JPH05119196A - Manufacture method of multitracer by reduced-pressure-heating fusion method - Google Patents

Abstract

PURPOSE:To obtain the method capable of efficiently taking out a radioactive isotope in a short time, effectively using even the radioactive isotope of a short half-life as a tracer and contriving the reduction of labor for the need of manufacture. CONSTITUTION:A nitrogen ion beam and the like of high energy is irradiated on a target 10 of a gold leaf and the like to produce a radioactive isotope. The target 10 is housed in a silica tube 1, whose inside is filled with a pressure- reduced atmosphere of 1Pa by the use of an oil-sealed rotary vacuum pump 3 and heated at the temperature of a melting point or higher of the target 10 for the purpose of melting it. This condition is held for an hour, the radioactive isotope is allowed to fly out and captured by adhering to a water- cooling cold finger 6 and the inner wall part of the silica tube 1 at low temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multitracer containing a plurality of kinds of radioisotopes, and more particularly to a method for producing a multitracer by a reduced pressure heating and melting method.

[0002]

2. Description of the Related Art Conventionally, a target such as gold or silver is irradiated with a beam such as an ion beam, a plurality of kinds of radioisotopes are generated in the target, and the radioisotope is extracted from the target to obtain a plurality of radioisotopes. Methods for producing so-called multitracers containing species of radioisotopes are known.

In such a conventional method, a wet method of analytical chemistry is used when extracting the radioisotope from the target. That is, in this method, the target is dissolved in an appropriate acid and the target substance is removed by the precipitation method to take out the radioisotope. For example, in the case of a gold target, the target is dissolved in aqua regia, the solution is evaporated to dryness, and then the residue is dissolved in concentrated hydrochloric acid.
Then, hydrogen peroxide is added dropwise to this solution to reduce the gold in the solution to a metal to cause precipitation. After the precipitate is filtered, this operation is further repeated to completely precipitate gold and take out the radioisotope. In addition, such a method is, for example, `` S.
Ambe et al. Chemistry Letters. 149-152 (1991) "and the like.

However, in the above-mentioned conventional method,
There is a problem in that a method depending on the chemical properties of each target substance must be developed, and an apparatus corresponding to the method and an expert having advanced analytical chemistry technology are required. In addition, it takes a long time (for example, about 3 days for gold) to take out the radioisotope from the target, which requires a great deal of labor, and is extremely disadvantageous when, for example, a short-lived nuclide is used as a tracer. There was a problem.

Therefore, the present inventors have heretofore considered that, for example, the above-mentioned gold target was housed in a quartz tube or the like and heated to about 1000 ° C. under a reduced pressure atmosphere, and the radioactive isotope jumped out from the solid-state gold target. The element is attached to a cold finger etc. provided in the quartz tube and washed out with dilute acid,
We are proposing a method of collection. According to such a method of heating under reduced pressure, it is possible to obtain a so-called carrier-free / salt-free multitracer containing nothing other than the radioisotope and the acid used for dissolution. Further, the same method can be used regardless of the type of the target substance, and further, the radioisotope can be easily extracted from the target in a shorter time than the wet method of analytical chemistry described above.

[0006]

However, for example, some radioisotopes have a short half-life (for example, about several hours), and a method capable of efficiently extracting the radioisotope in a shorter period of time. Was desired to be developed.

The present invention has been made in response to such a conventional situation, and it is possible to efficiently extract a radioisotope in a shorter time as compared with the conventional one, and a tracer even if the radioisotope has a short half-life. The present invention intends to provide a method for producing a multi-tracer by a reduced pressure heating and melting method, which can be effectively used as the above and can reduce the labor required for the production.

[0008]

That is, a method for producing a multi-tracer by a reduced pressure heating and melting method of the present invention comprises a step of irradiating a target with a beam to generate a radioactive element in the target, and the target in a hermetic chamber. And heating the target to a melting point or higher under a reduced pressure atmosphere to attach the radioactive element to a trapping section having a relatively low temperature in the hermetic chamber, and recovering the radioactive element attached to the trapping section. And a step of performing.

[0009]

In the method for producing a multi-tracer by the reduced pressure heating and melting method of the present invention having the above structure, first, a target such as gold, silver or copper is irradiated with a beam such as a high-energy ion beam, and the target is radioactive. Generate an element.
After that, the target is housed in an airtight chamber, heated to a temperature equal to or higher than the melting point in a decompressed atmosphere, and the radioactive element is ejected from the target in a molten state, and the radioactive element is trapped at a relatively low temperature, for example, the airtight chamber. It is attached to the cold finger etc. Then, the radioactive element attached to the cold finger or the like is recovered by washing out with a dilute acid or the like.

As described above, in the method for producing a multi-tracer by the reduced pressure heating and melting method of the present invention, the target is heated to a temperature equal to or higher than the melting point in a reduced pressure atmosphere, and the target is in a state where molecules are easily moved by melting the radioactive element. Therefore, radioactive elements can be efficiently extracted in a shorter time than the conventional method described above, and even radioactive elements with a short half-life can be effectively used as tracers and required for production. It is possible to reduce labor.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a structure of an apparatus for extracting a radioisotope from a target in a method for producing a multi-tracer by a reduced pressure heating and melting method according to an embodiment of the present invention. In FIG. 1, 1 is a cylindrical container shape. The formed quartz tube is shown. An oil rotary vacuum pump 3 is connected to the quartz tube 1 via an activated carbon trap 2 that can be cooled by liquid nitrogen, and is configured to reduce the pressure inside. A Pirani gauge 5 for measuring the degree of vacuum is connected to the exhaust pipe 4 connecting these. Further, in the quartz tube 1, a water-cooled cold finger 6 which constitutes a low temperature capturing part for capturing the radioisotope is provided.

On the other hand, outside the quartz tube 1, an electric heater 7 composed of a resistance heater or the like is provided so as to surround the outside of the quartz tube 1. This electric heater 7
It is connected to a temperature controller 9 configured to control the temperature of the quartz tube 1 to a predetermined temperature by adjusting the supplied power according to the temperature detection signal from the thermocouple 8.

In the present embodiment, the multi-tracer was manufactured as follows using the apparatus thus constructed.

Example 1 First, a diameter of 20 mm and a thickness of 100 μ
Using a gold foil of m as a target, the gold foil was irradiated with a high energy (135 MeV / u) nitrogen ion beam using a ring cyclotron to generate a radioisotope.

Next, as shown in FIG. 1, the gold foil (target) 10 is housed in a quartz tube 1 and the vacuum pump 3 is operated to create a depressurized atmosphere of 1 Pa in the quartz tube 1 to produce quartz. The inside of the tube 1 was heated to 1100 ° C., which is higher than the melting point (1064 ° C.) of gold, to melt the gold foil 10. Then, this state is maintained for 1 hour, the radioisotope is ejected from the molten gold foil 10, and the radioisotope is adhered to the water-cooled cold finger 6 and the low temperature inner wall portion of the quartz tube 1 to obtain the radioisotope. Captured.

After that, the quartz tube 1 was cooled, and the water-cooled cold fingers 6 and the inner wall of the quartz tube 1 were washed with dilute hydrochloric acid to take out the radioisotope captured at these sites. That is, this cleaning solution serves as a so-called carrier-free and salt-free multitracer containing nothing other than the radioactive isotope and hydrochloric acid used for dissolution.

FIG. 2 shows the results of measuring the gamma ray spectrum of the thus obtained multi-tracer. As can be seen from this figure, in this embodiment, yttrium, molybdenum, cesium, europium, gadolinium and hafnium are used. , A multitracer containing a radioisotope such as platinum was obtained.

A comparison of the yields of radioisotopes in this example and the conventional method is shown below. Here, in the conventional method, the gold foil 10 in which the radioisotope is generated as described above is housed in the quartz tube 1 and the pressure in the quartz tube 1 is adjusted.
The radioisotope was taken out from the solid gold foil 10 for 1 hour at 1 Pa and a temperature of 1000 ° C. (temperature below the melting point of gold).

[0020]

[Table 1]

As shown in the above table, in this example, the radioisotope was able to be extracted from each nuclide in a yield several times to several tens of times that of the conventional method. Therefore,
Even a radioisotope with a shorter half-life than before can be effectively used as a tracer,
The labor required for manufacturing can be reduced.

Example 2 First, the diameter is 20 mm and the thickness is 100 μ.
Using a silver foil of m as a target, the silver foil was irradiated with a high energy carbon ion beam using a ring cyclotron to generate a radioisotope.

Next, this silver foil was heated to 1000 ° C. in a quartz tube 1 in a reduced pressure atmosphere of 1 Pa to melt the silver foil. Then, this state is maintained for 1 hour, the radioisotope is ejected from the molten silver foil, and the radioisotope is deposited on the cold inner wall of the water-cooled cold finger 6 and the quartz tube 1 to remove the radioisotope. The multi-tracer was obtained by capturing and washing the water-cooled cold finger 6 and the inner wall of the quartz tube 1 with dilute hydrochloric acid.

FIG. 3 shows the results of measuring the gamma ray spectrum of the thus obtained multi-tracer. In this example, scandium, vanadium, manganese, copper, gallium, arsenic, selenium, strontium and yttrium are shown. , Multi-tracer containing radioisotopes such as zirconium, zirconium, technetium and ruthenium could be obtained.

(Example 3) First, the diameter is 20 mm and the thickness is 100 μ.
Using a copper foil of m as a target, the silver foil was irradiated with a high energy oxygen ion beam using a ring cyclotron to generate a radioisotope.

Next, this copper foil was heated to 1100 ° C. in a quartz tube 1 in a reduced pressure atmosphere of 1 Pa to melt the copper foil. Then, this state is maintained for 1 hour, the radioisotope is ejected from the molten copper foil, and the radioisotope is applied to the cold inner wall of the water-cooled cold finger 6 and the quartz tube 1 to remove the radioisotope. Was collected, and the water-cooled cold finger 6 and the inner wall of the quartz tube 1 were washed with dilute hydrochloric acid to obtain a multi-tracer.

FIG. 4 shows the results of measuring the gamma ray spectrum of the thus obtained multi-tracer. In this example, vanadium, manganese, cobalt,
We were able to obtain a multitracer containing radioisotopes such as copper and zinc.

[0028]

As described above, according to the method for producing a multi-tracer by the reduced pressure heating and melting method of the present invention, the radioisotope can be efficiently extracted in a shorter time as compared with the conventional method, and the half-life is short. Even a radioactive isotope can be effectively used as a tracer,
The labor required for manufacturing can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of an apparatus used in an embodiment method of the present invention.

FIG. 2 is a diagram showing a measurement result of a gamma ray spectrum of a multitracer obtained according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a measurement result of a gamma ray spectrum of a multitracer obtained according to the second embodiment of the present invention.

FIG. 4 is a diagram showing a measurement result of a gamma ray spectrum of a multitracer obtained according to a third embodiment of the present invention.

[Explanation of symbols]

 1 Quartz Tube 2 Activated Carbon Trap 3 Vacuum Pump 4 Exhaust Piping 5 Pirani Gauge 6 Water Cooled Cold Finger 7 Electric Heater 8 Thermocouple 9 Temperature Controller 10 Gold Foil (Target)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshitaka Okubo, 2-1, Hirosawa, Wako-shi, Saitama, RIKEN (72) Inventor Minoru Yanokura, 2-1-1, Hirosawa, Wako, Saitama () 72) Inventor Chen Shaoxu, No.164, Xingang West Road, Guangzhou, People's Republic of China, Nankai Ocean Research Institute, Chinese Academy of Sciences (72) Inventor, Armor Nurse Garg, India Nagpur 440010, Nagpur University (72) Inventor, Fumitoshi Abe, Wako, Saitama 2-1, Hirosawa City, RIKEN

Claims (1)

[Claims] 1. A step of irradiating a target with a beam to generate a radioactive element in the target, the step of accommodating the target in an airtight chamber, heating the target to a melting point or higher in a reduced pressure atmosphere, The method for producing a multi-tracer by a reduced pressure heating and melting method, comprising: a step of attaching the radioactive element to a capturing part having a relatively low temperature; and a step of recovering the radioactive element attached to the capturing part. ..