JPS61224382A - Pulse laser oscillator - Google Patents

Abstract

PURPOSE:To obtain the high-reliability pulse laser oscillator by connecting a constant voltage power source to a cathode heater and a reversal heater of CONSTITUTION:A laser gas 13 is flowed between a cathode 7 and an anode 8 in a laser box 14 in a direction of the arrow. A main capacitor 1 is charged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulsed laser oscillator, particularly to stabilizing the operation of a frozen thyratron, which is a switching element thereof.

[Conventional technology]

Figure 2 is a circuit configuration diagram schematically showing the circuit of a typical horizontally pumped pulsed laser oscillator of this type.
, XeC1), and nitrogen laser oscillators. In the figure, (1) is the main capacitor, (2) is the DC high voltage power supply that charges the main capacitor (1), and (3) is the main capacitor (1).
(4) is a charging inductance that forms a charging path, (4) is a hydrogen thyratron that switches the pulsed laser, and (6) is a hydrogen thyratron that switches the pulse laser.
) is a trigger for switching the hydrogen thyratron (ri), (6) is an inductance that limits the current flowing through the hydrogen thyratron (4), (7) (83 is a pair of stms disposed opposite to each other in the laser gas ( 7) is the cathode, (
8) is an anode. (9) is the discharge excitation part where the laser is excited by the main discharge, QQ is the ultraviolet light that pre-ionizes the discharge excitation part (9) prior to the main discharge, and (b) is the preliminary wt for generating ultraviolet light. Separation gap, K is the peaking capacitor for generating the main discharge, (6) is the laser gas, C
14 is a laser housing that seals off the laser gas, 4 is a Cytron 7 node, QQ is a Cytron cathode, Qη is the first grid, (to) is the first nigerid, 斡 is a cathode heater that heats the thyratron cathode (to), (e) is metal turnip 7~ containing water system, (2) is metal turnip 7/I/G
Rii per heater which heats l# and adjusts the hydrogen gas pressure in the hydrogen siatron (4), G is the heater section α field, a capacitor that absorbs the surge generated at @, 4 is the pulse blocking transformer, Sakaki is the cathode heater 4 is insulation transformer for reservoir heater, (to)
is a commercial frequency AC power supply.

Next, the operation will be explained. Laser gas (Ll (for example, a mixed gas consisting of Kr*FgeHe) sealed in the laser housing (to) is flowed from the direction of the arrow into the darkness of the cathode (7) and @ pole (8), and the DC high pressure region source ( 2), the main capacitor (1) is charged to a predetermined voltage, and when a pulse is applied from the trigger (6) to the first grid (B) and the second grid (To), the hydrogen thyratron (4) becomes conductive. state.At this time, the main capacitor (
The charge stored in 1) is transferred to peaking capacitor 4 through inductance (6). At this time, the pre-ionization gap Qυ is connected in the arc number region, and the ultraviolet light (g) generated from it ξ spreads the laser gas (2) near the cathode (7) and throughout the discharge excitation part (9). is in a weakly ionized state (-density n6''10'~108 1d)
becomes. When the voltage between the cathode (7) and the positive electrode (8) reaches the discharge starting voltage due to charging of the peaking capacitor (2), the charge stored in the peaking capacitor (4) becomes -
IdHζ flows through the air (7) and the anode (8), and a pulse discharge is formed in the discharge excitation part (9). This is because the discharge excitation part (9) is brought into a uniform pre-canning state in advance by the ultraviolet optical axis, resulting in a uniform discharge. In the discharge excitation part (9) formed by the discharge of ξ, a laser medium (for example, KrF 2 ) is excited, and laser oscillation occurs.

In such a pulsed laser oscillator, an average output is obtained by operating the laser several tens to several thousand times per second.

In order to perform such a high repetition operation, a switching element that satisfies the following specifications is required.

■ The range pressure (voltage that can be applied to the thyratron) is high. (Maximum 80 to 50KV) ■ High Pigumi flow. (Maximum of about 6 to 20 KA [) (Maximum of about 50 to 200 KA/μS) ■ The return time from a conductive state to a non-conductive state is quick. (1~
(6μ8 or less) ■ Highly repetitive operation is possible. (several hundred to several thousand pps
＞ ■ The life of the boat is long. (10 mm or more) At present, a hydrogen thyratron (4) is generally used as a switching element that satisfies these specifications. Hydrogen thyratron (4) is basically an 8-pole to 5-pole vacuum tube,
A small amount of water bulk gas (or heavy water gas) is sealed inside. Compared to rare gases or mercury, etc., which are generally sealed in vacuum tubes, hydrogen gas has the characteristics of less damage to the cathode caused by ion bombardment and faster recombination (that is, faster recovery time). Together, they enable high-repetition switching elements.

Here, the operation of the hydrogen thyratron (4) will be explained.

When a pulse voltage is applied from the trigger (6) to the first grid (B) while a high positive voltage is applied to the thyratron anode (to), weak ionization occurs between the anode (to) and the cathode (to). state. When a pulse voltage is applied from the trigger (5) to the second nigerid (to) after a certain delay time, a discharge is formed at the anode (2) and cathode αQ@ with little jitter, and the aqueous thyratron (4)
becomes conductive. This state of conduction lasts as long as current is applied by the external circuit or the voltage between the anode and the cathode is reversed, after which the gas inside the water-based thyratron (4) regenerates. After a bonding time, it returns to a non-conducting state.

In the next section, we will discuss the important setting of the heater voltage, which determines the operating characteristics of the hydrogen thyratron (4).

The voltage of the reservoir heater (2) has the following effects on the operation of the water bulk thyratron.

A decrease in the voltage of the reservoir heater (2) increases the holding voltage, decreases the return time, decreases the maximum current rise (dl), and reduces the cyrad dt
max Ron's lifespan is significantly reduced. Therefore, the reservoir heater voltage is increased to the limit voltage that can secure the minimum necessary holding voltage and recovery time, i (]r). It is desirable to set so that the characteristic of 3□ is maximized.

On the other hand, the four voltages of the cathode heater (to) are set to the optimum voltage from the viewpoint of appropriate emission of thermionic electrons from the cathode and the life of the cathode material and heater.

Conventionally, this type of heater power source has used a commercial frequency power source which has been stepped down to a set voltage using an isolation transformer (2).

[Problem that the invention seeks to solve]

The heater power supply for the hydrogen thyratron in the conventional pulse laser device was configured as described above.
The load changes drastically depending on the time of the day. For example, when using a commercial frequency power supply in a factory, the load changes depending on the time of day.
Due to the influence of tlJ, there were the following problems.

■ If other loads in the factory suddenly decrease.

As the voltage of the commercial frequency power supply increases, the voltage of the reservoir heater also increases. At this time, the holding voltage of the thyratron (4) decreases, so the thyratron (4) becomes conductive while the main capacitor (1) is being charged, the DC voltage power supply (2) is short-circuited, and the laser oscillation stops. At the same time, a large current flows through the thyratron, causing great damage to its electrode jar.

■ If other loads in the factory suddenly increase, the voltage of the commercial frequency power supply will decrease, and the reservoir heater voltage will decrease. This significantly worsens the customization of (-iT)max and shortens the life of the thyratron.

■ Even if the cathode heater voltage Cζ is set, due to fluctuations in the commercial frequency power supply in the factory, it may deviate from the appropriate voltage setting, damaging the thyratron cathode (to) and cathode heater (2), and shortening the life of the thyratron (4). Become.

This invention was made to solve the above-mentioned problems, and aims to obtain stable laser oscillation, a long life of 1 tJ, and a reliable pulsed laser oscillator. There is.

[Means for solving problems]

The pulse laser oscillator according to the present invention employs a constant voltage power source as the cathode heater and reservoir heater vi Wet source in the hydrogen thyratron, which is a switching element thereof.

[Effect]

In the pulsed laser oscillator according to the present invention, the cathode heater and reservoir heater of the hydrogen thyratron, which is the switching element, are always driven at a set voltage by a constant piezoelectric power source. To realize an i@note pulsed laser oscillator by ensuring maximum di/dt characteristics while securing time.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 匈 is a constant voltage power source for the cathode heater, and ii) is a constant voltage source for the reservoir heater.

In FIG. 1, the basic operation of the pulse laser is the same as that shown in the conventional example. However, the cathode heater and reservoir heater (2) of the hydrogen thyratron (4) each have an independent constant voltage of 1! Due to the IE power source and 4, it operates with the set applied voltage, and at this time it does not depend on voltage fluctuations of the commercial frequency power source 4.

Therefore, when used in a factory etc., regardless of the operating rate of the load, the hydrogen thyratron (4) always maintains the required holding voltage and recovery time while exhibiting the -maximum (dl > characteristic. , the water-accumulated thyratron (4) always exhibits stable operation, and its lifespan is significantly the same as above.Therefore, the pulsed laser oscillator with this switching device becomes a highly reliable device.

In general, the operating characteristics of the hydrogen thyratron (4) (when the applied voltage of the holding power server heater (2) changes by 0.1 V with respect to the set value voltage, the characteristics will change. Therefore, the heater voltage power supply ■, @ As for the specifications, it is desirable that the voltage fluctuation be ±0.05 V or less with respect to the set voltage.

In the above embodiment, the cathode heater (2) and the reservoir heater (2) each have an independent constant pressure (pressure source).

(2), but the hydrogen thyratron (accordingly, the cathode heater Q9 and the reservoir heater (2) are connected in series or in parallel and is operated by a single power source) It goes without saying that even if the present invention is applied to this case, the same effect will be achieved.

In addition, in the above embodiment, an example is described in which a so-called automatic standby wLIII type capacitive multi-line circuit is applied as a discharge circuit that applies a voltage to a pair of four terminals constituting a laser oscillator and causes a discharge. However, this does not limit the invention in any way, and it can be applied to any discharge circuit that applies voltage in a pulsed manner.

〔Effect of the invention〕

As described above, according to the present invention, a constant voltage 11t source is connected to the cathode heater and reservoir heater of a hydrogen thyratron used as a switching confectionery, so that a highly reliable pulsed laser oscillator can be obtained. be.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram schematically showing a circuit of a pulsed laser oscillator according to an embodiment of the present invention, and FIG. 2 is a circuit diagram schematically showing a circuit of a conventional pulsed laser oscillator. In the figure, (1) is the main capacitor, (2) is the DC high voltage power supply, (4) is the hydrogen thyratron, (7) is the cathode,
(8) is an anode, a ring is a peaking capacitor, a laser gas, o9 is a cathode heater, (2) a beam server heater, (2) is a constant voltage power source for the cathode heater, and (2) a constant voltage power source for the beam server heater. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Daikonjin Masuo Oiwa Procedural Amendment (Voluntary) 1. Indication of the case: Japanese Patent Application No. 60-67515 2, Title of the invention (d) - Laser oscillator 3, Representative Hitoshi Katayama of the person making the amendment (5) Subject of amendment (1) Name of the invention in the specification and patent Claims and Detailed Description of the Invention. (2) Drawings (Figure 1) 6. Contents of the amendment (1) In the title of invention column of the specification, the phrase "pulsed laser oscillator" is corrected to "laser oscillator." (2) The patent claim column of the specification is corrected as shown in the attached sheet. (3) Insert "TEAcO, laser," after "Xe(:l)," on page 2, line 41 of the specification. (4) "Hydrogen Thyratron" on page 4, line 4 is corrected to "Hydrogen Thyratron." (5) ``106-108 Co1'' in lines 4-6 of the same page≠
-・" is corrected to "106-108/-". (6) On page 4, line 7 of the same page, change ``to speed up'' to ``to reach,''
” is corrected. (7) "Specifications" on page 4, line 18 is corrected to "specifications". (8) “Kneading voltage” on page 4, line 20 of the same page is “holding voltage”
Correct. (9) Correct "heater" in line 4 of page 8 to "heater". aQ, page 11, line 17, ``mononoderi'' is corrected to ``monomoari''. Figure 1 of the alpha force drawing is corrected as shown in the attached sheet. 7. List of attached documents (1) One document stating the amended scope of claims (2) Drawing (Figure 1) One or more copies of claims (1) Disposed facing each other in laser gas a pair of electrodes, a discharge circuit that applies a voltage to the pair of electrodes in a pulsed manner, and a hydrogen thyratron that switches the discharge circuit, wherein a constant voltage power supply is applied to a cathode heater and a reservoir heater provided in the hydrogen thyratron. A laser device that detects when it is connected. (2) The width of voltage fluctuation of the constant voltage power supply is ±0.05V or less with respect to the set voltage.Claim 1Ju19
±:”” 1 sip

Claims (2)

[Claims] (1) A device comprising a pair of electrodes disposed opposite to each other in a laser gas, a discharge circuit that applies a voltage in pulses to the pair of electrodes, and a hydrogen thyratron that switches the discharge circuit, the hydrogen thyratron A pulse laser oscillator characterized in that a constant voltage power supply is connected to a cathode heater and a reservoir heater provided in the pulse laser oscillator. (2) The pulse laser oscillator according to claim 1, wherein the width of voltage fluctuation of the constant voltage power supply is ±0.05 V or less with respect to the set voltage.