RU2638566C2 - Method of increasing reliability of ring laser gyroscopes - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: ring laser gyroscope is placed on a vacuum post, pumped to a high vacuum, the tightness is checked. The internal volume of the resonator is cleaned by repeating three times the sequence of operations: filling with oxygen, burning in the discharge of oxygen, pumping out. Then the following sequence of operations is repeated three times: filling the resonator with a mixture of oxygen with neon, burning in the discharge of these gases, pumping out, then degassing the getters installed in the gyroscope. Cool screens are installed on the electrodes of the ring laser gyroscope and connected to a coolant or gas supply system. The gyroscope housing with the installed screens is heated to the temperature of 260°C, with a constant supply of cooling liquid or gas, degassing for 48 hours and after cooling to the temperature of 50-60°C threefold filling of the working helium-neon mixture, operating and pumping are performed. Then, the getters are activated, the helium-neon mixture is filled to the working pressure, the electrical parameters are measured, and the sealing is performed.

EFFECT: increasing the reliability of ring laser gyroscopes by increasing the tightness of the indium compound of the glass-ceramic housing with gold-plated anodes and increasing the efficiency of degassing the internal volume of the ring laser gyroscope from sorbed impurity gases.

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Description

The present invention relates to the field of laser technology, namely to ring monoblock laser gyroscopes designed to measure the angular velocity of rotation.

It is known to seal glass or ceramic with metal, which makes it possible to create a tight connection between the metal surface and the surface of glass or glass ceramics [US Patent No. 4432660, class. F19C 9/00, published 02.21.1984]. According to the invention, the tightness of this compound is maintained upon repeated cyclic temperature changes ranging from -50 ° C to + 100 ° C.

To achieve this result, the surface of the connected glass or glass ceramics should be as clean as possible. To obtain an ultrapure surface of glass or glass ceramics, it is bombarded with plasma, or ions in a vacuum, or ultraviolet light.

When the base metal is aluminum, the surface of the aluminum is first polished to match the quality of the surface of the glass or glass ceramic. Then nitric acid is used to etch aluminum, and its excess is washed off, mainly in distilled water. Next, the metal is annealed, and the metal surface is molded, pressing it to a smooth polished surface. For molding, it is preferable to use glass or a glass-ceramic surface, since aluminum does not adhere to this surface and its flatness is preserved after repeated operations.

Gold is then applied to the surface of aluminum, gold can be applied galvanically, but it has been found that sputtering or applying molten gold to the molded surface of aluminum is preferred. The purity of gold should be about 99.5%. The typical thickness of gold after sputtering, application of molten gold or plating is less than 100 microinches.

A blank of indium is placed above the surface of the gold. The purity of indium is usually 99.9%. Then, indium and gold are heated, heating in vacuum is preferred, above the melting point of indium (155 ° C) to about 175 ° C, until indium is fused with gold on the surface.

The surface of indium is further cleared as much as possible, for example, in plasma or by ion bombardment, or by ultraviolet radiation. After cleaning, indium becomes very sticky and has good adhesion to any contacting surface. The ultrapure surface of indium is then pressed against the ultrapure surface of glass or glass ceramic to form a sealed vacuum joint.

When the metal is copper, copper is not etched with nitric acid, and gold is applied galvanically. The surface is not molded, but is ground using small (usually 1200 microns) particles before plating copper with gold.

The disadvantage of this invention is the low reliability, due to the low tightness of the connection of glass or glass ceramics with gold, copper through indium seal, under thermal cyclic influences. As the temperature rises above 100 ° C, intermetallic compounds of these metals begin to form intensively between indium and gold or copper. With repeated cyclic exposure to temperatures from -50 ° C to + 100 ° C, brittle indium intermetallic compounds are destroyed, as a result of which the tightness of the indium compound is broken.

The prototype of the invention is a method of vacuum processing of small-sized monoblock gas-discharge lasers [RF Patent No. 21545410, class. H01J 9/38 published 08/27/2000].

Moreover, according to the invention, this method includes connecting the laser to a vacuum post, pumping it to a high vacuum, checking the structure for leaks, cleaning the active gas in the discharge and checking the laser parameters in the working gas mixture, pumping and heating at the maximum temperature that the laser design allows, filling the laser with a mixture of working gases and its sealing, in which a device for selective absorption of impurities is installed on the laser, and during heating, the laser is filled with a mixture of working gases With a temperature of 13.3-50540 Pa, it is held for 1-4 hours and then the laser is again pumped out to high vacuum. Filling and pumping is carried out at least 2 times, and during the last pumping, the mass spectrum of the residual gases is measured, and pumping is carried out for the time necessary for the mass spectrum of the residual gases to coincide with the reference, which was measured at a vacuum station with the laser disconnected and extremely high for a given vacuum post vacuum, but not worse than 1.33 × 10 ^-4 Pa.

The disadvantage of the prototype is that during heating at the maximum temperature that the laser design allows, a temperature of up to 120 ° C is achieved. This temperature does not allow for effective degassing of the glass-ceramic case, from impurity gases adsorbed on internal surfaces. Also at this temperature, brittle indium intermetallic compounds begin to form, which lead to a violation of the tightness of the indium seal of the glass-ceramic case with gold-plated anodes of a ring laser gyro.

The technical task of the invention is to increase the reliability of ring laser gyroscopes by increasing the tightness of the indium compound of the glass-ceramic case with gold-plated anodes and increasing the efficiency of degassing the internal volume of the ring laser gyro from sorbed impurity gases.

The essence of the invention is as follows. An annular laser gyroscope 1 is mounted on a vacuum post through a shtangel-electrode 2, pumped out to a high vacuum, and the tightness is checked. The internal volume is cleaned by repeating the sequence of operations three times: filling with oxygen, burning in the discharge of oxygen, pumping. Then, the following sequence of operations is repeated three times: filling with a mixture of oxygen with neon, burning in the discharge of these gases, pumping. Next is the degassing of gas getters installed in the gyroscope 3.

Cooled screens 5 are mounted on the electrodes 4 of the ring laser gyro 1 and connected to the coolant (gas) supply system 6. In FIG. 1 shows the layout of the cooled screens 5 on the electrodes 4 of the ring laser gyroscope KL-3.

The gyroscope case with mounted screens 5 is heated to a temperature of 260 ° C with a constant supply of coolant or gas, gassing is carried out for 48 hours, and after cooling to a temperature of 50-60 ° C, three-fold filling of the working helium-neon mixture is carried out, operating time and pumping out. Next, the activation of getters 3, filling with a helium-neon mixture to operating pressure, measuring electrical parameters and sealing.

The installation of cooled screens 5 on the electrodes makes it possible to increase the degassing temperature from 120 ° C to 260 ° C, while connecting the electrodes 4 to the housing through an indium gasket 7 maintains tightness and reliability. The temperature of the electrodes in this case is in the temperature range from 50 ° C to 60 ° C, depending on the type of coolant (gas) and its flow rate. At this temperature, the intermetallic compounds of indium with gold are formed extremely slowly, which subsequently does not lead to a violation of the tightness of the indium seal under thermocyclic influences.

An increase in temperature contributes to the effective degassing of the internal volumes of the body of the ring laser gyroscope and the desorption of impurity gases on the surfaces of the body. In FIG. Figure 2 shows the emission spectrum of a KL-3 helium-neon ring laser after degassing at a temperature of 120 ° C. In FIG. Figure 3 shows the emission spectrum of a KL-3 helium-neon ring laser after degassing at a temperature of 260 ° C. Moreover, in the emission spectrum in FIG. 3 are absent shown in FIG. 2 spectral lines of impurity gases: nitrogen (N) - 391.4 nm, oxygen (O) - 394.7 nm, carbon monoxide (CO) - 395.3 nm and hydrogen (H) - 410.1 nm, which indicates effective removal of impurity gases from the inner surfaces of the housing with increasing temperature degassing.

Thus, in the proposed method, the installation of cooled screens, cooling of the electrodes and increasing the degassing temperature, compared with the prototype, improves the reliability of the ring laser gyroscope by ensuring the unchanged composition of the working helium-neon mixture during operation and storage.

Claims (1)

A way to increase the reliability of ring laser gyroscopes, which is that the ring laser gyro is mounted on a vacuum post, pumped to high vacuum, check for leaks, the internal volume of the resonator is cleaned by repeating the sequence of operations three times: filling with oxygen, burning in an oxygen discharge, pumping, then repeating three times sequence of operations: filling the resonator with a mixture of oxygen with neon, burning in the discharge of these gases, pumping out, then degassing is carried out gas absorbers in a gyroscope, characterized in that cooled screens are installed on the electrodes of the ring laser gyroscope and connected to a coolant or gas supply system, the gyroscope housing with installed screens is heated to a temperature of 260 ° C with a constant supply of coolant or gas, for 48 hours and after cooling to a temperature of 50-60 ° C, three-time filling with a working helium-neon mixture is carried out, operating hours and pumping out, then getters are activated, n complements a helium-neon mixture to the operating pressure, measurement of electrical parameters and sealing.

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