JPH0568291B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a steam enclosure for isotope separation of metal atoms by laser method.

(Conventional technology) The separation and concentration technology of metal atomic isotopes using the laser method has a very high separation efficiency compared to the conventional gas diffusion method, nozzle method, chemical exchange method, centrifugation method, etc. It is said that it is not necessary.

By the way, an atomic method using metal atoms is known as a method for concentrating and separating isotopes using a laser method.

FIG. 5 is a block diagram conceptually showing an example of an apparatus for concentrating metal atoms using a laser method in the atomic method.

That is, reference numeral 1 in FIG. 5 indicates a steam enclosure of the concentrator, and a metal melting crucible 3 containing metal atoms 2 to be separated is placed in this vapor enclosure 1. When heated to generate an atomic beam 4, the atomic beam 4 advances upward. In this atomic beam 4, one isotopic atom 5 and the other isotopic atom 6 are mixed. Therefore, a selective excitation laser 7 having a frequency corresponding to one of the isotope atomic absorption lines in the atomic beam 4 is irradiated. Only one isotope atom 5 to be separated is excited by this selective excitation laser beam.

Next, an ionizing laser 8 is irradiated to ionize the excited isotope atoms 5. These two types of lasers 7 and 8 ionize one isotope atom 5 that is intended to be separated in the atomic beam 4 and change it into positive ions 9.

Now, when an electric field is created in the atomic beam 4 containing these ions using the ground electrode 10 and the cathode 11, only the positive ions 9 of the ionized isotope atoms 5 are electrostatically attracted to the cathode 11, and the final has cathode 1
It is adsorbed on the surface of 1.

On the other hand, the other neutral isotope 6 that is not ionized travels straight without being affected by this electric field and is collected and collected by the neutral atom collection plate 12.

The steam encloser 1 is provided with an evacuation opening 13, and the vacuum container 1 is provided around the outer periphery of the steam encloser.
Covered by 4. This steam enclosure 1 is arranged to prevent the metal atomic vapor in the system from being exposed to the vacuum vessel 14 and to control the angle of the vapor from the crucible.

(Problem to be solved by the invention) In order to improve the efficiency of system operation such as continuous operation, the isotope separation system has a steam enclosure
The evaporation angle is controlled to efficiently recover the metal vapor evaporated from the crucible 3, and the steam enclosure 1 is
It is necessary to continuously reflux the metal vapor adhering to the inner wall of the tube and the opening 13.

As described above, the steam encapsulator 1 is arranged parallel to the atomic beam 4 evaporating from the crucible 3, and is provided with an opening 13 for evacuating the inside of the steam encapsulator 1. When the metal atoms 2 in the crucible 3 are heated, they become an atomic beam 4 and travel upwards. However, since the conventional steam enclosure 1 is formed into a substantially square or rectangular shape as shown in FIG. Metal vapor stagnates in various parts of the lower part.

Also, the flux amount of metal vapor is φ/φ°=cos ⁿ
Since it is defined by α, as shown in Figure 3, α=
The amount of steam is converged within 35°. Therefore, if the angle of the inner wall of the steam enclosure 1 becomes large, the amount of steam tends to be diffused, and there is a problem that the atomic beam 4 is not used efficiently.

On the other hand, since the atomic beam 4 is randomly diffused, it comes into contact with the inner wall and opening 13 of the vapor enclosure 1 and becomes metal atoms 2 and adheres thereto. attached metal atom 2
When the amount of gas increases in the opening 13, the residual gas in the steam enclosure 1 increases due to clogging of the opening 13, and the ionization efficiency of metal atoms decreases. Furthermore, it is necessary to stop the system to process the attached metal atoms 2, which causes a problem of lowering the efficiency of the system.

The present invention has been made to solve the above-mentioned problems, and aims to effectively ionize the atomic beam by efficiently advancing the atomic beam upward and continuously refluxing the metal atoms attached to the inner wall of the steam enclosure. The object of the present invention is to provide a steam enclosure for isotope separation that is capable of isotope separation.

[Structure of the Invention] (Means for Solving the Problems) The present invention evaporates metal atoms to generate an atomic beam, irradiates the atomic beam with a laser, ionizes and collects isotope metal atoms, and generates isotope metal atoms. In a steam enclosure for isotope separation for obtaining a metal atom, a main body of the vapor enclosure is provided surrounding a crucible for holding and evaporating the metal atoms, and the main body is heated and maintained above the melting point of the metal atoms, The steam enclosure for isotope separation is characterized in that the side wall of the main body is inclined outward with respect to the crucible.

The longitudinal section of the main body of the steam enclosing vessel is open at an angle of 60° to 75° with the crucible on the lower side.

(Function) Since the steam enclosure according to the present invention controls the atomic beam at an optimal evaporation angle, the ionization efficiency of metal atoms is high, and metal atom positive ions can be easily recovered. Furthermore, the metal atoms adhering to the inner wall can be heated together with the wall of the vapor enclosure to a temperature higher than the melting temperature of the metal atoms, and the metal atoms can be made into a liquid state and allowed to flow downward into the crucible.

(Example) Hereinafter, an example of a steam enclosure for isotope separation according to the present invention will be described with reference to FIGS. 1 and 2.

Fig. 1 shows the steam enclosing body and the crucible connected to the lower part of the steam enclosing vessel body, and Fig. 2 shows the window provided in the steam enclosing vessel body and the shingle step member fitted into the window. is shown enlarged.

That is, in FIG. 1, reference numeral 15 indicates a steam enclosure body, which is formed into a fan shape with a predetermined inclination angle, and has a crucible 16 at the bottom.
is connected. The main body 15 has a window 17 on the side surface, into which a step member 19 formed by laminating a plurality of rib-shaped plates having ventilation passages 18 is fitted. Further, a heater 20 is wound around the outer peripheral surface of the main body 15. Metal atoms 2 are contained within the crucible 16 .

The steam encapsulator in which the main body 15 is connected to the crucible 16 in this way is covered by a vacuum container (not shown), and an electron beam is emitted from an electron gun (not shown) installed in the vacuum container to the steam encapsulator main body 15. The metal atoms 2 in the crucible 16 are irradiated through the through hole, which does not have any irradiation. Furthermore, since the molten metal in the crucible 16 is reduced by evaporation, a metal raw material supply device (not shown) is connected to the steam enclosure main body 15, and the metal atoms 2 are replenished into the crucible 16 by this metal raw material supply device. Ru.

Here, the inclination angle of the main body 15 is selected from 60° to 70° with the crucible 16 on the lower side.
Ionization of the atomic beam 4 evaporated from the atomic beam 4 can be promoted.

However, the metal atoms 2 in the crucible 16 are heated and evaporated into an atomic beam 4. The amount of diffusion of this atomic beam 4 on the wall of the vapor enclosure main body 15 is controlled. That is, as shown in the correlation between the steam flux angle distribution in Figure 3 and the wall vapor density of the steam enclosure body 15 in Figure 4, if the divergence angle of the steam enclosure body 15 is selected from 60° to 70°, the steam They agree that the effectiveness rate is extremely high.

Furthermore, when the steam enclosing vessel 15 is heated by the heater 20, the metal atoms 2 adhering to the inner wall of the steam enclosing vessel main body 15 and the ventilation passage 18 turn into a liquid state, and as they accumulate, they are transmitted along the inner wall by their own weight. The metal atoms are refluxed to the lower crucible 16 and can be effectively utilized.

By providing the vapor enclosure main body 15 with an inclination angle in this way, the evaporation angle of the atomic beam 4 can be controlled and the utilization efficiency of metal atoms can be improved.

In addition, the attached metal atoms can be effectively utilized, clogging of the vacuum pump is prevented, and vacuum pumping characteristics are improved.

[Effects of the Invention] According to the present invention, the atomic beam is controlled, the optimum utilization efficiency of metal atoms is obtained, and the steam efficiency is improved.

In addition, metal atoms attached to the steam encapsulator can be continuously returned to the crucible, making effective use of the metal atoms, preventing clogging of the air passage that serves as the vacuum exhaust port, and exhausting residual gas from the system. Vacuum characteristics are improved and continuous operation of the system is improved.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the steam enclosure for isotope separation according to the present invention, FIG. 2 is an inclined section showing the main part of FIG. 1, and FIG. 3 is a calculated value of the steam flux distribution. FIG. 4 is a characteristic diagram showing the relationship between the steam effective utilization rate and the angle of the steam enclosure, and FIG. 5 is a longitudinal sectional view conceptually showing a conventional isotope separation device. 2...metal atom, 3...crucible, 4...atomic beam, 5...one isotope, 6...other isotope, 7...excitation laser, 8...ionizing laser,
9...Positive ion, 10...Grounding electrode, 11...
Cathode, 12... Neutral atom collection plate, 13...
Opening, 14... Vacuum container, 15... Steam enclosure main body, 16... Crucible, 17... Window, 18... Air passage, 19... Sheathing member, 20... Heater.

Claims (1)

[Claims] 1. A steam enclosure for isotope separation for evaporating metal atoms to generate an atomic beam, irradiating the atomic beam with a laser, ionizing and collecting isotopic metal atoms, and obtaining isotopic metal atoms. A main body of the vapor enclosure is provided surrounding the crucible that holds and evaporates the metal atoms, the main body is heated to a temperature higher than the melting point of the metal atoms, and a side wall of the main body is placed outward with respect to the crucible. A steam enclosure for isotope separation characterized by being tilted. 2. A steam enclosure for isotope separation according to claim 1, characterized in that a vertical cross section of the main body of the steam enclosure opens at an inclination angle of 60° to 75° with the crucible on the lower side. .