Impedance matching circuit using insulating air-core transformer and mass spectrometer including same

Abstract

To provide an impedance matching circuit using an insulated air core transformer, and a mass spectrometer including the same, to increase the measurement accuracy.SOLUTION: A mass spectrometer includes: a sample introduction part; an ionization part connected to the sample introduction part and including a plasma coil that ionizes a sample introduced from the sample introduction part; an RF power supply part that is electrically connected to the ionization part and that supplies RF power to the ionization part; an ion lens part that includes an extraction lens adjacent to the ionization part, and a guide lens configured to guide an ion beam extracted from the extraction lens; and a detection part that detects the ion beam. The RF power supply part includes an impedance matching circuit that controls a voltage due to an inductance component of the plasma coil.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mass spectrometer, and more particularly to an impedance matching circuit using an insulating air-core transformer and a mass spectrometer including the same. [Background technology]

[0002] As air and water pollution, including particulate matter, increases, methods are needed that can measure and analyze it. Mass spectrometers are used for such measurement and analysis.

[0003] A mass spectrometer is an instrument that identifies or analyzes chemicals by mass analysis. Such mass spectrometers analyze the constituents of a sample by measuring the mass of the substance by its mass-to-charge ratio. Within the mass spectrometer, the sample is ionized using various methods. The ionized sample is accelerated as it passes through an electric and / or magnetic field. That is, some or all of the ionized sample is deflected by the electric and / or magnetic field. A detector detects the ionized sample.

[0004] Meanwhile, in a mass spectrometer using inductively coupled plasma (ICP), the analytical performance of the mass spectrometer is degraded by the influence of the electric field existing outside the plasma coil, and therefore a method for controlling the electric field existing outside the plasma coil is required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7288152 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned problems in the conventional technology, and an object of the present invention is to provide an impedance matching circuit using an insulating air-core transformer for improving measurement accuracy, and a mass spectrometer including the same. [Means for solving the problem]

[0007] A mass spectrometer according to an embodiment of the present invention comprises a sample introduction section, an ionization section connected to the sample introduction section and including a plasma coil that ionizes the sample introduced from the sample introduction section, an RF power supply section electrically connected to the ionization section and configured to supply RF power to the ionization section, an ion lens section including an extraction lens adjacent to the ionization section and a guide lens configured to guide the ion beam extracted from the extraction lens, and a detection section configured to detect the ion beam, wherein the RF power supply section includes an impedance matching circuit configured to control a voltage due to an inductance component of the plasma coil.

[0008] According to an embodiment of the present invention, the impedance matching circuit includes first and second capacitors connected in series via a node, the node being grounded, and setting respective values ​​of the first and second capacitors to reduce the voltage.

[0009] According to an embodiment of the present invention, when the first capacitor of the first and second capacitors is short-circuited, the output terminal of the impedance matching circuit connected to the first capacitor is grounded, and the output terminal of the impedance matching circuit connected to the second capacitor is applied with the sum of the respective voltages of the first and second capacitors before the first capacitor was short-circuited.

[0010] According to an embodiment of the present invention, the RF power supply unit includes an inductively coupled coil that is inductively coupled to the plasma coil, and sets values ​​of the first and second capacitors to adjust the RF potential ratio across the inductively coupled coil.

[0011] According to an embodiment of the present invention, the RF potential ratio is inversely proportional to the ratio of the respective values ​​of the first and second capacitors.

[0012] According to an embodiment of the present invention, the impedance matching circuit includes first and second variable capacitors, and the impedance matching circuit changes the values ​​of the first and second variable capacitors to match the impedance of the load of the plasma coil and the output impedance of the RF power supply.

[0013] According to an embodiment of the present invention, the impedance matching circuit includes an insulating air-core transformer consisting of an input coil and an output coil, the first variable capacitor is connected in series with the input coil, and the second variable capacitor is connected in parallel with the output coil.

[0014] According to an embodiment of the present invention, the imaginary part of the impedance of the load is adjusted by varying the value of the first variable capacitor.

[0015] According to an embodiment of the present invention, the value of the second variable capacitor is varied to adjust the real part of the impedance of the load.

[0016] An electronic circuit for supplying RF power to an inductively coupled plasma coil according to an embodiment of the present invention includes an RF power source that outputs an RF signal, an impedance matching circuit that processes and outputs the RF signal and is configured to control a voltage due to an inductance component of the plasma coil, and an inductively coupled coil that uses the inductive coupling to supply the RF power to the plasma coil based on the signal output from the impedance matching circuit, and the impedance matching circuit controls the voltage by setting respective values ​​of first and second capacitors.

[0017] According to an embodiment of the present invention, the first and second capacitors are connected in series via a node, and the node is grounded.

[0018] According to an embodiment of the present invention, when the first capacitor of the first and second capacitors is short-circuited, the output terminal of the impedance matching circuit connected to the first capacitor is grounded, and the output terminal of the impedance matching circuit connected to the second capacitor is applied with the sum of the respective voltages of the first and second capacitors before the first capacitor was short-circuited.

[0019] According to an embodiment of the present invention, the values ​​of the first and second capacitors are set to adjust the RF potential ratio across the inductive coupling coil.

[0020] According to an embodiment of the present invention, the RF potential ratio is inversely proportional to the ratio of the respective values ​​of the first and second capacitors.

[0021] According to an embodiment of the present invention, the impedance matching circuit includes first and second variable capacitors, The impedance matching circuit varies the values ​​of the first and second variable capacitors to match the impedance of the load of the plasma coil with the output impedance of the electronic circuit. Effect of the Invention

[0022] According to the present invention, the impedance matching circuit can prevent the performance of the mass spectrometer from being degraded due to the inductance component of the plasma coil. The influence of the electric field distributed outside the plasma coil can be minimized. This can improve the performance of the mass spectrometer according to the present invention. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a conceptual diagram illustrating an example of a mass spectrometer in accordance with one embodiment of the present invention. [Diagram 2] FIG. 2 illustrates an example of an RF power supply according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a circuit diagram showing an example of an RF power supply and plasma coil in accordance with one embodiment of the present invention. [Figure 4a] FIG. 2 is a diagram showing the flow of an ionized sample inside an ionization unit. [Figure 4b] FIG. 2 is a diagram showing the flow of an ionized sample inside an ionization unit. [Diagram 5] FIG. 2 illustrates an example of impedance matching according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, embodiments of the present invention are described clearly and in detail so that those skilled in the art can easily practice the present invention.

[0025] FIG. 1 is a conceptual diagram for explaining a mass spectrometer according to an embodiment of the present invention.

[0026] 1, a mass spectrometer 10 according to the present invention includes a sample introduction section 100, an ionization section 200, an interface section 300, an ion lens section 400, a reaction section 500, a mass separation section 600, and a detection section 700. The mass spectrometer 10 according to the present invention is illustrated and described as a mass spectrometer 10 using inductively coupled plasma (ICP), but this is only an example and the present invention is not limited thereto, and the mass spectrometer 10 according to the present invention may be a mass spectrometer 10 of various types including an ion lens section 400 as illustrated and described below.

[0027] The sample introduction section 100 includes a nebulizer 110 and a spray chamber 120. The nebulizer 110 converts a liquid sample into an aerosol state and injects the aerosol into the spray chamber 120. The spray chamber 120 is connected to the nebulizer 110. The spray chamber 120 reduces sample fluctuations and keeps the size and amount of the sample moving to the ionization section 200 (described later) constant. Specifically, the spray chamber 120 removes relatively large aerosols by temperature control and controls the flow of aerosols so that only relatively small aerosols move to the ionization section 200. Although not shown, a carrier gas may be supplied to the nebulizer 110 and / or the spray chamber 120 via at least one gas supply pipe. The carrier gas guides the sample to the plasma P.

[0028] The ionization section 200 is connected to the sample introduction section 100. The ionization section 200 is called, for example, a plasma torch. The ionization section 200 includes a first tube 210, a second tube 220, a third tube 230, an RF power supply section 260, and a plasma coil 270.

[0029] The first tube 210 is connected to the spray chamber 120 of the sample introduction section 100 and is disposed at the innermost part of the ionization section 200. The third tube 230 is disposed at the outermost part of the ionization section 200, and the second tube 220 is disposed between the first tube 210 and the third tube 230. The second tube 220 and the third tube 230 are connected to the first gas supply pipe 240 and the second gas supply pipe 250, respectively. The first to third tubes (210, 220, 230) may each have a hollow columnar shape extending in the first direction D1. In terms of the cross-sectional area cut on a plane perpendicular to the first direction D1, the first to third tubes (210, 220, 230) may have concentric circular shapes whose central axes coincide with each other. The first to third tubes (210, 220, 230) are made of, for example, quartz, alumina, platinum, or sapphire.

[0030] A sample and a carrier gas move through the first tube 210, an auxiliary gas moves through the first gas supply pipe 240 and the second tube 220, and a coolant gas moves through the second gas supply pipe 250 and the third tube 230. The auxiliary gas prevents or minimizes damage to the ends of the first and second tubes (210, 220) due to contact with the plasma P. The coolant gas prevents or minimizes damage to the inner wall of the third tube 230 due to contact with the plasma P. The carrier gas, the auxiliary gas, and the coolant gas include, for example, argon (Ar).

[0031] The RF power supply 260 provides RF power to the plasma coil 270. For example, the RF power supply 260 may be configured to deliver maximum power to the plasma coil 270. A more detailed description of the RF power supply 260 is provided below with reference to FIGS.

[0032] The plasma coil 270 has, for example, a helical shape that wraps around the outside of the third tube 230 at least two times. The plasma coil 270 generates a strong electromagnetic field that changes over time inside the ionization unit 200. For example, the plasma coil 270 generates a strong electromagnetic field that changes over time inside the ionization unit 200 based on RF power supplied from the RF power supply unit 260. The electromagnetic field generated by the plasma coil 270 discharges the gas inside to generate plasma P. The high-temperature plasma P ionizes the sample in an aerosol state introduced from the sample introduction unit 100.

[0033] The interface unit 300 extracts ionized samples from the plasma P generated in the ionization unit 200 in the form of an ion beam. The interface unit 300 is adjacent to the ionization unit 200 in a first direction D1. The interface unit 300 is connected to the chamber CH. The interface unit 300 is provided between the ionization unit 200 and the chamber CH. Although not shown, the interface unit 300 includes a sampler cone and a skimmer cone for extracting the ion beam. The sampler cone and the skimmer cone have a cone shape that is wider in a second direction D2 toward the first direction D1, for example.

[0034] An ion lens section 400, a reaction section 500, a mass separation section 600, and a detection section 700 are provided inside the chamber CH. The inside of the chamber CH is maintained in a vacuum state. At least one of the ion lens section 400, the reaction section 500, the mass separation section 600, and the detection section 700 is provided, for example, in a sub-chamber inside the chamber CH, and the sub-chamber is maintained in a vacuum state higher than that of the inside of the chamber CH. The ion lens section 400, the reaction section 500, the mass separation section 600, and the detection section 700 are arranged, for example, along a first direction D1, but the present invention is not limited thereto.

[0035] The ion lens unit 400 is provided between the interface unit 300 and the reaction unit 500. The ion lens unit 400 includes at least one lens and blocks photons, neutral particles, etc. through the one or more lenses to control the path of ions to be analyzed. For example, the ion lens unit 400 includes an extraction lens that extracts an ion beam, and a guide lens configured to guide the ion beam extracted from the extraction lens.

[0036] The reaction section 500 is provided between the ion lens section 400 and the mass separation section 600. The reaction section 500 may be referred to as a collision / reaction cell. Although not shown, a collision / reaction gas is supplied to the reaction section 500 through at least one gas supply pipe. The collision / reaction gas collides with various ions inside the reaction section 500 to convert interfering ions (e.g., 40Ar, 40Ar16O, 38ArH, etc.) into non-interfering species, or convert ions to be analyzed into ions having a different mass.

[0037] The mass separation unit 600 is provided between the reaction unit 500 and the detection unit 700. The mass separation unit 600 can use, for example, a quadrupole system, a double focusing magnetic sector system, or a time-of-flight system, and separates ions according to their mass-to-charge ratio (m / z).

[0038] The detection unit 700 is adjacent to the end of the mass separation unit 600 and detects the mass spectrum of the ions to be analyzed that are separated by the mass separation unit 600. The detection unit 700 may be, for example, a channel electron multiplier, a Faraday cup, or a discrete dynode electron multiplier.

[0039] 2 shows an example of an RF power supply according to an embodiment of the present invention. Referring to FIG. 1 and FIG. 2, an RF power supply section 260 includes an RF power supply circuit 261, an impedance matching circuit 262, and an RF power transmission circuit 263.

[0040] The RF power supply circuit 261 outputs a signal having an RF frequency (hereinafter referred to as an “RF signal”) to the impedance matching circuit 262. For example, the RF power supply circuit 261 outputs a high-frequency signal to the impedance matching circuit 262.

[0041] The impedance matching circuit 262 receives an RF signal from the RF power supply circuit 261, processes the received RF signal, and transmits the processed signal. For example, the impedance matching circuit 262 receives a high-frequency signal from the RF power supply circuit 261, amplifies the received high-frequency signal, and transmits the amplified signal to the RF power transmission circuit 263.

[0042] The impedance matching circuit 262 adjusts the RF power supplied to the plasma coil 270. For example, the impedance matching circuit 262 adjusts the RF power supplied to the plasma coil 270 by setting the RF potential ratio transmitted to the RF power transmission circuit 263.

[0043] The impedance matching circuit 262 matches the impedance of the load of the plasma coil 270 with the output impedance of the RF power supply unit 260. For example, the impedance matching circuit 262 matches the impedance of the load of the plasma coil 270 with the output impedance of the impedance matching circuit 262. As a result of the matching, the impedance matching circuit 262 can efficiently supply RF power to the plasma coil 270 and prevent reflected power from the plasma coil 270. Here, the reflected power means power that at least a part of the RF power supplied to the plasma coil 270 is reflected from the plasma coil 270 and returns to the RF power supply unit 260.

[0044] The RF power transmission circuit 263 receives the processed signal from the impedance matching circuit 262. The RF power transmission circuit 263 supplies RF power to the plasma coil 270 based on the received signal. For example, the RF power transmission circuit 263 supplies RF power to the plasma coil 270 based on the received signal using an inductive coupling method.

[0045] 3 is a circuit diagram showing a specific example of an RF power supply unit and a plasma coil according to an embodiment of the present invention. Referring to FIG. 1 to FIG. 3, an RF power supply unit 260 and a plasma coil 270a are inductively coupled.

[0046] The RF power supply circuit 261 includes an RF power source 261a. The RF power source 261a outputs an RF signal to the impedance matching circuit 262. For example, the RF power source 261a outputs a high-frequency signal to the impedance matching circuit 262. A first end of the RF power source 261a is coupled to the impedance matching circuit 262, and a second end of the RF power source 261a is grounded.

[0047] The impedance matching circuit 262 includes an insulating air-core transformer 262a, an input fixed capacitor 262b, an input variable capacitor 262c, an output variable capacitor 262d, and output fixed capacitors 262e and 262f.

[0048] In one embodiment, the impedance matching circuit 262 further includes a metal box surrounding the impedance matching circuit 262. The metal box may be grounded. The metal box is configured to be electrically insulated from the impedance matching circuit 262.

[0049] The isolated air core transformer 262a includes an input coil 262a_1 and an output coil 262a_2. The isolated air core transformer 262a processes and outputs an RF signal received from the RF power source 261a. For example, the isolated air core transformer 262a amplifies and outputs a signal received from the RF power source 261a.

[0050] Meanwhile, the impedance matching circuit 262 is divided or insulated based on the input coil 262a_1 and the output coil 262a_2 of the insulating air-core transformer 262a. For example, the impedance matching circuit 262 is divided into a primary circuit including the input coil 262a_1 and a secondary circuit including the output coil 262a_2, and the primary circuit and the secondary circuit are insulated from each other.

[0051] In one embodiment, the secondary circuit forms a resonant tank. For example, the output coil 262a_2, the output variable capacitor 262d, and the output fixed capacitors 262e and 262f form a resonant tank. When the secondary circuit forms a resonant tank, the secondary circuit filters the frequency to stably transmit the RF power. Note that the secondary circuit can stably charge and discharge the energy by the RF power to supply the RF power constantly.

[0052] In one embodiment, the exterior of the insulating air core transformer 262a is coated with an insulating material, which is an electrically non-conductive material.

[0053] In one embodiment, the exterior of each of the input coil 262a_1 and the output coil 262a_2 of the insulating air-core transformer 262a is coated with an insulating material.

[0054] The input fixed capacitor 262b is coupled in parallel with the input coil 262a_1 to compensate for leakage inductance due to the input coil 262a_1. For example, first ends of the input fixed capacitor 262b and the input coil 262a_1 are coupled to the RF power source 261a. Second ends of the input fixed capacitor 262b and the input coil 262a_1 are coupled to a first end of the input variable capacitor 262c. A second end of the input variable capacitor 262c may be grounded.

[0055] The output variable capacitor 262d is connected in parallel with the output coil 262a_2. For example, a first end of the output variable capacitor 262d is connected to a first end of the output coil 262a_2, and a second end of the output variable capacitor 262d is connected to a second end of the output coil 262a_2.

[0056] The impedance matching circuit 262 varies the values ​​of the input variable capacitor 262c and the output variable capacitor 262d to match the impedance of a load 270b (hereinafter referred to as "load 270b") of the plasma coil 270a with the output impedance of the RF power supply unit 260. For example, the impedance matching circuit 262 varies the value of the input variable capacitor 262c so that the imaginary part of the impedance of the load 270b corresponds to the imaginary part of the output impedance of the RF power supply unit 260. The impedance matching circuit 262 varies the value of the output variable capacitor 262d so that the real part of the impedance of the load 270b corresponds to the real part of the output impedance of the RF power supply unit 260.

[0057] The output fixed capacitors 262e and 262f are connected in series. The output fixed capacitors 262e and 262f connected in series are connected in parallel with the output coil 262a_2 and the output variable capacitor 262d, respectively. For example, a first end of the output fixed capacitor 262e, a first end of the output coil 262a_2, and a first end of the output variable capacitor 262d are connected. A second end of the output fixed capacitor 262f, a second end of the output coil 262a_2, and a second end of the output variable capacitor 262d are connected.

[0058] A second end of the output fixed capacitor 262e and a first end of the output fixed capacitor 262f are coupled to a node N. The node N may be grounded. Hereinafter, such a structure is referred to as a center tap (CT) structure.

[0059] The impedance matching circuit 262 adjusts the RF potential ratio of the output terminals OT1, OT2 using a center tap CT structure. The RF potential ratio of the output terminals OT1, OT2 is inversely proportional to the ratio of the values ​​of the output fixed capacitors 262e, 262f. The impedance matching circuit 262 sets (or tunes) the values ​​of the output fixed capacitors 262e, 262f to adjust the RF potential ratio of the output terminals OT1, OT2.

[0060] For example, when the output fixed capacitor 262e of the output fixed capacitors 262e and 262f is short-circuited, the output terminal OT1 connected to the output fixed capacitor 262e is grounded by the center tap CT structure, and the maximum voltage (i.e., the sum of the respective voltages of the output fixed capacitors 262e and 262f before the output fixed capacitor 262e is short-circuited) is applied to the output terminal OT2.

[0061] For example, when the output fixed capacitor 262f of the output fixed capacitors 262e, 262f is short-circuited, the output terminal OT2 connected to the output fixed capacitor 262f is grounded by the center tap CT structure, and the maximum voltage (i.e., the sum of the voltages of the output fixed capacitors 262e, 262f before the output fixed capacitor 262f was short-circuited) is applied to the output terminal OT1.

[0062] As described above, the impedance matching circuit 262 sets the values ​​of the output fixed capacitors 262e, 262f having the center tap CT to adjust the RF potential ratio of the output terminals OT1, OT2.

[0063] In one embodiment, the impedance matching circuit 262 sets the values ​​of the output fixed capacitors 262e, 262f to account for the parasitic capacitance "C" component of the plasma coil 270a.

[0064] In one embodiment, the impedance matching circuit 262 may further include switches coupled in parallel with the output fixed capacitors 262e and 262f, respectively. For example, a first switch is coupled in parallel with the output fixed capacitor 262e, and a second switch is coupled in parallel with the output fixed capacitor 262f. In this case, when the first switch is turned on, the second switch is turned off, and when the first switch is turned off, the second switch is turned on. Each of the output fixed capacitors 262e and 262f is short-circuited by the on / off operation of the switch.

[0065] The RF power transmitting circuit 263 includes output terminals OT1 and OT2 and an inductive coupling coil 263a. A first end of the inductive coupling coil 263a is coupled to the output terminal OT1, and a second end of the inductive coupling coil 263a is coupled to the output terminal OT2. The inductive coupling coil 263a supplies RF power based on a signal received from the impedance matching circuit 262 to the plasma coil 270a using an inductive coupling method. For example, the inductive coupling coil 263a supplies RF power based on the respective RF potentials of the first and second ends of the inductive coupling coil 263a (i.e., the respective RF potentials of the output terminals OT1 and OT2) to the plasma coil 270a.

[0066] In one embodiment, the output terminals OT1, OT2 may be electrically isolated from the impedance matching circuit 262.

[0067] On the other hand, when plasma coil 270a receives RF power from RF transmission circuit 263, an electric field is formed around plasma coil 270a. Plasma coil 270a is affected by the electric field formed around it.

[0068] For example, a voltage (hereinafter, referred to as a "plasma coil voltage") that forms an electric field by the "L" component of the plasma coil 270a is generated in the plasma coil 270a. The plasma coil voltage generates a plasma potential, and the plasma potential increases the energy possessed by the ionized sample inside the ionization unit 200. That is, the velocity of the ionized sample entering the sampler cone increases, which results in a loss of ions.

[0069] In the present invention, the RF potential ratio of the output terminals OT1, OT2 can be set arbitrarily using a center tap structure. That is, the impedance matching circuit 262 according to the present invention can arbitrarily set the RF potential ratio of the output terminals OT1, OT2 by setting the values ​​of the output fixed capacitors 262e, 262f having a center tap CT structure in order to reduce the plasma coil voltage. For example, the impedance matching circuit 262 sets the values ​​of the output fixed capacitors 262e, 262f so that the plasma coil voltage becomes "0".

[0070] 4a and 4b show the flow of the ionized sample inside the ionization unit. In Fig. 4a and 4b, it is assumed that the thickness of the arrow represents the intensity of the energy possessed by the ionized sample or the magnitude of the velocity of the ionized sample. For example, it is assumed that the thicker the arrow, the greater the intensity of the energy possessed by the ionized sample or the magnitude of the velocity of the ionized sample.

[0071] FIG. 4a shows the flow of the ionized sample when the center tap CT structure is not applied. Referring to FIG. 1, FIG. 3 and FIG. 4a, when RF power is supplied from the RF transmission circuit 263, the plasma coil voltage Vp is generated in the plasma coil 270a by the "L" component of the plasma coil 270a. Therefore, the energy of the ionized sample may be large. Or, the velocity of the ionized sample may be high.

[0072] 4b shows the flow of the ionized sample when the center tap CT structure according to the present invention is applied. Referring to FIG. 1, FIG. 3, and FIG. 4b, when RF power is supplied from the RF transmission circuit 263, the plasma coil 270a may not generate the plasma coil voltage Vp.

[0073] 4a and 4b, the energy of the ionized sample when the center tap CT structure is not applied may be greater than the energy of the ionized sample when the center tap CT structure is applied, or the velocity of the ionized sample when the center tap CT structure is not applied may be greater than the velocity of the ionized sample when the center tap CT structure is applied.

[0074] FIG. 5 shows an example of impedance matching of the impedance matching circuit of FIG. 3. In FIG. 5, the horizontal axis indicates the operating frequency of the RF power supply 261a, and the vertical axis indicates the impedance of the load 270b of the plasma coil 270a. In FIG. 5, it is assumed that the operating frequency of the RF power supply 261a is 27 megahertz (MHz), and the output impedance of the RF power supply 260 is 50 ohms (Ω). With reference to FIG. 3 and FIG. 5, the impedance matching circuit 262 changes the values ​​of the input variable capacitor 262c and the output variable capacitor 262d to match the impedance of the load 270b with the output impedance of the RF power supply 260. As in FIG. 5, it can be seen that the impedance matching circuit 262 changes the output variable capacitor 262d to adjust the real part of the impedance of the load 270b to 48.431 ohms, and changes the input variable capacitor 262c to adjust the imaginary part of the impedance of the load 270b to −1.427 ohms.

[0075] In the above-described embodiment, the terms "first", "second", "third", etc. are used to describe components according to the technical idea of ​​the present invention. However, the terms "first", "second", "third", etc. are used to distinguish components from each other and do not limit the present invention. For example, the terms "first", "second", "third", etc. do not imply any order or any form of numerical meaning.

[0076] The above-mentioned contents are specific examples for carrying out the present invention. The present invention includes not only the above-mentioned embodiments, but also embodiments that can be simply modified or easily modified. Note that the present invention also includes techniques that can be easily modified and carried out using the above-mentioned embodiments. [Explanation of symbols]

[0077] 10 Mass spectrometer 100 Sample introduction section 110 Nebulizer 120 Spray Chamber 200 Ionization unit 210 1st Tube 220 2nd Tube 230 3rd Tube 240 First Gas Supply Pipe 250 Second Gas Supply Pipe 260 RF Power Supply 261 RF Power Supply Circuit 261a RF power supply 262 Impedance Matching Circuit 262a Insulated air-core transformer 262b Input Fixed Capacitor 262c Input variable capacitor 262d Output variable capacitor 262e, 262f Output fixed capacitor 263 RF power transmission circuit 263a Inductively Coupled Coil 270, 270a Plasma coil 270b load 300 Interface section 400 Ion lens section 500 reaction units 600 Mass separation section 700 Detector

Claims

1. A sample introduction section; an ionization unit connected to the sample introduction unit and including a plasma coil for ionizing the sample introduced from the sample introduction unit; an RF power supply electrically connected to the ionization unit and configured to supply RF power to the ionization unit; an ion lens section including an extraction lens adjacent to the ionization section and a guide lens configured to guide the ion beam extracted from the extraction lens; a detector configured to detect the ion beam; The RF power supply includes: an impedance matching circuit configured to control a voltage due to an inductance component of the plasma coil; The impedance matching circuit includes first and second capacitors connected in series via a node; The node is grounded; setting respective values ​​of the first and second capacitors to decrease the voltage; the impedance matching circuit includes first and second variable capacitors; the impedance matching circuit varies the values ​​of the first and second variable capacitors to match an impedance of a load of the plasma coil and an output impedance of the RF power supply; the impedance matching circuit includes an insulating air-core transformer having an input coil and an output coil; the first variable capacitor is connected in series with the input coil; The mass spectrometer according to claim 1, wherein the second variable capacitor is connected in parallel with the output coil.

2. 2. The mass spectrometer of claim 1, wherein when the first capacitor of the first and second capacitors is short-circuited, an output terminal of the impedance matching circuit connected to the first capacitor is grounded, and a sum of the voltages of the first and second capacitors before the first capacitor is short-circuited is applied to an output terminal of the impedance matching circuit connected to the second capacitor.

3. the RF power supply unit includes an inductively coupled coil inductively coupled to the plasma coil; 3. The mass spectrometer of claim 2, wherein the values ​​of the first and second capacitors are set to adjust the ratio of RF potentials across the inductively coupled coil.

4. 4. The mass spectrometer of claim 3, wherein the RF potential ratio is inversely proportional to the ratio of the respective values ​​of the first and second capacitors.

5. 2. The mass spectrometer of claim 1, wherein the value of the first variable capacitor is varied to adjust an imaginary part of the impedance of the load.

6. 2. The mass spectrometer of claim 1, wherein the value of the second variable capacitor is varied to adjust a real part of the impedance of the load.

7. 1. An electronic circuit for providing RF power to an inductively coupled plasma coil, comprising: An RF power source that outputs an RF signal; An impedance matching circuit configured to process and output the RF signal and control a voltage due to an inductance component of the plasma coil; an inductive coupling coil that utilizes the inductive coupling to supply the RF power based on the signal output from the impedance matching circuit to the plasma coil; the impedance matching circuit controls the voltage by setting values ​​of first and second capacitors; the impedance matching circuit includes first and second variable capacitors; the impedance matching circuit includes an insulating air-core transformer having an input coil and an output coil; the first variable capacitor is connected in series with the input coil; The second variable capacitor is connected in parallel with the output coil.

8. the first and second capacitors are connected in series via a node; 8. The electronic circuit of claim 7, wherein the node is grounded.

9. 9. The electronic circuit of claim 8, wherein when the first capacitor of the first and second capacitors is short-circuited, an output terminal of the impedance matching circuit connected to the first capacitor is grounded, and a sum of the voltages of the first and second capacitors before the first capacitor is short-circuited is applied to an output terminal of the impedance matching circuit connected to the second capacitor.

10. 10. The electronic circuit of claim 9, wherein the respective values ​​of the first and second capacitors are set to adjust a ratio of RF potentials across the inductively coupled coil.

11. 11. The electronic circuit of claim 10, wherein the RF potential ratio is inversely proportional to the ratio of the respective values ​​of the first and second capacitors.

12. the impedance matching circuit includes the first and second variable capacitors; 12. The electronic circuit according to claim 11, wherein the impedance matching circuit changes the values ​​of the first and second variable capacitors to match an impedance of the load of the plasma coil and an output impedance of the electronic circuit.

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