JPS63164199A - Target unit for x-ray generator - Google Patents

Abstract

PURPOSE:To make it possible to use a target material efficiently and to operate continuously for long, by forming the target unit to link a specific space to a target pool through a target material feeding pipe, and to radiate laser beams to a membrane formed in the space by the surface tension, by using a liquid target material. CONSTITUTION:As a target material, a metal is used, for example, and the target material is inserted to a target pool 1 as a powder, for example, and, heated and melted by a heating coil 4, or a liquid metal already molten by heating is inserted to the target pool 1. The liquid target material L in the target pool 1 is fed by a gas pressure from a pressure gas leading pipe 1a, through a target material feeding pipe 3, to a space 2a inside a liquid membrane forming ring 2, where a liquid membrane is is formed. To the liquid membrane Ls as a target, laser beams are radiated to generate X-rays. In such a way, the target material need not be replace for a long period, and can be used efficiently and effectively.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is an apparatus that irradiates a predetermined target with a laser beam to turn it into plasma and generates X-rays. The present invention relates to a device for supplying and holding equipment.

<Prior art> In this type of X-ray generator, metal, ice, or an inert gas crystal is generally used as the target material, but the target material is decomposed or vaporized by laser beam irradiation. exhaust. Therefore, it is necessary to supply target materials one after another to the laser beam irradiation position.

Conventionally, methods for performing this supply include a method of rotating a cylindrical target material, a method of translating a flat target material, and a method of sending a thin film (tape-like) target material.

<Problems to be Solved by the Invention> According to the conventional target material supply methods as described above, it is necessary to frequently replace the target material, the device cannot be operated continuously for a long time, and During operation, manual target interaction work is required at relatively short intervals. Furthermore, the spot diameter of the laser beam is usually set to about several tens of micrometers to several hundreds of micrometers, and this creates a through hole of about several hundred micrometers in the target, but in order to update the beam irradiated surface of this target, it is necessary to A movement of about 5 to l u+ is required. This is therefore uneconomical, as the target material is replaced in largely unused condition with little actual wear.

Furthermore, according to conventional feeding methods, the target material is mechanically moved, which may cause the position of the target to fluctuate. Since the laser beam is focused on the target by the lens, this target position variation causes a change in the focused spot size, which adversely affects the generation of X-rays.
In addition, the X-ray generation position changes and the size of the radiation source increases in appearance, which causes many problems.

The present invention has been made to solve the above-mentioned drawbacks of the conventional devices all at once; it eliminates the need to replace the target material for a long time (in addition, it allows the target material to be used effectively without wasting it, and furthermore, it The purpose of the present invention is to provide a target device for an X-ray generator with extremely little fluctuation.

<Means for Solving the Problems> A configuration for achieving the above object will be described with reference to FIGS. 1 and 2 corresponding to the embodiment. a ring-shaped member (liquid film forming ring) 2 formed to surround a predetermined space 2a as a center;
, the space 2a of the ring-shaped member 2 and the target reservoir 1
It is characterized by having a target material supply pipe 3 that communicates with the space 2a, and using a liquid film formed in the space 2a by surface tension as the target to be irradiated with the laser beam.

<Operation> The liquid target material stored in the target reservoir 1 is supplied to the space 2a via the target material supply pipe 3,
Here, a liquid film L3 is formed due to surface tension. This liquid film Ls is destroyed by laser beam irradiation, but
By appropriately setting the pressure inside the target reservoir 1, the cross-sectional area of the target material supply pipe 3, and the viscosity characteristics of the liquid target material, the liquid target material is sequentially supplied to the space 2a, and the liquid The film regenerates itself.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a longitudinal cross-sectional view showing the main structure of an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view taken along the line ■-■.

A target material supply pipe 3, which is a thin tube that communicates with the inside of the target reservoir 1 and extends downward, is fixed to the bottom of the target reservoir 1 having a predetermined internal capacity, and the lower end of the target material supply pipe 3 liquid film forming ring 2
is supported.

The liquid film forming ring 2 is a ring-shaped member with an inner diameter of, for example, about 0.5 to 1 ++n, and a space 2a formed therein is connected to the inside of the target reservoir 1 via the target material supply pipe 3. It's communicating.

At a predetermined upper portion of the target reservoir 1, a pressurized gas introduction pipe 1a is provided which communicates with a gas supply source (not shown) for supplying gas at a predetermined pressure into the target reservoir 1. Also,
Heating coils 4 are disposed close to the outer circumferential surfaces of the target reservoir 1 and the target material supply pipe 3, respectively, to maintain the interiors thereof at a predetermined high temperature.

Next, the usage and operation of the above embodiment will be described.

In this embodiment, for example, metal is used as the target material, and this target metal is inserted into the target reservoir 1 in the form of powder, and is heated and melted by the heating coil 4, or is already melted by heating. The liquid metal thus obtained is inserted into the target reservoir 1. The liquid target material in the target reservoir 1 is supplied to the internal space 2a of the liquid film forming ring 2 via the target material supply pipe 3 by the gas pressure from the pressurized gas introduction pipe 1a, and here, as shown in FIG. A liquid film is formed as shown in the figure. This liquid film is shown in a concave shape in FIG.
The film thickness and shape vary depending on the size of a, the amount of liquid target material supplied, target temperature, material, etc.

Calculations to determine this shape, etc. are called a plateau problem, and are determined by solving differential equations, but in reality, it is necessary to determine the optimal combination of conditions through experiments. In this embodiment, the shape and thickness of the liquid film are controlled by changing the pressure and supply rate of the pressurized gas from the pressurized gas introduction pipe 1a and the temperature of the liquid target material by the heating coil 4. can be controlled.

A laser beam is irradiated onto the liquid film as described above to generate X&'i. By this beam irradiation, the target material is locally decomposed and evaporated, and the liquid film is destroyed, but the liquid target material film is destroyed by the pressure of the gas flowing into the target reservoir 1 from the pressurized gas introduction pipe 1a. Space 2a sequentially via material supply pipe 3
The liquid film is supplied to the membrane and regenerated. That is, the liquid target material is appropriately supplied to the space 2a by the amount consumed by the laser beam irradiation.

In the above embodiment, the space 2a for forming the liquid film is circular, but the film may be formed in any other shape, such as a square or a triangle.

In addition, although the case where liquid metal is used as the target material has been described above, by replacing the heating coil 4 with a freezing device, for example, a liquefied inert gas can be used as the target material. If liquid materials are used in the vicinity, thermal means to maintain the target in a liquefied state are not necessarily required.

Furthermore, for example, a rotatable disk may be provided with a plurality of microscopic holes, each of which is configured to form a liquid film, and the liquid film formed at a position other than the laser beam irradiation position may be sequentially supplied to the irradiation position. can also be applied.

<Effects of the Invention> As described above, the present invention includes a target reservoir for storing target material in a liquid phase, and a ring-shaped member formed to surround a predetermined space around the target reservoir. At the same time, the above-mentioned space is communicated with the target reservoir through a target material supply pipe, and the laser beam is irradiated with a film of the liquid target material formed by surface tension in this space as a target. The liquid film is self-regenerated by supplying an additional amount to the space corresponding to the amount consumed by decomposition and evaporation, and the target material can be used efficiently. As a result, there is no need to replace and attach the target material as in the past. Continuous operation for long periods of time is possible.

For the same reason, without using expensive metal thin films,
Moreover, it is economical because the target material can be used without waste.

Furthermore, since the target is a film that is sequentially formed on a ring-shaped member that is fixedly provided, there is no need for a conventional mechanical material feeding mechanism, which reduces target position fluctuations and reduces the need for moving parts. Because there is no such thing, the device can be highly reliable.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the main structure of an embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view taken along the line ■-■. 1...Target reservoir 2...Liquid film forming ring 3...Target material supply pipe 4...Heating coil

Claims (1)

[Claims] In a device that generates X-rays by irradiating a target material with a laser beam, it is a device for supplying and holding the target material at a laser beam irradiation position, and a target reservoir that stores the target material in a liquid state. , a ring-shaped member formed to surround a predetermined space as a center, and a target material supply pipe that communicates the space of the ring-shaped member with the target reservoir, and has a surface tension in the space. A target device for an X-ray generator, characterized in that a liquid film formed by the method is used as a target to be irradiated with a laser beam.