Ionization power supply assembly and power control method

Abstract

This invention discloses an ionization power supply assembly and a power control method. The ionization power supply assembly includes an insulating base, a voltage multiplier rectifier, a first discharge needle assembly, a second discharge needle assembly, and a discharge orifice plate. The first and second discharge needle assemblies extend through the voltage multiplier rectifier and into the insulating base, with one side of the insulating base contacting one side of the voltage multiplier rectifier. A discharge orifice plate is provided at one end of the insulating base. The first discharge needle is electrically connected to the high-voltage output terminal of the positive polarity voltage multiplier plate, and the second discharge needle is electrically connected to the high-voltage output terminal of the negative polarity voltage multiplier plate. The ionization assembly is fixed to one end of a drift tube, sealing the drift tube. The discharge needles are connected to the internal gas path of the drift tube and are sealed to the insulating base and the voltage multiplier rectifier. This invention enables the ionization of air to generate an ion source with controllable polarity and duration. The ions generated by polarity conversion maintain the same polarity as the drift electric field, and the ionization intensity and ionization time are controllable.

Description

Technical Field

[0001] This invention relates to the field of ion mobility spectrometry instruments, and in particular to an ionization power supply assembly and a power control method. Background Technology

[0002] Ion mobility spectrometry (IMS) is a novel gas-phase analysis and detection technique developed over the past few decades. It primarily characterizes different chemical substances by measuring the migration rate of gaseous ions in the atmosphere, thus achieving the purpose of substance analysis and detection. Ion mobility spectrometers have demonstrated superior potential in numerous fields such as environmental monitoring, biomedicine, and food hygiene.

[0003] The sample to be tested needs to generate relatively stable product ions through processes such as proton abstraction, electron attachment, and electron exchange under the action of an ionization source. The ionization source mainly ionizes sample molecules into ions under atmospheric pressure for separation and detection in the drift region. Generally, the ionization source should be able to fully ionize the sample while being minimally affected by drift gas components. Commonly used ionization methods include: radioactive ionization, corona discharge ionization, plasma ionization, ultraviolet lamp ionization, laser ionization, electrospray ionization, flame ionization, and surface ionization. Currently, the most commonly used ionization source is a metal foil made of radioactive material. It requires no external power supply and is simple to use, but it is also radioactive and may cause environmental pollution. Its use, transportation, processing, and disposal are subject to strict regulations. Furthermore, the narrow linear range, poor selectivity, and radioactive pollution of radioactive ionization sources significantly limit the development of IMS detection technology. Corona discharge is one of the main discharge methods for generating plasma under normal pressure. Compared with radioactive ionization sources, corona discharge produces a higher electron density, thus improving the overall detection sensitivity of the instrument and achieving a wider dynamic range. Corona discharge ion mobility spectrometry can detect some non-volatile alkanes and aromatic compounds that radioactive ion mobility spectrometry cannot detect or has very low sensitivity for, and can also directly analyze liquid samples.

[0004] Corona discharge mainly includes two types: direct current corona discharge and pulsed corona discharge. Early research largely focused on direct current corona discharge, which produces nitrogen oxides (NOx). XO3 can interfere with gas-phase molecular-ion reactions and alter the chemical properties of the analyte, significantly reducing the detection sensitivity of negative ions, or even rendering them undetectable. Furthermore, the wear and tear on the discharge needle electrode in corona discharge poses a challenge to the widespread application of this technology. Existing technologies describe corona discharge ion sources as having unparalleled advantages as ion sources for IMS due to their low energy consumption, high ion current, simple structure, single and stable ion generation, and ease of miniaturization. However, corona discharge ion sources also have several drawbacks.

[0005] Robert et al. analyzed the mechanism of corona discharge. During positive corona discharge, regardless of whether the carrier gas is air or nitrogen, the positively reacting ions produced are all H(H₂O)n, the same as those produced by the radioactive source. During negative corona discharge, when air is used as the carrier gas, neutral gas molecules are produced. Ozone and nitrogen oxides interfere with the reaction of the generated ions, producing O₂ (excluding those from the radioactive source). - 2 ions will also produce CO. - 3. NO - 2 and NO - 3. The generated ions, depending on the carrier gas flow rate, can transform between different ions, causing instability. The formation of these ions inhibits O2 production. - The generation of 2, however, cannot react with some compounds, such as methyl salicylate, which may result in the failure to obtain the corresponding IMS spectrum. Methyl salicylate is an essential mimicry for detection, and the inability to detect it would be a fatal flaw. With increasing discharge time, the needle electrode of the corona discharge will suffer wear, causing instability in the discharge current and affecting the ionization effect. The focus of corona discharge research is, on the one hand, to adopt various measures to achieve stable discharge for the longest possible time, and on the other hand, to generate stable reactive ions in negative corona discharge to achieve stable detection of various sample molecules.

[0006] The existing technology uses a self-made corona discharge ionization source to create an ion mobility spectrometer testing platform to detect low-concentration formaldehyde sample gas. The corona discharge used is a needle mesh discharge, and the lifespan of the discharge needle has not been verified.

[0007] Existing technologies have explored schemes for the coordinated detection of positive and negative ions in ion mobility spectrometers, employing a single discharge needle and using a polarity-switching DC high voltage to achieve plasma discharge; other existing technologies employ DC high voltage corona discharge, which uses a wire plate discharge method; still others employ multiple corona needles with independently controllable high voltage on / off, aiming to solve the problem of discharge needle lifespan; and some existing technologies involve positive ion detection pulsed corona discharge ion mobility spectrometers.

[0008] However, the above patents all have their own shortcomings, either failing to effectively solve the problem of the lifespan of the discharge needle, or failing to eliminate the generation of CO. - 3. NO - 2, and NO - Issues such as 3, or lack of practical application; existing technology discloses a bipolar controllable pulsed corona discharge ionization source and uses a pinhole discharge structure; The inventors confirmed during the experiment that if the structure and circuit of the ionization source are not properly matched, the discharge needle and discharge plate can be damaged in a short time, ranging from several months to about a week. Summary of the Invention

[0009] In view of the above reasons, the present invention relates to an ionization source and a power supply control method, and the specific technical solution of the present invention is as follows: An ionization power supply assembly includes an insulating base, a voltage multiplier rectifier, a first discharge needle assembly, a second discharge needle assembly, and a discharge orifice plate. The first discharge needle assembly and the second discharge needle assembly pass through the voltage multiplier rectifier and extend into the insulating base. One side of the insulating base contacts one side of the voltage multiplier rectifier, and one end of the insulating base is provided with a discharge orifice plate. The first discharge needle is electrically connected to the high voltage output terminal of the positive polarity voltage multiplier plate, and the second discharge needle is electrically connected to the high voltage output terminal of the negative polarity voltage multiplier plate. The ionization component is fixed to one end of the drift tube, thus sealing the drift tube. The discharge needle is connected to the internal gas path of the drift tube and is sealed with the insulating base and voltage multiplier rectifier.

[0010] Furthermore, the insulating base is used to fix the discharge plate, the first discharge needle, and the second discharge needle, and it is also provided with grooves and holes for airflow, and is fixed to one end face of the drift tube. The insulating base houses the first discharge needle assembly, the second discharge needle assembly, the discharge orifice plate, and the vent area, forming a cylindrical ionization chamber.

[0011] Furthermore, the inner diameter of the vent hole is 2.5-4.5 mm.

[0012] Furthermore, the voltage doubler rectifier boosts the voltage to ±(3.5-8.5)kV, and a constant current resistor is set between its output terminal and the discharge needle, so that the output ion current can be adjusted and stabilized within the range of 0.2-20uA.

[0013] Furthermore, the first discharge needle assembly includes a first discharge needle, and the second discharge needle assembly includes a second discharge needle. The first discharge needle and the second discharge needle have a tip radius of 50 μm or less. The discharge needle is made of tungsten alloy material and has a needle diameter of 0.7 mm. It is embedded in a copper screw and can be adjusted with a screw sleeve to adjust the distance from the needle tip to the center of the discharge hole, which is 1.8-4.0 mm.

[0014] Furthermore, the discharge plate is placed vertically on the base along with the first discharge needle assembly and the second discharge needle assembly. It has a first discharge hole and a second discharge hole at the corresponding position of the needle tip. The first discharge hole and the second discharge hole are slightly smaller than the diameter of the exhaust hole of the base by 2.5-4.5mm. The first discharge hole and the second discharge hole are shared with the exhaust port of the drift tube circulation gas, and the airflow flows in the opposite direction through the discharge needle tip.

[0015] Furthermore, the ionization power supply is installed at the end of the drift tube near the discharge needle and connected to the voltage multiplier rectifier. The ionization power supply includes: a power regulator, a polarity conversion module, and a current regulator. The power regulator adjusts the voltage of the power supply to a suitable voltage for the subsequent Royer converter circuit, generating a self-excited oscillator current to drive the high-voltage transformer to achieve DC-to-AC conversion and generate a sinusoidal voltage. The current controller controls the opto-isolation switch to achieve ion flow output of different polarities. The ions generated by the polarity conversion maintain the same polarity as the drift electric field, and the magnitude and duration of the output ion flow are controlled as needed. The current controller collects the high-voltage output voltage, which is isolated by a high-voltage capacitor to achieve electrical insulation. The current controller outputs a control voltage to obtain a stable high-voltage AC voltage, which is converted into a constant current source through a high-resistance resistor to output a stable ion flow.

[0016] Furthermore, the power regulator operates in the range of 300kHz-3MHz and outputs a DC power supply of 1-8V to provide power for the subsequent Royer converter circuit. The Royer converter circuit uses two transistors to generate self-excited oscillation, which drives the primary of the high-voltage transformer to generate a high-voltage sine wave with a frequency of about 40kHz and an output amplitude of up to 2000Vpp. The polarity conversion uses an opto-isolating switch to control the input of the voltage doubler rectifier, which in turn controls the switching of the ionization power supply. One opto-isolating switch is used for the positive polarity, and another opto-isolating switch is used for the negative polarity.

[0017] This invention also relates to a power control method, wherein an ionization power supply is installed at one end of a drift tube near the discharge needle and connected to a voltage doubler rectifier; an ionization component is fixed to one end of the drift tube to seal the drift tube, and the discharge needle of the ionization component is connected to the internal gas path of the drift tube and sealed with an insulating base and a voltage doubler rectifier; in the ionization power supply, a power regulator adjusts the voltage of the power supply to a suitable voltage for the subsequent Royer conversion circuit to generate a self-excited oscillator current, which drives a high-voltage transformer to achieve DC-to-AC conversion and generate a sinusoidal voltage; The current controller controls the opto-isolation switch to achieve ion flow output of different polarities. The ions generated by the polarity conversion maintain the same polarity as the drift electric field, and the magnitude and duration of the output ion flow are controlled as needed. The current controller collects the high-voltage output voltage, which is isolated by a high-voltage capacitor to achieve electrical insulation. The current controller outputs a control voltage to obtain a stable high-voltage AC voltage, which is converted into a constant current source through a high-resistance resistor to output a stable ion flow.

[0018] In this invention, the insulating base is made of a highly insulating material; The discharge needle and the discharge orifice plate area form a cylindrical ionization chamber, the inner diameter of which is selected from 1.5-6mm; In the voltage multiplier rectifier, the voltage multiplier rectifier circuit is divided into positive and negative polarities, which boosts the voltage to ±(3.5-8.5)kV. The output ion current can be adjusted and stably output within the range of 1-20uA. The voltage multiplier structure is integrated with the discharge needle. The first discharge needle is electrically connected to the high-voltage output terminal of the positive polarity voltage multiplier plate, and the second discharge needle is electrically connected to the high-voltage output terminal of the negative polarity voltage multiplier plate. The discharge needles are made of tungsten alloy material and are embedded in copper screws. The distance from the needle tip to the center of the discharge hole can be adjusted by cooperating with the screw sleeve. The discharge plate is placed perpendicular to the discharge needle, and a discharge hole is opened at the position corresponding to the needle tip; the discharge hole is shared with the outlet of the circulating gas in the drift tube, and the airflow flows in the opposite direction through the tip of the discharge needle. The current stabilizer controller uses a microcontroller to acquire the high-voltage output voltage via an AD converter. Due to insulation requirements, the acquired high voltage is isolated using a high-voltage capacitor, achieving electrical insulation. The current stabilizer controller outputs a control voltage from the microcontroller via the DA converter to obtain a stable high-voltage AC output. This voltage is then converted into a constant current source through a high-resistance resistor, outputting a stable ion flow. The polarity conversion is also achieved by the same microcontroller controlling an opto-isolating switch to achieve ion flow outputs of different polarities. The ionization polarity matches the drift tube polarity, and the magnitude and duration of the ion flow output are controlled as needed. Polarity switching uses an opto-isolating switch to control the input of the voltage multiplier rectifier, which in turn controls the switching of the ionization power supply. The voltage regulator controller uses a microprocessor with an internal ADC device to acquire the high-voltage output voltage and control the voltage of the power regulation chip through an extended DAC converter, thereby stabilizing the output voltage and ultimately obtaining a stable output current.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention enables the generation of ion sources from air ionization, where both polarity and duration are controllable. The ions generated by polarity conversion maintain the same polarity as the drift electric field, and the ionization intensity and ionization time are controllable, allowing for the generation of suitable ions for ion mobility spectrometry as needed.

[0020] This invention solves the problem of easy ablation of the discharge needle and discharge orifice plate. After more than 100,000 hours of cumulative testing and verification, the ionization source works normally, and no ablation of the discharge needle was found after disassembly and inspection. This invention also solves the problem of CO generation by the ionization source. - 3. NO - 2 and NO - 3. Plasma produces harmful spectral peaks and interferes with detection results, thus obtaining a pure background spectrum.

[0021] This invention effectively solves the above-mentioned problems by rationally arranging the ionization chamber formed by the discharge needle assembly, discharge orifice plate, and exhaust orifice area, and by controlling the polarity and current intensity of the ionization current. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is an exploded view of the ionization component of the present invention; Figure 2 This is a diagram of the ionization component assembly of the present invention; Figure 3 This is a diagram showing the installation positions of the ion assembly and drift tube of the present invention. Figure 4 This is a circuit diagram of the power regulator and Royer converter of the present invention; Figure 5 This is the polarity conversion control circuit of the present invention; Figure 6 This is the voltage doubler rectifier circuit of the present invention; Figure 7 This is a circuit diagram of the voltage regulator and polarity controller of the present invention; Figure 8 The ion migration spectrum obtained using the ionization source of the present invention; Figure 9 The ion migration spectrum was obtained using an unoptimized ionization source. Figure 10 This is an actual image of the electrode after corrosion. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] Unless otherwise defined, the technical or scientific terms used in the embodiments of this application shall have the ordinary meaning understood by one of ordinary skill in the art. The terms "first," "second," and similar terms used in this embodiment do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements. Terms such as "upper," "lower," "left," "right," "horizontal," and "vertical" are used only relative to the orientation of the components in the accompanying drawings. These directional terms are relative concepts used for relative description and clarification, and they may change accordingly depending on the orientation of the components in the accompanying drawings.

[0026] This embodiment is a specific example of an ionization power supply component proposed in this invention. It is not difficult to obtain other technical indicators by changing some parameters.

[0027] like Figure 1 As shown, the ionization power supply assembly of this embodiment includes an insulating base 100, a voltage multiplier rectifier 101, a first discharge needle assembly 102, a second discharge needle assembly 103, and a discharge orifice plate 104, which are stacked sequentially and assembled and fixed with screws, as shown. Figure 1 As shown. The first discharge needle assembly 102 and the second discharge needle assembly 103 pass through the voltage multiplier rectifier 101 and extend into the insulating base 100. One side of the insulating base 100 contacts one side of the voltage multiplier rectifier 101, and one end of the insulating base 100 is provided with a discharge orifice plate 104.

[0028] The assembled ionization assembly is fixed to one end of the drift tube with screws, thus sealing the drift tube. The discharge needle is connected to the internal gas path of the drift tube and is sealed to the insulating base 100 and the voltage multiplier rectifier 102. Figure 2 As shown.

[0029] The insulating base 100 is made of a highly insulating material and is used to fix the discharge plate 104, the first discharge needle 102, and the second discharge needle 103. It also has grooves and holes for airflow and is fixed to one end face of the drift tube with mounting screws.

[0030] The insulating base houses the first discharge needle assembly 102, the second discharge needle assembly 103, the discharge orifice plate 104, and the exhaust port area, forming a cylindrical ionization chamber. The inner diameter of the exhaust port is selected to be 2.5 mm.

[0031] The voltage multiplier rectifier 101 has a positive and a negative polarity, both using a 6-fold voltage multiplier circuit to boost the voltage to ±(3.5-8.5)kV. A constant current resistor is installed between its output terminal and the discharge needle. Its key feature is that the output ion current can be adjusted and stabilized within the range of 0.2-20uA. The voltage multiplier rectifier is structurally integrated with the discharge needle, such as... Figure 1-2 As shown, the voltage doubler rectifier circuit is as follows: Figure 6 As shown.

[0032] The first discharge needle assembly 102 includes a first discharge needle, and the second discharge needle assembly 103 includes a second discharge needle. The first discharge needle and the second discharge needle have a tip radius of 50 μm or less. The discharge needle is made of tungsten alloy material and has a needle diameter of 0.7 mm. It is embedded in a copper screw and can be adjusted with a screw sleeve to adjust the distance from the needle tip to the center of the discharge hole. The distance is 1.2-5.0 mm.

[0033] The discharge plate 104 is vertically mounted to the first discharge needle assembly 102 and the second discharge needle assembly 103, and is fixed to the base with five 1.5mm screws. A first discharge hole 106 and a second discharge hole 107 are opened at the corresponding positions of the needle tips. The first discharge hole 106 and the second discharge hole 107 are slightly smaller than the diameter of the base's exhaust hole (2.5mm), but in this embodiment, 2.2mm is chosen. The first discharge hole 106 and the second discharge hole 107 share the exhaust port of the drift tube's circulating gas, and the airflow flows in the opposite direction past the discharge needle tip. Figure 1 , 2 As shown.

[0034] The ionization power supply 108 is installed at the end of the drift tube near the discharge needle, and is connected to the high-voltage positive input terminal JP8, high-voltage common input terminal JP9, and high-voltage negative input terminal JP10 of the voltage multiplier rectifier 101 via a high-voltage connection wire. Figure 3 , Figure 5 and Figure 6 As shown.

[0035] The ionization power supply 108 includes: a power regulator, a polarity conversion module, and a current regulator.

[0036] like Figure 4As shown, the power regulator uses a DC-DC regulator chip, model TPS54202, with an operating frequency of 500kHz. It regulates the 12V power supply, outputting a voltage of 1-8V from V0, which powers the subsequent Royer converter circuit to generate a self-excited oscillator current, driving the high-voltage transformer to achieve DC-to-AC conversion.

[0037] The Royer converter circuit uses two transistors Q3 and Q4 to generate self-excited oscillation, driving the primary winding of the high-voltage transformer. The secondary winding couples out a high-voltage sine wave with a frequency of approximately 40kHz and an output amplitude of 250-2000Vpp. The output high voltage is connected to the opto-isolation switches HU9 and HU10 of the polarity conversion board through AC output terminals A1 and B. Figure 4 , Figure 5 As shown.

[0038] The current stabilizing controller includes a microcontroller U5, model GD32F103, which acquires the high-voltage output AC voltage via AD conversion. The acquired high voltage is amplified by a differential amplifier U19B, rectified, and converted into DC voltage, which is then output to the microcontroller U5 via AN4-HV2. High-voltage acquisition uses a high-voltage capacitor for isolation, achieving electrical insulation. The current stabilizing controller, through the microcontroller U5 and a DAC chip U7 (model DAC8571 or TM8112), obtains a stable high-voltage AC voltage output, which is output through an interface, connected to a polarity conversion circuit, then to a rectifier circuit, and finally converted into a constant current source through a high-resistance resistor. The output is connected to the first discharge pin 102, the second discharge pin 103, and the discharge orifice plate. Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown.

[0039] The polarity conversion module is controlled by a microcontroller U5 through HV2-_EN and HV2+_EN, which control the input terminals of opto-isolation switches HU9 and HU10 to achieve computer program control of polarity. Figure 5 , Figure 7 As shown.

[0040] The polarity conversion module uses opto-isolating switches to control the input of the voltage multiplier rectifier, ultimately controlling the switching of the ionization power supply. The positive polarity uses opto-isolating switch HU9, and the negative polarity uses opto-isolating switch HU10. The opto-switches used are AQV258H and APV258HEX. The polarity control is program-controlled and adapted to the operating polarity of the drift tube. Its output is connected to the high-voltage positive input terminal JP8, high-voltage common input terminal JP9, and high-voltage negative input terminal JP10 of the voltage multiplier rectifier via interfaces HV2-, HV2-MV, and HV2+. Figure 5 As shown.

[0041] Figure 8 Using the ionization source of the present invention, a pure ion background spectrum is generated by controlling the magnitude and time of the ion flow and adjusting the position of the discharge needle assembly. Figure 9 When the distance between the discharge needle and the orifice plate is less than 1.5 mm or the ion current is greater than 40 μA, the ion migration spectrum generated by this ionization source shows an increase in NOx products, a complex ion background spectrum, and a large number of interfering peaks. It is evident that improper adjustment of the discharge needle and inappropriate control of the ion current result in poor performance.

[0042] The inventors confirmed during experiments that when the structure and circuitry of the ionization source are not properly matched, the discharge needle and discharge plate can be damaged within a short period of time, ranging from several months to about a week. Figure 10 This image shows the corrosion of the discharge mesh after one week of continuous operation. The corrosion of the discharge needle is even more severe, with a large amount of oxide adhering to both the stainless steel discharge mesh and the discharge needle. In the image, 301 represents a slightly corroded mesh, 302 represents a severely corroded discharge needle, and 303 represents a mesh with a large amount of deposits after corrosion.

[0043] The ionization source of this invention has been continuously operated on 16 prototypes for a year and a half, with a cumulative testing time of over 100,000 hours. The ionization source works normally, and no phenomena such as discharge needle ablation or electrochemical corrosion were found after disassembly and inspection. It effectively overcomes the problems of short lifespan and unstable productization of ionization sources that have existed in the industry, and achieves good results.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ionization power supply assembly, characterized in that: It includes an insulating base, a voltage multiplier rectifier, a first discharge needle assembly, a second discharge needle assembly, and a discharge orifice plate; The first discharge needle assembly and the second discharge needle assembly pass through the voltage multiplier rectifier and extend into the insulating base. One side of the insulating base contacts one side of the voltage multiplier rectifier, and one end of the insulating base is provided with a discharge orifice plate. The first discharge needle is electrically connected to the high voltage output terminal of the positive polarity voltage multiplier plate, and the second discharge needle is electrically connected to the high voltage output terminal of the negative polarity voltage multiplier plate. The ionization component is fixed to one end of the drift tube to seal the drift tube. The discharge needle is connected to the internal gas path of the drift tube and is sealed with the insulating base and voltage multiplier rectifier. The ionization power supply is installed at the end of the drift tube near the discharge needle and is connected to the voltage multiplier rectifier. The ionization power supply includes: a power regulator, a polarity conversion module, and a current regulator. The power regulator adjusts the voltage of the power supply to a suitable voltage for the subsequent Royer converter circuit, generating a self-excited oscillator current to drive the high-voltage transformer to achieve DC-to-AC conversion and generate a sinusoidal voltage. The current controller controls the opto-isolation switch to achieve ion flow output of different polarities. The ions generated by the polarity conversion maintain the same polarity as the drift electric field, and the magnitude and duration of the output ion flow are controlled as needed. The current controller collects the high-voltage output voltage, which is isolated by a high-voltage capacitor to achieve electrical insulation. The current controller outputs a control voltage to obtain a stable high-voltage AC voltage, which is converted into a constant current source through a high-resistance resistor to output a stable ion flow.

2. The ionization power supply assembly according to claim 1, characterized in that: The insulating base is used to fix the discharge plate, the first discharge needle, and the second discharge needle. It is also provided with grooves and holes for airflow and is fixed to one end face of the drift tube. The insulating base houses the first discharge needle assembly, the second discharge needle assembly, the discharge orifice plate, and the vent area, forming a cylindrical ionization chamber.

3. The ionization power supply assembly according to claim 2, characterized in that: The inner diameter of the vent hole is 2.5-4.5mm.

4. The ionization power supply assembly according to claim 1, characterized in that: The voltage multiplier rectifier boosts the voltage to ±(3.5-8.5)kV. A constant current resistor is installed between its output terminal and the discharge needle, and the output ion current can be adjusted and stabilized within the range of 0.2-20uA.

5. The ionization power supply assembly according to claim 1, characterized in that: The first discharge needle assembly includes a first discharge needle, and the second discharge needle assembly includes a second discharge needle. The first discharge needle and the second discharge needle have a tip radius of 50 μm or less. The discharge needle is made of tungsten alloy material and has a needle diameter of 0.7 mm. It is embedded in a copper screw and can be adjusted with a screw sleeve to adjust the distance from the needle tip to the center of the discharge hole, which is 1.8-4.0 mm.

6. The ionization power supply assembly according to claim 4, characterized in that: The discharge plate is placed vertically on the base along with the first discharge needle assembly and the second discharge needle assembly. It has a first discharge hole and a second discharge hole at the corresponding position of the needle tip. The first discharge hole and the second discharge hole are slightly smaller than the diameter of the exhaust hole of the base by 2.5-4.5mm. The first discharge hole and the second discharge hole are shared with the outlet of the circulating gas of the drift tube, and the airflow flows in the opposite direction through the discharge needle tip.

7. The ionization power supply assembly according to claim 1, characterized in that: The power regulator operates in the range of 300kHz-3MHz and outputs 1-8V DC power to provide power to the subsequent Royer converter circuit. The Royer converter circuit uses two transistors to generate self-excited oscillation, which drives the primary of the high-voltage transformer to generate a high-voltage sine wave with a frequency of 40kHz and an output amplitude of up to 2000Vpp. The polarity conversion uses an opto-isolating switch to control the input of the voltage doubler rectifier, which in turn controls the switching of the ionization power supply. One opto-isolating switch is used for the positive polarity, and another opto-isolating switch is used for the negative polarity.

8. A power supply control method, characterized in that: The ionization power supply is installed at the end of the drift tube near the discharge needle and connected to the voltage doubler rectifier. The ionization assembly is fixed to one end of the drift tube, sealing the drift tube. The discharge needle of the ionization assembly is connected to the internal gas path of the drift tube and sealed with the insulating base and the voltage doubler rectifier. In the ionization power supply, the power regulator adjusts the voltage of the power supply to a suitable voltage for the subsequent Royer conversion circuit, generating a self-excited oscillator current to drive the high-voltage transformer to achieve DC to AC conversion and generate a sinusoidal voltage. The current controller controls the opto-isolation switch to achieve ion flow output of different polarities. The ions generated by the polarity conversion maintain the same polarity as the drift electric field, and the magnitude and duration of the output ion flow are controlled as needed. The current controller collects the high-voltage output voltage, which is isolated by a high-voltage capacitor to achieve electrical insulation. The current controller outputs a control voltage to obtain a stable high-voltage AC voltage, which is converted into a constant current source through a high-resistance resistor to output a stable ion flow.

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