JPS63217676A - Pulse gas laser device - Google Patents

Abstract

PURPOSE:To obtain an intense pulse X-ray source by supplying a cathode for generating electron beams consisting of a porous metal or a porous metallic carbide with a gas or a liquid metal from a gas source or a liquid metal source mounted outside an X-ray generating chamber. CONSTITUTION:When voltage is applied to a cathode 5 and an anode 6 under the state in which a trace quantity of a gas 9 is fed through the porous cathode 5, an intense electric field is generated on the surface of the cathode 5, and cold cathode electron emission is generated. Ionization plasma is generated near the surface of the porous cathode 5 by the electric field and electrons, and electrons are led out of the plasma and accelerated and made to collide with a target (the anode) 6, thus generating X-rays. A previously utilized gas 2 is discharged outside an X-ray generator by an exhauster 10. Accordingly, an intense (large flux) pulse X-ray source can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pulsed gas laser device among gas lasers, and particularly to a device for pre-exciting a laser gas by irradiating it with X-rays.

(Prior Art) In the conventional X-ray pre-excitation method, an X-ray tube using a normal hot cathode or a cold cathode is used as an X-ray generator. In the pulsed laser X-ray pre-excitation method, the pulse width is usually 1 μa.
A reasonably powerful pulsed X-ray source is required.

Hot cathode X-ray tubes cannot emit strong X-rays in a pulsed manner due to the response time of heating the hot cathode, resulting in insufficient radiation.

On the other hand, the cold cathode method does not require a hot cathode and requires fewer components, but requires a sharp cathode tip and a high applied voltage. Moreover, since the operation is difficult to stabilize, it cannot be used except for special purposes.

(Problems to be Solved by the Invention) In order to obtain strong pulsed X-rays, it is necessary to obtain a large current electron beam from the cathode of the X-ray generator. Therefore, in the hot cathode method, it is necessary to increase the cathode temperature, but a high operating temperature has the disadvantage of shortening the life of the cathode.

On the other hand, in the cold cathode method, it is necessary to make the cathode tip sharp and apply a high voltage to generate a strong electric field at the cathode tip. Therefore, electron emission is easily influenced by the shape of the cathode tip. Furthermore, since a high voltage is applied, there are many X-rays with a shorter wavelength than the X-rays with a wavelength suitable for excitation of the laser gas, and the excitation efficiency decreases.

An object of the present invention is to provide a pulsed gas laser device using an X-ray generation method using a plasma cathode, which has a simple structure and can generate a pulsed large current electron beam, eliminating the above-mentioned drawbacks of hot cathodes and cold cathodes.

[Structure of the invention]

(Means for Solving the Problems) The present invention relates to a plasma cathode generation method in which plasma is generated near the surface of a cathode and electrons are extracted from the plasma.

The cathode for X-ray generation is made of porous metal or porous metal carbide, and includes a device for supplying gas or liquid metal from outside the X-ray generator through this porous material, a device for exhausting the gas, and a device for X-ray generation. It consists of a target (anode). A power source for electron acceleration will also be provided.

(Function) When a voltage is applied to the cathode and anode while a small amount of gas is supplied through the porous cathode, a strong electric field is generated on the cathode surface and cold cathode electron emission occurs. This electric field and electrons ionize the gas near the surface of the porous cathode to generate plasma. This plasma pulls out the stain and targets (anode)
Accelerate the collision to generate X-rays. The used gas is exhausted to the outside of the X-ray generator using an exhaust system.

When liquid metal is supplied from a porous cathode, the voltage applied to the cathode and anode creates a strong electric field on the cathode surface, and the electrostatic force of this electric field stretches the liquid metal, creating an even stronger electric field at its tip. . Therefore, plasma is generated due to the increase in field emission current and the evaporation of the liquid metal, and it functions as a plasma cathode.

(Example) FIG. 1 shows an example of the present invention. A laser gas 2 is introduced between the main discharge electrodes 1 and 11 for excitation, and discharge is excited by a power source 3. Almost at the same time as this power supply 3 is turned on, or before
The X-ray generator is activated and the generated X-rays 8 are placed on the main electrode.
The laser gas enters through the line-transmitting film 11 and pre-excites the laser gas in the main discharge region 4.

Due to this preliminary excitation, a uniform glow discharge is generated and maintained in the main discharge region 4, and good oscillation can be obtained.

The laser oscillator is omitted from the figure.

In FIG. 1, the electron beam generating cathode 5 is made of porous metal or porous metal carbide, and a gas source or liquid metal source 9 is provided on this cathode outside the X-ray generating chamber.
Supply yoshigas or liquid metal.

A voltage is applied from a power source 7 between the cathode 5 and the X-ray generation target (anode) 6. Plasma is generated near the surface of the cathode 5 according to the principle described in the section (Operation). Electrons are extracted from this plasma and hit the target 6 to generate X-rays 8. The gas used for plasma generation is exhausted to the outside through an exhaust bag (10, the partition of the X-ray generation chamber is not shown).

〔Effect of the invention〕

A powerful (large flux) pulsed X-ray source is realized using a plasma cathode that can stably obtain a large current electron beam with a simple cathode structure.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention. 1.11... Main discharge electrode, 3... Main discharge power supply, 5...
・XW! A porous cathode for generation, 6... target for X-ray generation, 9... gas or liquid metal source, 10...
Exhaust device. Agent Patent Attorney Nori Chika Yudo Kikuo Takehana

Claims (2)

[Claims] (1) In a gas laser device that pre-excites laser gas with X-rays, an electron beam source for generating X-rays (electron beam cathode) is made of a porous metal or a porous intermetallic compound, and diluted through the porous cathode. 1. A pulsed gas laser device comprising means for supplying a gas or liquid metal. (2) The pulsed gas laser device according to claim 1, wherein the porous cathode is made of at least Mo, Ta, Ti, W, or any one of these carbides.