JP4194483B2 - Separation and production method of high purity 76Br, 77Br, 79Kr using isotope separator - Google Patents

Description

The present invention relates to a method for producing ⁷⁶ Br used for diagnosis and treatment in medicine and agriculture, and more specifically, sodium bromide is irradiated with accelerated protons, and the generated radioactive krypton isotope group isotopes. The present invention relates to a method for simultaneously producing high-purity ⁷⁶ Br, ⁷⁷ Br, and ⁷⁹ Kr without performing chemical separation after isotope separation by a separator.

That is, after irradiating sodium bromide with accelerated protons, the generated radioactive krypton isotope group is separated based on its mass by an isotope separator, and the individual isotopes are ion-implanted into an aluminum foil. By separating and recovering, and individually recovering the adsorbed material and generating and recovering it as a gas, high-purity ⁷⁶ Br, ⁷⁷ Br, and ⁷⁹ Kr isotopes are separated and recovered.

^{As a} method for producing ⁷⁶ Br, there is a production method using ⁷⁶ Se (p, n) ⁷⁶ Br, ⁷⁵ As ( ³ He, 2n) ⁷⁶ Br, ^nat Br (p, 3n) ⁷⁶ Kr → ⁷⁶ Br reaction (for example, Non-patent document 1, Non-patent document 2 and Non-patent document 3). ^{In the} method using ⁷⁶ Se as a target, since only 9% of ⁷⁶ Se exists in nature, it is necessary to purchase a very expensive target in which ⁷⁶ Se is concentrated to 90% or more in advance. ^The method using ⁷⁵ As and ^nat Br (naturally occurring bromine) as a target does not require a concentrated target, but it is known that about 2 to 10% of ⁷⁷ Br as a by-product is mixed. It is an inevitable fact. In preparing the target, ⁷⁶ Se is re-prepared to a compound that can withstand the exothermic heat of irradiation, followed by irradiation. Preparation takes several days.

In separation and purification after irradiation, in the case of ⁷⁵ Se and ⁷⁵ As, separation is performed over several days using a dry distillation method. ^{At nat} Br, the primary product, ⁷⁶ Kr gas, is recovered and then recovered after waiting for its collapse to ⁷⁶ Br. In this case, no special chemical separation operation is required.
Kovacs Z. et al., Int. J. Appl. Radiat. Isot., 36, (1985) 635-642 Blessing G. et al., Int. J. Appl. Radiat. Isot., 33, (1982) 333-339 De Jong D., et al., Int. J. Appl. Radiat. Isot., 30, (1979) 188-190

In view of the above problems, the present invention does not require a concentration target, produces ⁷⁶ Br with high purity, and further effectively uses ⁷⁷ Br and ⁷⁹ Kr as by-products and simplifies work, thereby improving efficiency. The purpose is to develop a practical manufacturing method.

In both the direct method and the indirect method for producing ⁷⁶ Br, ⁷⁷ Br having a half-life longer than ⁷⁶ Br is mixed in the final product. Diagnosis and treatment using such a final product is thought to promote inaccuracy of diagnosis and unnecessary exposure. In addition, the manufacturing method using the concentrated target increases the running cost, requires a long time for readjustment of the target, and requires sufficient experience. Similarly, the separation and purification time after irradiation is very long.

The present inventors have intensively studied aiming at a method for producing high purity ⁷⁶ Br without shortening the production time and using a concentrated target, and have reached the present invention.
In other words, low-cost and easy-to-handle sodium bromide is irradiated with a proton beam, and the generated radioactive krypton isotope group is introduced into an isotope separator and collected by mass in aluminum foil. It is characterized by a method for producing high purity ⁷⁶ Br obtained after recovering krypton gas and decaying radioactive krypton. Furthermore, ⁷⁷ Br and ⁷⁹ Kr, which were impurities in the conventional method, can be simultaneously isolated.

In addition, by connecting an isotope separator to the accelerator and irradiating with a large current, the radioactive krypton isotope group generated by irradiation heat generation from the sodium bromide target is directly introduced into the isotope separator and continuously irradiated. It is possible to produce ⁷⁶ Br, ⁷⁷ Br, and ⁷⁹ Kr at the same time.

As described in detail above, the present invention makes it possible to produce high-purity ⁷⁶ Br, which can be expected to improve diagnostics and prevent exposure in medicine and agriculture using ⁷⁶ Br. Also, like ⁷⁶ Br, ⁷⁷ Br and ⁷⁹ Kr are useful radioisotopes in medicine, so by using the production method according to the present invention, when manufacturing and selling radioisotopes is a business, This leads to efficient manufacturing and cost reduction.

As shown in FIG. 1, by introducing a radioactive krypton ^76,77,79 Kr isotope gas mixture 7 isotope separator 6 to the principle of mass separation method using a magnetic field from the bomb, radioactive krypton ^{76, 77 79} Kr isotope mixed beam 5, which is separated based on mass, and isotopes 1, 2 and 3 are separated and recovered in an aluminum foil 4.

  That is, the Kr isotope group is accelerated after being ionized by the cylindrical portion constituting the isotope separator 6. Therefore, the Kr isotope group has a certain energy, and the beam 5 having this energy is divided for each mass and then ion-implanted into the aluminum foil.

Next, as shown in FIG. 2, placed in an aluminum foil (c) a ⁷⁶ Kr gas generating vials (b) containing a ,, ⁷⁶ Kr in the case of separating and recovering ⁷⁶ Kr, it vacuum line ( After connecting and connecting to the e) and reducing the pressure, injecting concentrated hydrochloric acid from the syringe for injection of hydrochloric acid (d) to dissolve the aluminum foil,
⁷⁶ Kr gas is generated. After the aluminum foil is dissolved, the generated gas is introduced and recovered by a pressure difference into a recovery vial (A) connected to the gas generation bottle (A) via a three-way valve (F). At that time, the bottle (a) is cooled by liquid nitrogen.

Hereinafter, the present invention will be described in more detail by way of examples. In this example, ^76,77,79 Kr is separated, but ⁷⁶ Kr becomes ⁷⁶ Br due to radioactive decay. In such a relationship, ⁷⁶ Kr is called the parent nuclide, and ⁷⁶ Br generated after the decay is called the daughter nuclide. Therefore, if the parent nuclide ⁽⁷⁶ Kr) is Rarere obtained in high purity, the naturally daughter ⁽⁷⁶ Br) can also be obtained in high purity. This is also true between ⁷⁷ Kr and ⁷⁷ Br.

Sodium bromide was pelletized by a pressure molding method and used as a target. A 65 MeV proton beam was incident on sodium bromide, and radioactive ^76,77,79 Kr isotope groups were generated in the target by the ^nat Br (p, 3n) reaction. After irradiation, only the ^76,77,79 Kr isotope group was recovered from the sodium bromide target by dry distillation, the ^76,77,79 Kr isotope group was introduced into the isotope separator, and after isotopic separation, the aluminum foil ⁷⁶ Kr was isolated in it. After recovery, the aluminum foil was inserted into a sealed vial, and after decompression, the aluminum foil was dissolved by injecting 0.6 ml of concentrated hydrochloric acid to generate ⁷⁶ Kr gas. After all the aluminum foil was dissolved, a newly prepared decompression vial was connected to this vial, and only ⁷⁶ Kr gas was collected due to the pressure difference. ⁷⁶ Br obtained after the collapse of the ⁷⁶ Kr are of distilled water was poured into the vial, and collected as an aqueous solution. ⁷⁷ Kr after isotope separation can be recovered by the same operation. ^{For 79} Kr, the operation ends when it is recovered by the pressure difference.

From the above experiments, ⁷⁶ Br, ⁷⁷ Br and ⁷⁹ Kr were obtained with a purity of 99.99% or more. When this result is compared with the conventional method using the same nuclear reaction, in the conventional method, about 10% of by-product ( ⁷⁷ Br) is mixed, but in the method of the present invention, the result is hardly mixed. Has been obtained.

In addition, although the example which manufactured without connecting an isotope separator to an accelerator was shown here, by connecting an accelerator and an isotope separator in principle using this invention, it is continuous. Simultaneous mass production of ⁷⁶ Br, ⁷⁷ Br and ⁷⁹ Kr is possible by irradiation and isotope separation.

It is a figure which shows the isotope separation part of this invention. It is a figure which shows the collection | recovery method of this invention.

Explanation of symbols

1 ⁷⁶ Kr 2 ⁷⁷ Kr 3 ⁷⁹ Kr
4 Aluminum foil 5 Radioactive krypton isotope mixed beam 6 Isotope separator 7 Radioactive krypton isotope mixed gas

(A) Collection vial (b) ⁷⁶ Kr gas generation vial (c) Aluminum foil containing ⁷⁶ Kr (d) Injection cylinder for hydrochloric acid injection (e) Vacuum line (f) Three-way valve

Claims (1)

A sodium bromide target obtained by forming sodium bromide into a pellet is irradiated with a proton beam to generate radioactive ^76,77,79 Kr isotope groups in the sodium bromide target. by distillation only ^76,77,79 Kr isotope group sodium targets collected as ^76,77,79 Kr isotope group mixed gas, each of ^76,77,79 and introducing the mixed gas isotope separator In a method for separating and producing high purity ⁷⁶ Br, ⁷⁷ Br, ⁷⁹ Kr obtained without chemical separation, comprising separating and recovering Kr isotopes in three separate aluminum foils,
The aluminum foils ^obtained by separating and recovering ^76,77,79 Kr isotopes in the three separate aluminum foils were respectively inserted into sealed bottles, decompressed, dissolved in aluminum foil by hydrochloric acid injection, and newly prepared 3 Two separate vacuum bottles were connected to the dissolution bottle and the pressure difference was ^76,77,79 Kr The method comprising separating and recovering each of the gases into the vacuum bottle.

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