High-sensitivity hot-cathode ion gauge capable of measuring lower limit in strong magnetic field environment

Abstract

The application discloses a high-sensitivity hot cathode ionization gauge which can be used in a strong magnetic field environment and has a lower lower limit of measurement, and the hot cathode ionization gauge mainly comprises a cathode filament, an anode grid, an ion collecting electrode and a metal shell; wherein the cathode filament is a spiral thick filament structure and is used for resisting the Ampere force in the strong magnetic field; the anode grid is a spiral structure or a cage structure, which comprises a left anode grid and a right anode grid and is symmetrically arranged with the cathode filament as the center; the ion collecting electrode is a metal filament structure, which comprises a left ion collecting electrode and a right ion collecting electrode; the metal shell is a cylindrical structure, and the electric potential of the metal shell is arranged to be grounded; the cathode filament, the anode grid, the ion collecting electrode and the metal shell are coaxially arranged, and when working in the magnetic field environment, the electrode axis arrangement direction is parallel to the magnetic field direction. Compared with the traditional hot cathode ionization gauge used in the strong magnetic field environment, the application can effectively prolong the service life of the cathode filament, improve the sensitivity of the ionization gauge, and extend the lower limit of measurement to 10 ‑9 Pa.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vacuum measurement, and particularly relates to a high-sensitivity hot cathode ionization gauge with a lower lower limit for measurement in a strong magnetic field environment. BACKGROUND

[0002] With the continuous development of science and technology, vacuum pressure measurement technology is widely used in frontier fields such as nuclear fusion and particle accelerators. The special magnetic field environment brings great challenges to traditional vacuum pressure measurement. In the magnetic field environment, the motion of charged particles in the ionization gauge is affected by the Lorentz force, the trajectory of the charged particles changes, and the ionization gauge ion signal sensitivity changes significantly, which makes the traditional ionization gauge difficult to work normally in the magnetic field environment. Therefore, domestic and foreign researchers have further optimized the design of the traditional ionization gauge to meet the needs of vacuum measurement in the magnetic field environment.

[0003] In the patent document with the publication number CN101046423A, a fast-response ionization vacuum gauge with high anti-interference capability is disclosed. The patent uses a flat plate type collector, grid and control electrode, and installs the vacuum gauge in a shielding cover. The vacuum gauge and the control power source are connected by a shielding cable, which overcomes the characteristics that ordinary ionization gauges cannot work in a strong magnetic field environment, and improves the response speed and anti-interference capability of the gauge tube. However, in this method, the functional electrodes are arranged on only one side of the emission cathode, which reduces the utilization rate of the hot emission electrons. The electrode adopts a flat plate structure, which limits the motion trajectory of the charged particles to the horizontal direction, and the ion collector is greatly affected by the x-ray effect, which limits the sensitivity and lower limit of the vacuum gauge.

[0004] In the patent document with the publication number CN107527786A, a carbon nanotube cathode ionization gauge with a lower lower limit is disclosed. The patent uses a carbon nanotube cathode as a field emission electron source, and uses the top end face of the cage-shaped anode grid to directly extract electrons, which improves the effective utilization rate of ionization electrons. However, the cold cathode ionization gauge has problems such as nonlinearity, instability, large pumping speed, discharge delay effect at low pressure, discontinuity of current and pressure in a wide pressure range, etc. In addition, the gap between the carbon nanotube cathode and the anode grid in this method is very small, and the installation operation requires high requirements. In addition, high voltage is usually used, and too high electrode voltage may cause problems such as complex measurement circuit and gauge tube leakage.

[0005] Therefore, it is necessary to propose a new type of ionization vacuum gauge, which can overcome the problems caused by high voltage of the cold cathode ionization gauge electrode, and at the same time ensure a longer service life of the ionization gauge in the magnetic field environment, and has higher sensitivity and lower limit of measurement. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the present application aims to provide a high-sensitivity hot cathode ionization gauge with a lower lower limit of measurement in a strong magnetic field environment, which can effectively increase the service life of the cathode filament and improve the sensitivity of the ionization gauge, and the lower limit of measurement can be extended to 10 -9 Pa.

[0007] The technical scheme of the present application is as follows:

[0008] The high-sensitivity hot cathode ionization gauge with a lower lower limit of measurement in a strong magnetic field environment has the following characteristics: a cathode filament, an anode grid, an ion collector, and a metal shell; the cathode filament is a spiral thick filament structure; the anode grid includes a right anode grid and a left anode grid; the ion collector includes a right ion collector and a left ion collector; the metal shell is a cylindrical structure; and the cathode filament, the right anode grid, the right ion collector, the metal shell, the left anode grid, and the left ion collector are coaxially arranged.

[0009] Further, the cathode filament is a spiral thick filament structure for resisting the Ampere force in a strong magnetic field, and the filament material is tungsten or tungsten alloy.

[0010] Further, the cathode filament has 1.5 turns, a filament diameter of 0.2mm-0.6mm, and a spiral diameter of 2mm-10mm, and adopts a direct current power supply or an alternating current power supply mode.

[0011] Further, the anode grid is a spiral structure or a cage structure, which includes a right anode grid and a left anode grid, and the left anode grid and the right anode grid are symmetrically arranged with the cathode filament as the center.

[0012] Further, the left and right ends of the left and right anode grids are in a mesh structure, the inner diameter of the anode grid is 6mm-16mm, and the grid wire diameter is 0.1mm-0.4mm.

[0013] Further, the ion collector is a metal filament structure with a diameter of 0.4mm-0.8mm, which includes a left ion collector and a right ion collector, and is symmetrically arranged with the cathode filament as the center and located on the axis of the left and right anode grids.

[0014] Further, the metal shell is a cylindrical structure connected and installed at the middle position, and the potential is arranged to be grounded with an inner diameter of 20mm-40mm.

[0015] Further, the cathode filament, the right anode grid, the right ion collector, the metal shell, the left anode grid, and the left ion collector are coaxially arranged, and when working in a magnetic field environment, the axial arrangement direction is parallel to the magnetic field direction.

[0016] Compared with the prior art, the beneficial effects of the present application are embodied in:

[0017] 1. The high-sensitivity hot cathode ionization gauge capable of measuring lower limit in a strong magnetic field environment of the present application can meet the vacuum measurement work in a strong magnetic field or a non-magnetic field environment, overcoming the shortcomings of ordinary ionization gauges that cannot work in a strong magnetic field environment.

[0018] 2. In the present application, the cathode filament is a spiral thick filament structure, which is used to resist the ampere force suffered by the cathode filament in a strong magnetic field. The spiral structure makes the direction of the ampere force suffered by the cathode filament inward, thereby improving the service life of the cathode filament in a magnetic field environment.

[0019] 3. In the present application, the anode grid is a spiral structure or a cage structure, which effectively prolongs the motion trajectory of the emitted electrons of the cathode, increases the collision probability of the emitted electrons and gas molecules, and further effectively improves the sensitivity of the hot cathode ionization gauge.

[0020] 4. In the present application, the ion collector is a metal filament structure, which reduces the area of the ion collector, thereby reducing the adverse effects of x-ray effects. In a strong magnetic field environment with a magnetic field strength less than 6T, the measurement lower limit of the hot cathode ionization gauge can be extended to 10 -9 Pa.

[0021] 5. In the present application, the cathode filament is taken as the center, and the anode grid and the ion collector are symmetrically arranged on both sides, so that the emitted electrons can oscillate back and forth in the left and right ionization zones, thereby improving the reciprocating path of the emitted electrons in the space of the anode grid, further improving the sensitivity of the ionization gauge, and reducing the proportion of the emitted electrons returning to the cathode filament, thereby increasing the utilization rate of the emitted electrons. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic view of the high-sensitivity hot cathode ionization gauge capable of measuring lower limit in a strong magnetic field environment of the present application;

[0023] In the figure, the reference numerals are as follows: 1-cathode filament; 2-right anode grid; 3-right ion collector; 4-metal shell; 5-left anode grid; 6-left ion collector. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below in combination with the drawings, such as Figure 1As shown, the high-sensitivity hot cathode ionization gauge with lower lower limit of measurement in strong magnetic field environment in the present example comprises a cathode filament 1, an anode grid, an ion collector and a metal shell 4; wherein the cathode filament 1 is a spiral thick filament structure; the anode grid comprises a right anode grid 2 and a left anode grid 5; the ion collector comprises a right ion collector 3 and a left ion collector 6; the metal shell 4 is a cylindrical structure; the cathode filament 1, the right anode grid 2, the right ion collector 3, the metal shell 4, the left anode grid 5 and the left ion collector 6 are coaxially arranged.

[0025] The cathode filament 1 is a spiral thick filament structure for resisting the Ampere force in the strong magnetic field, and the filament material is tungsten or tungsten alloy. In the present embodiment, the tungsten filament doped with LaB6 is selected.

[0026] The number of turns of the cathode filament 1 is 1.5 turns, the filament diameter is between 0.2mm and 0.6mm, and the spiral diameter is between 2mm and 10mm. The filament is heated by direct current or alternating current power supply to provide hot electrons. In the present embodiment, the filament diameter is 0.4mm, the spiral diameter is 3mm, and the direct current power supply is adopted.

[0027] The anode grid is a spiral structure or a cage structure. In the present embodiment, the spiral structure is selected, which comprises the right anode grid 2 and the left anode grid 5. The left anode grid 5 and the right anode grid 2 are symmetrically arranged with the cathode filament 1 as the center. The anode grid is connected to a high potential to provide an extraction electric field for the hot electrons emitted by the cathode filament 1, accelerate the hot electrons, increase the energy of the hot electrons, and make the hot electrons oscillate back and forth inside and outside the anode grid to increase the electron motion trajectory and collide with the space gas molecules to ionize.

[0028] The left and right ends of the left anode grid 5 and the right anode grid 2 are in a mesh structure, which is conducive to repelling the positive ions generated by ionization in the anode space to the ion collector with a lower potential for reception. The inner diameter of the anode grid is between 6mm and 16mm, and in the present embodiment, it is 15mm. The grid mesh wire diameter is between 0.1mm and 0.4mm, and in the present embodiment, it is 0.2mm.

[0029] The ion collector is a metal filament structure, which reduces the area of the ion collector and in turn reduces the adverse effects of x-ray effects, effectively prolongs the lower limit of measurement, and the filament diameter is between 0.4mm and 0.8mm, and in the present embodiment, it is 0.6mm. The ion collector comprises the left ion collector 6 and the right ion collector 3, and is respectively located on the axis of the left anode grid 5 and the right anode grid 2, and is symmetrically arranged with the cathode filament 1 as the center, for collecting the positive ions ionized in the ionization region.

[0030] The metal shell 4 is a cylindrical structure, which is connected and installed at the middle position. The potential of the metal shell 4 is arranged to be grounded to prevent the escape of electrons and make the electrons oscillate inside and outside the anode grid. The inner diameter is between 20mm and 40mm, and in the present embodiment, it is 30mm.

[0031] In this embodiment, the cathode filament 1, the right anode grid 2, the right ion collector 3, the metal shell 4, the left anode grid 5 and the left ion collector 6 are coaxially arranged, and when working in a magnetic field environment, the axial arrangement direction is arranged parallel to the magnetic field direction, so that the emitted electrons perform reciprocating spiral motion in the direction parallel to the magnetic field under the restriction of the magnetic field.

[0032] The above only describes the preferred embodiments of the present application, and those of ordinary skill in the art can make modifications, equivalent replacements and improvements to the present application within the spirit and principles of the present application, and these modifications and improvements shall be included in the protection scope of the present application.

Claims

1. A high-sensitivity hot-cathode ionization gauge capable of measuring in a strong magnetic field environment with a lower lower limit, characterized in that it comprises a cathode filament (1), an anode grid, an ion collector, and a metal housing (4); wherein, The cathode filament (1) is a spiral thick filament structure; the anode grid comprises a right anode grid (2) and a left anode grid (5), the left anode grid (5) and the right anode grid (2) are mesh structures at left and right ends, the anode grid is a spiral structure or a cage structure; the ion collector comprises a right ion collector (3) and a left ion collector (6), the ion collector is a metal filament structure, the diameter is between 0.4mm and 0.8mm, the left ion collector (6) and the right ion collector (3) are respectively located on the axis of the left anode grid (5) and the right anode grid (2) and are symmetrically arranged with the cathode filament (1) as the center; the metal shell (4) is a cylindrical structure; the cathode filament (1), the right anode grid (2), the right ion collector (3), the metal shell (4), the left anode grid (5) and the left ion collector (6) are coaxially arranged and work in a magnetic field environment, and the axial arrangement direction is parallel to the magnetic field direction.

2. The high-sensitivity hot-cathode ionization gauge capable of being used in a strong magnetic field environment and having a lower lower limit of measurement according to claim 1, characterized in that: The cathode filament (1) is a spiral thick filament structure, which is used to resist the Ampere force in a strong magnetic field, and the filament material is tungsten or tungsten alloy.

3. The high-sensitivity hot-cathode ionization gauge with lower lower limit of measurement in a strong magnetic field environment according to claim 2, characterized in that: The cathode filament (1) has 1.5 turns, the filament diameter is between 0.2mm and 0.6mm, and the spiral diameter is between 2mm and 10mm, and the cathode filament (1) adopts a direct current power supply or an alternating current power supply mode.

4. The high-sensitivity hot-cathode ionization gauge with lower lower limit of measurement in a strong magnetic field environment according to claim 1, characterized in that: The anode grid is a spiral structure or a cage structure, which comprises a right anode grid (2) and a left anode grid (5), and the left anode grid (5) and the right anode grid (2) are symmetrically arranged with the cathode filament (1) as the center.

5. The high-sensitivity hot-cathode ionization gauge with lower lower limit of measurement in a strong magnetic field environment according to claim 4, characterized in that: The left anode grid (5) and the right anode grid (2) are mesh structures at left and right ends, the anode grid inner diameter is between 6mm and 16mm, and the grid mesh wire diameter is between 0.1mm and 0.4mm.

6. The high-sensitivity hot-cathode ionization gauge with lower lower limit of measurement in a strong magnetic field environment according to claim 1, characterized in that: The metal shell (4) is a cylindrical structure, which is connected and installed at a middle position, the potential is arranged to be grounded, and the inner diameter is between 20mm and 40mm.

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