Vacuum density meter and method for vacuum degree detection based on vacuum density meter

Abstract

The present disclosure relates to the field of vacuum measurement technology, and discloses a vacuum density meter and a method for vacuum degree detection based on the vacuum density meter. The vacuum density meter includes a shielding chamber and a discharge chamber. The shielding chamber includes a shielding cover; the discharge chamber is located in the shielding cover, including a magnetic circuit and an anode. The magnetic circuit includes a magnetic bottom plate, a discharge chamber shell, a magnetic pole and a magnetic core. The magnetic bottom plate and the discharge chamber shell form a discharge area with a discharge outlet. The magnetic pole, the magnetic core and at least part of the anode are located in the discharge area and are arranged opposite to the discharge outlet. The magnetic field generated by the magnetic pole passes through the magnetic bottom plate, the discharge chamber shell and the magnetic core in sequence and then returns to the magnetic pole. The anode is used to connect the positive pole of the first power supply, and the shielding cover and the discharge chamber shell are used to connect the negative pole of the second power supply. The detection accuracy can be improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of vacuum measurement, and in particular to a vacuum density meter and a method for detecting vacuum degree based on the vacuum density meter. Background Art

[0002] As a measuring instrument, vacuum densitometer is mainly used to detect the gas density, i.e. vacuum degree, in artificial or natural vacuum environment. The current vacuum densitometer can achieve high accuracy when detecting low vacuum environment above 1 Pa, but there are still many problems when detecting high vacuum environment below 1 Pa, and the detection accuracy needs to be improved. Summary of the invention

[0003] In view of this, an embodiment of the present disclosure provides a vacuum density meter and a method for vacuum degree detection based on the vacuum density meter, which can improve the detection accuracy.

[0004] In one aspect, the present disclosure provides a vacuum density meter, the vacuum density meter comprising:

[0005] Shielded room, including shielding enclosure;

[0006] The discharge chamber is located in the shielding cover, and includes a magnetic circuit and an anode. The magnetic circuit includes a magnetic conductive bottom plate, a discharge chamber shell, a magnetic pole and a magnetic core. The magnetic conductive bottom plate and the discharge chamber shell form a discharge area with a discharge outlet. The magnetic pole, the magnetic core and at least part of the anode are located in the discharge area and are arranged opposite to the discharge outlet. The magnetic field generated by the magnetic pole passes through the magnetic conductive bottom plate, the discharge chamber shell and the magnetic core in sequence and then returns to the magnetic pole. The anode is used to connect the positive pole of the first power supply, and the shielding cover and the discharge chamber shell are used to connect the negative pole of the second power supply.

[0007] Another aspect of the present disclosure provides a method for vacuum degree detection based on the above vacuum density meter, the method comprising:

[0008] detecting a target current magnitude of the anode;

[0009] Determining a target correlation between the target current magnitude and the target voltage magnitude according to the target voltage magnitude provided by the first power supply;

[0010] Among multiple pre-prepared calibration curves, a target calibration curve corresponding to the target correlation is searched, and the vacuum degree represented by the target calibration curve is used as the detected vacuum degree, wherein the calibration curve represents the correlation between the current size of the anode and the voltage size provided by the first power supply, and different calibration curves correspond to different vacuum degrees.

[0011] Another aspect of the present disclosure provides a method for vacuum degree detection based on the above vacuum density meter, the method comprising:

[0012] Detecting the target current magnitude of the shielding cover;

[0013] Determining a target correlation between the target current magnitude and the target voltage magnitude according to the target voltage magnitude provided by the second power supply;

[0014] Among multiple pre-prepared calibration curves, a target calibration curve corresponding to the target correlation is searched, and the vacuum degree represented by the target calibration curve is used as the detected vacuum degree, wherein the calibration curve represents the correlation between the current size of the shielding cover and the voltage size provided by the second power supply, and different calibration curves correspond to different vacuum degrees.

[0015] In the technical solutions of some embodiments of the present application, a magnetic circuit constructed based on a magnetic conductive bottom plate, a discharge chamber housing, a magnetic pole and a magnetic core can generate a magnetic field with an inclined angle and a large magnetic mirror ratio between the discharge chamber housing and the magnetic core. When the anode is connected to the positive pole of the first power supply, and the shielding cover and the discharge chamber housing are connected to the negative pole of the second power supply, the electrons captured by the magnetic field can move back and forth in the magnetic field. Since the movement path of the electrons is effectively extended, the utilization rate of the electrons can be greatly improved, so that the electrons can collide with more gas molecules or atoms in the vacuum environment to form a relatively large detection current. Because the larger detection current is easy to detect, the detection accuracy can be improved when the vacuum degree of the vacuum environment is detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features and advantages of the present disclosure will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present disclosure in any way. In the accompanying drawings:

[0017] Figure 1 A cross-sectional view of a vacuum density meter provided by some embodiments of the present application is shown;

[0018] Figure 2 A schematic diagram of a shielding cover provided in some embodiments of the present application is shown;

[0019] Figure 3 A schematic diagram of a shielding target plate provided in some embodiments of the present application is shown;

[0020] Figure 4 A schematic diagram of a combination of a shielding cover and a discharge chamber provided in some embodiments of the present application is shown;

[0021] Figure 5 A schematic diagram of the structure of an anode provided in some embodiments of the present application is shown;

[0022] Figure 6 A schematic diagram of power connection of a vacuum density meter provided in some embodiments of the present application is shown;

[0023] Figure 7 A schematic diagram showing power connection of a vacuum density meter provided in some other embodiments of the present application is shown;

[0024] Figure 8 A schematic diagram showing a flow chart of a vacuum degree detection method provided in some embodiments of the present application;

[0025] Fig. 9 A schematic flow chart of a vacuum degree detection method provided by other embodiments of the present application is shown;

[0026] Fig.10 A calibration schematic diagram of a vacuum density meter provided in some embodiments of the present application is shown. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0028] At present, vacuum density meters are mainly divided into hot cathode vacuum density meters and cold cathode vacuum density meters. Among them, the hot cathode vacuum density meter detects the vacuum degree by heating the electronic filament to emit electrons and ionize the local gas. Although this vacuum density meter can detect the vacuum degree of a high vacuum environment, it has high requirements for the environment. In an environment that exceeds the rated working vacuum, the filament may break, and the filament may suffer from material loss and ionization characteristic attenuation after working for a long time, thus affecting the detection accuracy. The cold cathode vacuum density meter uses high voltage to initially ionize the primary electrons of space or materials, and then maintains the subsequent ionization. Although this vacuum density meter has low environmental requirements, it requires a certain discharge voltage and has no additional electrons, so the ionization ability is limited, and the detection accuracy in a high vacuum environment is low.

[0029] In view of this, the present application provides a vacuum density meter that can solve the above problems. Figure 1 , a cross-sectional view of a vacuum density meter provided for some embodiments of the present application. Figure 1In the embodiment, the vacuum densitometer includes a shielding chamber 100 and a discharge chamber 101. The shielding chamber 100 includes a shielding cover 11. The discharge chamber 101 is located in the shielding cover 11, and includes a magnetic circuit 102 and an anode 5. The magnetic circuit 102 includes a magnetic bottom plate 3, a discharge chamber shell 4, a magnetic pole 6 and a magnetic core 7. The magnetic bottom plate 3 and the discharge chamber shell 4 enclose a discharge area 1012 having a discharge outlet 1011. The magnetic pole 6, the magnetic core 7 and at least part of the anode 5 are located in the discharge area 1012 and are arranged opposite to the discharge outlet 1011. The magnetic field generated by the magnetic pole 6 passes through the magnetic bottom plate 3, the discharge chamber shell 4 and the magnetic core 7 in sequence and then returns to the magnetic pole 6. The anode 5 is used to connect the positive pole of the first power supply, and the shielding cover 11 and the discharge chamber shell 4 are used to connect the negative pole of the second power supply.

[0030] Specifically, the discharge area 1012 may be a semi-open cylindrical discharge area having a discharge outlet 1011. The shape of the discharge area 1012 may be designed according to actual conditions. Figure 1 The shape of the discharge region 1012 shown does not constitute a limitation of the present application.

[0031] The magnetic pole 6, the magnetic core 7 and at least part of the anode 5 can divide the discharge region 1012 into annular plus cylindrical sub-discharge regions.

[0032] The first power supply and the second power supply may be high voltage power supplies, and the first power supply and the second power supply may be the same power supply or different power supplies.

[0033] The magnetic bottom plate 3, the discharge chamber shell 4 and the magnetic core 7 are made of magnetic conductive materials, so as to ensure the normal construction of the magnetic circuit 102. In this embodiment, the magnetic bottom plate 3, the discharge chamber shell 4 and the magnetic core 7 can be made of materials with good magnetic conductive properties such as DT4 and 1J22.

[0034] The magnetic pole 6 can generate a magnetic field by permanent magnet excitation or electromagnetic coil excitation.

[0035] The magnetic pole 6 may be in contact with the magnetic bottom plate 3, and the magnetic bottom plate 3 may be in contact with the discharge chamber shell 4. The magnetic field generated by the magnetic pole 6 may first be conducted to the magnetic bottom plate 3, then to the discharge chamber shell 4 directly in contact with the magnetic bottom plate 3, then to the edge of the upper portion of the discharge chamber shell 4, then to the magnetic core 7 through space, and finally back to the magnetic pole 6. In this way, a complete magnetic circuit 102 is formed.

[0036] Based on the magnetic circuit 102, a magnetic field with an inclined angle and a large magnetic mirror ratio (such as Figure 1), and the magnetic field can be used to capture electrons in a vacuum environment. After the anode 5 is connected to the positive pole of the first power supply, and the shielding cover 11 and the discharge chamber shell 4 are connected to the negative pole of the second power supply, the electrons captured by the magnetic field move toward the anode 5 and the magnetic pole 6 under the attraction of the high voltage, but due to the magnetic mirror effect of the magnetic field, when approaching the magnetic pole 6 and the anode 5, the electrons will be repelled in the opposite direction and move in the direction away from the anode 5 and the magnetic pole 6. After moving to a certain distance, the attraction of the anode 5 on the electrons is stronger than the magnetic mirror effect, and the electrons move toward the anode 5 and the magnetic pole 6 again, and move back and forth repeatedly until the electrons lose energy or collide with other particles.

[0037] During the above movement, the electrons collide and ionize with rarefied gas molecules or atoms in the vacuum environment, discharge and generate plasma. At the same time, the coupling between the electron movement, the electron potential difference and the electrostatic magnetic field can accelerate the ions in the plasma. According to the thermal potential theory, when the electron temperature gradient is ignored, the accelerating electric field is roughly perpendicular to the magnetic field. Therefore, an accelerating electric field inclined in the direction of the discharge outlet 1011 can be formed, so that the ions in the plasma are discharged from the discharge chamber 101 in the direction of the discharge outlet 1011.

[0038] In some embodiments, the shielding cover 11 can collect the plasma discharged from the discharge chamber 101 and form an ion current, and the size of the ion current in the shielding cover 11 is related to the number of gas molecules or atoms in the vacuum environment. Therefore, by detecting the size of the ion current formed in the shielding cover 11, the vacuum degree of the vacuum environment can be calculated accordingly.

[0039] In other embodiments, a high-voltage power supply loop may be formed between the anode 5 and the connected power supply, and the current in the high-voltage power supply loop is also related to the number of gas molecules or atoms in the vacuum environment. Therefore, the vacuum degree of the vacuum environment can also be inferred by detecting the current of the anode 5. The current in the anode 5 can also be called a discharge current.

[0040] In the discharge chamber 101 of the present application, since there are active magnetic fields, active electric fields and electric fields caused by potential differences, and the physical phenomena in the discharge chamber 101 can be explained based on the Hall effect, the discharge chamber 101 is also called a Hall effect discharge chamber.

[0041] In summary, in the technical solutions of some embodiments of the present application, the magnetic circuit 102 constructed based on the magnetic conductive bottom plate 3, the discharge chamber housing 4, the magnetic pole 6 and the magnetic core 7 can generate a magnetic field with an inclined angle and a large magnetic mirror ratio between the discharge chamber housing 4 and the magnetic core 7. When the anode 5 is connected to the positive pole of the first power supply, and the shielding cover 11 and the discharge chamber housing 4 are connected to the negative pole of the second power supply, the electrons captured by the magnetic field can move back and forth in the magnetic field. Since the movement path of the electrons is effectively extended, the utilization rate of the electrons can be greatly improved, so that the electrons can collide with more gas molecules or atoms in the vacuum environment to form a relatively large detection current. Because the larger detection current is easy to detect, the detection accuracy can be improved when the vacuum degree of the vacuum environment is detected.

[0042] In addition, the present application improves the utilization rate of electrons by extending the electron movement path. Thus, on the one hand, a relatively stable detection current can be obtained in a high vacuum environment, thereby enabling more accurate vacuum degree detection in a high vacuum environment; on the other hand, it is not restricted by the vacuum environment and has greater applicability.

[0043] In some embodiments, the shielding cover 11 may be made of metal material, such as stainless steel, molybdenum, copper, etc.

[0044] In some embodiments, the shielding chamber 100 can also keep the gas density inside and outside the shielding cover 11 uniform, thereby ensuring that the vacuum degree detected in the discharge chamber 101 is the real vacuum degree of the vacuum environment where the vacuum densitometer is located.

[0045] For details, please refer to Figure 1 and Figure 2 The shielding cover 11 may include a first mesh 111, through which gas molecules or atoms outside the shielding cover 11 may enter the shielding cover 11, and at least part of the gas molecules or atoms entering the shielding cover 11 may enter the discharge region 1012 through the discharge outlet 1011. Through the first mesh 111, the gas inside and outside the shielding cover 11 may communicate with each other, so that the gas density inside and outside the shielding cover 11 remains uniform, and then, the vacuum degree detected in the discharge chamber 101 may be used as the vacuum degree of the vacuum environment where the vacuum density meter is located, thereby improving the detection accuracy.

[0046] In some embodiments, in addition to collecting plasma and forming ion current, the shielding cover 11 can also block the high-energy ion flow with a large divergence angle discharged from the discharge outlet 1011, preventing these high-energy ions from entering the vacuum environment and interfering with other equipment. However, since the intensity of the high-energy ion flow discharged from the discharge outlet 1011 is relatively large, the thickness or material of the shielding cover 11 may not be sufficient to withstand the intensity of the high-energy ion flow discharged from the discharge outlet 1011. Therefore, the shielding chamber 100 also includes a shielding target plate 12 arranged on the shielding cover 11. The shielding target plate 12 is used to connect the negative electrode of the second power supply, and the shielding target plate 12 is arranged relative to the discharge outlet 1011 to receive the ion flow generated in the discharge area discharged from the discharge outlet 1011. Specifically, the structure, material, etc. of the shielding target plate 12 may not be exactly the same as that of the shielding cover 11. For example, the shielding target plate 12 may be relatively thick, so that it can better withstand the bombardment of the high-energy ion flow discharged from the discharge outlet 1011.

[0047] In the above embodiment, by arranging the shielding target plate 12 at a position opposite to the discharge outlet 1011, the high-energy ion flow discharged from the discharge outlet 1011 can be effectively prevented from entering the vacuum environment, thereby protecting other devices in the vacuum environment from being affected by the high-energy ion flow.

[0048] Combined with reference Figure 3 , which is a schematic diagram of a shielding target plate 12 provided in some embodiments of the present application. Figure 3 In the embodiment, the shielding target plate 12 is circular, including a shielding target center 121 and a shielding target edge body 122. The shielding target center 121 and the shielding target edge body 122 have different thicknesses, or the shielding target center 121 and the shielding target edge body 122 are made of different materials. Specifically, the shielding target center 121 may be the main part subjected to the bombardment of the high-energy ion flow, and therefore, the thickness of the shielding target center 121 may be greater than the thickness of the shielding target edge body 122, or the material of the shielding target center 121 may be more bombardment-resistant than that of the shielding target edge body 122. In this way, the high-energy ion flow discharged from the discharge outlet 1011 can be effectively prevented from entering the vacuum environment.

[0049] In some embodiments, the material of the shielding target plate 12 may be a material resistant to high-energy ion sputtering, such as ceramic, molybdenum, titanium, etc.

[0050] In some embodiments, the thickness of the shielding target center 121 may be 1.5 times, 2 times, 4 times, etc., the average thickness of the shielding target plate 12 .

[0051] Further, see Figure 3In some embodiments, the shielding target center 121 is a solid structure, and the shielding target edge body 122 includes a second mesh 1221. The gas molecules or atoms outside the shielding cover 11 can enter the shielding cover through the second mesh 1221, and at least part of the gas molecules or atoms entering the shielding cover 11 can enter the discharge area 1012 through the discharge outlet 1011. On the basis of the first mesh 111, combined with the second mesh 1221, the uniformity of the gas density inside and outside the shielding cover 11 can be improved, thereby improving the detection accuracy.

[0052] In the above embodiment, the first mesh 111 and the second mesh 1221 can be dense meshes in an array. The shape of the mesh can be designed according to actual needs, such as circular, square, hexagonal or other shapes.

[0053] Further, see Figure 1 , Figure 3 and Figure 4 . In some embodiments, the vacuum densitometer of the present application further includes a main base 1, a shielding cover 11 is installed on the main base 1, and the discharge chamber 101 is located in the space enclosed by the shielding cover 11 and the main base 1. Specifically, the shielding cover 11 may include an upper mounting platform 112 and a lower mounting platform 113, wherein the upper mounting platform 112 is used to fix the shielding target plate 12 to the shielding cover 11, and the lower mounting platform 113 is used to fix the shielding cover 11 to the main base 1. In this way, the discharge chamber 101 can be located in a relatively closed space, and through the shielding cover 11, the shielding target plate 12 and the main base 1, the high-energy ion flow generated in the discharge chamber 101 can be effectively blocked from diffusing into the vacuum environment outside the shielding cover 11, thereby preventing other equipment in the vacuum environment from being affected.

[0054] The discharge chamber 101 is further described below.

[0055] Combined with reference Figure 1 In some embodiments, the discharge chamber 101 may further include an insulator 10, which is located between the anode 5 and other components except the anode 5, and is used to isolate the anode 5 from other components. In this way, the normal discharge of the discharge chamber 101 is determined.

[0056] The material of the insulator 10 can be an insulating material, such as ceramic, quartz, plastic, etc.

[0057] In some embodiments, the discharge chamber housing 4 has a housing terminal (not shown), and the discharge chamber 101 may further include a protection ring 9, which is sleeved on the housing terminal and is used to receive the ion flow generated in the discharge region 1012 and discharged from the discharge outlet 1011. In this way, the housing terminal of the discharge chamber housing 4 can be protected from the bombardment and erosion of the high-energy ion flow.

[0058] The material of the protection ring 9 can be a sputtering-resistant material, and can be either conductive or non-conductive, such as ceramic, graphite, stainless steel, molybdenum, titanium, and the like.

[0059] In some embodiments, the discharge chamber 101 may further include a discharge chamber base 2, which is used to install the anode 5 and components in the magnetic circuit 102, and the material of the discharge chamber base 2 is an insulating material (such as ceramic, plastic, etc.).

[0060] Specifically, the discharge chamber base 2 may include one or more vacancies or slots, and these vacancies or slots are used to directly or indirectly install, fix or position components in the discharge chamber 101 .

[0061] Combined with reference Figure 5 , which is a schematic diagram of the structure of the anode 5 provided in some embodiments of the present application. Figure 5 In the embodiment, the anode 5 includes an anode ring 51 and a fixing device 52. The anode ring 51 is used to connect the positive electrode of the first power supply, and the fixing device 52 is used to fix the anode ring 51 into the discharge chamber 101.

[0062] The anode ring 51 may be a ring structure or other structures, such as a segmented structure.

[0063] The material of the anode 5 can be metal materials such as stainless steel, molybdenum, and copper.

[0064] Continue reading Figure 1 In some embodiments, the vacuum density meter may further include a hot cathode 13, the hot cathode 13 includes an emitter 131, the shielding cover 11 includes a third mesh 114, the emitter 131 enters the shielding cover 11 through the third mesh 114, and when the hot cathode 13 is connected to the third power supply, the hot cathode 13 emits electrons into the shielding cover 11 through the emitter 131, and at least part of the electrons emitted by the hot cathode 13 enter the discharge area 1012 through the discharge outlet 1011.

[0065] Specifically, the hot cathode 13 may include a heating wire 132. When the hot cathode 13 is connected to the third power source, after current is applied to the heating wire 132, the heating wire 132 may heat the emitter 131, and after the emitter 131 reaches the electron emission temperature, it may emit electrons.

[0066] By emitting electrons into the shielding cover 11 through the hot cathode 13, the electron concentration in the discharge area 1012 can be increased, thereby generating a larger detection current and further improving the detection accuracy. It should be noted that in the solution of the present application, since the electron utilization rate is relatively high, even if the hot cathode 13 does not emit electrons into the shielding cover 11, a relatively high detection accuracy can be achieved. Of course, after using the hot cathode 13 to emit electrons into the shielding cover 11, the detection accuracy can be further improved.

[0067] In some embodiments, the emitter surface of the hot cathode 13 may be perpendicular to the plane of the discharge outlet 1011 or may be at an acute angle, so as to ensure that as many electrons emitted by the hot cathode 13 as possible can enter the discharge region 1012 .

[0068] In some embodiments, the hot cathode 13 may include a thermal emission cathode based on the thermal emission effect of the cathode material.

[0069] Combined with reference Figure 6 , which is a schematic diagram of the power connection of the vacuum density meter provided in some embodiments of the present application. Figure 6 In the discharge chamber 101, the high-voltage power supply Phv serves as the first power supply and the second power supply, and the heating power supply Pheat serves as the third power supply. The positive electrode of the high-voltage power supply Phv is connected to the anode 5, and the positive electrode of the heating power supply Pheat is connected to the heating wire 132 of the hot cathode 13. The shielding cover 11, the shielding target plate 12, the hot cathode 13 shell, and the discharge chamber shell 4 are connected to the negative electrodes of the high-voltage power supply Phv and the heating power supply Pheat. In the discharge chamber 101, the anode 5 carries a positive potential, and the other components carry a negative potential. The electrons in the generated plasma tend to move toward the anode 5 after losing energy through ionization collision, and the ions tend to move toward other components carrying negative potentials, so as to prevent the ions from moving to the space outside the shielding cover 11 and the shielding target plate 12.

[0070] Combined with reference Figure 7 , is a schematic diagram of power connection of a vacuum density meter provided in other embodiments of the present application. Figure 7 In the figure, the high-voltage power supply Phv serves as the first power supply, the bias power supply Pbias serves as the second power supply, and the heating power supply Pheat serves as the third power supply. The positive electrode of the high-voltage power supply Phv is connected to the anode 5, the positive electrode of the heating power supply Pheat is connected to the heating wire 132 of the hot cathode 13, and the negative electrode of the bias power supply Pbias is connected to the shielding cover 11 and the shielding target plate 12. The shell of the hot cathode 13 and the discharge chamber shell 4 are connected to the negative electrodes of the high-voltage power supply Phv and the heating power supply Pheat, and the positive electrode of the bias power supply Pbias is grounded. The shielding cover 11 and the shielding target plate 12 are applied with a negative potential relative to the 0 potential, which can attract and collect the ions carrying the positive potential generated by the Hall effect discharge chamber, thereby forming an ion current.

[0071] Further, based on the above description, since the current magnitude of the anode 5 and the current magnitude of the shielding cover 11 can both reflect the vacuum degree of the vacuum environment, two different vacuum degree detection methods can be used using the vacuum density meter of the present application. Figure 8 , which is a flow chart of a vacuum degree detection method provided in some embodiments of the present application. Figure 8 In the present invention, the vacuum degree detection method comprises the following steps:

[0072] Step S81 , detecting the target current size of the anode 5 .

[0073] Step S82: determining a target correlation between a target current magnitude and a target voltage magnitude according to a target voltage magnitude provided by the first power source.

[0074] Step S83, searching for a target calibration curve corresponding to the target correlation among a plurality of pre-planned calibration curves, and using the vacuum degree represented by the target calibration curve as the detected vacuum degree, wherein the calibration curve represents the correlation between the current magnitude of the anode 5 and the voltage magnitude provided by the first power supply, and different calibration curves correspond to different vacuum degrees.

[0075] Specifically, under different vacuum degrees, the voltage magnitude provided by the first power supply and the current magnitude of the anode 5 may have different correlations. The so-called correlation is the linear relationship between the voltage magnitude provided by the first power supply and the current magnitude of the anode 5. For example, when the vacuum degree of the vacuum environment is 0.01 Pa, the linear relationship between the voltage magnitude U provided by the first power supply and the current magnitude I of the anode 5 is U=5I+0.3; when the vacuum degree of the vacuum environment is 0.03 Pa, the linear relationship between the voltage magnitude U provided by the first power supply and the current magnitude I of the anode 5 is U=3I+0.4.

[0076] Therefore, calibration curves characterizing the voltage-current relationship can be fitted in advance for different vacuum degrees. After detecting the target voltage provided by the first power supply and the target current in the anode 5, the corresponding target calibration curve can be found according to the correlation between the two. The correlation corresponding to the target calibration curve is the value detected by the vacuum density meter.

[0077] Combined with reference Fig. 9 , which is a flow chart of a vacuum degree detection method provided in other embodiments of the present application. Fig. 9 In the present invention, the vacuum degree detection method comprises the following steps:

[0078] Step S91 , detecting the target current magnitude of the shielding cover 11 .

[0079] Step S92: determining a target correlation between a target current magnitude and a target voltage magnitude according to a target voltage magnitude provided by the second power source.

[0080] Step S93, searching for a target calibration curve corresponding to the target correlation among multiple pre-planned calibration curves, and taking the vacuum degree represented by the target calibration curve as the detected vacuum degree, wherein the calibration curve represents the correlation between the current size of the shielding cover 11 and the voltage size provided by the second power supply, and different calibration curves correspond to different vacuum degrees.

[0081] Fig. 9 The principle and Figure 8 Similar, I won’t go into details here.

[0082] The following describes how to calibrate the vacuum density meter of this application. Fig.10 , which is a calibration diagram of a vacuum density meter provided in some embodiments of the present application. Fig.10 In the embodiment, the Hall vacuum density meter 73 is the vacuum density meter to be calibrated in the present application. The equipment used to calibrate the Hall vacuum density meter 73 includes:

[0083] The vacuum device 71 is used to provide a vacuum environment for the Hall vacuum density meter 73;

[0084] A gas mass flow rate controller 72, used to inject gas into the vacuum device 71 through a pipeline to change the vacuum degree in the vacuum device 71;

[0085] The standard vacuum density meter 74 is used to provide a standard reference for the vacuum degree in the vacuum equipment 71 .

[0086] based on Fig.10 The voltage provided by the first power supply is called the discharge voltage, and the current of the anode 5 is called the discharge current, or the voltage provided by the second power supply is called the discharge voltage, and the current of the shielding cover 11 is called the discharge current. The following is a calibration step in a cold cathode mode. The so-called cold cathode mode means that the hot cathode in the Hall vacuum density meter 73 does not emit electrons. The calibration steps in this mode may specifically include the following steps:

[0087] A0, configure the standard vacuum density meter 74, the Hall vacuum density meter 73 and the gas mass flow rate controller 72, and complete the connection of the gas circuit to enter the standby state.

[0088] A1, start the vacuuming process, and maintain the vacuum degree in the vacuum equipment 71 at the background vacuum, which is about 0.000001 to 0.00001 Pa.

[0089] A2, start the gas mass flow rate controller 72, introduce gas into the vacuum device 71, and gradually change the vacuum degree in the vacuum device 71. Step A2 specifically includes sub-steps A201 to A204.

[0090] A201, at each order of magnitude, at least four or more data points are obtained to ensure that the vacuum environment of each order of magnitude is simulated as extensively as possible.

[0091] A202, record the corresponding relationship between the mass flow rate of the gas introduced each time and the reading of the standard vacuum density meter 74.

[0092] A203, when the vacuum degree reaches the upper limit of the working range of the standard vacuum density meter 74, the gas mass flow rate controller 72 is turned off, and the corresponding data between the mass flow rate of the incoming gas and the vacuum reading of the standard vacuum density meter 74 are sorted out.

[0093] A204, fit the mass flow rate-vacuum reading data to confirm the linearity between the two. If the linear correlation R is greater than 0.995, it is considered that the gas mass flow rate controller 72 and the standard flow meter have good calibration linearity, and the Hall vacuum density meter 73 can be calibrated.

[0094] A3, start the gas mass flow rate controller 72 again, and inject gas according to the data point corresponding to the vacuum reading in A2. Step A3 specifically includes sub-steps A301 to A306.

[0095] A301, start the Hall vacuum density meter 73, start the Hall vacuum density meter 73 with a higher discharge voltage at the first vacuum data point, ensure that the Hall vacuum density meter 73 discharges normally, and record the discharge current corresponding to the discharge voltage.

[0096] A302, gradually increase the vacuum degree according to the vacuum reading data table in A2, and record the discharge current corresponding to the discharge voltage at each vacuum degree.

[0097] A303, when the power generation current of the Hall vacuum density meter 73 exceeds a certain value, such as 20 mA (or other values) at the first voltage level, or when the discharge current begins to become unstable at the next few vacuum degree data points, increase a voltage level in advance and synchronously record the discharge current corresponding to all discharge voltages at the current vacuum data point.

[0098] A304, continuously increase the vacuum degree according to the vacuum reading data table, continuously enable new discharge voltage gears according to A303, and close the discharge voltage gear that causes the discharge current to become unstable.

[0099] A305, sort out the discharge currents at different discharge voltage levels corresponding to the vacuum degree on the vacuum reading data table, and screen the data of the discharge current at each discharge voltage level, select the data with good linearity, and perform linear fitting to determine the correlation R;

[0100] A306, the discharge voltage-discharge current fitting line corresponding to each voltage level is the calibration curve of the Hall vacuum density meter 73 in the cold cathode working mode. Different discharge voltage levels can be selected according to different vacuum degrees, and the vacuum degree can be measured by the correspondence between the discharge current and the discharge voltage.

[0101] A4, turn off all equipment, start the vacuum shutdown process, and complete the vacuum calibration of the Hall vacuum density meter 73 in the cold cathode mode.

[0102] The following is a calibration procedure in a hot cathode-cold cathode mixed mode. The so-called hot cathode-cold cathode mixed mode means that the hot cathode in the Hall vacuum densitometer 73 emits electrons into the shielding cover 11. The calibration procedure in this mode may specifically include the following steps:

[0103] B1 is the same as the above step A1 and will not be described in detail here.

[0104] B2 is the same as the above step B1 and will not be described in detail here.

[0105] B3, when the vacuum degree reaches the local vacuum, which is about 0.000001 or 0.00001 Pa, start the hot cathode and enter the hot cathode working mode. And start the gas mass flow rate controller 72 to inject gas into the vacuum device 71 according to the vacuum reading data table. Step B3 may include sub-steps B301 to B307.

[0106] B301, start the Hall vacuum density meter 73, start the Hall vacuum density meter 73 with a higher discharge voltage at the first vacuum data point, ensure the normal discharge of the Hall vacuum density meter 73, and record the discharge current corresponding to the discharge voltage.

[0107] B302, gradually increase the vacuum degree according to the vacuum reading data table in B2, and record the discharge current corresponding to the discharge voltage at each vacuum degree.

[0108] B303, when the current of the Hall vacuum density meter 73 exceeds a certain value, such as 20 mA (or other), or when the discharge current begins to become unstable at the next few vacuum data points, increase a voltage level in advance and synchronously record the discharge current corresponding to all discharge voltages at the current vacuum data point.

[0109] B304, when the vacuum degree reaches 0.001 Pa or above, turn off the hot cathode, end the hot cathode working mode, and switch to the cold cathode working mode.

[0110] B305, continuously increase the vacuum degree according to the vacuum reading data table, continuously enable new discharge voltage gears according to B303, and close the discharge voltage gear that causes the discharge current to become unstable.

[0111] B306, sort out the discharge currents at different discharge voltage levels corresponding to the vacuum degree on the vacuum reading data table, and screen the data of the discharge current at each discharge voltage level, select data with good linearity, and perform linear fitting to determine the correlation R.

[0112] B307, the discharge voltage-discharge current fitting line corresponding to each voltage level is the calibration line of the Hall vacuum density meter 73 in the cold cathode working mode. Different discharge voltage levels can be selected according to different vacuum degrees, and the vacuum degree can be measured by the correspondence between the discharge current and the discharge voltage.

[0113] B4, turn off all equipment, start the vacuum shutdown process, and complete the vacuum calibration of the Hall vacuum density meter 73 in the hot cathode-cold cathode mixed working mode.

[0114] Although the embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A vacuum density meter, characterized in that: The vacuum density meter comprises: A shielding room (100), comprising a shielding cover (11); The discharge chamber (101) is located in the shielding cover (11), and comprises a magnetic circuit (102) and an anode (5); the magnetic circuit (102) comprises a magnetic conductive bottom plate (3), a discharge chamber shell (4), a magnetic pole (6) and a magnetic core (7); the magnetic conductive bottom plate (3) and the discharge chamber shell (4) enclose a discharge area (1012) having a discharge outlet (1011); the magnetic pole (6), the magnetic core (7) and at least part of the anode (5) are located in the discharge area (1012) and are arranged opposite to the discharge outlet (1011); the magnetic field generated by the magnetic pole (6) passes through the magnetic conductive bottom plate (3), the discharge chamber shell (4) and the magnetic core (7) in sequence and then returns to the magnetic pole (6); the anode (5) is used to connect to the positive pole of a first power source; the shielding cover (11) and the discharge chamber shell (4) are used to connect to the negative pole of a second power source.

2. The vacuum density meter according to claim 1, characterized in that: The shielding cover (11) comprises a first mesh (111), gas molecules or atoms outside the shielding cover (11) enter the shielding cover (11) through the first mesh (111), and at least part of the gas molecules or atoms entering the shielding cover (11) enter the discharge area (1012) through the discharge outlet (1011).

3. The vacuum density meter according to claim 1, characterized in that: The shielding chamber (100) further comprises a shielding target plate (12) arranged on the shielding cover (11), the shielding target plate (12) being used to connect to the negative electrode of the second power supply, and the shielding target plate (12) being arranged opposite to the discharge outlet (1011) and being used to receive an ion flow generated in the discharge area (1012) and discharged from the discharge outlet (1011).

4. The vacuum density meter according to claim 3, characterized in that: The shielding target plate (12) comprises a shielding target center (121) and a shielding target edge body (122); the shielding target center (121) and the shielding target edge body (122) have different thicknesses, or the shielding target center (121) and the shielding target edge body (122) are made of different materials.

5. The vacuum density meter according to claim 4, characterized in that: The shielding target center (121) is a solid structure, and the shielding target edge body (122) comprises a second mesh hole, through which gas molecules or atoms outside the shielding cover (11) enter the shielding cover (11), and at least part of the gas molecules or atoms that enter the shielding cover (11) enter the discharge area (1012) through the discharge outlet (1011).

6. The vacuum density meter according to claim 1, wherein: The vacuum density meter further comprises a hot cathode (13), wherein the hot cathode (13) comprises an emitter (131), and the shielding cover (11) comprises a third mesh (114), wherein the emitter (131) enters the shielding cover (11) through the third mesh (114), and when the hot cathode (13) is connected to a third power source, the hot cathode (13) emits electrons into the shielding cover (11) through the emitter (131), and at least part of the electrons emitted by the hot cathode (13) enter the discharge region (1012) through the discharge outlet (1011).

7. The vacuum density meter according to claim 1, wherein: The discharge chamber (101) further comprises an insulator (10), wherein the insulator (10) is located between the anode (5) and other components except the anode (5), and is used to isolate the anode (5) from other components; and / or The discharge chamber shell (4) has a shell terminal, and the discharge chamber (101) further comprises a protective ring, which is sleeved on the shell terminal and is used to receive the ion flow generated in the discharge area (1012) and discharged from the discharge outlet (1011); and / or The discharge chamber (101) further comprises a discharge chamber base (2), wherein the discharge chamber base (2) is used to mount the anode (5) and components in the magnetic circuit (102), and the material of the discharge chamber base (2) is an insulating material.

8. The vacuum density meter according to claim 1, characterized in that: The vacuum densitometer further comprises a main base (1), the shielding cover (11) is mounted on the main base (1), and the discharge chamber (101) is located in a space enclosed by the shielding cover (11) and the main base (1).

9. A method for vacuum degree detection based on the vacuum density meter according to any one of claims 1 to 8, characterized in that: The method comprises: Detecting the target current magnitude of the anode (5); Determining a target correlation between the target current magnitude and the target voltage magnitude according to the target voltage magnitude provided by the first power supply; Among a plurality of pre-planned calibration curves, a target calibration curve corresponding to the target correlation is searched, and the vacuum degree represented by the target calibration curve is used as the detected vacuum degree, wherein the calibration curve represents the correlation between the current magnitude of the anode (5) and the voltage magnitude provided by the first power supply, and different calibration curves correspond to different vacuum degrees.

10. A method for vacuum degree detection based on the vacuum density meter according to any one of claims 1 to 8, characterized in that: The method comprises: Detecting the target current magnitude of the shielding cover (11); Determining a target correlation between the target current magnitude and the target voltage magnitude according to the target voltage magnitude provided by the second power supply; Among a plurality of pre-planned calibration curves, a target calibration curve corresponding to the target correlation is searched, and the vacuum degree represented by the target calibration curve is used as the detected vacuum degree, wherein the calibration curve represents the correlation between the current magnitude of the shielding cover (11) and the voltage magnitude provided by the second power supply, and different calibration curves correspond to different vacuum degrees.

Images