JP2021092483A - Producing method and device for astatine isotope, and separation/recovery method and device for astatine isotope - Google Patents

Abstract

To provide a method for efficiently and quickly separating an astatine isotope.SOLUTION: A method for producing an astatine isotope includes: an irradiation step S30 of irradiating an irradiation sample containing bismuth that is an element to be irradiated with helium accelerated by an accelerator; and recovery steps S40 to S60 of recovering an astatine isotope produced in the irradiation step. The recovery steps includes a step of transferring a gaseous astatine isotope using aerosol.SELECTED DRAWING: Figure 3

Description

Embodiments of the present invention relate to a method and apparatus for producing an astatine isotope, and a method and apparatus for separating and recovering an astatine isotope.

In recent years, in cancer treatment, cancer treatment using alpha rays has attracted attention. This is because the range of alpha rays is short, so cancer treatment using alpha rays can selectively attack target cancer cells, and the effect on normal cells is small.

Among the radioactive sources for cancer treatment using alpha-ray drugs, astatine-111 is the most promising radioisotope because it has a short half-life and rapidly decays into stable nuclei.

International Publication No. 2015/195042

While astatine-111 is expected as a radioactive source for cancer treatment, its short half-life causes the produced astatine-111 to almost disappear if it takes a long time to separate. A quick separation method is required.

So far, there are roughly two methods that have been developed and studied for the methods for separating and recovering the produced astatine-211.

The first method is a method in which astatine-211 produced in a target material is acid-dissolved together with a bismuth target material, astatine is dissolved in a solution, and the solution is purified by a method such as solvent extraction. However, there are problems that time is required for separation operations such as dissolution and extraction, and the amount of waste generated is large.

The second method heat-separates astatine by utilizing the difference in boiling point and melting point of astatine to be separated / recovered and aluminum which may be generally used as a membrane of bismuth target which is a target material. The method. In this method, astatine-211 adheres to the wall surface of the capillary or the like, which is a recovery unit or a transport unit. Therefore, it is necessary to elute and recover the astatine-211 attached using an organic solvent, an alkaline solution, or the like.

In addition to these methods, a method using a gas jet has long been known for superheavy elements and the like as a general method for separating and recovering nuclides synthesized rapidly and continuously. This method is a method in which an aerosol such as potassium iodide coexists with helium gas or the like to transport a synthetic nuclide that jumps out to the rear of the target material due to recoil at the time of beam irradiation for nuclide synthesis. However, little research has been done on whether this method is applicable to astatines.

An embodiment of the present invention aims to efficiently and rapidly separate an astatine isotope from radionuclides used in cancer treatment and other uses.

In order to achieve the above-mentioned object, the method for producing an astatine isotope according to the present embodiment is generated by an irradiation step of irradiating an irradiation sample containing bismuth, which is an element to be irradiated, with helium accelerated by an accelerator, and the irradiation step. It comprises a recovery step of recovering the astatine isotope, and the recovery step comprises the step of transferring the gaseous astatine isotope using an aerosol.

In addition, the method for separating and recovering the astatine isotope according to the present embodiment involves a recovery step of recovering the astatine isotope produced by irradiating an irradiated sample containing the irradiated element bismuth with helium accelerated by an accelerator. The recovery step comprises the step of transferring the gaseous astatine isotope with an aerosol.

Further, the method for separating and recovering an astatine isotope according to the present embodiment includes a reaction vessel formed so as to store an irradiation sample containing an irradiated element and to introduce helium accelerated by an accelerator that irradiates the irradiation sample. , Aerosol generation for transferring the astatine isotope generated by the irradiation of helium accelerated by the accelerator of the element to be irradiated by the heating container capable of heating the irradiated sample irradiated in the reaction container. A device and a recovery container for recovering the astatine isotope carried by the aerosol are provided, and the heating container makes the irradiated sample lower than the boiling point of the irradiated element and higher than the boiling point of the radioisotope. It is characterized by raising the temperature to a temperature.

Further, in the astatine isotope production apparatus according to the present embodiment, the tape-shaped irradiation sample in which the bismuth layer is formed on the base material tape is continuously taken in and taken out, and the tape-shaped irradiation sample is continuously taken out and taken out. To transfer the reaction vessel formed so that helium accelerated by the accelerator that continuously irradiates the sample can be introduced and the astatine isotope produced by the irradiation of the tape-shaped irradiated sample with helium accelerated by the accelerator. The astatine generator is provided with a recovery container for recovering the astatine isotope carried by the aerosol.

Further, the astatine isotope separation / recovery apparatus according to the present embodiment includes a heating container capable of heating an irradiated sample containing an irradiated element and irradiated with helium accelerated by an accelerator, and the irradiated element by the heating. The heating container comprises an aerosol generator for transferring the astatine isotope generated by irradiation of helium accelerated by the accelerator and a recovery container for recovering the astatine isotope carried by the aerosol. The irradiated sample is heated to a temperature lower than the boiling point of the irradiated element and higher than the boiling point of the astatine isotope.

It is a vertical cross-sectional view which shows the structure of the apparatus for irradiation of the irradiation sample among the apparatus for producing an astatine isotope which concerns on 1st Embodiment. It is a vertical cross-sectional view which shows the structure of the astatine isotope separation / recovery apparatus which concerns on 1st Embodiment. It is a flow figure which shows the procedure of the manufacturing method of the astatine isotope which concerns on 1st Embodiment. It is a flow figure which shows the detailed procedure of separation of an astatine isotope in the method for producing an astatine isotope which concerns on 1st Embodiment. It is a flow figure which shows the detailed procedure of recovery of an astatine isotope in the method for producing an astatine isotope which concerns on 1st Embodiment. It is a vertical cross-sectional view which shows the structure of the astatine isotope production apparatus which concerns on 2nd Embodiment. It is a perspective view which shows the structure of the transfer part of the irradiation sample of the astatine isotope production apparatus which concerns on 2nd Embodiment. It is a flow figure which shows the procedure of the manufacturing method of the astatine isotope which concerns on 2nd Embodiment. FIG. 5 is a flow chart showing a detailed procedure for transferring an irradiated sample into a heating container in the method for producing an astatine isotope according to the second embodiment. It is a vertical cross-sectional view which shows the structure of the astatine isotope production apparatus which concerns on 3rd Embodiment. It is a flow figure which shows the procedure of the manufacturing method of the astatine isotope which concerns on 3rd Embodiment. It is a flow figure which shows the procedure of transfer of the irradiation sample in the method for producing an astatine isotope which concerns on 3rd Embodiment. It is a cross-sectional view taken along the line XIII-XIII of FIG. 14 which shows the structure of the astatine isotope production apparatus which concerns on 4th Embodiment. FIG. 13 is a partial cross-sectional view taken along the line XIV-XIV of FIG. 13 showing a configuration of an astatine isotope production apparatus according to a fourth embodiment. It is a vertical cross-sectional view which shows the detailed structure of the part A of FIG. 14 of the astatine isotope production apparatus which concerns on 4th Embodiment. It is a flow figure which shows the procedure of the manufacturing method of the astatine isotope which concerns on 4th Embodiment.

Hereinafter, a method and apparatus for producing an astatine isotope, a separation / recovery method and an apparatus according to an embodiment of the present invention will be described with reference to the drawings. Here, parts that are the same as or similar to each other are designated by a common reference numeral, and redundant description will be omitted.

[First Embodiment]
FIG. 1 is a vertical cross-sectional view showing a configuration of an irradiation unit 110 for irradiation of an irradiation sample in the astatine isotope production apparatus according to the first embodiment.

The irradiation unit 110 includes a reaction vessel 20 and a vacuum pump 70 for irradiating the irradiation sample 10 with helium accelerated by the accelerator from the irradiation device 1.

The reaction vessel 20 has a vessel body 21 and a sample holding portion 24. The sample holding portion 24 is provided in the container main body 21 and mounts the irradiation sample 10 in a horizontal state. The irradiation sample 10 has an irradiation material saucer 12 and a bismuth irradiation material 11 housed therein. Here, the bismuth irradiating material 11 is bismuth in a solid state at room temperature. The material of the irradiator pan 12 is nuclear stable to the irradiation of accelerator-accelerated helium, for example aluminum, and produces no secondary products, and its melting point is also compared to bismuth and astatine. It is a very expensive material. The number of the irradiation samples 10 mounted on the sample holding unit 24 may be two, more, or one as shown in FIG.

Further, the container body 21 is provided with an irradiation window 22 that allows helium accelerated by the accelerator from the radiation irradiation device 1 to pass through. Here, the helium accelerated by the accelerator that has passed through the irradiation window 22 has a positional relationship so as to reach the bismuth irradiation material 11 in the irradiation material tray 12.

When the irradiated sample 10 is irradiated with helium accelerated by the accelerator, the bismuth 209 in the irradiated sample 10 is converted to astatine-111 to produce astatine-111.

When the energy of helium accelerated by the irradiated accelerator reaches about 30 MeV, not only astatine-215 but also astatine-210 is produced. Astatine-210 undergoes beta decay to polonium-210. Polonium-210 is an α-ray source and does not emit gamma rays or the like, so it can be said to be a dangerous substance in the sense that it is difficult to detect its existence. Therefore, the energy of helium accelerated by the irradiated accelerator is managed with an upper limit of, for example, about 29 MeV or less so as not to lead to the formation of polonium-210.

An exhaust port 28 is formed in the container body 21 and communicates with the vacuum pump 70. The vacuum pump 70 has an ability to lower the inside of the reaction vessel 20 to a predetermined pressure. Here, the predetermined pressure is set from the condition that the decrease in the intensity and energy of the helium reaching the bismuth irradiation material 11 is kept within a predetermined range with respect to the helium accelerated by the accelerator emitted from the irradiation device 1. To.

The container body 21 is further formed with an opening / closing opening 25 for taking in / out the irradiation sample 10, and is closed by a closing lid 26.

FIG. 2 is a vertical cross-sectional view showing the configuration of the astatine isotope separation / recovery device 120 according to the first embodiment. The separation / recovery device 120 is a device for separating and recovering astatine-111 generated in the irradiation sample 10 irradiated with helium accelerated by the accelerator in the irradiation unit 110.

The separation / recovery device 120 includes a heating container 30, an aerosol supply section 40, a recovery section 50, and an exhaust section 60.

The heating container 30 has a container body 31, a sample holding portion 32, and a heater 37.

The sample holding unit 32 is inside the container body 31, and carries the irradiated sample 10 after irradiation brought into the container body 31. The configuration of the sample holding unit 32 is not limited to the two-stage configuration as shown in FIG. It may be set from the taking in and out of the irradiation sample 10, the positional relationship with the heater 37, and the like.

The heater 37 is a plurality of electric heaters attached to the container body 31. The number is not limited to one, and may be one. Further, the heater 37 is not limited to the electric heater, and may be, for example, a heat transfer tube through which a heating fluid is passed.

The heater 37 has a capacity for heating the inside of the container body 31 and raising the irradiated irradiation sample 10 to a predetermined temperature. Here, the predetermined temperature is a temperature exceeding the boiling point of astatine and lower than the boiling point of bismuth. The temperature is equal to or higher than the melting point of bismuth. By raising the temperature to a predetermined temperature, bismuth becomes liquid and astatine becomes gaseous.

Table 1 shows the melting points (° C.) and boiling points (° C.) of astatine and bismuth. Further, aluminum is also shown as an example of the material used for the irradiation material saucer 12 of the irradiation sample 10. The temperature is omitted after the decimal point.

The container body 31 is formed with an in / out opening 38 for taking in / out the irradiation sample 10, an aerosol supply port 33, and a recovery port 34. The aerosol supply port 33 communicates with the aerosol supply unit 40. Further, the collection port 34 communicates with the collection unit 50.

The aerosol supply unit 40 is a device for supplying the aerosol to the container body 31. The aerosol supply unit 40 includes a supply container 41, a gas supply unit 45, a supply pipe 42, and a stop valve 43. The supply container 41 is a portion for generating or storing an aerosol. Here, the aerosol is, for example, particles such as potassium chloride and potassium iodide. The particle size of the particles is, for example, about 1 nm to about 1 mm. The gas supply unit 45 supplies a carrier gas for moving the aerosol, for example, an inert gas such as helium gas.

The aerosol generated or stored in the supply container 41 is introduced into the container body 31 of the heating container 30 from the supply pipe 42 by the gas from the gas supply unit 45 according to the opening and closing of the stop valve 43. The astatine that has become gaseous in the container body 31 is adsorbed on the aerosol.

The recovery unit 50 is a portion that recovers the astatine adsorbed on the aerosol.

The recovery unit 50 has a recovery container 51, a dissolution liquid 52 in the recovery container 51, and a recovery pipe 53 connecting the recovery port 34 of the heating container 30 and the recovery container 51.

The lysing solution 52 held in the recovery container 51 dissolves the aerosol. Here, the solution is water or an alkaline solution. As the alkaline solution, for example, a solution corresponding to the component of the aerosol is preferable, such as potassium hydroxide in the case of potassium chloride or potassium iodide.

The tip of the recovery tube 53 in the recovery container 51 is opened below the liquid surface of the solution 52 and submerged in water.

The collection container 51 is connected to the exhaust unit 60 as a vent line. The exhaust unit 60 has an exhaust pipe 61 and an exhaust filter 62. The gas flowing into the recovery container 51 is released to the atmosphere via the exhaust filter 62.

FIG. 3 is a flow chart showing the procedure of the method for producing an astatine isotope according to the first embodiment.

As a method for producing an astatine isotope, first, an irradiated sample is prepared (step S10). Here, the irradiation sample 10 is not limited to a form in which the bismuth irradiation material 11 as shown in FIGS. 1 and 2 is held in the irradiation material saucer 12. For example, the bismuth irradiation material 11 may be sealed in aluminum or the like.

Next, the irradiation sample 10 is placed in the reaction vessel 20 (step S20). That is, as shown in FIG. 1, the irradiation sample 10 is mounted on the sample holding portion 24 in the reaction vessel 20 from the loading / unloading opening 25.

Next, the irradiation sample 10 is irradiated with helium accelerated by the accelerator (step S30). Prior to irradiation with helium accelerated by an accelerator with appropriate energy, the inside of the container body 21 is lowered to a predetermined pressure by a vacuum pump 70.

Next, the irradiated sample 10 is transferred to the heating container 30 (step S40).

Next, the produced astatine isotope is separated (step S50).

FIG. 4 is a flow diagram showing a detailed procedure for separating an astatine isotope in the method for producing an astatine isotope according to the first embodiment.

As the astatine isotope separation step S50, first, the inside of the heating container 30 is formed in a closed state (step S51). Next, the temperature inside the heating container 30 is raised (step S52). Specifically, the temperature inside the heating container 30 is raised to a predetermined temperature.

Next, the astatine isotope produced is recovered (step S60).

FIG. 5 is a flow diagram showing a detailed procedure for recovering an astatine isotope in the method for producing an astatine isotope according to the first embodiment.

In the astatine isotope recovery step S60, first, the aerosol is transferred from the aerosol supply unit 40 into the heating container 30 (step S61). That is, the stop valve 43 is opened, and the aerosol is injected into the heating container 30 with the gas from the gas supply unit 45.

Further, the aerosol adsorbed by astatine is transferred to the recovery unit 50 (step S62). Steps S61 and S62 are continuously performed by supplying the supply gas. As a result, the gas containing the aerosol is ejected into the solution 52 in the recovery container 51 of the recovery unit 50. The aerosol in the gas containing the aerosol ejected into the solution 52 dissolves in the solution 52 together with the astatine adhering to the aerosol. The insoluble carrier gas flows out to the exhaust unit 60, and is discharged or recycled to the outside air via the exhaust filter 62.

Next, the astatine isotope is recovered from the solution 52 in the recovery container 51 (step S63). Recovery at this time can be easily performed by ordinary chemical treatment.

In the conventional method of transferring astatine-111 separated by the heating part only with the carrier gas, astatine-111 adheres to the wall surface of the capillary or the like which is the recovery part or the transport part, so that an organic solvent or an alkaline solution can be used. It is necessary to elute and recover the attached astatine-211 using the drug.

On the other hand, in the present embodiment, after separating astatine-111 generated by irradiating bismuth 209 with helium accelerated by an accelerator in a heating container 31, astatine-111 is adsorbed on aerosol to the recovery unit 50. It is a transfer method. As a result, it is possible to prevent astatine-211 from adhering to the path leading to the recovery part such as the capillary, the recovery efficiency can be improved, and it is not necessary to treat the waste liquid generated by washing.

As described above, the astatine isotope can be separated efficiently and rapidly by the astatine isotope production apparatus 100 according to the present embodiment and the method for producing the astatine isotope using the apparatus 100.

[Second Embodiment]
The second embodiment is a modification of the first embodiment.

In the first embodiment, the irradiated sample 10 irradiated in the reaction vessel 20 is taken out from the loading / unloading opening 25 formed in the reaction vessel 20, and is taken out from the loading / unloading opening 38 formed in the heating vessel 30 into the container body 31. It is mounted on the sample holding portion 32 of the above.

On the other hand, in the second embodiment, the irradiated sample 10 irradiated in the reaction vessel 20 is configured to be transferred from the reaction vessel 20 into the heating vessel 30 without being taken out to the outside. In other respects, it is similar to the first embodiment.

FIG. 6 is a vertical cross-sectional view showing the configuration of the astatine isotope production apparatus according to the second embodiment. Further, FIG. 7 is a perspective view showing a configuration of a transfer portion of an irradiated sample of the astatine isotope production apparatus according to the second embodiment.

The astatine isotope production apparatus 100a has an intermediate portion 130 arranged between the irradiation unit 110 and the separation / recovery apparatus 120.

The intermediate portion 130 includes an intermediate portion container 131, a turntable 132, and a rotation drive unit 133.

The intermediate container 131 is sandwiched between the container body 21 of the reaction container 20 and the container body 31 of the heating container 30, and is mounted on the rotation drive unit 133 provided inside the intermediate portion container 131 and the rotation drive unit 133. It has a turntable 132 that is rotationally driven by 133.

The irradiation sample 10 is mounted on the turntable 132. A part of the turntable 132 projects into the container body 21 of the reaction vessel 20 and the container body 31 of the heating vessel 30. Therefore, the irradiation sample 10 mounted on the turntable 132 can be in a state of being present inside each of the container body 21 of the reaction container 20 and the container body 31 of the heating container 30.

As shown in FIG. 7, when the turntable 132 is rotated, the container body 21 of the reaction vessel 20 is provided with a take-in / out opening 25 so as not to interfere with the irradiation sample 10 mounted on the turntable 132. A taking-in / out opening 38 is formed in the container main body 31 of the container 30.

Therefore, the container body 21 is provided with a reaction container partition door 27 for closing the loading / unloading opening 25, and the container body 31 is provided with a heating container partition door 35 for closing the loading / unloading opening 38. ing. The reaction container partition door 27 and the heating container partition door 35 are in close contact with the turntable 132 in the closed state, respectively, and the sealing property is ensured.

Further, the intermediate portion 130 communicates with a vacuum pump (not shown), and the inside of the intermediate portion container 131 can be transferred to a vacuum state.

Further, although not shown, the intermediate portion 130 is formed with an opening for taking in and out from the outside.

The aerosol supply unit 40 and the recovery unit 50 are the same as those in the first embodiment.

FIG. 8 is a flow chart showing the procedure of the method for producing an astatine isotope according to the second embodiment.

The preparation of the irradiation sample 10 in step S10 is the same as in the first embodiment.

Next, in the reaction vessel 20, the irradiation sample 10 is placed on the turntable 132 (step S20a).

Next, the irradiation sample 10 is irradiated with helium accelerated by the accelerator (step S30).

Next, the irradiated sample 10 is transferred into the heating container 30 (step S40a).

FIG. 9 is a flow diagram showing a detailed procedure for transferring the irradiated sample into the heating container in the method for producing the astatine isotope according to the second embodiment.

As the transfer step S40a of the irradiation sample into the heating container, first, the intermediate portion 130 is moved to the vacuum state (step S41a).

Next, the reaction container partition door 27 and the heating container partition door 35 are opened, respectively (step S42a).

Next, the turntable 132 is rotated (step S43a). The turntable 132 is rotated 180 degrees, for example. As a result, the irradiation sample 10 mounted on the turntable 132 in the reaction vessel 20 moves into the heating vessel 30.

Next, the reaction container partition door 27 and the heating container partition door 35 are each closed (step S44a).

As described above, in the second embodiment, the irradiation sample 10 can be moved from the reaction vessel 20 to the heating vessel 30 without taking it out. Further, the irradiation sample 10 can be taken in and out at the intermediate portion 130. As a result, for example, the irradiation sample 10 can be irradiated and transferred to the heating device 20 without destroying the vacuum state in the reaction vessel 20, and the production efficiency of astatine can be improved.

[Third Embodiment]
FIG. 10 is a vertical cross-sectional view showing the configuration of the astatine isotope production apparatus 100b according to the third embodiment.

The third embodiment is a modification of the first embodiment. In the third embodiment, similarly to the second embodiment, the irradiation sample 10a irradiated in the reaction vessel 20 is transferred from the reaction vessel 20 into the heating vessel 30 without being taken out to the outside. It is configured as follows. In other respects, it is similar to the first embodiment.

Here, the irradiation sample 10a in the present embodiment has a bismuth irradiation material 11 and an irradiation material storage unit 13 for storing the bismuth irradiation material 11 so that the bismuth irradiation material 11 does not flow out regardless of the posture of the irradiation sample 10a.

The astatine isotope production device 100b includes an irradiation unit 110, a separation / recovery device 120, and an intermediate unit 130 that communicates them.

The irradiation unit 110 is different from the first embodiment in that the irradiation sample 10a is taken in and out of the reaction vessel 20. A closing lid 26a and an inlet sample holding portion 24a are provided at the introduction portion of the irradiation sample 10a into the reaction vessel 20. The irradiated sample 10a is introduced by opening the closing lid 26a, and is first held by the inlet sample holding portion 24a. The inlet sample holding portion 24a can be opened and closed by a driving unit (not shown), holds the irradiation sample 10a in the closed state, and the irradiation sample 10a falls downward due to gravity in the open state.

An irradiation point sample holding portion 24b is provided at the irradiation point in the reaction vessel 20. The irradiation site sample holding unit 24b can also be opened and closed by a driving unit (not shown) like the inlet sample holding unit 24a. When the irradiation sample 10a is not held by the irradiation site sample holding unit 24b and the irradiation site sample holding unit 24b is closed and the inlet sample holding unit 24a that holds the irradiation sample 10a is opened, the inlet sample holding unit 24a is opened. The held irradiation sample 10a falls by gravity and is held by the irradiation site sample holding portion 24b.

The intermediate portion 130 includes a communication pipe 134 that communicates the reaction vessel 20 and the heating container 30, a first sluice valve 135 and a second sluice valve 136 provided in the communication pipe 134, and an exhaust portion 137 that connects to the communication pipe 134. Have.

The irradiation sample 10a can be stored in the portion of the communication pipe 134 between the first sluice valve 135 and the second sluice valve 136.

The exhaust portion 137 is provided with a stop valve 137a. The exhaust unit 137 can shift the pressure of the portion of the communication pipe 134 sandwiched between the first sluice valve 135 and the second sluice valve 136 to a substantially vacuum state.

A sample holding portion 32 is provided in the heating container 30. The sample holding unit 32 can hold the irradiation sample 10a that passes through the communication pipe 134 and enters the heating container 30 due to gravity drop.

FIG. 11 is a flow chart showing the procedure of the method for producing an astatine isotope according to the third embodiment.

The preparation of the irradiation sample 10a in step S10 is the same as in the first embodiment.

Next, the irradiated sample 10a is introduced into the reaction vessel 20 (step S20b). Specifically, the closing lid 26a is opened, the irradiation sample 10a is introduced, and the sample is held by the inlet sample holding portion 24a. Further, the inlet sample holding portion 24a is opened, and the irradiation sample 10a that falls due to gravity is held by the irradiation location sample holding portion 24b.

Next, the irradiation sample 10a is irradiated with helium accelerated by the accelerator (step S30).

Next, the irradiated sample 10a is transferred into the heating container 30 (step S40b).

FIG. 12 is a flow chart showing a procedure for transferring an irradiated sample in the method for producing an astatine isotope according to the third embodiment.

The irradiation sample transfer step S40b has the following steps.

First, it shifts to a vacuum state between the first sluice valve 135 and the second sluice valve 136 (step S41b). Specifically, the stop valve 137a is opened, and the exhaust portion 137 reduces the pressure of the portion of the communication pipe 134 between the first sluice valve 135 and the second sluice valve 136 to the same pressure as the pressure inside the reaction vessel 20. Let me.

Next, the first sluice valve 135 is opened (step S42b). By opening the first sluice valve 135, the portion of the communication pipe 134 between the first sluice valve 135 and the second sluice valve 136 communicates with the space inside the container body 21 of the reaction vessel 20.

Next, the sample holding portion 24b at the irradiation site is opened (step S43b). As a result, the irradiation sample 10a held in the irradiation point sample holding portion 24b in the container main body 21 drops by gravity and is held by the second sluice valve 136 (step S44b).

The portion of the communication pipe 134 between the first sluice valve 135 and the second sluice valve 136 is pressurized to the same pressure as in the heating container 30 (step S45b).

Next, the second sluice valve 136 is opened (step S46b). By opening the second sluice valve 136, the irradiation sample 10a held by the second sluice valve 136 is gravitationally dropped into the heating container 30. The irradiated sample 10a that has moved into the heating container 30 is held by the sample holding portion 32 in the heating container 30.

As described above, in the third embodiment, as in the second embodiment, the irradiation sample 10a can be moved from the reaction vessel 20 to the heating vessel 30 without taking it out. As a result, for example, the vacuum state in the reaction vessel 20 can be maintained, the irradiation sample 10a can be irradiated, and the astatine can be transferred to the heating device 20, and the production efficiency of astatine can be improved.

[Fourth Embodiment]
FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 14 showing the configuration of the astatine isotope production apparatus according to the fourth embodiment, and FIG. 14 is the astatine isotope production apparatus according to the fourth embodiment. FIG. 13 is a cross-sectional view taken along the line XIV-XIV of FIG. 13 showing the configuration of the above. Further, FIG. 15 is a vertical cross-sectional view showing a detailed configuration of part A of FIG. 14 of the astatine isotope production apparatus according to the fourth embodiment.

First, the irradiation sample is a tape-shaped irradiation sample 15. As shown in FIG. 15, the tape-shaped irradiation sample 15 has a base material tape 15a and a bismuth layer 15b formed on one surface of the base tape 15a. The material of the base material tape 15a is, for example, aluminum. The thickness of the base material tape 15a is, for example, 1 to several microns (μm). The thickness of the bismuth layer 15b is, for example, 50 to 100 nm.

As shown in FIG. 13, the astatine isotope production apparatus 100c in the present embodiment includes a reaction vessel 20, an aerosol supply unit 40, a recovery unit 50, and an exhaust unit 60. Therefore, it does not have a heating part as an astatine separator. The aerosol supply unit 40, the recovery unit 50, and the exhaust unit 60 are the same as those in the first embodiment.

As shown in FIG. 14, the reaction vessel 20 is formed with an aerosol inflow port 28a communicating with the aerosol supply unit 40, an exhaust port 28 communicating with the recovery unit 50, and an irradiation window 22.

Further, the reaction vessel 20 is configured such that a plurality of tape-shaped irradiation samples 15 are continuously passed through the inside thereof so that the reaction vessel 20 can be continuously irradiated. For this purpose, the reaction vessel 20 has a plurality of roller mechanisms.

That is, the reaction vessel 20 has an inlet roller 23 for introducing the plurality of tape-shaped irradiation samples 15 into the reaction vessel 20, and an outlet roller 29 for taking out the plurality of tape-shaped irradiation samples 15 out of the reaction vessel 20. Further, as shown in FIG. 15, the reaction vessel 20 has an inlet side first branch roller 23a, an inlet side second branch roller 23b, an outlet side first merging roller 29a, and an outlet side second merging roller 29b. The inlet roller 23 and the outlet roller 29 are each provided with a drive unit, but the drive unit is not shown. Here, the drive unit may be provided only on the outlet roller 29. Further, the inlet side first branch roller 23a, the inlet side second branch roller 23b, the outlet side first merging roller 29a, and the outlet side second merging roller 29b each rotate according to the movement of the tape-shaped irradiation sample 15. It has only a guide function.

The inlet roller 23 and the outlet roller 29 each have a pair of rotating portions, and the tape-shaped irradiation sample 15 is sandwiched between these rotating portions and transferred in the rotational direction. The inlet roller 23 and the outlet roller 29 are provided on the walls corresponding to each other.

FIG. 15 shows a case where the number of tape-shaped irradiation samples 15 is four. However, the number of tape-shaped irradiation samples 15 may be other than four. The number of rollers in the reaction vessel 20 may be set according to the number of tape-shaped irradiation samples 15.

By arranging the inlet-side first branch roller 23a in the rear stage of the inlet roller 23 and arranging the inlet-side second branch roller 23b in the rear stage of the inlet-side first branch roller 23a, four sheets sent out from the inlet roller 23. The distance between the tape-shaped irradiation samples 15 is secured. On the contrary, the outlet side first merging roller 29a is arranged after the inlet side second branch roller 23b, the outlet side first merging roller 29a is after the outlet side first merging roller 29a, and the outlet side second merging roller 29 is in front of the outlet roller 29. By arranging 29b, four tape-shaped irradiation samples 15 having a mutual spacing are integrated so as to overlap each other and sent out from the outlet roller 29.

FIG. 16 is a flow chart showing the procedure of the method for producing an astatine isotope according to the fourth embodiment.

First, an irradiation sample is prepared (step S10c). Here, the irradiation sample is a tape-shaped irradiation sample 15.

Next, the tape-shaped irradiation sample 15 is transferred into the reaction vessel 20 at a predetermined speed (step S20c). Here, all the tape-shaped irradiation samples 15 are mounted in the direction in which the bismuth layer 15b is arranged on the side opposite to the direction of the radiation irradiation device 1.

Next, the tape-shaped irradiation sample 15 is irradiated with helium accelerated by an accelerator to separate the produced astatine isotope (step S30c). Irradiation of bismuth with accelerator-accelerated helium produces isotopes of astatine. At this time, the astatine atom rebounds, that is, jumps out in the direction opposite to the direction of the radiation irradiation device 1. In the present embodiment, since the bismuth layer 15b is thin, the astatine isotope that has jumped out due to the rebound jumps out to the outside of the bismuth layer 15b, that is, the space behind the tape-shaped irradiation sample 15 when viewed from the radiation irradiation device 1. ..

Next, a gas containing an aerosol is injected into and discharged into the reaction vessel 20 (step S40c). Specifically, the stop valve 43 is opened, the aerosol is driven by the carrier gas, and the aerosol is allowed to flow into the reaction vessel 20. Since the plurality of tape-shaped irradiation samples 15 are arranged at intervals from each other, a flow path is formed, and the gas containing the aerosol passes through this flow path. The astatine isotope transferred to the back side of the tape-shaped irradiation sample 15 is adsorbed on this aerosol.

Next, the astatine isotope produced from the discharged aerosol is recovered (step S50c). That is, the aerosol on which the astatine isotope is adsorbed flows into the recovery container 50, and the astatine isotope is recovered.

As described above, in the present embodiment, the astatine is separated in the reaction vessel 20 by utilizing the rebound phenomenon by using the tape-shaped irradiation sample 15 having a thin thickness in the irradiation direction of helium accelerated by the accelerator. Can be done. Further, since the tape-shaped irradiation sample 15 is used, the irradiation position can be continuously changed. Thus, in this embodiment, the astatine isotope can be continuously produced and separated. In addition, the generated astatine isotope can be continuously transferred to the recovery unit 50.

As a result, in this embodiment, the astatine isotope can be separated efficiently and rapidly.

[Other Embodiments]
Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention.

Moreover, you may combine the features of each embodiment. For example, the features of the second embodiment and the features of the third embodiment may be combined.

In addition, the embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention.

The embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Radiation irradiation device, 10, 10a ... Irradiation sample, 11 ... Bismus irradiation material, 12 ... Irradiation material container, 13 ... Irradiation material storage, 15 ... Tape-like irradiation sample, 15a ... Base tape, 15b ... Bismus layer, 20 ... Reaction vessel, 21 ... Container body, 22 ... Irradiation window, 23 ... Inlet roller, 23a ... Inlet side first branch roller, 23b ... Inlet side second branch roller, 24 ... Sample holding part, 24a ... Inlet sample holding part , 24b ... Irradiation site sample holding part, 25 ... In / out opening, 26, 26a ... Closing lid, 27 ... Reaction vessel partition door, 28 ... Exhaust port, 28a ... Aerosol inlet, 29 ... Outlet roller, 29a ... Outlet side first Confluence roller, 29b ... Outlet side second merging roller, 30 ... Heating container, 31 ... Container body, 32 ... Sample holding part, 33 ... Aerosol supply port, 34 ... Recovery port, 35 ... Heating container partition door, 37 ... Heater, 38 ... In / out opening, 40 ... Aerosol supply unit, 41 ... Supply container, 42 ... Supply pipe, 43 ... Stop valve, 45 ... Gas supply unit, 50 ... Recovery unit, 51 ... Recovery container, 52 ... Solution, 53 ... Recovery Pipe, 60 ... Exhaust part, 61 ... Exhaust pipe, 62 ... Exhaust filter, 70 ... Vacuum pump, 100, 100a, 100b, 100c ... Astatin isotope production device, 110 ... Irradiation part, 120 ... Separation / recovery device, 130 ... Intermediate part, 131 ... Intermediate part container, 132 ... Turntable, 133 ... Rotation drive part, 134 ... Communication pipe, 135 ... 1st sluice valve, 136 ... 2nd sluice valve, 137 ... Exhaust part, 137a ... Stop valve

Claims (15)

An irradiation step of irradiating an irradiation sample containing bismuth, which is an element to be irradiated, with helium accelerated by an accelerator, and
A recovery step for recovering the astatine isotope produced in the irradiation step, and a recovery step.
Have,
The recovery step comprises the step of transferring the gaseous astatine isotope using an aerosol.
A method for producing an astatine isotope. The method for producing an astatine isotope according to claim 1, wherein the recovery step includes a step of heating the irradiated sample irradiated in the irradiation step to raise the temperature to a predetermined temperature. The method for producing an astatine isotope according to claim 2, wherein the predetermined temperature is a temperature exceeding the boiling point of astatine and lower than the boiling point of bismuth. The astatine according to any one of claims 1 to 3, wherein the recovery step includes a step of transferring the irradiated sample irradiated in the irradiation step to a heating container for heating. Method for producing isotopes. The method for producing an astatine isotope according to claim 4, wherein in the step of transferring the irradiated sample to the heating container, the irradiated sample is transferred from the irradiated position to the heated position by a turntable. The astatine according to claim 4, wherein in the step of transferring the irradiated sample to the heating container, the irradiated sample is transferred from the irradiated position to the heated position by spontaneous dropping by opening and closing the partition mechanism. Method for producing isotopes. The irradiation step includes a step of separating the astatine isotope by rebound by irradiating the irradiated sample with helium accelerated by an accelerator.
The irradiation sample is a tape-shaped irradiation sample in which a bismuth layer, which is an element to be irradiated, is formed on the back surface of the tape-shaped base material.
The method for producing an astatine isotope according to claim 1. In the irradiation step, the irradiated portion is continuously moved by continuously moving the tape-shaped irradiation sample in the longitudinal direction.
The method for producing an astatine isotope according to claim 7. The method for producing an astatine isotope according to claim 1 to 8, wherein the recovery step includes a step of dissolving astatine in a liquid to recover the astatine isotope. It has a recovery step of recovering the astatine isotope produced by irradiating an irradiated sample containing the irradiated element bismuth with helium accelerated by an accelerator.
The recovery step comprises the step of transferring the gaseous astatine isotope using an aerosol.
A method for separating and recovering an astatine isotope. A reaction vessel formed so that an irradiation sample containing an irradiation element can be stored and helium accelerated by an accelerator that irradiates the irradiation sample can be introduced.
A heating container capable of heating the irradiated sample irradiated in the reaction container, and
An aerosol generator for transferring an astatine isotope produced by irradiation of helium accelerated by the accelerator of the element to be irradiated by the heating with an aerosol, and an aerosol generator.
A recovery container for recovering the astatine isotope carried by the aerosol, and a recovery container.
With
The heating vessel heats the irradiated sample to a temperature lower than the boiling point of the irradiated element and higher than the boiling point of the astatine isotope.
An astatine isotope production apparatus characterized in that. Using a tape-shaped irradiation sample in which a bismuth layer was formed on the base tape,
A reaction vessel formed so that helium accelerated by an accelerator that continuously takes in and takes out the tape-shaped irradiation sample and continuously irradiates the tape-shaped irradiation sample can be introduced.
An aerosol generator for transferring the astatine isotope produced by irradiation of the tape-shaped irradiation sample with helium accelerated by an accelerator, and
A recovery container for recovering the astatine isotope carried by the aerosol, and a recovery container.
An astatine isotope production apparatus comprising. There are a plurality of tape-shaped irradiation samples,
The reaction vessel has a plurality of guide rollers for ensuring a distance between the plurality of tape-shaped irradiated samples.
The apparatus for producing an astatine isotope according to claim 12. The apparatus for producing an astatine isotope according to any one of claims 11 to 13, wherein the recovery container holds a liquid that dissolves the astatine isotope carried by the aerosol. A heating container that can heat an irradiated sample that contains an element to be irradiated and is irradiated with helium accelerated by an accelerator.
An aerosol generator for transferring an astatine isotope produced by irradiation of helium accelerated by the accelerator of the element to be irradiated by the heating with an aerosol, and an aerosol generator.
A recovery container for recovering the astatine isotope carried by the aerosol, and a recovery container.
With
The heating vessel heats the irradiated sample to a temperature lower than the boiling point of the irradiated element and higher than the boiling point of the astatine isotope.
An astatine isotope separation / recovery device characterized by this.

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