JPS61226628A - Vacuum gage - Google Patents

Abstract

PURPOSE:To facilitate electric discharge even at an area with low pressure by providing a filament to the inside of a vacuum gage and making a thermion and gas generating from the filament a trigger of the electric discharge. CONSTITUTION:The filament 9 is provided to the inside of an electrode through a hole made on the cathode 2 or an insulator 10 via the insulators 11 and 12 in a vacuum vessel 4. In case the electric discharge is not generated by closing a point of contact 13 and impressing the electrode with the high voltage by an electric source 7, a point of contact 15 is closed and electricity is turned on the filament 9 and the thermion and the gas adsorbed on the filament are discharged by which both make the trigger and generate the electric discharge and the pressure measurement is made possible. Once the electric discharge is generated within the measuring range of the vacuum gage, the subsequent measurement is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a discharge-type vacuum measurement that measures pressure using a discharge current, and particularly to a vacuum gauge that facilitates the initiation of discharge even on the high vacuum side.

[Background of the invention]

Conventional magnetic field? The discharge type ionization vacuum gauge used was published in ``Physics and Applications of Vacuum (1981) J (Kumagai, Tominaga, and 2 others).
The structure shown in FIG. 6-30 is widely used. Next, a measurement method using the vacuum gauge will be explained using FIGS. 10 to 3. The dXx diagram schematically shows the vacuum gauge and the inspiratory circuit for measurement. Two opposing cathodes 1 and 2 are placed in a vacuum container 4 with an insulator 5 in between, and a magnetic field B is applied to them in a perpendicular direction. Further, a cylindrical anode 3 parallel to the magnetic field is provided with an insulator 6 interposed therebetween. There is a high pressure fjL between the cathodes 1 and 2 and the anode 3.
A high voltage is applied by source 7. At this time, due to the above voltage, fcW! is emitted from the cathode 1.2. The lion moves back and forth between the cathodes 1 and 2 many times while performing a spiral motion due to the magnetic field. In response to this, the electrons are separated from all gas molecules, and ions are generated between the cathode and anode, and these ions flow into the cathode.

As a result, an electric field appears in a direction perpendicular to the magnetic field B, which has a greater force on the electrons, and the electrons flow toward the anode 3, causing a discharge. The pressure can be determined by measuring this discharged L current with an ammeter 8. Figure 2 shows the relationship between pressure and discharge DC. However, as shown in Figure 3, the above-mentioned discharge-type ICM vacuum gauge has the problem that in low-pressure areas, it takes a long time to discharge after voltage is applied, or that discharge does not occur. Ta.

[Purpose of the invention]

An object of the present invention is to provide a discharge f11m ionization vacuum gauge that facilitates discharge Wt even in a low pressure region.

[Summary of the invention]

Even in the pressure range where discharge occurs, once discharge occurs,
The discharge continues. Therefore, the present invention focuses on electrons and ions, which are the triggers of discharge, and attempts to generate them externally.For this purpose, a filament is installed inside the JIC empty space, and the filament and ions are generated externally. The generated thermoelectrons and gas are used as a trigger for discharge.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows the entire vacuum gauge according to the present invention, including a sectional view of the vacuum gauge and a schematic diagram of the circuit. In the figure, 4 indicates a vacuum container, and within this vacuum container 4, two opposing cathodes 1°2 are installed with an insulator 5 in between, and a magnetic field B is applied to them in the perpendicular direction. ing. Further, an anode 3 parallel to the magnetic field is provided with an insulator 6 interposed therebetween. A voltage is applied between the cathodes 1 and 2 and the anode 3 by high voltage IK#7. Furthermore, inside the vacuum container 4, an insulator 11 is provided.
A filament 9 is provided inside the electrode through a hole drilled in the cathode 2 or through the insulator 1 (1).

Since the present invention has the above-described configuration, if no discharge occurs even if the contact 13 is closed and a high voltage is applied to the electrode by the power source 7 within the measurement range of the discharge type ionization vacuum gauge, The contact 15r is closed and the filament 9iC is energized to release the thermoelectrons and the gas adsorbed on the filament. Both act as a trigger and release N! t- wake up and pressure measurement becomes possible. Once a discharge occurs within the measurement range of the vacuum gauge, subsequent measurements are possible.

In Fig. 4, the filaments are installed inside the cathode and anode, but as shown in Fig. 5, the filaments 9 are placed outside the electrodes.
Even if there is, the effect of the present invention can be obtained. In addition, the control circuit 1
6 was installed, no discharge occurred, and the current meter 8 was set, and the discharge flL
It is also possible to provide a discharge trigger circuit that automatically closes the contacts of the power source 13 when the backward flow is zero, and opens the power source 13 when the broadcast magnetic current flows.

〔Effect of the invention〕

As explained above, according to the present invention, when no discharge occurs, it is possible to apply a trigger using thermionic electrons and gas, enabling the discharge to occur and achieving normal vacuum measurement.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view and circuit diagram of a conventional vacuum gauge, Figures 2 and 3 are diagrams explaining the characteristics of a conventional vacuum gauge, Figure 4,
FIG. 5 is a sectional view and a schematic diagram of a circuit of a vacuum gauge according to the present invention. DESCRIPTION OF SYMBOLS 1, 2... Cathode, 3... Anode, 4... Vacuum container, 9... Filament, 10... Hole or insulator. ■ 1 Mouth 1g Tomi Z Diagram Eka (lσ1p) l nin/7 (zuri r) Fuji 4 n B Fuji 5 Diagram

Claims (1)

[Claims] 1. Two or more cathodes facing each other, an anode that applies a magnetic field perpendicular to the cathode surface and is provided parallel to the magnetic field, and a vacuum container that houses these cathodes and anodes. The electrode is supported on the flange via an insulator, and by applying a high voltage between the cathode and the anode, a discharge occurs due to electrons emitted from the cathode, and the discharge current is detected. A vacuum gauge for obtaining a pressure indication value, characterized in that a filament is installed in the vacuum container. 2. The vacuum gauge according to claim 1, wherein the filament is automatically energized when no discharge occurs even when a voltage is applied to the electrodes, and the filament energization is stopped after discharge.