JP2564062B2 - Gas laser device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device which excites a gas laser medium by discharge to generate laser light.

[0002]

_2. Description of the Prior Art In a gas laser device such as an excimer laser or a CO ₂ laser, a main discharge is ignited before a main discharge is ignited in a discharge space between a pair of main electrodes arranged in an airtight container. Pre-ionization of the discharge space is performed. There are various methods for preionization, but part 1
As a method, a method using X-ray is known.

6 and 7 show a conventional preionization means utilizing X-rays. FIG. 6 uses a cold cathode transmission type X-ray generator 1. That is, 2 in the figure is an airtight container. In the airtight container 2, a pair of main electrodes, a cathode 3a and an anode 3b, are arranged so as to face each other with a space therebetween. Anode 3 placed on the upper side
In b, a concave portion 4 opened on the back side is formed over the entire length in the length direction. A transparent window 5 for transmitting X-rays is formed on the peripheral wall of the airtight container 2 facing the recess 4. The X-ray generator 1 is arranged outside the airtight container 2 facing the transmission window 5.

The X-ray generator 1 has an X-ray tube 6 having substantially the same length as the anode 3b. An anode 7 is provided on a side wall of the X-ray tube 6 facing the transmission window 5, and a cathode 8 is provided inside the X-ray tube 6 so as to face the anode 7. A high voltage is supplied to the cathode 8 from a high voltage power source (not shown). Further, a vacuum exhaust device 9 is connected to the X-ray tube 6 so as to maintain the inside thereof in a predetermined vacuum state.

However, according to such a configuration,
Since a large X-ray tube 6 having a length substantially the same as that of the anode 3b is required, it may be impossible to maintain the internal vacuum state unless the evacuation device 9 is constantly operated. Since 7 also serves as an X-ray window, the anode 7 cannot be cooled efficiently, so that it is difficult to perform high repetition operation or continuous operation for a long time, and laser light cannot be output efficiently. There was that.

The structure shown in FIG. 7 is a hot cathode reflection type, and a plurality of sealed X-ray tubes 11 are arranged so as to face the transmission window 5 formed in the airtight container 2. This X
The ray tube 11 is formed by arranging a cathode 12b and an anode 12c in a tube 12a made of a material that transmits X-rays.

According to the structure using the closed X-ray tube 11 having the above structure, it is possible to reduce the size, simplify the structure, and improve the maintainability. However, in the sealed X-ray tube 11 having the above structure, since the anode 12c is housed in the tube 12a, the anode 12c cannot be directly cooled. Therefore, as in the case shown in FIG. 6, when a high repetitive operation or a continuous operation for a long time is performed, such operation cannot be performed due to the heat loss of the anode 12c, and the laser light is also efficiently emitted. There was a case that it could not be output.

[0008]

As described above, the conventional X
Since it was not possible to cool the anode of the line source efficiently, it was not possible to perform high-repetition operation or continuous operation for a long time.
There have been cases where the laser light cannot be output efficiently.

The present invention has been made in view of the above circumstances. An object of the invention is to enable a highly repetitive operation and a continuous operation for a long time to efficiently output laser light. -To provide the device.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a pair of main electrodes facing each other in an airtight container in which a gas laser medium is sealed, and a discharge space between these main electrodes. In a gas laser device for pre-ionizing the parts by X-ray pre-ionization means prior to main discharge between the main electrodes, the pre-ionization means has a cylindrical shape and an X-ray transmission window is formed on one end face in the axial direction. A tube, a plurality of X-ray tubes each having a cylindrical anode closely attached to the inner wall of the tube and a cathode arranged so as to be surrounded by the anode, and a circulation path for circulating a cooling medium on the peripheral wall. And a case that accommodates the plurality of X-ray tubes arranged side by side.

[0011]

According to the above construction, since the anode can be directly and efficiently cooled by the case, it becomes possible to continuously irradiate the discharge space with X-rays with high repetition and for a long time. -The light can be output efficiently.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The gas laser device shown in FIG.
The airtight container 21 has a double-cylinder shape and includes an inner cylinder 21b and a cylinder 1a. A gas laser medium is enclosed in the airtight container 21, and the gas laser medium can be circulated in the direction of the arrow in an annular circulation path formed in the airtight container 21 by a blower 22 disposed inside. It has become.

A pair of heat exchangers 23 are arranged in the circulation path, and an anode 24 and a cathode 25 which are main electrodes are provided.
And are spaced apart and opposed to each other in the vertical direction, and are arranged along a direction orthogonal to the flow direction of the gas laser medium. The anode 2
Reference numeral 4 is attached to an upper holder 26 provided on the outer cylinder 21a, and the cathode 25 is attached to a lower holder 27 provided on the inner cylinder 21b. A peaking capacitor 28 is provided on the back side of the cathode 25, and the cathode 25 and the anode 2 are provided.
4 is connected by a conductor 29 via a peaking capacitor 28. A high voltage pulsed from a high voltage power source (not shown) is input to the anode 24 and the cathode 25 via the conductor 29.

The anode 24 is formed with a recess 31 open to the back side thereof. A through hole 32 having a length substantially corresponding to the concave portion 31 is formed at a position corresponding to the concave portion 31 of the upper holding body 26, and a housing step portion 33 is formed around the through hole 32. . Preliminary ionization means 34 is provided on the storage step portion 33. The preionization means 34 has a case 35 made of a metal having a high thermal conductivity such as copper. A circulation path 36 for circulating a coolant such as cooling water is spirally formed on the peripheral wall of the case 35.

In the case 35, a plurality of hollow cylindrical accommodating portions 37 are defined by partition walls 35a which are erected at predetermined intervals in the longitudinal direction. Further, a through hole 37a is formed at the bottom of the case 35 and extends over the entire length in the longitudinal direction. The through hole 37a communicates with the through hole 32 formed in the upper holding body 26. In addition, each storage unit 37
An X-ray tube 38 is housed in. As shown in FIG. 5, this X-ray tube 38 is made of a cylindrical KOV and has a cylindrical anode 39 on its inner wall. This X-ray tube 38 is KO
It is formed of a metal such as V, tantalum, or tungsten. An X-ray transmission window 41 made of beryllium is formed on one end surface of the anode 39, and the other end surface is closed by an insulating member 42 made of a glass material or the like.

Inside the anode 39, a cathode 43 is provided.
Are housed, and both ends are airtightly led out from the insulating member 42. The cathode 43 is an impregnated cathode formed by a wire rod in which tungsten is impregnated with barium, and is concentrically housed in the anode 39. The X-ray tube 38 is housed in each housing 37 with the transmission window 41 facing the through hole. X-ray tube 3
In the state where 8 is accommodated in the accommodating portion 37, the outer peripheral surface of the anode 39 is in contact with the inner peripheral surface of the accommodating portion 37 via the X-ray tube 38. A heater circuit 44 is connected to the cathode 43. Further, a negative high voltage pulse is applied to the cathode 43 from an X-ray pulse power source (not shown). The X-ray tube 38 is a case 35.
Grounded through.

In the gas laser device having the above structure, first, the cathode 43 of the X-ray tube 38 is heated by the heater circuit 44. To generate laser light in that state, a trigger pulse is input to the X-ray pulse power source and a negative high voltage pulse is applied to the cathode 43. As a result, the thermoelectrons emitted from the cathode 43 are transferred to the anode 39.
And an X-ray is generated. The X-rays are emitted from the transmission window 41, pass through the through hole 37a of the accommodating portion 37 and the concave portion 31 of the anode 24, and irradiate the space between the anode 24 and the cathode 25, that is, the discharge space S, and the discharge The space S is preionized. As the preionization in the discharge space S progresses, the main discharge is ignited between the anode 24 and the cathode 25, and the gas laser medium in the discharge space S is excited, thereby generating laser light. To do.

A case 35 accommodating and holding the X-ray tube 38.
Refrigerant circulates in the circulation path 36 of the housing 35 of the case 35.
The peripheral wall forming 7 is cooled. The X-ray tube 38 is in contact with the inner peripheral surface of the peripheral wall of the accommodating portion 37. for that reason,
Since the anode 39 of the X-ray tube 38 is cooled by the case 35, the X-ray tube 38 is cooled by the X-ray tube 38 without causing damage due to heat generation.
The wire tube 38 can be operated with high repetition and for a long time. As a result, the number of repetitions of main discharge is increased and
The output can be increased.

Further, since the anode 39 of the X-ray tube 38 is formed into a cylindrical shape, X-rays from the X-ray tube 38 are anodic.
It is emitted only in two directions along the axial direction of 9. Therefore, the X-ray shield of the X-ray tube 38 can be surely performed with a simple structure. Further, since the X-ray tube 38 is a closed type, it does not need to be exhausted by the vacuum exhaust device, so that the structure can be downsized and simplified. Moreover, since the X-ray tube 38 having a reduced degree of vacuum is only taken out from the housing portion 37 and replaced, maintenance is easy. Further, by controlling the current flowing through the cathode 43 of each X-ray tube 38, it is possible to uniformly perform the preionization of the discharge space S. Although in the above-described embodiment, the direct heat type impregathode is used as the cathode, it is also possible to use the indirectly heated impregathoid.

[0020]

As described above, according to the present invention, the X-ray preionization means for preionizing the discharge space between the pair of main electrodes is provided with the case in which the circulation path for circulating the cooling medium is formed on the peripheral wall. A tube having a cylindrical shape and an X-ray transmission window formed on one end surface in the axial direction, and a cylindrical anode closely attached to the inner wall surface of the tube.
And a plurality of X-ray tubes formed from a cathode arranged inside the anode and accommodated side by side in the case. Therefore, the anode of the X-ray tube can be satisfactorily cooled by the case, so that the X-ray tube can be operated with high repetition for a long time.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a case portion.

FIG. 3 is an enlarged cross-sectional view of a part of X-ray preionization means.

FIG. 4 is a sectional view taken along the line BB of FIG.

FIG. 5 is a sectional view of an X-ray tube.

FIG. 6 is a schematic view of a conventional gas laser device.

FIG. 7 is a schematic view of a gas laser device showing another conventional example.

[Explanation of symbols]

21 ... Airtight container, 24 ... Cathode (main electrode), 25 ... Anode (main electrode), 34 ... X-ray preionization means, 35 ... Case,
36 ... Circulation path, 38 ... X-ray tube, 39 ... Anode, 41 ...
Transparent window, 43 ...

Claims (1)

(57) [Claims] 1. A pair of main electrodes are opposed to each other in an airtight container in which a gas laser medium is sealed, and a discharge space between these main electrodes is preliminarily X-ray-prepared before main discharge between the main electrodes. In the gas laser device for pre-ionization by the ionization means, the pre-ionization means is a tube having a cylindrical shape and an X-ray transmission window formed on one end face in the axial direction, and a cylindrical anode close to the inner wall of the tube. And a plurality of X-ray tubes each having a cathode arranged so as to be surrounded by the anode, and a circulation path for circulating a cooling medium is formed on a peripheral wall to accommodate the plurality of X-ray tubes in parallel. -A gas laser device, characterized in that