DD141737A1 - DISCHARGE TUBE AND METHOD FOR REGENERATING GAS DISCHARGE LASERS - Google Patents

Abstract

Discharge tube and method for regenerating gas discharge lasers with helium filling. The invention relates to the design and treatment of noble gas lasers which become unusable by helium outdiffusion. The aging of a blown gas laser is greatly reduced by surrounding the discharge tube with a vacuum-tight cavity containing helium. The back diffusion of helium is done by observing the radiant power and allowing the regeneration of gas lasers. For example, gas lasers of any design are fired and operated in a regeneration vessel filled with helium until the normal radiator performance is restored. 2 shows the gas laser 6 in the cavity 8 with the radiation power meter 5. -Figur-

Description

Field of application of the invention

The invention relates to a discharge tube and a method for regenerating gas discharge lasers with helium filling.

Characteristic of the known technical solutions

In the known noble gas lasers whose laser-active gas filling contains helium fractions, the laser power is dependent on the total gas pressure and the partial pressures of the gas components in the discharge tube. For the total gas pressure and the partial pressures in the discharge tube, there is a value at which maximum laser power is achieved. Deviations from even one of these

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Values cause the laser to lose power, which can lead to photostimulation. , -

Is is known that change the pressure conditions in the resonator chamber and the efficiency deteriorates when operating a gas laser. Pas has different causes. The temperature increase and the electrical pressure lead to a change in the gas composition and to a diffusion of gas components to the cathode.

A technical solution for maintaining the pressure conditions in the resonator chamber is that additional hydrogen is added and a circulation of the working gas is carried out with flow velocities of 280 m / s.

Another means for regulating the gas pressure, in particular with molten gas lasers is a gas reserve chamber and an additional connecting line between the cathode and anode chamber, the inner wall is covered with getter means and the Sber the additional cross-section enables the back diffusion to the anode.

Tight measures, however, are only insufficiently suitable to prevent the reduction of the efficiency of molten gas laser during operation and to increase the life of the discharge tube, because the composition of the working gas changes in operation permanently by outdiffusion of helium. As a result of this naturally occurring and inevitable helium outdiffusion, reductions in the radiant power and finally complete exposure of the laser radiation with the gas discharge still present result over time.

Object of the invention "

The invention aims at increasing the lifetime of helium filling gas discharge lasers, extending their service life under conditions of maximum laser emission, and regenerating

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ration of discharge tubes rendered useless by helium outdiffusion ·

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Outline of the essence of the invention

The object of the invention is to stop the aging of a molten gas laser by preventing or greatly reducing the outdiffusion of helium through the glass body of the gas discharge tube.

Furthermore, discharge tubes whose helium pressure has fallen below the optimum pressure are to be regenerated. The effect is exploited here that helium diffuses markedly through glasses.

According to the invention, this object is achieved in that the discharge tube is surrounded by a second wall "helium is passed into the resulting, the discharge tube surrounding cavity until about a helium partial pressure as in the tube interior is reached," Thereafter, this cavity is vacuum-tight against the outside atmosphere-complete ·

According to the invention, discharge tubes of gas discharge lasers surrounded by a second wall are regenerated, if their radiant power has been reduced or lost by helium outdiffusion.

For this purpose, the cavity surrounded by the second wall is filled for several hours with pure helium of approximately atmospheric pressure. The gas discharge in the laser tube is to be ignited at the beginning of this regeneration and maintained during the entire regeneration period.

Due to the difference in the helium partial pressures outside and inside the gas discharge tube, helium will diffuse into the tube interior and the helium partial pressure inside the tube will increase again.

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Because of the large partial pressure differeos between inside and outside much more helium diffuses into the tube interior during this regeneration in the unit of time than helium diffused out during normal aging. As a result, the proportion of helium in the laser gas relatively quickly approaches the target value again. With the aid of a radiation power measurement, it is possible to observe the increase of the laser radiation power and to determine the time of the maximum of the radiation power at which the radiation power begins to sink again.

As soon as this time is reached, the helium pressure in the cavity surrounded by the second wall must be lowered again to the value of the helium partial pressure prevailing in the interior of the discharge tube and then the vacuum-tight closure of the cavity against the outside atmosphere is required.

Similarly, according to the invention, aged discharge tubes are regenerated by gas discharge lasers which are not enclosed by a cavity surrounded by a second wall. For this purpose, the laser head is exposed to the discharge tube in a regeneration tank for several hours a pure helium atmosphere of about atmospheric pressure. The gas discharge in the laser tube is to be ignited at the beginning of the regeneration and maintained during the entire regeneration time with tuned optical resonator of the laser. The increase in the helium partial pressure in the interior caused by the helium pressure difference between the discharge tube interior and the surroundings of the discharge tube can be observed by measuring the growth or insertion and growth of the laser power. Once the laser power has reached its maximum value, discontinue the regeneration process by removing the laser head from the helium atmosphere and exposing it more normally *

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Embodiment 1

The invention will be explained with reference to schematic representations. Figure 1 illustrates the discharge tube 1 of a gas discharge laser, which is surrounded by a second wall 2, whereby the cavity 3 almost completely surrounds the discharge tube 1 · filler neck 4- allow the cavity 3 according to the invention to fill with helium, Ms about a helium partial pressure is reached in the interior of the discharge tube · Then the filler neck are sealed vacuum-tight, optionally melted. In this case, an increase in the operating time is achieved because the aging process is delayed.

If the discharge tube to be regenerated, the cavity 3 is to be filled with pure helium of about atmospheric pressure and the gas discharge is to ignite. With the help of a radiation power measurement, the increase of the laser power is followed up to the desired value and then the helium partial pressure in the cavity is again adapted to the internal value.

A second example is intended to explain the regeneration of gas discharge lasers which do not have a cavity formed by a second wall.

A gas discharge laser 6 of this type is shown in Fig. 2 in a regeneration vessel 7, for example, a plastic sheath, given so that the discharge tube including the laser head are in the cavity 8. A radiation power meter 5 makes it possible to determine the laser power. The regeneration process is initiated by the filling of the cavity 8 with helium of about one atmosphere and by igniting the gas discharge in the discharge tube of the gas discharge laser and is terminated when the maximum power is reached.

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A variant of this arrangement for regeneration is shown in FIG. 3. Here, the regeneration container 7 is made transparent by the exit window 9, thus the radiation power meter 5 can remain outside the regeneration container.

Claims (3)

claim A discharge tube of a gas discharge laser, characterized in that the discharge tube (1) is surrounded by a second wall (2) and the cavity (3) is sealed vacuum-tight to the outside and filled with helium, which is about * the same partial pressure as the helium in the discharge tube under normal laser conditions · 2. Method for Regenerating Gas Discharge Lasers, characterized in that in a discharge tube aged or precipitated by helium outdiffusion, a surrounding cavity is filled with pure helium of atmospheric pressure until the helium partial pressure corresponding to the normal laser power returns to the discharge tube when the gas discharge is ignited has set · 3 · A process according to pt. 2, characterized in that the arrival · grow the Heliumpartialdruckes inside of the discharge tube during the regeneration and the achievement of the normal value are determined by the at tuned optical resonator and ignited gas discharge during the entire regeneration ¹ time Laser power is measured « For this Λ page. Drawing.