A mass spectrometer ion source filament control and detection circuit

Abstract

The invention discloses a mass spectrometer ion source filament control and detection circuit, comprising an MCU module and a filament switch control and over-temperature protection module, a filament consumption current detection module, a filament emission current detection module, an electron acceleration electric field control and detection module, and a filament drive control module connected to the MCU module; the MCU module monitors the filament consumption current, the filament emission current, the filament working state, the acceleration electric field voltage, etc. in real time, and provides a feedback loop for control, thereby effectively reducing the deviation of the ion source caused by the existence of an error voltage and ensuring the stability of the ion source emission current.

Description

Technical Field

[0001] The invention belongs to the technical field of ion sources for mass spectrometers, and in particular relates to a filament control and detection circuit for an ion source of a mass spectrometer. Background Art

[0002] The ion source of the mass spectrometer consists of a filament, an ionization chamber, and a magnet. In the ion source, the filament is heated to generate hot electrons, which are accelerated by the accelerating voltage and affected by the magnetic field of the magnet, and move in a spiral shape to the positive electrode. The sample is introduced in a direction perpendicular to the direction of the accelerated electrons, and the sample is ionized after the interaction with the electrons. The ionized molecules are pushed to the mass analyzer by the ion acceleration electrode.

[0003] The prior art provides a variety of ion sources to provide a stable output voltage to achieve the purpose of improving the detection quality of the mass spectrometer. For example, the Chinese invention patent with the publication number CN114203518A provides an electron bombardment ion source control circuit based on an isolation operational amplifier and a power amplifier triode, which belongs to the technical field of mass spectrometry ionization source. This circuit includes a main power input module, an EI filament voltage control module, an EI filament voltage detection module, an EI filament selection control module and an EI emission current detection module. The main power input module provides a driving voltage for the EI filament voltage control module, the EI filament voltage detection module, the EI filament selection control module and the EI emission current detection module. The EI filament voltage control module is used to control the voltage applied to both ends of the filament, the EI filament voltage detection module is used to detect the voltage at both ends of the filament, the EI filament selection control module is used to select the working state of the filament, and the EI emission current detection module is used to detect the situation of the filament emitting electrons. The output voltage of this circuit is stable, which can effectively improve the quality of mass spectrometry detection.

[0004] For example, Chinese invention patent CN103094033A discloses a method for adjusting the arc current balance of a dual-filament ion source, which includes: a filament power supply 1 (1), a filament power supply 2 (2), a bias power supply 1 (3), a bias power supply 2 (4), an arc voltage power supply (5), a comparator 1 (6), a comparator 2 (7), and two Hall sensors (8). The filament power supplies 1 (1) and 2 (2) are used to heat the filament of the ion source. When the heating temperature of the filament reaches a certain level, the filament will emit electrons. The bias power supplies 1 (3) and 2 (4) are added between the cathode and the filament, so that the electrons hit the cathode with a certain energy to form a bias current. Similarly, under continuous bombardment, the cathode surface emits electrons. The arc voltage power supply (5) is connected between the arc chamber and the cathode. Under the action of the arc voltage electric field, the electrons move toward the arc chamber and are finally adsorbed on the arc chamber to form an arc current. First, adjust the filament power supply 1 (1) until the bias current reaches the set value, and then adjust the bias power supply 1 (3). Under the action of the arc voltage electric field, the arc current value formed by the electrons is equal to the set value. Then, based on the filament power supply 1 (1) and the bias power supply 1 (3), adjust the filament power supply 2 (2) and the bias power supply 2 (4) respectively. Through the detected current feedback value, the input value of the power supply is continuously adjusted until the bias current and the arc current are equal to the set value. Such a double closed-loop control can achieve a method of balancing the arc current of a dual-filament ion source.

[0005] However, the prior art still has the following technical problems to be solved: the ion source filament has a life span and is complicated to replace; the number of electrons emitted by the filament needs to be stable, otherwise it will affect the sample ionization effect; when the filament is working, the MOS tube Q1 and the triode Q2 in the circuit generate severe heat, and the temperature needs to be monitored and protected; the MCU needs to monitor the filament current consumption, filament emission current, filament working status, accelerating electric field voltage, etc. in real time, etc. Summary of the invention

[0006] Aiming at the defects of the prior art, a mass spectrometer ion source filament control and detection circuit is proposed.

[0007] In order to solve the above technical problems, the present invention proposes a mass spectrometer ion source filament control and detection circuit, including an MCU module and a filament switch control and over-temperature protection module connected to the MCU module, a filament consumption current detection module, a filament emission current detection module, an electron acceleration electric field control and detection module, and a filament drive control module, wherein:

[0008] The filament switch control and over-temperature protection module is used to receive the filament switch signal of the MCU module. The filament switch control and over-temperature protection module is connected to the filament power supply and the filament drive control module at the same time, and is used to control whether the filament is working; the filament switch control and over-temperature protection module is also connected to the temperature switch. The temperature switch, MOS tube Q1, and transistor Q2 are installed on the same radiator. When the temperature of the radiator is too high and the temperature switch is triggered, a disconnection signal will be output at this time to turn off the filament power supply and the filament switch signal, which plays a protective role;

[0009] The filament current consumption detection module detects the current consumed by the filament through a differential operational amplifier. When the current consumption is too large, it outputs a shutdown signal to the filament drive control module for protection and sends it to the MCU module for display.

[0010] The filament emission current detection module detects the emission electron current through a differential operational amplifier, provides the current signal to the filament drive control module to control the filament, and sends it to the MCU module for display;

[0011] The electron acceleration electric field control and detection module generates an electric field to accelerate the electrons emitted by the filament. The electric field voltage can be set and detected.

[0012] The filament drive control module controls the filament operation by comparing the emission current setting value with the emission current collection value to ensure the stability of the filament emission current.

[0013] Furthermore, it also includes a filament switch detection module connected to the MCU module, the filament switch detection module detects the real-time working state of the filament through an optical coupler and sends it to the MCU module for status display;

[0014] Furthermore, it also includes a filament switching control module connected to the MCU module; the filament switching control module switches one of the two filaments to work through a relay controlled by the MCU module, and the circuit can work normally even if one filament is damaged, thereby reducing the number of maintenance times and extending the life of the instrument;

[0015] Furthermore, the filament switch signal of the MCU module and the output signal of the temperature switch are output to the filament power supply and filament drive control module after passing through the AND gate U5; the filament power supply and filament drive circuit will work normally only when the two signals are valid at the same time;

[0016] Further, the filament consumption current detection module includes a differential operational amplifier U2, which collects the voltage difference on the precision resistor R1 and converts it into a filament consumption current signal through the operational amplifier U1, which is provided to the MCU and the filament drive circuit for limiting the filament consumption current;

[0017] Furthermore, the filament switching control module includes an optocoupler U3, which is used to detect whether the filament is working and output a filament switch signal to the MCU module;

[0018] Further, the filament switching control module includes a relay connected to the MCU module, and the relay can be connected to the filament S1 and the filament S2 respectively according to the output filament switching control signal to select the required filament;

[0019] Furthermore, the electron accelerating electric field control and detection module includes an electron accelerating electric field power supply module, which can output the required voltage, and the MCU collects the output voltage;

[0020] Furthermore, the filament drive control module includes a differential operational amplifier U6, which collects the voltage difference on the precision resistor R5, converts it into a filament emission current through an operational amplifier U7, and outputs it to the filament drive control circuit as a filament emission current feedback loop; after conversion by an operational amplifier U8, it is sent to the MCU for filament emission current display;

[0021] Furthermore, the filament consumption current, the filament setting current, and the filament emission current act together on the operational amplifier U4, U4 outputs a control signal to the transistor Q2, Q2 outputs a control MOS tube Q1, and Q1 controls the on and off of the filament, so that the filament emission current is equal to the set current;

[0022] The beneficial effects of the present invention are as follows: the MCU module monitors the filament consumption current, filament emission current, filament working status, accelerating electric field voltage, etc. in real time, and provides a feedback loop for control, which effectively reduces the deviation of the ion source caused by the existence of the error voltage and ensures the stability of the ion source emission current. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Functional block diagram of the present invention

[0024] Figure 2 This is a structural diagram of the electronic circuit of the present invention; DETAILED DESCRIPTION

[0025] The present invention proposes a mass spectrometer ion source filament control and detection circuit. Figure 1-2 The specific embodiments of the present invention are further explained.

[0026] It should be noted that the embodiments described in the present invention are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of protection of the present invention.

[0027] The present invention relates to a mass spectrometer filament control detection circuit, see attached Figure 1 , including an MCU module and a filament switch control and over-temperature protection module, a filament consumption current detection module, a filament emission current detection module, an electron acceleration electric field control and detection module, and a filament drive control module connected to the MCU module, wherein:

[0028] The filament switch control and over-temperature protection module is used to receive the filament switch signal of the MCU module. The filament switch control and over-temperature protection module is connected to the filament power supply and the filament drive control module at the same time, and is used to control whether the filament is working; the filament switch control and over-temperature protection module is also connected to the temperature switch. The temperature switch, MOS tube Q1, and transistor Q2 are installed on the same radiator. When the temperature of the radiator is too high and the temperature switch is triggered, a disconnection signal will be output at this time to turn off the filament power supply and the filament switch signal, which plays a protective role;

[0029] The filament current consumption detection module detects the current consumed by the filament through a differential operational amplifier. When the current consumption is too large, it outputs a shutdown signal to the filament drive control module for protection and sends it to the MCU module for display.

[0030] The filament emission current detection module detects the emission electron current through a differential operational amplifier, provides the current signal to the filament drive control module to control the filament, and sends it to the MCU module for display;

[0031] The electron acceleration electric field control and detection module generates an electric field to accelerate the electrons emitted by the filament. The electric field voltage can be set and detected.

[0032] The filament drive control module controls the filament operation by comparing the emission current setting value with the emission current collection value to ensure the stability of the filament emission current.

[0033] As a further improvement of the technical solution of the present invention, it also includes a filament switch detection module connected to the MCU module, the filament switch detection module detects the real-time working state of the filament through an optical coupler and sends it to the MCU module for status display;

[0034] Furthermore, it also includes a filament switching control module connected to the MCU module; the filament switching control module switches one of the two filaments to work through a relay controlled by the MCU module, and the circuit can work normally even if one filament is damaged, thereby reducing the number of maintenance times and extending the life of the instrument;

[0035] Combine the following Figure 2 The various components of the circuit and their connection relationships are further introduced:

[0036] The filament switch signal of the MCU module and the output signal of the temperature switch are output to the filament power supply and filament drive control module after passing through the AND gate U5; the filament power supply and filament drive circuit will work normally only when the two signals are valid at the same time;

[0037] The filament consumption current detection module includes a differential operational amplifier U2, which collects the voltage difference on the precision resistor R1 and converts it into a filament consumption current signal through the operational amplifier U1. The signal is provided to the MCU and the filament drive circuit to limit the filament consumption current;

[0038] The filament switching control module includes an optocoupler U3, which is used to detect whether the filament is working and output the filament switch signal to the MCU module;

[0039] The filament switching control module includes a relay connected to the MCU module, and the relay can be connected to the filament S1 and the filament S2 respectively according to the output filament switching control signal to select the required filament;

[0040] The electron acceleration electric field control and detection module includes an electron acceleration electric field power supply module, which can output the required voltage, and the MCU collects the output voltage;

[0041] The filament drive control module includes a differential operational amplifier U6, which collects the voltage difference on the precision resistor R5, converts it into a filament emission current through an operational amplifier U7, and outputs it to the filament drive control circuit as a filament emission current feedback loop; after conversion by an operational amplifier U8, it is sent to the MCU for filament emission current display;

[0042] The filament consumption current, filament setting current and filament emission current act together on the operational amplifier U4. U4 outputs a control signal to the transistor Q2. The Q2 output controls the MOS tube Q1. Q1 controls the on and off of the filament, so that the filament emission current is equal to the set current.

[0043] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific 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 in the scope of protection of the present invention.

Claims

1. A mass spectrometer ion source filament control and detection circuit, characterized in that: It includes an MCU module and a filament switch control and over-temperature protection module, a filament consumption current detection module, a filament emission current detection module, an electron acceleration electric field control and detection module, and a filament drive control module connected to the MCU module, wherein: The filament switch control and over-temperature protection module is used to receive the filament switch signal of the MCU module. The filament switch control and over-temperature protection module is connected to the filament power supply and the filament drive control module at the same time, and is used to control whether the filament is working; the filament switch control and over-temperature protection module is also connected to the temperature switch. The temperature switch, MOS tube Q1, and transistor Q2 are installed on the same radiator. When the temperature of the radiator is too high and the temperature switch is triggered, a disconnection signal will be output at this time to turn off the filament power supply and the filament switch signal, which plays a protective role; The filament current consumption detection module detects the current consumed by the filament through a differential operational amplifier. When the current consumption is too large, it outputs a shutdown signal to the filament drive control module for protection and sends it to the MCU module for display. The filament emission current detection module detects the emission electron current through a differential operational amplifier, provides the current signal to the filament drive control module to control the filament, and sends it to the MCU module for display; The electron acceleration electric field control and detection module generates an electric field to accelerate the electrons emitted by the filament. The electric field voltage can be set and detected. The filament drive control module controls the filament operation by comparing the emission current setting value with the emission current collection value to ensure the stability of the filament emission current.

2. The mass spectrometer ion source filament control and detection circuit according to claim 1, characterized in that: It also includes a filament switch detection module connected to the MCU module. The filament switch detection module detects the real-time working status of the filament through an optical coupler and sends it to the MCU module for status display.

3. A mass spectrometer ion source filament control and detection circuit according to claim 2, characterized in that: It also includes a filament switching control module connected to the MCU module; the filament switching control module switches one of the two filaments through a relay controlled by the MCU module to work.

4. A mass spectrometer ion source filament control and detection circuit according to claim 3, characterized in that: The filament switch signal of the MCU module and the output signal of the temperature switch are output to the filament power supply and filament drive control module after passing through the AND gate U5; the filament power supply and filament drive circuit will work normally only when the two signals are valid at the same time.

5. A mass spectrometer ion source filament control and detection circuit according to claim 4, characterized in that: The filament consumption current detection module includes a differential operational amplifier U2, which collects the voltage difference on the precision resistor R1 and converts it into a filament consumption current signal through the operational amplifier U1. The signal is provided to the MCU and the filament drive circuit for limiting the filament consumption current.

6. A mass spectrometer ion source filament control and detection circuit according to claim 5, characterized in that: The filament switching control module includes an optocoupler U3, which is used to detect whether the filament is working and output a filament switch signal to the MCU module.

7. A mass spectrometer ion source filament control and detection circuit according to claim 6, characterized in that: The filament switching control module includes a relay connected to the MCU module, and the relay can be respectively connected to the filament S1 and the filament S2 according to the output filament switching control signal to select the required filament.

8. A mass spectrometer ion source filament control and detection circuit according to claim 7, characterized in that: The electron accelerating electric field control and detection module includes an electron accelerating electric field power supply module, which can output the required voltage, and the MCU collects the output voltage at the same time.

9. A mass spectrometer ion source filament control and detection circuit according to claim 8, characterized in that: The filament drive control module includes a differential operational amplifier U6, which collects the voltage difference on the precision resistor R5, converts it into a filament emission current through an operational amplifier U7, and outputs it to the filament drive control circuit as a filament emission current feedback loop; after conversion by an operational amplifier U8, it is sent to the MCU for filament emission current display.

10. A mass spectrometer ion source filament control and detection circuit according to claim 9, characterized in that: The filament consumption current, filament setting current and filament emission current act together on the operational amplifier U4. U4 outputs a control signal to the transistor Q2. The Q2 output controls the MOS tube Q1. Q1 controls the on and off of the filament so that the current emitted by the filament is equal to the set current.

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