, migration electric field strength 200 V / cm, ion gate opening time 0.2 ms, period 20 ms, and both the drift gas and sample carrier gas were compressed air treated with silica gel, activated carbon, and molecular sieves, with a water vapor content below 10 ppm. The drift gas flow rate was 500 sccm, the carrier gas flow rate was 150 sccm, and the migration tube temperature was 100℃ during the experiment.

[0031] Figure 2 The migration spectra before and after compression using multi-pulse field ion implantation are presented.

Claims

1. A multi-pulse field ion implantation compressed ion migration tube, characterized in that: It includes an insulating inner cylinder (11), a BN ion gate (1), and a Faraday disk (6); the BN ion gate (1) divides the insulating inner cylinder (11) into two regions: an ionization reaction zone and a migration zone; a drift gas inlet (7) is provided in the migration zone near the Faraday disk (6), a gas outlet (9) is provided on the side of the ionization reaction zone away from the BN ion gate (1), and a sample inlet (8) is provided on the side near the BN ion gate (1); When the gate of the BN ion (1) is opened, the electric potential U1 is applied, the electric field strength in the ionization reaction region is E1, and the electric field strength in the migration region is E2. A metal grid perpendicular to the ion migration tube axis is provided at a position L1 within the ionization reaction zone, at a distance (distance along the ion migration tube axis) from the BN ion gate (1), as a pulsed ion implantation grid (2); the potential applied to the pulsed ion implantation grid is U1 + El × L1 + P1, where P1 is the pulsed square wave voltage required to be applied to the pulsed ion implantation grid; El is in V / cm, L1 is in cm, and U1 and P1 are in V; Within the migration region, at a distance of L2 from the BN ion gate (1), a pulse compression metal grid (3) perpendicular to the ion migration tube axis is provided; the potential applied to the pulse compression metal grid (3) is U1-E2×L2+P2, where P2 is the pulse square wave voltage required to be applied to the pulse compression metal grid, E2 is in V / cm, L2 is in cm, and U1 and P2 are in V.

2. The ion migration tube according to claim 1, characterized in that: The BN ion gate (1) is composed of two sets of alternating resistance wires. When the gate is open, the potential difference between the two sets of metal wires is zero. When the gate is closed, there is a potential difference between the two sets of metal wires. After the gate is closed, the potential difference between the two sets of metal wires remains unchanged for 200-500 microseconds. However, the potentials applied to the two sets of metal wires are switched or exchanged, and the switching or exchange frequency is not less than 50kHz.

3. The ion migration tube according to claim 1, characterized in that: The pulse compression metal grid contains at least one or more parallel spaced-apart grids; the pulse square wave voltage on it is at least 50V; and the pulse width is less than or equal to 200µs.

4. The ion migration tube according to claim 1, characterized in that: The pulsed ion implantation grid contains at least one or more parallel-spaced grids; the pulsed square wave voltage on it is at least 50V; and the pulse width is less than or equal to 200µs.

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