X-ray fluorescence analyzer and power supply device

Abstract

The invention provides a fluorescent X-ray analyzer and a power supply device. The X-ray fluorescence analyzer is provided with: an X-ray bulb that irradiates primary X-rays; a first power supply for supplying a filament current; a second power supply that applies a tube voltage; a first diode connected to the power line; a Zener diode connected to the ground terminal; and an operational amplifier having an output terminal, an inverting input terminal, and a non-inverting input terminal. The non-inverting input terminal is connected to the power line, and the output terminal is connected to the second terminal and the inverting input terminal.

Description

Technical Field

[0001] The present disclosure relates to a fluorescent X-ray analysis device and a power supply device. Background Art

[0002] Conventionally, a fluorescent X-ray analysis device for analyzing a sample by irradiating X-rays is known. International Publication No. 2018 / 002977 describes an X-ray tube in which a filament and a target are arranged at intervals from each other. The analysis device of International Publication No. 2018 / 002977 generates a tube current by applying a tube voltage between the filament and the target, and generates X-rays by the collision of thermal electrons with the target.

[0003] X-rays generated by the collision of thermal electrons with a target are called "primary X-rays". Primary X-rays are irradiated onto a solid, powdery, or liquid sample, and fluorescent X-rays are emitted from the sample by the irradiation of the primary X-rays. In an analysis device using fluorescent X-rays, the emitted fluorescent X-rays are detected by a spectrometer to perform qualitative or quantitative analysis of the elements contained in the sample.

[0004] The analysis device of International Publication No. 2018 / 002977 has a tube voltage control circuit for applying a high voltage to a target and a filament current control circuit for supplying a constant current to a filament. The tube voltage control circuit performs feedback control so that the potential of the target does not deviate from the target tube voltage value. Summary of the invention

[0005] In such an analysis device, a Zener diode can be provided as a protection circuit to prevent accidental discharge due to application of a high voltage. When discharge exceeding the Zener voltage occurs, the Zener diode allows the discharge current to flow to the ground terminal to protect the circuit in the analysis device.

[0006] However, in the Zener diode, due to its characteristics, when a reverse voltage smaller than the Zener voltage is applied, a leakage current called "reverse current" is generated. Therefore, during the period when a tube voltage is applied to generate primary X-rays and a tube current flows due to the application of the tube voltage, a leakage current is generated in the Zener diode. The tube current control circuit performs feedback control using the current value affected by the leakage current as input, so there is a case where the X-ray analysis device has a deviation between the tube current value as an input value for feedback control and the tube current value of the tube current actually flowing in the tube bulb.

[0007] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to suppress the leakage of tube current in a Zener diode for discharge protection in a fluorescent X-ray analysis device that generates X-rays by applying a tube voltage to a filament and a target.

[0008] A fluorescent X-ray analysis device according to an aspect of the present disclosure includes: an X-ray tube including a filament and a target for irradiating a sample with primary X-rays; a detector for detecting secondary X-rays generated from the sample; a first power supply for supplying a filament current to the filament via a power line; a second power supply for applying a tube voltage to the target; a first diode having a first terminal and a second terminal, wherein the first terminal is connected to the power line; a Zener diode having a third terminal and a fourth terminal, wherein the third terminal is connected to the second terminal, and the fourth terminal is connected to a ground terminal; and an operational amplifier having an output terminal, an inverting input terminal, and a non-inverting input terminal. The non-inverting input terminal is connected to the power line, and the output terminal is connected to the second terminal and the inverting input terminal.

[0009] A power supply device according to another aspect of the present disclosure is a power supply device that supplies current to an X-ray tube including a filament and a target. The power supply device includes: a first power supply that supplies filament current to the filament via a power line; a second power supply that applies a tube voltage to the target; a first diode having a first terminal and a second terminal, and the first terminal is connected to the power line; a Zener diode having a third terminal and a fourth terminal, and the third terminal is connected to the second terminal, and the fourth terminal is connected to the ground terminal; and an operational amplifier having an output terminal, an inverting input terminal, and a non-inverting input terminal. The non-inverting input terminal is connected to the power line, and the output terminal is connected to the second terminal and the inverting input terminal.

[0010] The above-mentioned objects, features, aspects and advantages and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram schematically showing a power supply device and an X-ray tube of a fluorescent X-ray analyzer.

[0012] Figure 2 It is the equivalent circuit diagram of the protection circuit.

[0013] Figure 3 This is a circuit diagram for explaining the power supply of an operational amplifier.

[0014] Figure 4 1 is a circuit diagram between the terminal T1 and the terminal T2 in the power supply device of the comparative example. DETAILED DESCRIPTION

[0015] [Implementation Method]

[0016] The present embodiment will be described in detail with reference to the accompanying drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated in principle.

[0017] <Structure of power supply unit and X-ray tube>

[0018] Figure 1 1 is a diagram schematically showing a power supply device 100 and an X-ray tube 200 of a fluorescence X-ray analysis device 1000. The fluorescence X-ray analysis device 1000 is, for example, an energy dispersive X-ray fluorescence analysis device (EDX: Energy Dispersive X-ray Fluorescence Spectrometer). In this embodiment, an example of applying the power supply device 100 that generates primary X-rays to the fluorescence X-ray analysis device 1000 is described.

[0019] like Figure 1 As shown, the fluorescent X-ray analysis device 1000 includes a power supply device 100, an X-ray tube 200, and a detector 300. The power supply device 100 applies a voltage to the X-ray tube 200 to excite the primary X-ray 10. The primary X-ray 10 is irradiated to the sample S. The sample S irradiated with the primary X-ray 10 emits fluorescent X-rays 20. The fluorescent X-rays 20 emitted from the sample S are called "secondary X-rays" relative to the primary X-rays. The detector 300 detects the fluorescent X-rays 20. Thus, the fluorescent X-ray analysis device 1000 can perform quantitative analysis or qualitative analysis of the sample S.

[0020] The X-ray tube 200 includes a target Tg1 and a filament F1. The target Tg1 is an anode, and the filament F1 is a cathode. The target Tg1 and the filament F1 are arranged at a distance from each other in the X-ray tube 200. The power supply device 100 includes a filament power supply unit 110, a high voltage power supply unit 120, and a tube current control unit 130.

[0021] The filament power supply unit 110 applies a voltage to both ends of the filament F1 to heat the filament F1. Hereinafter, the current supplied by the voltage applied by the filament power supply unit 110 is referred to as "filament current". The high voltage power supply unit 120 applies a high voltage to the target Tg1 and the filament F1. Hereinafter, the high voltage applied by the high voltage power supply unit 120 is referred to as "tube voltage". The tube current control unit 130 performs feedback control for adjusting the output of the filament power supply unit 110 based on the current value of the current flowing in the power line L4.

[0022] In the X-ray tube 200, the filament F1 is heated by the filament power supply 110 to generate thermal electrons. The high voltage power supply 120 applies a tube voltage between the filament F1 and the target Tg1, and the thermal electrons collide with the target Tg1, thereby generating the primary X-rays 10.

[0023] like Figure 1As shown, the filament power supply unit 110 is connected to the filament F1 via the power line L1 and the power line L1A. The power line L1 is connected to one end of the filament F1, and the power line L1A is connected to the other end of the filament F1. The terminals T1 and T1A of the filament power supply unit 110 are connected to the power lines L1 and L1A, respectively. The terminals T2 and T2A of the power supply device 100 are connected to the filament F1. The connection point Cp1 is the connection point between the connection point between the terminal T1 and the terminal T2 and the connection point between the terminal T1A and the terminal T2A. A resistor R322 is connected between the connection point between the terminal T1 and the terminal T2 and the connection point Cp1. A resistor R316 is connected between the connection point between the terminal T1A and the terminal T2A and the connection point Cp1. In one example, the resistance value of the resistors R316 and R322 is 100Ω, and the rated power is 0.5W. One end of the power line L4 is connected to the connection point Cp1, and the other end of the power line L4 is connected to the ground terminal GND via a resistor. In addition, one end of the power line L4 may be connected to either the connection point between the terminal T1 and the terminal T2 or the connection point between the terminal T1A and the terminal T2A instead of the connection point Cp1.

[0024] On power line L1, protection circuit P1 is connected between terminal T1 and terminal T2. Similarly, on power line L1A, protection circuit P1A is connected between terminal T1A and terminal T2A. Protection circuits P1 and P1A include Zener diodes described below.

[0025] Thus, even when an unexpected discharge occurs in the X-ray tube 200, the protection circuits P1 and P1A can protect the filament power supply unit 110 and the tube current control unit 130 from the overvoltage caused by the discharge. In addition, when the control unit of the high-voltage power supply unit 120 and the tube current control unit 130 are mounted on the same substrate, the protection circuits P1 and P1A can also protect the high-voltage power supply unit 120 from the overvoltage caused by the discharge.

[0026] The high voltage power supply unit 120 has a transformer, a rectifier and other circuits for generating a high voltage to be applied to the X-ray tube 200. Figure 1 As shown, the high-voltage power supply unit 120 is connected to the target Tg1 via the power line L3. In addition, the high-voltage power supply unit 120 is connected to the ground terminal GND via the power line L5.

[0027] The filament power supply unit 110 supplies a filament current to the filament F1 of the X-ray tube 200 to adjust the tube current. The tube current control unit 130 detects the tube current flowing through the power line L4 by using a resistor and converts the tube current into a voltage, amplifies it through the amplifier Am1, and thus detects the tube current value of the tube current flowing in the power line L4. The tube current control unit 130 sends the detected tube current value to the filament current control unit 111. The tube current flowing in the power line L4 returns from the power line L5 to the high-voltage power supply unit 120 via the resistor and the ground terminal GND. In addition, it is also possible to determine whether the tube current value sent by the tube current control unit 130 to the filament current control unit 111 is valid based on the upper limit value and the lower limit value of the filament current that are predetermined. In addition, in the tube current control unit 130, an error amplifier can be configured on the output side of the amplifier Am1.

[0028] The filament current control unit 111 controls the output of the filament current according to the tube current value detected by the tube current control unit 130. In this way, in the fluorescence X-ray analysis device 1000 of this embodiment, feedback control of the filament current is performed based on the tube current value flowing through the power line L4. In addition, the filament power supply unit 110 can correspond to the "first power supply unit" in the present disclosure. The high voltage power supply unit 120 can correspond to the "second power supply unit" in the present disclosure.

[0029] <Circuit Structure>

[0030] Figure 2 This is the equivalent circuit diagram of the protection circuit P1. Figure 2 The power supply device 100 includes capacitors C32 to C39, Schottky diodes D31, D32, D33, and D35, a Zener diode D34, an operational amplifier M7, and resistors R31 to R33 between the terminal T1 and the terminal T2 as a protection circuit P1. The protection circuit P1A has Figure 2 Therefore, the description of the protection circuit P1A will not be repeated below.

[0031] like Figure 2 As shown, the power line L1 connects the terminal T1 and the terminal T2. One end of each of the capacitors C32 to C37 is connected to the power line L1. In addition, the other end of each of the capacitors C32 to C37 is connected to the ground terminal GND. Thus, in the power supply device 100, when a discharge current flows in the power line L1 due to an unexpected high voltage discharge, the capacitors C32 to C37 can suppress the voltage rise. Figure 2 In the example, the number of capacitors C32 to C37 is 6. In addition, the total capacitance value of the capacitors C32 to C37 provided to suppress the voltage increase is preferably equal to or less than the capacitance that does not affect the control of the tube current control unit 130 .

[0032] In one example, the electrostatic capacitance of capacitors C32 and C33 is 100 pF, and the rated voltage is 100 V. The electrostatic capacitance of capacitors C34 and C35 is 2200 pF, and the rated voltage is 100 V. The electrostatic capacitance of capacitors C36 and C37 is 0.01 μF, and the rated voltage is 250 V. Thus, in this embodiment, six capacitors C32 to C37 are provided for the purpose of suppressing the voltage rise caused by the discharge of the high voltage. In addition, each of the capacitors C32 to C37 can correspond to the "first capacitor" in the present disclosure.

[0033] The power supply device 100 includes a Schottky diode D33. The Schottky diode D33 includes a terminal E1 and a terminal E2. Figure 2 In the example of , terminal E1 is an anode and terminal E2 is a cathode. Terminal E1 is connected to power line L1. Terminal E2 is connected to Zener diode D34.

[0034] In addition, the Schottky diode D33 can correspond to the “first diode” in the present disclosure. The terminal E1 of the Schottky diode D33 can correspond to the “first terminal” in the present disclosure. The terminal E2 of the Schottky diode D33 can correspond to the “second terminal” in the present disclosure.

[0035] In the present embodiment, the Zener diode D34 is a bidirectional Zener diode. That is, the Zener diode D34 has two Zener diodes arranged opposite to each other. The Zener diode D34 has a terminal E3 and a terminal E4. The terminal E3 of the Zener diode D34 is connected to the terminal E2 of the Schottky diode D33. The terminal E4 is connected to the ground terminal GND. The terminal E3 of the Zener diode D34 can correspond to the "third terminal" in the present disclosure. The terminal E4 of the Zener diode D34 can correspond to the "fourth terminal" in the present disclosure. In the present embodiment, the Zener diode D34 is more specifically a transient voltage suppression (Transient-VoltageSuppression: TVS) diode.

[0036] The power supply device 100 includes a Schottky diode D31 in addition to the Schottky diode D33. The Schottky diode D31 includes a terminal E5 and a terminal E6. Figure 2 In the example, terminal E5 is the cathode and terminal E6 is the anode. In addition, the Schottky diode D31 can correspond to the "second diode" in the present disclosure. The terminal E5 of the Schottky diode D31 can correspond to the "fifth terminal" in the present disclosure. The terminal E6 of the Schottky diode D31 can correspond to the "sixth terminal" in the present disclosure. In addition, the Schottky diodes D31 and D33 can also be other types of diodes such as fast recovery diodes (FRD: Fast Recovery Diode).

[0037] like Figure 2 As shown, in the power supply device 100 of this embodiment, Schottky diodes D31 and D33 are connected in parallel so that the directions of the anode and cathode are opposite to each other. When an unexpected discharge occurs in the X-ray tube 200, it is impossible to determine which polarity of the discharge current flows in the power line L1. Therefore, by Figure 2 As shown, Schottky diodes D31 and D33 with anodes and cathodes in opposite directions are connected in parallel to power line L1. This allows the discharge current to flow from power line L1 to Zener diode D34 via one of Schottky diodes D31 and D33 regardless of the polarity of the discharge current.

[0038] In the present embodiment, the power supply device 100 has an operational amplifier M7 for forming a voltage follower circuit. The operational amplifier M7 has an inverting input terminal, a non-inverting input terminal, and an output terminal, and is connected between the power line L1 and the connection node N10. The connection node N10 is a connection node between the Schottky diode D33 and the Zener diode D34.

[0039] The output terminal of the operational amplifier M7 is connected to the connection node N10 via the resistors R31 and R32 connected in series. The non-inverting input terminal of the operational amplifier M7 is connected to the power line L1 via the resistor R33. In addition, the output terminal of the operational amplifier M7 is also connected to the inverting input terminal of the operational amplifier M7. The resistors R31 and R32 are provided to protect the operational amplifier M7. In one example, the resistance value of the resistors R31 and R32 is 100Ω, and the rated power is 0.5W.

[0040] A clamp circuit is formed between the resistor R32 and the output terminal of the operational amplifier M7 by Schottky diodes D32 and D35 . Figure 3 1 is a circuit diagram for explaining the power supply of the operational amplifier M7. A +15V DC power supply is connected to the positive power supply terminal of the operational amplifier M7. A -5V DC power supply is connected to the negative power supply terminal of the operational amplifier M7. In addition, the voltage values ​​of the positive power supply terminal and the negative power supply terminal of the operational amplifier M7 are examples, and other voltage values ​​may also be used.

[0041] Capacitors C48, C49, C50, C51 and resistors R37, R38 are connected to the power line of the operational amplifier M7. Capacitors C48, C49, C50, C51 are so-called bypass capacitors. In one example, the electrostatic capacitance of capacitors C49 and C50 is 0.1μF and the rated voltage is 100V. The electrostatic capacitance of capacitors C48 and C51 is 4.7μF and the rated voltage is 50V. By providing capacitors C48 to C51 and resistors R37 and R38, the noise generated in the power line of the operational amplifier M7 can be reduced. In addition, capacitors C48 to C51 and Schottky diodes D32 and D35 suppress the voltage rise of the output terminal of the operational amplifier M7 to protect the operational amplifier M7.

[0042] Return to Figure 2 As described above, the output terminal of the operational amplifier M7 is connected to the inverting input terminal of the operational amplifier M7. Since the operational amplifier M7 functions as a voltage follower circuit, the output voltage of the operational amplifier M7 and the input voltage from the non-inverting input terminal have the same potential.

[0043] As a result, the difference between the potential at the terminal E2 of the Schottky diode D33 connected to the output terminal of the operational amplifier M7 and the potential of the power line L1 connected to the input terminal of the operational amplifier M7 is close to zero. Similarly, the difference between the potential at the terminal E6 of the Schottky diode D31 connected to the output terminal of the operational amplifier M7 and the potential of the power line L1 connected to the input terminal of the operational amplifier M7 is close to zero. When a difference occurs between the anode voltage and the cathode voltage in the Schottky diodes D31 and D33, current flows. In the present embodiment, the difference between the anode voltage and the cathode voltage of the Schottky diodes D31 and D33 is close to zero by the operational amplifier M7.

[0044] Thus, discharge does not occur, and during the period when the tube current flows due to application of the tube voltage for generating the primary X-rays, the current value of the current flowing through the Schottky diodes D31 and D33 becomes a value close to zero. Figure 4 1 is a circuit diagram between the terminal T1 and the terminal T2 in the power supply device 100Z of the comparative example. In the power supply device 100Z of the comparative example, the voltage follower circuit formed by the operational amplifier M7 is not provided, and the Zener diode D34 is directly connected to the power line L1.

[0045] In the comparative example, while the tube voltage is applied to generate the primary X-ray 10 and the tube current flows, a voltage lower than the operating voltage of the Zener diode D34 is continuously applied to the Zener diode D34, and a part of the tube current flowing in the power line L1 flows into the ground terminal GND as a leakage current. As a result, in the comparative example, due to the leakage current, a difference is generated between the tube current value of the tube current actually flowing in the tube bulb and the current value (the current value of the current flowing in the power line L4) used as an input for feedback control.

[0046] On the other hand, Figure 2 In the power supply device 100 of the present embodiment, during the period when the tube voltage is applied to generate the primary X-ray 10 and the tube current flows, the potential difference between the two terminals of the Schottky diodes D31 and D33 is close to zero through the voltage follower circuit formed by the operational amplifier M7. That is, the current value flowing from the power line L1 through the Schottky diodes D31 and D33 to the Zener diode D34 is close to zero. Therefore, in the present embodiment, it is possible to suppress the tube current from leaking in the Zener diode D34.

[0047] Capacitor C38 is connected in parallel with Schottky diode D33 between power line L1 and Zener diode D34. More specifically, one end of capacitor C38 is connected to power line L1, and the other end of capacitor C38 is connected to terminal E3 of Zener diode D34 via connection node N10.

[0048] Thus, in the power supply device 100, when the discharge current flows into the Schottky diodes D31 and D33 due to discharge, a temporary path is formed by the capacitor C38 as a path for the discharge current to flow from the power line L1 to the Zener diode D34. The discharge current basically flows through the Schottky diode D31 or the Schottky diode D33. The capacitor C38 is set as a path for the discharge current to flow from the power line L1 to the Zener diode D34 until the Schottky diode D31 or the Schottky diode D33 is turned on. In addition, the capacitor C38 can correspond to the "second capacitor" in the present disclosure.

[0049] <About Response Speed>

[0050] In this embodiment, the response speed of the voltage follower circuit formed by the operational amplifier M7 is adjusted to be within a specified range. If the response speed of the voltage follower circuit is too fast, even if discharge occurs, the potential difference between the two terminals of the Schottky diodes D31 and 33 is close to zero due to the voltage follower circuit, and the discharge current cannot flow to the Zener diode D34.

[0051] On the other hand, if the response speed of the voltage follower circuit is too slow, a potential difference may be generated at both terminals of the Schottky diodes D31 and 33 during the period when the tube voltage is applied to generate the primary X-rays and the tube current flows in a state where no discharge occurs. Specifically, when the voltage value of the power line L1 changes due to the change in the current value of the current flowing in the power line L1, if the response speed of the voltage follower circuit is too slow, a potential difference corresponding to the amount of the change is generated at both terminals of the Schottky diodes D31 and 33. As a result, the tube current flows from the Schottky diode D31 to the Zener diode D34, and the tube current leaks. At this time, if the response speed of the voltage follower circuit is slower than the response speed of the feedback control of the tube current control, a deviation occurs between the tube current value as the input value of the feedback control and the tube current value of the tube current actually flowing in the tube bulb.

[0052] The response speed of the voltage follower circuit is expected to be within a specified range. In this embodiment, the response speed of the voltage follower circuit is adjusted using resistor R33 and capacitor C39. In one example, the resistance value of resistor R33 is 10kΩ and the rated power is 0.25W. The electrostatic capacitance of capacitor C39 is 2200pF and the rated voltage is 100V.

[0053] One end of the resistor R33 is connected to the power line L1. The other end of the resistor R33 is connected to the non-inverting input terminal of the operational amplifier M7 and one end of the capacitor C39. The other end of the capacitor C39 is connected to the ground terminal. The capacitor C39 and the resistor R33 function as a delay circuit.

[0054] Thus, the response speed of the voltage follower circuit can be delayed when the voltage value of the power line L1 changes due to the change in the current value of the current flowing in the power line L1. That is, in this embodiment, by providing the resistor R33 and the capacitor C39, the response speed of the voltage follower circuit composed of the operational amplifier M7 can be adjusted. In addition, the capacitor C39 and the resistor R33 also have the function of protecting the operational amplifier M7. In this way, in this embodiment, a filter circuit that functions as a delay circuit is formed on the input side of the operational amplifier M7.

[0055] In addition, in this embodiment, a filter circuit is also formed by the parasitic capacitance of the Zener diode D34 and the resistors R31 and R32. In this embodiment, the operational amplifier M7 can be protected by providing the Zener diode D34 and the resistors R31 and R32. In this way, in this embodiment, a filter circuit is formed not only on the input side of the operational amplifier M7, but also on the output side.

[0056] As described above, in this embodiment, by suppressing the leakage of the tube current in the Zener diode D34, it is possible to suppress the deviation between the tube current value as the input value of the feedback control and the tube current value of the tube current actually flowing in the tube bulb. If the tube current value of the tube current flowing in the power line L4 is small, the influence of the leakage current on the deviation between the tube current value as the input value of the feedback control and the tube current value of the tube current actually flowing in the tube bulb becomes large. In this embodiment, even if the influence of the leakage current becomes large due to the small tube current value, it is possible to suppress the deviation between the tube current value as the input value of the feedback control and the tube current value of the tube current actually flowing in the tube bulb by suppressing the occurrence of the leakage of the tube current in the Zener diode D34.

[0057] Furthermore, in the present embodiment, the current value flowing into the Zener diode D34 via the Schottky diodes D31 and D33 can be made close to zero. Therefore, in the present embodiment, the tube current leakage can be suppressed regardless of the characteristics of the Zener diode D34.

[0058] In addition, in this embodiment, since the circuit is composed of common electronic components such as a Zener diode, a Schottky diode, a capacitor, and an operational amplifier, it is possible to suppress an increase in cost. In addition, for the error caused by the leakage of the tube current in the Zener diode, it is also considered to correct the set value of the tube current using a correction coefficient, but in this case, the development cost of software for calculating the correction coefficient is incurred. In this embodiment, it is possible to suppress the deviation between the tube current value as the input value of the feedback control and the tube current value of the tube current actually flowing in the tube bulb without incurring the development cost of software for correcting the feedback control.

[0059] Furthermore, in the power supply device 100 of the present embodiment, it is possible to suppress the tube current leakage regardless of the temperature variation and discharge protection performance of the Zener diode D34.

[0060] In the present embodiment, an example in which the power supply device 100 for generating X-rays is applied to the fluorescent X-ray analysis device 1000 is described. However, the power supply device 100 for generating X-rays can be applied not to the fluorescent X-ray analysis device but to, for example, an X-ray device, a CT device, a radiographic device, etc. That is, the power supply device 100 can be applied to various devices that generate X-rays by applying a tube voltage to the filament F1 and the target Tg1.

[0061] [Way]

[0062] It will be understood by those skilled in the art that the above-mentioned multiple exemplary embodiments are specific examples of the following aspects.

[0063] (Item 1) A fluorescent X-ray analysis device according to one embodiment includes: an X-ray tube including a filament and a target for irradiating a sample with primary X-rays; a detector for detecting secondary X-rays generated from the sample; a first power supply for supplying a filament current to the filament via a power line; a second power supply for applying a tube voltage to the target; a first diode having a first terminal and a second terminal, wherein the first terminal is connected to the power line; a Zener diode having a third terminal and a fourth terminal, wherein the third terminal is connected to the second terminal and the fourth terminal is connected to a ground terminal; and an operational amplifier having an output terminal, an inverting input terminal, and a non-inverting input terminal. The non-inverting input terminal is connected to the power line, and the output terminal is connected to the second terminal and the inverting input terminal.

[0064] According to the first aspect, in the fluorescent X-ray analysis apparatus that generates X-rays by applying a tube voltage to a filament and a target, it is possible to suppress leakage of tube current in the Zener diode for discharge protection.

[0065] (Item 2) In the fluorescent X-ray analysis device described in Item 1, there is also a second diode, the second diode has a fifth terminal and a sixth terminal, the fifth terminal is connected to the power line, the sixth terminal is connected to the third terminal and the output terminal, the first terminal is an anode, the second terminal is a cathode, the fifth terminal is a cathode, the sixth terminal is an anode, and the Zener diode is a bidirectional Zener diode.

[0066] According to the X-ray fluorescence analysis apparatus 1000 described in the second aspect, regardless of the direction of the polarity of the discharge current, the discharge current can flow from the power line to the Zener diode via any of the Schottky diodes.

[0067] (Item 3) The X-ray fluorescence analysis device according to Item 1 or Item 2 further includes a first capacitor, one end of the first capacitor being connected to the power line and the other end of the first capacitor being connected to a ground terminal.

[0068] According to the X-ray fluorescence analysis device described in the third aspect, when a discharge current flows in the power line due to an unexpected high voltage discharge, the first capacitor can suppress a voltage increase.

[0069] (Item 4) The X-ray fluorescence analysis device according to any one of Items 1 to 3 further includes a second capacitor connected in parallel with the first diode.

[0070] According to the fluorescent X-ray analysis device described in the fourth aspect, when discharge occurs and a discharge current flows into the Schottky diode, a temporary path is formed by the capacitor as a path for the discharge current to flow from the power line to the Zener diode.

[0071] (Item 5) In the fluorescent X-ray analysis device described in any one of Items 1 to 4, a filter circuit is further provided, and the filter circuit is provided in at least one of the non-inverting input terminal and the output terminal.

[0072] According to the fluorescent X-ray analysis device described in item 5, the response speed of the voltage follower circuit composed of the operational amplifier can be adjusted by providing at least one of a resistor and a capacitor, and a Zener diode and a resistor. Thus, the voltage follower circuit is configured not to follow the voltage fluctuation in the power line.

[0073] (Item 6) The X-ray fluorescence analysis device according to any one of Items 1 to 5 further includes a clamp circuit connected to the output terminal.

[0074] According to the fluorescent X-ray analysis device described in the sixth item, the operational amplifier can be protected.

[0075] (Item 7) A power supply device according to one embodiment is a power supply device that supplies current to an X-ray tube including a filament and a target. The power supply device includes: a first power supply that supplies filament current to the filament via a power line; a second power supply that applies a tube voltage to the target; a first diode having a first terminal and a second terminal, wherein the first terminal is connected to the power line; a Zener diode having a third terminal and a fourth terminal, wherein the third terminal is connected to the second terminal, and the fourth terminal is connected to the ground terminal; and an operational amplifier having an output terminal, an inverting input terminal, and a non-inverting input terminal. The non-inverting input terminal is connected to the power line, and the output terminal is connected to the second terminal and the inverting input terminal.

[0076] According to the power supply device 100 described in the seventh aspect, in the X-ray fluorescence analyzer that generates X-rays by applying a tube voltage to a filament and a target, it is possible to suppress the leakage of the tube current in the Zener diode for discharge protection.

[0077] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered in all respects as illustrative rather than restrictive. The scope of the present invention is indicated by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

Claims

1. A fluorescent X-ray analysis device, comprising: An X-ray tube ball, which includes a filament and a target, and is used to irradiate primary X-rays to the sample; a detector that detects secondary X-rays generated from the sample; a first power source for supplying a filament current to the filament via a power line; a second power supply that applies a tube voltage to the target; a first diode having a first terminal and a second terminal, wherein the first terminal is connected to the power line; a Zener diode having a third terminal and a fourth terminal, wherein the third terminal is connected to the second terminal, and the fourth terminal is connected to a ground terminal; as well as an operational amplifier having an output terminal, an inverting input terminal and a non-inverting input terminal, wherein the non-inverting input terminal is connected to the power line, The output terminal is connected to the second terminal and the inverting input terminal.

2. The fluorescent X-ray analysis device according to claim 1, wherein: A second diode is further provided, the second diode having a fifth terminal and a sixth terminal, wherein the fifth terminal is connected to the power line, The sixth terminal is connected to the third terminal and the output terminal. The first terminal is an anode, The second terminal is a cathode, The fifth terminal is a cathode, The sixth terminal is an anode, The Zener diode is a bidirectional Zener diode.

3. The fluorescent X-ray analysis device according to claim 1, wherein: A first capacitor is further provided, one end of the first capacitor being connected to the power line and the other end of the first capacitor being connected to a ground terminal.

4. The fluorescent X-ray analysis device according to claim 1, wherein: A second capacitor is further provided, and the second capacitor is connected in parallel with the first diode.

5. The fluorescent X-ray analysis device according to claim 1, wherein: A filter circuit is further provided, and the filter circuit is provided at at least one of the non-inverting input terminal and the output terminal.

6. The fluorescent X-ray analysis device according to claim 1, wherein: A clamp circuit is further provided, and the clamp circuit is connected to the output terminal.

7. A power supply device for supplying current to an X-ray tube including a filament and a target, the power supply device comprising: a first power source for supplying a filament current to the filament via a power line; a second power supply that applies a tube voltage to the target; a first diode having a first terminal and a second terminal, wherein the first terminal is connected to the power line; a Zener diode having a third terminal and a fourth terminal, wherein the third terminal is connected to the second terminal, and the fourth terminal is connected to a ground terminal; as well as an operational amplifier having an output terminal, an inverting input terminal and a non-inverting input terminal, wherein the non-inverting input terminal is connected to the power line, The output terminal is connected to the second terminal and the inverting input terminal.

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