JPH03139890A - X-ray preliminary ionization pulse laser device - Google Patents

Abstract

PURPOSE:To use a switching element which is for small current and low voltage and whose rise time is rather long by connecting, in parallel, a capacitor for main discharge to the main discharge part formed by a pair of main electrode, and further providing an X-ray generator, which produces plasma by applying generated X-ray to the main discharge part and causes pulse discharge between main electrodes. CONSTITUTION:A switching element 23 is closed, and a capacitor 3 for creeping discharge is discharged so as to cause creeping discharge on the surface of a base 9 within a vacuum chamber 21 and to generate X rays. The X rays generated here penetrate the diaphragm 17 of a main electrode 5 and are applied to a main discharge part M and generate plasma. As a result, the impedance of the main discharge part M drops, and a capacitor 1 for main discharge performs discharge between the main electrodes 5 and 7 and pumps laser gas to output a laser beam and perform laser oscillation. This X-ray generator (S) 15 may be provided behind both main electrodes 5 and 7 or behind either main electrode 5 or 7. Hereby, as a switching element 23, the one which operates by a low voltage enough to cause creeping discharge and whose rise time is long can be used.

Description

[Detailed Description of the Invention] [Objective of the Invention J (Field of Industrial Application) This invention aims to excite a laser medium such as an excimer laser, a halogen gas laser, a TEACO2 laser, a metal vapor laser, etc. by pulse discharge, and create a resonator. The present invention relates to a pulse laser device that performs laser oscillation using.

(Prior Art) Excimer lasers, halogen gas lasers, TEACO2 lasers, metal vapor lasers, and the like are available as laser devices that excite laser gas to perform pulsed laser oscillation.

Except for high-output electron beam excitation, these are generally discharge excitation.

FIG. 6 shows an example of a conventional discharge-excited pulsed laser circuit.

This is designed to perform pulsed discharge by applying pulsed voltage to two main electrodes 101 and 103 placed oppositely in laser gas.

In order to stably perform this pulse discharge, 5iIl is used in advance.
Preliminary ionization is usually performed using i-electrons, and normal preionization is performed using multiple spark gaps 1 installed near the electrodes.
This is done using ultraviolet rays generated from the arc discharge of 05.

In the case shown in FIG. 6, this preliminary discharge is performed by a separate pulse circuit.

In the figure, 107 is a capacitor, 109 is a switching element, 111 is a charging resistor, and 113 is an inductance.

The timing of the preliminary discharge and the main discharge is such that the main discharge is delayed by several tens of nanoseconds to several hundred nanoseconds rather than the preliminary discharge.

FIG. 7 shows a system in which the preliminary discharge and main discharge are performed in one circuit, which is called an automatic preliminary ionization type.

To briefly explain this operation, by short-circuiting the switching element (thyratron) 109, current flows from the pre-charged capacitor 107 through the spark gap 105, and the capacitor 114 is charged.

At this time, when preliminary ionization is performed and the capacitor 107 is sufficiently charged, discharge occurs between the two main electrodes 101 and 103, and laser oscillation is performed.

In addition, in the conventional method, the switching element required for the main discharge circuit has a very fast rise time of 1 Qns to 10 Qns, and a very large peak current of several KA to several tens of KA. Something that can flow is needed.

Currently, thyratrons are used for this switching element, but they have become very expensive.

Additionally, this thyratron had a short lifespan, making it unreliable.

One idea to solve these drawbacks is to use the discharge section itself as a switching element without using a switching element in the main discharge circuit.

That is, by applying a high voltage between the anode and cathode and pre-ionizing the discharge area, plasma is generated in the discharge area.
It causes electric discharge.

Ultraviolet preionization has been used for this preionization, but the preionization is not very strong and the spatial pattern is poor, so the discharge tends to become unstable, so it has not been put to practical use.

Further, when X-rays are used as a pre-ionization source, more powerful pre-ionization with good spatial uniformity can be performed, and a high-output, high-efficiency, high-repetition pulsed laser can be realized.

However, this X-ray source uses a field emission cathode or a hot cathode, and requires a switching element that can withstand high voltage.

A conventional example using a field emission type cathode is shown in FIG.

To explain this conventional example, a field emission type cathode 119 and an xi generating anode 121 made of an S film such as tantalum are arranged inside a vacuum sealed chamber 117 provided on the back side of a main electrode 115 which is a cathode. Ogi, capacitor 123 in advance
By charging the main electrode (cathode) 1 and short-circuiting the high voltage switching element (thyratron) 125,
15. A high voltage is generated between the main electrode (anode) 127. Then, electrons 129 are emitted from the main electrode 115, accelerated toward the main electrode 127, and braking occurs when they collide with the main electrode 127. X-rays from the radiation are taken out to the discharge section M through a diaphragm 131 made of a thin film of titanium or the like.

At this time, the voltage applied to the capacitor 123 is several tens of K.
Since the voltage is high, V~200KV, switching element 1
25 requires something that can withstand high voltage, making it extremely expensive, short in durability, and low in reliability.

In FIG. 8, 133 and 135 are inductances, 137 are diodes, 139 are switching elements, and 141 are capacitors.

(Problems to be Solved by the Invention) As described above, in the conventional pulse laser device, the switching element required for the main discharge circuit is required to be able to flow a large current at high speed. The element currently used is a thyratron, which is extremely expensive, has a short lifespan, and is low in reliability.

There was an idea to use the discharge section itself as a switching element without using a switching element in the main discharge circuit, but the pre-ionization was not very strong and the spatial
Due to the poor condition, the discharge tends to become unstable, so it has not been put to practical use.

By using X-rays as a pre-ionization source, it is possible to create a high-output, high-efficiency, high-repetition pulsed laser.

However, in this case as well, the switching elements used in the conventional Xlil generating section need to be able to withstand high voltages, and are conventionally very expensive, have a short lifespan, and have low reliability.

The object of the present invention is to solve the above problems and provide an X-ray preionization pulse laser device that is small, simple in structure, inexpensive, and highly reliable.

[Structure of the invention] (Means for solving the problem) The X-ray preionization pulse laser device according to the first invention includes:
In a pulse laser device that excites a laser medium and fires a laser beam by performing a pulse discharge between a pair of main electrodes installed oppositely in a laser tube, a main discharge portion formed by the pair of main electrodes is provided. The main discharge capacitor is connected in parallel, and an X-ray generating section is provided that generates a pulse discharge between the main electrodes by irradiating the generated X-rays onto the main discharge section and generating plasma. do.

Further, in the present invention, the X-ray generating section has a vacuum sealed chamber, a creeping discharge section is disposed in the vacuum sealed chamber, and a switching element and a creeping discharge capacitor are connected in series to the creeping discharge section. The present invention is characterized in that, after charging the creeping discharge capacitor, the switching element is made conductive to cause the creeping discharge portion to generate creeping discharge, thereby generating X-rays.

A second invention is a pulsed laser device that excites a laser medium and oscillates a laser by performing pulse discharge between a pair of main electrodes arranged oppositely in a laser tube, in which a laser beam formed by the pair of main electrodes is provided. XI in the main discharge part
! An XwAR generating section is provided which performs preliminary ionization by irradiating i1, this X-ray generation section has a vacuum sealed chamber, a creeping discharge section is provided in this vacuum sealed chamber, and a pair of creeping discharge electrodes are provided in the creeping discharge section. an X disposed opposite to the creeping discharge section;
A line-generating anode is provided in the vacuum-tight chamber, and a capacitor and a creeping discharge capacitor are connected in series between the X-ray generating anode and one of the creeping discharge electrodes. A switching element is connected between the creeping discharge electrode and the inductance between the point between both capacitors and the other creeping discharge electrode is set by arranging the creeping discharge part, the creeping discharge capacitor, and the switching element, or After connecting these two capacitors so that the opposite side of both capacitors has a positive potential with respect to the point between the two capacitors, the switching element is made conductive to discharge the creeping discharge capacitor, and the creeping discharge capacitor is discharged. Generate plasma by causing a discharge, and at the same time reverse the potential of the creeping discharge capacitor, and generate X-rays by accelerating electrons in the plasma by the capacitor and the creeping capacitor and colliding with the XII generation anode. It is characterized by

Furthermore, this invention connects a main discharge capacitor in parallel to the pair of main electrodes, and after charging the main discharge capacitor, the main discharge part is irradiated with X-rays generated by the X-ray generator. It is characterized in that a pulse discharge is generated between the main electrodes by generating plasma.

The creeping discharge section uses ferrite, ceramics, other metal oxides, or a composite thereof as a substrate material, and a discharge channel is formed on the surface by rapidly heating and cooling the surface portion to make it amorphous. It is characterized by the formation of

(Function) In the first invention, after charging the main discharge capacitor connected in parallel to the main discharge part, the X-ray generating part generates X-rays, and the main discharge part is irradiated with the X-rays. By generating plasma in the discharge section, a main discharge is generated between the main electrodes to excite the laser medium, and a resonator is used to perform laser oscillation.

In addition, as this X-ray generating section, a vacuum sealed chamber is provided on the back side of the main electrode or near the main discharge section, and a creeping discharge section is placed inside this vacuum sealed chamber to cause creeping discharge.
Generate a line.

At this time, as the switching element, one with a low current and a relatively slow rise can be used to cause creeping discharge.

In particular, according to this invention, the main part of the creeping surface 11i itself is used as a switching element without using a switching element in the main discharge circuit, and by using X-rays as a preliminary ionization source, a powerful and spatially specific A good pre-ionization is performed.

Further, in the second invention, as a circuit configuration of the X-ray generating section, a capacitor and a creeping discharge capacitor are connected in series,
The capacitors are connected to one creeping discharge electrode of the creeping discharge section through a switching element and an inductance, the opposite side of the creeping discharge capacitor is connected to the creeping discharge electrode, and the other end of the capacitor is connected to the creeping discharge electrode. Connected to the generation anode.

After charging so that the opposite side of the point between the capacitor and the creeping discharge capacitor has a positive potential with respect to each point, the switching element is made conductive to discharge the creeping discharge capacitor, and the creeping discharge portion is discharged. Plasma is generated by causing a discharge, and the voltage of the creeping discharge capacitor is reversed, and the electric field generated by both capacitors accelerates the electrons in the plasma and causes them to collide with the anode, thereby generating X-rays.

As the switching element, one having a low voltage and a relatively slow rise can be used in order to cause creeping discharge.

(Example) Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a circuit diagram including a cross section of the main part of the embodiment of the first invention, and FIG. 1 is a side sectional view showing the relationship between the main electrode and the creeping discharge electrode that generates Shown in Figure 2.

In this embodiment, X-rays are used as a backup voltage l1m1 source, and the creeping discharge section itself is used as a switching element of the main discharge circuit. 1 is a main discharge capacitor, 3 is a creeping discharge capacitor, and 5 and 7 are A pair of main electrodes forming the main discharge part M, 5 is a cathode, 7 is an anode, 9 is a substrate such as ferrite forming the creeping discharge part m, 11.13 is a creeping discharge electrode, and X-rays are generated by the creeping discharge. An X-ray generator 15 that generates
are formed, 17 is a diaphragm, 19 is a discharge channel, 21
23 is a switching element such as a thyratron or a semiconductor element, 25 is a diode, and 27° and 29 are charging inductances.

The main electrodes 5.7 are installed facing each other inside the laser tube, and the creeping discharge electrode 11 is attached to the base plate 9 in the vacuum-tight chamber 21 behind the main electrode 5 in the elongated direction as shown in FIG. Creeping discharge electrodes 13 are provided facing each other on both sides and spaced apart from each other. Therefore, originally, the discharge batteries 11 and 13 overlap in FIG. 1, but for convenience of explanation, the creeping discharge electrode 13
is shown slightly shifted to the left with respect to the same electrode 11. However, in reality, even if there is some deviation, it is unavoidable.

For the group 51ii9, in addition to ferrite, ceramics or other gold [monide] or a composite thereof is used.

In addition, a part of the surface of the substrate 9 is heated in advance by electric discharge or the like.
The discharge channel 19 is formed as a creeping discharge portion m which is rapidly cooled to become amorphous and has a low surface resistance, allowing discharge to easily pass therethrough. However, this surface treatment can also be omitted.

The diaphragm 17 constitutes a diaphragm of the vacuum-tight chamber 21, which is made of a thin film of titanium, aluminum, or the like that transmits X-rays.

Next, I will explain its effect.

The main discharge capacitor 1 and the creeping discharge capacitor 3 are charged in advance to a high voltage of 10 to several tens of KV, and by closing the switching element 23, the creeping discharge capacitor 3 is charged on the surface of the substrate 9 in the vacuum-tight room 21. The discharge generates creeping discharge, and this creeping discharge generates X-rays in a vacuum.

In FIG. 2, the creeping discharge is generated parallel to the longitudinal direction of the main electrode 5 from the center to both the left and right sides.

The X-rays generated here pass through the diaphragm 17 of the main electrode 5 and are irradiated onto the main discharge section M (main discharge region), causing preliminary ionization of the main discharge section M, that is, generating plasma.

As a result, the impedance of the main discharge section M decreases, and the main discharge capacitor 1 discharges between the main electrodes 5 and 7, excites the laser gas, emits a laser beam in the direction of the arrow, and generates laser oscillation. I do.

This X-ray generator 15 may be located behind both main electrodes 5.7, or may be located behind either one of the main electrodes 5.7.

In addition, the X
A line generating section 15 may be arranged.

In this way, in this embodiment, the creeping discharge part itself is used as the switching element of the main discharge circuit without using a switching element in the main discharge circuit, so that the switching element 23 is used only for causing the creeping discharge. Low voltage and relatively slow rise can be used.

Note that, for charging each of the capacitors 1.3, resonance charging, a charging method using an inverter circuit, etc. can be used.

Other common xi#IAs may be used as the X-ray source.

Next, FIG. 3 shows a circuit diagram including a cross section of essential parts of an embodiment of the second invention.

This embodiment is characterized by the circuit configuration of the Xa generating section 15, in which two creeping discharge electrodes 11 and 13 are connected to the center and both left and right ends of the substrate 9 constituting the creeping discharge section m, respectively. An X-ray generating anode 35 made of a diaphragm made of tantalum or the like is placed opposite the discharge electrodes 11, 13.

Additionally, a vacuum sealed chamber 2 is provided outside the X-ray generating anode 35.
A diaphragm 17 between the main discharge section M and the main discharge section M is provided.

The capacitor 31 and the creeping discharge capacitor 3 are connected in series between the X-ray generating anode 35 and the creeping discharge electrode 11. That is, if the point between both capacitors 31.3 is A, and the points on both sides are B and C, point B is connected to the X-ray generating anode 35, point 0 is connected to the creeping discharge electrode 11, and point A A switching element 23 (for example, a thyratron) is connected between the creeping discharge electrode 13 and the creeping discharge electrode 13 .

Furthermore, the circuit formed by the creeping discharge part m, the creeping capacitor 3, and the switching element 23 becomes an Ii dynamic type discharge, and the inductance between the point A and the creeping discharge N electrode 13 is the creeping discharge part. m and creeping discharge capacitor 3
and the switching cable 23 are set to account for most of the circuit inductance.

This depends on the actual arrangement of the creeping discharge part l, the creeping discharge capacitor 3, and the switching element 23, or by connecting an inductance 37 between the point A and the creeping discharge electrode 13 as shown in FIG. This is achieved by

Then, after charging the capacitor 31 and the creeping discharge capacitor 3 using resonance charging or an inverter power supply so that the B point and the 0 point have a positive potential with respect to the A point, the switching cable 23 is made conductive and the creeping discharge capacitor 3 is charged. When the capacitor 3 is discharged to cause creeping discharge along the creeping discharge portion m, plasma is generated in the creeping discharge circuit and the voltage of the creeping discharge capacitor 3 is reversed by the vibrating type IIi current.

Since the inductance between point A and the creeping discharge electrode 13 is set to account for most of the circuit inductance of the creeping discharge circuit, both the creeping electrodes 11 and 13 have a negative high potential. A voltage generated by the capacitor 31 and the creeping discharge capacitor 3, that is, a voltage approximately twice the initial charged N voltage is applied between the entire creeping discharge portion m and the X-ray generating anode 35.

The electric field accelerates electrons 39 in the plasma generated in the creeping discharge portion l, and collides with the X-ray generating anode 35, thereby generating X-rays due to bremsstrahlung radiation. This X-ray is detected by the distance y between the vacuum sealed chamber 21 and the main discharge section M! 17 and irradiates the main discharge part M to perform preliminary ionization. Therefore, as the switching element for X-ray generation, it is only necessary to use a switching element that has a low voltage and a relatively slow rise for causing creeping discharge.

Thereafter, after several tens to several hundreds of nanoseconds, the switching element 42 (thyratron in the embodiment shown in FIG. 3) of the main discharge circuit is closed, and a pulse discharge is generated in the main electrode 5.7fffi to perform laser oscillation.

The main discharge capacitor 41 is connected to the main discharge section M in parallel.

Reference numeral 43 is a diode, and reference numeral 45 is an inductance.

FIG. 4 shows a second embodiment of the second invention, and is an example in which a metal block such as molybdenum or tungsten is used instead of a diaphragm as an anode 47 for generating X-rays that collides with electrons.

Electrons 39 extracted from the creeping discharge portion collide with an X-ray generating electrode 47 made of a metal block and emit X-rays.

The X-rays are irradiated onto the discharge section M through the diaphragm 17 to perform preliminary ionization.

Other operations are the same as in the case of FIG. 3 above.

Reference numeral 49 is an inductance.

FIG. 5 shows a third embodiment of the second invention, in which the main discharge section M is used as a switching element without using a switching cable that requires a large current to flow at high speed in the main discharge circuit. It is something that can be written.

By using the X-ray generator 15 as a pre-ionization device, strong pre-ionization with good spatial uniformity is achieved, so a stable and highly oscillating discharge can be achieved without using a switching element in the main discharge circuit. can be realized.

The operation will be explained below.

The capacitor 31, creeping discharge capacitor 3, and main discharge capacitor 41 are charged in advance to generate X-rays.

The operation of the X-ray generator 15 is the same as in the embodiment shown in FIG. 3 above.

The X-rays generated here pass through the diaphragm 17 and are irradiated onto the main discharge section M, causing preliminary ionization of the main discharge section M, that is, generating plasma.

As a result, the impedance of the main discharge section M decreases, and the main discharge capacitor 41 discharges between the main electrodes 5.7 to excite the laser gas and perform laser oscillation.

By adopting this method, it is only necessary to use switching elements for the entire laser system that have low voltage, low current, and relatively slow rise to cause creeping discharge.

Regarding the circuit configurations in each of the above embodiments, circuit configurations other than those shown in these embodiments that have the same effects can be considered, and the present invention can be implemented with various modifications without departing from the spirit thereof.

[Effects of the Invention] As described above, by using the present invention, sufficient preliminary ionization can be performed with a simple circuit configuration, and switching elements with low current, low voltage, and relatively slow rise can be used. A high-output, pre-ionization pulse laser device that is inexpensive, has high laser oscillation efficiency, and can be used in a variety of applications has been realized.

[Brief explanation of the drawing]

1, 3, 4, and 5 are circuit configuration diagrams including cross sections of essential parts of the X-ray preionization pulse laser device in each embodiment of the present invention, and FIG. The side sectional views of the creeping discharge section and FIGS. 6 to 8 are circuit configuration diagrams of conventional examples. 1.41... Main discharge capacitor 3... Creeping discharge capacitor 5.7... Main electrode 9... Base 11.13.
... creeping discharge electrode 15 ... XIfA generation part 17 ... diaphragm 19 ...
...Discharge channel 21...Vacuum sealed room 23.42
...Switching element 25.43...Diode 27.29...Charging inductance 31...Capacitor 35...Anode for X-ray generation 37.45...
・Inductance

Claims (5)

[Claims] (1) In a pulse laser device that excites a laser medium and oscillates a laser by performing pulse discharge between a pair of main electrodes installed oppositely in a laser tube, a main electrode formed by the pair of main electrodes is used. A main discharge capacitor is connected in parallel to the discharge section, and an X-ray generating section is provided that generates a pulse discharge between the main electrodes by irradiating the main discharge section with generated X-rays and generating plasma. An X-ray preionization pulse laser device characterized by: (2) The X-ray generating section has a vacuum-tight chamber, a creeping discharge section is disposed in the vacuum-tight chamber, a switching element and a creeping discharge capacitor are connected in series to the creeping discharge section, and a creeping discharge section is connected in series to the creeping discharge section. 2. The X-ray pre-ionization pulse laser according to claim 1, wherein the X-ray preionization pulse laser generates X-rays by causing a creeping discharge portion to generate a creeping discharge by making a switching element conductive after charging a discharging capacitor. Device. (3) In a pulse laser device that excites a laser medium and oscillates a laser by performing pulse discharge between a pair of main electrodes arranged oppositely in a laser tube, a main discharge section formed by the pair of main electrodes. An X-ray generating section is provided which performs preliminary ionization by irradiating X-rays to the Provide a discharge electrode,
An X-ray generating anode disposed opposite to the creeping discharge portion is provided in the vacuum-tight chamber, and a capacitor and a creeping discharge capacitor are connected in series between the X-ray generating anode and one of the creeping discharge electrodes. A switching element is connected between both capacitors and the other creeping discharge electrode, and the inductance between the point between both capacitors and the other creeping discharge electrode is the same as that between the creeping discharge part and the creeping discharge capacitor. The creeping discharge section, the creeping discharge capacitor, and the switching element are arranged so that they account for most of the circuit inductance created by the
After charging these two capacitors so that the opposite side of both capacitors has a positive potential with respect to the point between the two capacitors, the switching element is made conductive to discharge the creeping discharge capacitor and cause creeping discharge in the discharge part. It generates plasma by inverting the potential of the creeping discharge capacitor, and the electrons in the plasma are accelerated by the capacitor and the creeping capacitor and collide with the X-ray generating anode, thereby generating X-rays. X-ray pre-ionization pulse laser device. (4) A main discharge capacitor is connected in parallel to the pair of main electrodes, and after charging the main discharge capacitor, the main discharge section is irradiated with X-rays generated by the X-ray generator to generate plasma. 4. The X-ray preionization pulse laser device according to claim 3, wherein the pulsed discharge is generated between the main electrodes. (5) The creeping discharge section uses ferrite, ceramics, other metal oxides, or a composite thereof as the substrate material, and a part of the surface is rapidly heated and rapidly cooled to become amorphous, so that a discharge is generated on the surface. Claims 1, 2, and 3 characterized in that a channel is formed.
or the X-ray preionization pulse laser device according to 4.