Gas laser

According to the invention, the gas laser comprises a housing which accommodates two electrodes. One of the electrodes is sectional and has a ballast resistor connected to each section. One of the electrodes is so secured in the housing that it is possible to vary the spacing between the electrodes in the direction of the flow of a gas mixture passed through an active zone between the electrodes where the laser effect is produced. The invention provides for a maximum efficiency of the laser under different operating conditions.

FIELD OF THE INVENTION 
The present invention relates to stimulated radiation devices and, more 
particularly, to gas lasers. 
The invention can be used to advantage in different industries and is 
applicable to welding, cutting and heat treatment of different materials. 
BACKGROUND OF THE INVENTION 
There are many production processes in which laser technology proves to be 
superior to conventional techniques of working materials. The laser beam 
is particularly effective in special processes involving such factors as 
aggressive media and radiation. Production processes of this type call for 
gas lasers of ever increasing power, which makes it extremely important to 
maintain optimum operating conditions of such lasers. 
There is known a gas laser comprising a housing which accommodates two 
electrodes. One of the electrodes is sectional and has a ballast resistor 
connected to each of its sections. A gas mixture is passed through an 
active zone between the electrodes, where the laser effect is produced. 
Both electrodes are rigidly fixed. 
However, only one mode of operation can be optimized with the fixed 
arrangement of the electrodes. 
The laser under review has other disadvantages. It is known, for instance, 
that the electric resistance of the gas mixture in the active zone, where 
the laser effect is produced, is not constant in the direction of motion 
of the gas mixture. In order to equalize the current flowing through the 
ballast resistors, such resistors are selected so that their resistance 
values increase as the sections of the sectional electrode become 
increasingly remote from the inlet through which the gas mixture is forced 
to the active zone wherein the laser effect is produced. This complication 
makes gas lasers hard to manufacture and operate. 
Furthermore, any variation in the parameters of the gas mixture, such as 
the composition or pressure, cuases a change in the electric 
characteristics of the active zone where the laser effect is produced. 
This affects the uniformity of current distribution among the individual 
sections of the sectional electrode, which, in turn, reduces the 
efficiency of the laser and in some cases is the cause of an arc 
discharge. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to ensure a maximum efficiency of 
gas lasers in different operating conditions. 
It is another object of the invention to provide a gas laser featuring a 
maximum efficiency in different operating conditions. 
It is still another object of the invention to increase the gas laser 
output. 
It is yet another object of the invention to reduce resistance values of 
the ballast resistors. 
The foregoing objects are attained by providing a gas laser comprising a 
housing which accommodates two electrodes, whereof one is sectional and 
has a ballast resistor connected to each of its sections, the laser effect 
being produced in an active zone between the electrodes, through which a 
gas mixture is passed, the gas laser being characterized, according to the 
invention, in that one of the electrodes is so secured in the housing that 
it is possible to vary the spacing between the electrodes in the direction 
of the gas mixture flow.

DETAILED DESCRIPTION OF THE INVENTION 
The gas laser according to the invention comprises a housing 1 (FIG. 1) of 
an electrically insulating material, which accommodates two electrodes 2 
and 3. One of these is a section electrode, whereas the other is a 
plate-type electrode. The electrode 2 is the cathode, and the electrode 3 
is the anode. Each section 4 of the electrode 2 is connected to one of the 
leads of a ballast resistor 5 having its second lead connected to a first 
input terminal 6. A second input terminal 7 is connected to the electrode 
3. The latter is secured in the housing 1 by means of an articulated joint 
8 (FIGS. 1 and 2) so that it is possible to vary the spacing between the 
electrodes 2 and 3 in the direction of the gas mixture flow. The gas laser 
of this invention is provided with a means 9 for adjusting the deflection 
of the electrode 3. The means 9 is a screw pair comprising an adjusting 
screw 10 and a threaded hole 11 provided in the housing 1. The screw 10 is 
driven through the hole 11 to be in contact with the electrode 3. The 
laser effect is produced in an active zone 12 between the electrodes 2 and 
3 (FIG. 1), through which the gas mixture is passed. The housing 1 further 
accommodates a gas mixture pumping means 13 and a heat exchanger 14 for 
cooling the gas mixture. The means 13 and heat exchanger 14 communicate 
with each other and with the active zone 12. The gas laser also includes a 
cavity 15 whose optical axis 16 traverses the zone 12. 
The gas laser according to the invention operates as follows. 
A high-voltage source (not shown) is connected to the input terminals 6 and 
7. The means 13 forces a gas mixture flow at a predetermined velocity 
through the active zone 12 where the laser effect is produced. The 
direction of the gas mixture flow is indicated by the arrow. 
The high voltage applied to the electrodes 2 and 3 produces a discharge 
possessing prescribed parameters in the active zone 12; as a result, there 
is a flow of current through the ballast resistors 5. A change in the 
parameters of the gas mixture, such as the composition or pressure, alters 
the electric characteristics of the active zone 12 and effects the 
uniformity of the distribution of currents flowing through the sections 4 
of the electrode 2 and the ballast resistors 5. 
The means 9 for adjusting the deflection of th electrode 3 secured in the 
housing 1 by means of the articulated joint 8 ensures a maximum efficiency 
of the laser in different operating conditions. This is done with the aid 
of the adjusting screw 10 which is in direct contact with the electrode 3. 
The screw 10 brings the electrode 3 to a position which compensates for 
the changes in the electric characteristics of the active zone 12 and 
restores the uniformity of the distribution of currents flowing through 
the ballast resistors 5. 
The invention eliminates the necessity of imposing stringent accuracy 
requirements upon the selection of ballast resistors, which makes it 
easier to manufacture and operate gas lasers.