Method for producing 226ra target, method for producing 225ac, and electrodeposition solution for producing 226ra target

Abstract

One embodiment of the present application relates to 226 A method for manufacturing a Ra target, 225 A method for manufacturing an Ac or 226 An electrodeposition solution for manufacturing an Ra target, 226 A method for manufacturing an Ra target includes an electrodeposition process of electrodeposition of an Ra substance on a substrate using an electrodeposition solution containing 226 Ra ions and a pH buffer. 226 Ra substance.

Description

Technical Field

[0001] One embodiment of the present invention relates to 226 Ra target manufacturing method, 225 Ac manufacturing method or 226 Electrodeposition solution for Ra target manufacturing. Background Technology

[0002] As one of the nuclides that emit alpha rays 225 Ac is a radionuclide with a half-life of 10 days. In recent years, it has been anticipated as a therapeutic radionuclide for cancer treatment and other purposes.

[0003] 225 Ac, for example, can be directed to using an accelerator. 226 Protons are irradiated onto a Ra target, thereby producing them using (p, 2n) nuclear reactions.

[0004] As a manufacturer of such 226 The Ra target method uses a plating solution containing isopropanol to electrodeposit a substance containing isopropanol on an aluminum surface. 226 Methods for Ra substances are known (see Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2007-508531 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in the past 226 In the electrodeposition method of Ra, due to the reduced conductivity of the electrodeposition solution, in order to achieve a specified amount of... 226 Ra electrodeposition requires the application of high voltage. Therefore, power supplies and equipment are sometimes enlarged, and a cooling process is needed to remove the generated heat. Furthermore, it has been found that even when high voltage is applied as described above, the components contained in the electrodeposition solution cannot be deposited. 226 Ra ions are efficiently electrodeposited onto the substrate.

[0010] One embodiment of the present invention provides a method that allows the electrodeposition solution to contain [a specific substance] even without applying a high voltage. 226 Ra ions are efficiently electrodeposited on the substrate. 226 Method for manufacturing Ra targets.

[0011] Methods for solving problems

[0012] The inventors of this application have repeatedly and thoroughly studied methods for solving the above-mentioned problems, and as a result, they have found that if a prescribed manufacturing method is used, the above-mentioned problems can be solved, thereby completing this invention.

[0013] One aspect of the present invention is as follows: 226 A method for manufacturing a Ra target, comprising the following electrodeposition step: using a target containing... 226 Electrodeposition solution containing Ra ions and pH buffer, so that... 226 Ra material is electrodeposited on the substrate.

[0014] In addition, another aspect of the present invention is... 225 The method for manufacturing Ac includes, via the above-mentioned, 226 Ra target manufacturing method 226 Ra target irradiation is an irradiation process that selects at least one of charged particles, photons, and neutrons.

[0015] In addition, another aspect of the present invention is 226 Electrodeposition solution for Ra target fabrication, which contains 226 It contains Ra ions and pH buffers, and is essentially alcohol-free.

[0016] The effects of the invention

[0017] According to one embodiment of the present invention, even without applying a high voltage, it is possible to deposit the following in the electrodeposition solution: 226 Ra ions are efficiently electrodeposited onto the substrate. Therefore, according to one embodiment of the present invention, it is possible to manufacture... 226 The equipment for Ra targets has been miniaturized, and it is also possible to manufacture them without a cooling process. 226 Ra target. That is, according to one embodiment of the present invention, it is possible to manufacture using a space-saving, energy-efficient, and simple method. 226 Ra target.

[0018] Furthermore, according to one embodiment of the present invention, it is possible to manufacture a product containing a predetermined amount of... 226 Ra substance 226 The Ra target allows for the easy manufacture of specified quantities in a space-saving and energy-efficient manner. 225 Ac. Detailed Implementation

[0019] [ 226 [Method for manufacturing Ra target]

[0020] One embodiment of the present invention relates to 226 The method for manufacturing a Ra target (hereinafter also referred to as "this manufacturing method") includes the following electrodeposition process: using a target containing... 226 Electrodeposition solution containing Ra ions and pH buffer, so that...226 Ra material is electrodeposited on the substrate.

[0021] According to this manufacturing method, containing 226 Ra material was electrodeposited onto the substrate. 226 Ra substances can be cited as examples 226 Ra metal or 226 Ra salt. That is, the salt obtained by this manufacturing method. 226 Ra target includes 226 Ra metal or 226 Ra salt.

[0022] <Electrodeposition solution>

[0023] Electrodeposition solution as long as it contains 226 Liquids containing Ra ions and pH buffers are not particularly limited and may contain other components as needed.

[0024] To further enhance the effects of the present invention, the electrodeposition solution is preferably an aqueous solution. In this case, pure water or ultrapure water is preferred.

[0025] In this manufacturing method, more than two electrodeposition solutions can be used, but usually one electrodeposition solution is used.

[0026] In the aforementioned previous context 226 In the electrodeposition method of Ra material, alcohols such as isopropanol are used.

[0027] However, the inventors of this application discovered through research that, according to this manufacturing method, even without the use of alcohol, it is possible to produce a product containing... 226 Ra material is electrodeposited onto the substrate. Therefore, it is possible to suppress the decrease in conductivity of the electrodeposition solution and to ensure that the Ra material contained in the electrodeposition solution remains conductive even without applying a high voltage. 226 Considering factors such as the efficient electrodeposition of Ra ions onto the substrate, the electrodeposition solution preferably does not contain alcohol.

[0028] Examples of alcohols include alkyl alcohols with 1 to 5 carbon atoms, such as ethanol, 1-propanol, and isopropanol.

[0029] In addition, for the same reason that it does not contain alcohol, it is also preferred that the electrodeposition solution does not contain acetone.

[0030] Here, "substantially does not contain alcohol or acetone" means that alcohol or acetone is not intentionally added to the electrodeposition solution. Specifically, the content of alcohol and acetone in the electrodeposition solution is preferably less than 0.01% by mass, with the lower limit being 0% by mass.

[0031] From being able to make more efficient 226Considering factors such as Ra ion electrodeposition on the substrate, the electrodeposition solution preferably contains carboxylic acid ions (COO). - More preferably, it contains acetate ions.

[0032] From the ability to make 226 Considering factors such as more efficient electrodeposition of Ra ions onto the substrate, the electrodeposition solution at the beginning of the electrodeposition process is preferably acidic, with a pH of 4 or higher, more preferably 5 to 6. Furthermore, the pH of the electrodeposition solution during the electrodeposition process (in the middle) is preferably 4 to 9, more preferably 6 to 8. While the pH of the prepared electrodeposition solution can be measured using a pH meter, pH test paper, etc., it is preferable to calculate it based on the types and amounts of raw materials incorporated into the electrodeposition solution, and preferably to adjust it by considering the types and amounts of raw materials incorporated into the electrodeposition solution.

[0033] <<Acid>>

[0034] The electrodeposition solution is preferably prepared using acid.

[0035] As an acid, there are no particular limitations, but it can make... 226 Considering factors such as the more efficient electrodeposition of Ra ions onto the substrate, the preferred method is to... 226 Ra ions are not chelating acids.

[0036] One type of acid can be used alone, or two or more types can be used.

[0037] Examples of acids include inorganic acids and carboxylic acids with 2 to 6 carbon atoms. Examples of inorganic acids include nitric acid, hydrochloric acid, and boric acid. Examples of carboxylic acids with 2 to 6 carbon atoms include acetic acid, succinic acid, and benzoic acid.

[0038] From improving 225 Considering factors such as the yield of Ac, the preferred acid is a monovalent or divalent acid.

[0039] The concentration of acid in the electrodeposition solution can be appropriately selected depending on the type of acid used, but it is preferable to use an acidic solution at the beginning of the electrodeposition process. Specifically, a concentration of 0.005–0.2 mol / L is preferred, and more preferably 0.005–0.05 mol / L. If the acid concentration is within this range, it is possible to… 226 Ra ions are electrodeposited onto the substrate more efficiently.

[0040] It should be noted that, for the same reason, especially when hydrochloric acid is used as the acid, its concentration in the electrodeposition solution is preferably 0.04 mol / L or less, more preferably 0.005 - 0.035 mol / L. When nitric acid is used as the acid, its concentration in the electrodeposition solution is preferably 0.2 mol / L or less, more preferably 0.005 - 0.1 mol / L.

[0041] In addition, when acetic acid is used as the acid, its concentration in the electrodeposition solution is preferably 0.2 mol / L or less, more preferably 0.05 - 0.1 mol / L.

[0042] Relative to 226 0.02 mol / L of Ra ions, the usage amount of the acid is preferably 0.5 mol / L or less, more preferably 0.001 - 0.4 mol / L.

[0043] According to this manufacturing method, even when the acid is used in such amounts, it is possible to 226 electrodeposit Ra ions on the substrate more efficiently.

[0044] <<pH buffer>>

[0045] As the pH buffer, there is no particular limitation as long as it can prevent a sharp change in pH. However, it is preferable to use a pH buffer that can maintain the pH of the electrodeposition solution during the electrodeposition process (in the middle) at around 4 - 9, preferably around 6 - 8.

[0046] As the pH buffer, there is no particular limitation, and usually a pH buffer solution is used.

[0047] The pH buffer for the electrodeposition solution can be one kind or two or more kinds.

[0048] Examples of the pH buffer include ammonium chloride; carbonates such as ammonium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, and magnesium carbonate; bicarbonates such as ammonium bicarbonate, sodium bicarbonate, and potassium bicarbonate; acetates such as ammonium acetate, sodium acetate, and potassium acetate; succinates such as monosodium succinate, disodium succinate, monopotassium succinate, dipotassium succinate, monoammonium succinate, and diammonium succinate; benzoates such as sodium benzoate, potassium benzoate, and ammonium benzoate. Among these, considering aspects such as easily maintaining the pH of the electrodeposition solution in the above range during the electrodeposition process and enabling 226 more efficient electrodeposition of Ra ions on the substrate, carboxylates are preferred, monovalent or divalent carboxylates are more preferred, acetates are further preferred, and ammonium acetate is even more preferred.

[0049] The concentration of the pH buffer in the electrodeposition solution can be appropriately selected depending on the type of pH buffer used, but it is preferable to use it in such a way that the pH of the electrodeposition solution in the electrodeposition process is within the aforementioned range. Specifically, a concentration of 0.2–1.0 mol / L is preferred, and 0.2–0.8 mol / L is more preferable. If the concentration of the pH buffer is within this range, it is possible to… 226 Ra ions are electrodeposited onto the substrate more efficiently.

[0050] In addition, from the ability to make 226 Considering factors such as more efficient electrodeposition of Ra ions onto the substrate, the preferred ratio of acid to pH buffer in the electrodeposition solution is such that the electrodeposition solution is acidic at the beginning of the electrodeposition process.

[0051] From the ability to make 226 Considering factors such as the more efficient electrodeposition of Ra ions onto the substrate, compared to 226 The amount of pH buffer used for Ra ions of 0.02 mol / L is preferably 0.1 to 11.0 mol / L, more preferably 0.2 to 11.0 mol / L.

[0052] << 226 Ra ions >>

[0053] As 226 Ra ions, as long as 226 Ra exists in ionic form, so there are no particular limitations; it is commonly used... 226 Ra salt or a solution containing that salt.

[0054] As 226 Ra salts vary depending on the type of acid or base solution used in the purification processes described below. Specifically, examples include... 226 Ra can be nitrate, chloride, hydroxide, carboxylate, ammonium, or carbonate salts. Any of these salts can be used, but from this point of view, nitrate, chloride, or carboxylate salts are preferred because the electrodeposition solution at the start of the electrodeposition process is preferably acidic.

[0055] According to this manufacturing method, it is possible to make the electrodeposition solution contain... 226 Ra ions are efficiently electrodeposited onto the substrate; therefore, the electrodeposition solution contains... 226 The amount of Ra ions depends on the electrodeposition target. 226 The Ra value should be selected appropriately. Electrodeposition is required. 226 The Ra value, for example, can be considered using the obtained... 226 Ra target to manufacture 225 The amount of radiation allowed by the facility during Ac is determined by factors such as the amount of radiation.

[0056] For electrodeposition solution 226In terms of the amount of Ra ions, for example in the electrodeposition process... 226 When the Ra amount is 50 mg, it is preferably 50 to 150 mg, and more preferably 50 to 100 mg.

[0057] As 226 Ra ions can be used commercially available... 226 Ra, or the product obtained by purifying it, is intended for use as a radiation source in medical and industrial fields. 226 The solution of Ra contains 226 The product obtained by purifying a solution of Ra salt, or the product to be manufactured 225 Ac after 226 Ra target dissolution yields a product containing 226 Products obtained by purifying a solution of Ra salt, etc.

[0058] As a response to containing 226 Methods for purifying solutions of Ra salts include, for example, methods comprising the following steps: an adsorption step (R1), in which the Ra salt solution is subjected to an adsorption process under alkaline conditions. 226 Ra solution (a) is contacted with a support (hereinafter also referred to as "support (i)") that has the function of selectively adsorbing divalent cations, so that... 226 Ra ions are adsorbed onto the support (i); and in the elution step (R2), under acidic conditions... 226 Ra ions are eluted from the support (i). This purification process allows for the removal of Ra ions from the support (i). 226 Ra ion concentration reduces impurities, enabling more efficient [processing / processing]. 226 Ra ions are electrodeposited on the substrate.

[0059] As for the support (i), there are no particular limitations as long as it can form a complex with metal ions under alkaline conditions and elute the metal ions under acidic conditions; for example, supports having divalent cation exchange groups can be cited. Specifically, supports having iminodiacetic acid groups, polyamine groups, or methyl polysaccharide groups can be cited as divalent cation exchange groups, with iminodiacetic acid groups being preferred. For supports having divalent cation exchange groups, there are no particular limitations as long as the divalent cation exchange groups are maintained on a solid-phase support such as a resin. As a more preferred example, styrene-divinylbenzene copolymers that retain iminodiacetic acid groups can be cited. Commercially available resins with such iminodiacetic acid groups include the "Chelex" series manufactured by Bio-Rad, the "DIAION" series manufactured by Mitsubishi Chemical Co., Ltd., and the "Amberlite" series manufactured by Dow Chemical Co., Ltd. More specifically, "Chelex100" manufactured by Bio-Rad (particle size: 50-100 mesh, ionic type: Na type, Fe type) can be cited.

[0060] The carrier (i) can be used to fill the tube. There are no particular limitations as long as the tube can be filled with the carrier (i) and is flexible. It is preferably a flexible tube made of rubber or resin, and more preferably a medical tube.

[0061] By using such tubes, a longer length can be achieved compared to conventional glass columns, thus increasing the theoretical plate number and consequently improving... 226 The adsorption efficiency of Ra ions. Additionally, it is possible to introduce radioactive materials (containing...) 226 The Ra solution is disposed of simply in a manner that does not cause radioactive contamination to other appliances, equipment, etc., while the carrier (i) of the liquid is filled in the tube.

[0062] As a specific example of the elution process (R2), one could exemplify this by introducing an inorganic acid liquid into the support (i), thereby eluting the adsorbed substances on the support (i). 226 Ra ion elution method.

[0063] As an inorganic acid, as long as it can adsorb onto the support (i) 226 The Ra component dissolves to form ions, and there are no particular limitations; examples include hydrochloric acid and nitric acid.

[0064] It should be noted that, from the ability to 226 From the perspective of efficient elution of Ra ions from the support and efficient removal of anions from inorganic acids in subsequent processes, the concentration of inorganic acid is preferably 0.1 to 12 mol / L, more preferably 0.3 to 5 mol / L, even more preferably 0.5 to 2 mol / L, and particularly preferably 0.7 to 1.5 mol / L.

[0065] It should be noted that a cleaning process for the carrier (i) can be included between process (R1) and process (R2). Specifically, this can be achieved by passing water into the carrier (i). This cleaning process can further reduce the proportion of impurities.

[0066] For those containing substances eluted in the elution process (R2) 226 For solutions containing Ra ions, an anion exchange process (R3) is preferably performed by passing the solution through an anion exchange resin.

[0067] If anions (e.g., chloride ions) from the inorganic acid (e.g., hydrochloric acid) used in the elution step (R2) remain in the solution, they may sometimes affect the electrodeposition process. 226 The electrodeposition rate of Ra ions is affected. Therefore, it is preferable to use an anion exchange step (R3) to process the ions eluted in the elution step (R2). 226The solution of Ra ions is treated because it reduces the number of anions derived from inorganic acids by exchanging them with hydroxide ions, thereby improving the electrodeposition process. 226 Electrodeposition efficiency of Ra ions.

[0068] As an anion exchange resin, there are no particular limitations as long as it can exchange anions derived from inorganic acids (such as chloride ions) with hydroxide ions, but strongly basic anion exchange resins are preferred, and resins containing quaternary ammonium salts are more preferred. Commercially available anion exchange resins of this type include, for example, the "MONOSPHERE" series manufactured by Dow Chemical and the "AG" series manufactured by Bio-Rad, and more specifically, "MONOSPHERE 550A" (particle size: 590±50 mesh, ionic type: OH type).

[0069] It should be noted that the anion exchange resin can be used by filling the tube in the same way as the support (i). As a usable tube, a tube identical to the aforementioned tube filled with support (i) can be cited.

[0070] <<Other Ingredients>>

[0071] The electrodeposition solution may include, as needed and without impairing the effects of the present invention, components used in conventional electroplating, etc. One or more other components may be used.

[0072] The electrodeposition solution preferably contains water, and the amount of water in the electrodeposition solution is, for example, relative to the amount of water to be electrodeposited. 226 When the Ra amount is 50 mg, 15 to 50 mL is preferred.

[0073] From the perspective of adjusting the pH of the electrodeposition solution, an alkali can also be used appropriately. Examples of alkalis include sodium hydroxide, potassium hydroxide, and ammonia.

[0074] As a specific example of an electrodeposition solution, an electrodeposition solution that satisfies the following (a) to (d) is preferred.

[0075] (a) includes 226 Ra ions and pH buffers

[0076] (b) Does not substantially contain alcohols

[0077] (c) Contains one or more acids, which are monocarboxylic or dicarboxylic acids.

[0078] (d) Contains carboxylate ions, preferably acetate ions.

[0079] In addition, as other specific examples of electrodeposition solutions, electrodeposition solutions that satisfy (a), (b), (e) and (f) below are preferred.

[0080] (a) contains 226 Ra ions and pH buffers

[0081] (b) Does not substantially contain alcohols

[0082] (e) Contains one or more acids

[0083] (f) As a pH buffer, it contains a carboxylate, preferably a mono- or di-carboxylate, and more preferably an acetate.

[0084] <Electrodeposition Process>

[0085] For the electrodeposition process, as long as electrodeposition can be performed on the substrate... 226 Ra metal or its salts are not particularly limited and can be used in the same process as conventional electroplating, for example, by inserting an anode and a cathode in an electrodeposition solution and passing current between these electrodes.

[0086] There are no particular limitations on the anode; for example, a platinum electrode can be used. Conversely, the cathode can be any substrate described later.

[0087] <<Substrate>>

[0088] As a supply 226 The substrate for Ra electrodeposition is not particularly limited as long as it is conductive. However, since it is preferable to use an accelerator such as a cyclotron or a linear accelerator to irradiate the obtained target with particles such as protons and gamma rays, it is preferable to use a substrate that can be used appropriately even when irradiated with such particles. Specifically, a metallic substrate is preferred.

[0089] Examples of metals that can be used as substrates include aluminum, copper, titanium, silver, gold, iron, nickel, niobium, and alloys containing these metals (e.g., phosphor bronze, brass, zinc cupronickel, beryllium copper alloy, Cosne alloy, stainless steel).

[0090] Alternatively, the substrate can be obtained by plating these metals onto a conductive support.

[0091] As a substrate, it is less likely to adversely affect devices used when irradiated with charged particles, photons, or neutrons; it can suppress the incorporation of metals from the substrate during the manufacture of radioactive isotopes (RI); and it is suitable for use with targets after RI manufacturing. 226 Considering factors such as the ability to suppress the incorporation of metals from the substrate when Ra ions are present, gold plates or gold-plated plates are preferred. Furthermore, using gold plates or gold-plated plates as the substrate also allows for… 226Ra ions are electrodeposited onto the substrate more efficiently.

[0092] The shape of the substrate is not particularly limited and can be appropriately selected according to the desired target shape, but a plate shape is preferred.

[0093] <<Electrodeposition Conditions>>

[0094] When used as a power source to carry current, there are no particular limitations; DC power supplies, AC power supplies, pulse power supplies, PR pulse power supplies, etc., can be used. Among these, the one that is easiest to improve... 226 The diffusion of Ra ions causes the presence of 226 Considering factors such as uniform electrodeposition of Ra materials, suppression of heat generation, and the ability to perform electrodeposition with a small power supply, pulse power supplies and PR pulse power supplies are preferred.

[0095] When using a pulsed power supply or a PR pulsed power supply, it is preferable to keep the on-current and off-current small, thereby keeping the voltage in electrodeposition low. In this case, for example, the value of the on-current is preferably 0.1 to 0.3 A, and the value of the off-current is preferably 0.0 to 0.2 A.

[0096] Considering the ease with which bubbles generated during electrodeposition can detach from the electrode, both short on-time and off-time are preferable. In this case, for example, the on-time is preferably 10–90 msec, and the off-time is preferably 10–90 msec.

[0097] The electrodeposition time varies depending on the current flowing through it, and on the substrate to be electrodeposited. 226 Ra can be adjusted appropriately, but when using a pulse power supply or PR pulse power supply, it is easier to obtain the desired output. 225 Considering factors such as the target of Ac, it is preferable to use 30 minutes or more, and more preferably 1 to 24 hours.

[0098] There is no particular limitation on the temperature (temperature of the electrodeposition solution) during the electrodeposition process, but for example, temperatures of around 10 to 80°C can be cited.

[0099] [ 225 Ac manufacturing method]

[0100] One embodiment of the present invention relates to 225 The manufacturing method of Ac includes feeding the product manufactured by this manufacturing method into the substrate. 226 Ra target irradiation is an irradiation process that selects at least one type of particle from charged particles, photons, and neutrons.

[0101] As a particle, it is preferably a proton, a deuterium nucleus, an alpha particle, or a gamma ray, and more preferably a proton.

[0102] Specifically, the irradiation process includes the following steps: accelerating particles such as protons and gamma rays using an accelerator such as a cyclotron or linear accelerator (preferably a cyclotron), and irradiating the accelerated particles onto a material manufactured by this method. 226 Ra target.

[0103] By to 226 Particles irradiated by a Ra target are generated, depending on the circumstances, through processes such as fission. 225 Ac. By generating from such a source. 225 Ac's target 225 Ac can be separated and purified to obtain purified form. 225 Ac.

[0104] As a general 225 There are no particular limitations on the method for separating and purifying Ac; any previously known method can be used. For example, the following methods can be cited: using acids, etc., to separate Ac... 225 The target of Ac dissolves, and alkali is added to the resulting solution, thereby causing the target to contain Ac. 225 The salt of Ac precipitates out, and the salt is then separated and purified.

[0105] Example

[0106] The present invention will be further illustrated below through experimental examples, but the present invention is not limited thereto.

[0107] It should be noted that the use 226 Experiments with Ra cannot be easily performed due to issues such as radioactivity; therefore, in some of the following experiments, methods considered to produce [a specific type of Ra] are used. 226 Ra yielded the same results as barium. Ra is an alkaline earth metal and has similar properties to barium, which is also an alkaline earth metal and has a similar mass number. Furthermore, the properties of radium and barium are known to be very similar, based on previous experience with the co-precipitation of radium with barium sulfate in the extraction of radium from pitchblende after uranium extraction.

[0108] [Experimental Example 1]

[0109] Barium chloride dihydrate was dissolved in 0.05 mol / L hydrochloric acid aqueous solution to prepare a Ba hydrochloric acid aqueous solution with a mass of 60 mg and a volume of 2 mL. The electrodeposition solution was prepared by mixing 14.4 mL of 0.35 mol / L ammonium acetate aqueous solution, 1.6 mL of 0.1 mol / L nitric acid aqueous solution, and 2 mL of the prepared Ba hydrochloric acid aqueous solution. The pH of the electrodeposition solution, as determined by pH paper, was 5–6. It should be noted that ultrapure water was used in the preparation of all aqueous solutions. Table 1 shows the concentrations of each component in the electrodeposition solution and the volume of the electrodeposition solution.

[0110] The prepared electrodeposition solution was loaded into an electrodeposition tank, and a platinum electrode was inserted as the anode, while a φ10 mm gold plate (thickness: 0.2 mm) was inserted as the cathode (substrate). Then, using an MPS-II-012010S10 (manufactured by Chiyoda Electronics Co., Ltd.) as the power source for electrodeposition, a pulsed current was passed through these electrodes [continuously and repeatedly applying a current of 0.1 A for 10 msec and maintaining it at a current of 0.0 A for 10 msec (on-current: 0.1 A, on-time: 10 msec, off-current: 0.0 A, off-time: 10 msec)] for 3.5 hours, thereby electrodepositing Ba (Ba salt) onto the gold plate.

[0111] After the pulsed current was applied for 3.5 hours, the gold plate was removed, rinsed with ultrapure water, and dried at 100°C for 1 hour.

[0112] The mass increase after electrodeposition was calculated based on the change in mass of the gold plate after drying compared to before electrodeposition. It should be noted that the "average mass increase after electrodeposition" listed in the table below is the average mass increase after electrodeposition from several identical experiments. The results are shown in Table 1.

[0113] [Experimental Examples 2-20]

[0114] As described in Table 1 or 2, the types, amounts (concentrations), volumes, substrates, and electrodeposition times of the components in the electrodeposition solution were varied. Otherwise, the procedure was the same as in Example 1, and the average mass gain after electrodeposition was calculated. The results are shown in Table 1 or 2. It should be noted that the pH of the electrodeposition solutions obtained in these examples is considered to be in the range of 5–7.

[0115] [Table 1]

[0116]

[0117] [Table 2]

[0118]

[0119] [Experimental Examples 21-25]

[0120] As shown in Table 3, the amounts (concentrations) and volumes of the components in the electrodeposition solution were varied, except that the electrodeposition solution was prepared in the same manner as in Experimental Example 1. It should be noted that the pH of the electrodeposition solutions obtained in these experimental examples is considered to be 5–6.

[0121] Using the obtained electrodeposition solution, and with an SUS plate (24×24mm, thickness: 2mm) as the substrate, the pulse current conditions and electrodeposition time were varied as described in Table 3. Otherwise, the procedure was the same as in Experimental Example 1, and the average mass gain after electrodeposition was calculated. The results are shown in Table 3.

[0122] [Table 3]

[0123]

[0124] [Experimental Example 26]

[0125] As described in Table 4, the types and amounts (concentrations) of the components in the electrodeposition solution were changed. A φ20mm gold plate (thickness: 0.2mm) was used as the substrate. Otherwise, the procedure was the same as in Test Example 1, and the average mass increase after electrodeposition was calculated. The results are shown in Table 4. It should be noted that the pH of the electrodeposition solution obtained in Test Example 26, as measured by pH test paper, was 6.

[0126] [Table 4]

[0127]

[0128] [Experimental Example 27]

[0129] The amount (concentration) of each component in the electrodeposition solution was changed as described in Table 5. Otherwise, the electrodeposition solution was prepared in the same manner as in Experimental Example 1.

[0130] Using the obtained electrodeposition solution, an MPS-II-012010S10 (manufactured by Chiyoda Electronics Co., Ltd.) was used as the power source for electrodeposition, and a constant current of 0.1 A was applied for 210 minutes. Otherwise, the procedure was the same as in Example 1, and the average mass gain after electrodeposition was calculated. The results are shown in Table 5. It should be noted that the pH of the electrodeposition solution obtained in Example 27 is assumed to be 6.

[0131] [Table 5]

[0132]

[0133] [Experimental Example 28]

[0134] Barium chloride dihydrate was dissolved in 0.05 mol / L hydrochloric acid aqueous solution to prepare a Ba hydrochloric acid aqueous solution with a mass of 34 mg and a volume of 1.1 mL. 12.5 mL of 1 mol / L acetic acid aqueous solution, 11.4 mL of 1.1 mol / L ammonia solution, and 1.1 mL of the prepared Ba hydrochloric acid aqueous solution were mixed to prepare 25 mL of electrodeposition solution. It should be noted that ultrapure water was used in the preparation of all aqueous solutions.

[0135] Using the obtained electrodeposition solution, a φ20mm gold plate (thickness: 0.2mm) was used as the substrate. The electrodeposition time was changed to 3 hours. Otherwise, the procedure was the same as in Experimental Example 1, and the mass gain after electrodeposition was calculated. The mass gain after electrodeposition was 31.3mg.

[0136] [Experimental Example 29]

[0137] Barium chloride dihydrate was dissolved in 0.05 mol / L hydrochloric acid aqueous solution to prepare a Ba hydrochloric acid aqueous solution with a mass of 34 mg and a volume of 1.1 mL. 15.625 mL of 0.4 mol / L succinic acid aqueous solution, 8.275 mL of 1.5 mol / L ammonia solution, and 1.1 mL of the prepared Ba hydrochloric acid aqueous solution were mixed to prepare 25 mL of electrodeposition solution. It should be noted that ultrapure water was used in the preparation of all aqueous solutions.

[0138] Using the obtained electrodeposition solution, a φ20mm gold plate (thickness: 0.2mm) was used as the substrate. The electrodeposition time was changed to 3 hours. Otherwise, the procedure was the same as in Experimental Example 1, and the mass gain after electrodeposition was calculated. The mass gain after electrodeposition was 18.4mg.

[0139] [Experimental Examples 30-32]

[0140] After irradiating with 3-5 mL of 1 mol / L hydrochloric acid, the protons were completely dissolved. 226 Ra target (size: Φ10mm, thickness: 5mm, conical shape) 226 Dissolve and recover Ra (mass: 0.4–0.6 mg) containing Ra. 226 Ra solution (a-1).

[0141] Next, Chelex 100 (manufactured by Bio-Rad, particle size: 50-100 mesh, ionic form: Na form, usage: 3 mL) was used to convert it into NH4. + The product obtained was filled into a medical tube (extension tube, manufactured by Yakusho Co., Ltd., 3.2×4.4×500mm (4mL), MS-FL) with an inner diameter of 3.2mm, an outer diameter of 4.4mm, and a length of 50cm. The product was then dispensed at a flow rate of 1-2mL / min. 226 50–80 mL of Ra solution (a-1) (pH > 9) is passed through the solution, and the eluent is used as waste. Next, 10 mL of water is passed through the Chelex 100 at a flow rate of 1–2 mL / min, and the eluent is also used as waste.

[0142] Next, MONOSPHERE 550A (manufactured by Dow Chemical, particle size: 590±50 mesh, ionic type: OH type, usage: 20mL) was washed sequentially with hydrochloric acid, water, sodium hydroxide, and water, and then filled into a medical tube (extension tube, manufactured by Yakumitsu Corporation, 3.2×4.4×500mm (4mL), MS-FL) with an inner diameter of 3.2mm, an outer diameter of 4.4mm, and a length of 200cm. This tube was then connected to the tube filled with Chelex 100 after 10mL of water had been introduced.

[0143] 10 mL of 1.0 mol / L hydrochloric acid was passed through the Chelex 100 side of the tube connected as described above at a flow rate of 1 mL / min, followed by 8 cc of water, to obtain a Ra hydroxide solution. The resulting solution was evaporated to dryness, and the dried solids were dissolved in 1 mL of 0.1 mol / L hydrochloric acid. 2 mL of a 0.5 mol / L ammonium acetate aqueous solution was mixed into this solution to prepare the electrodeposition solution. The pH of the resulting electrodeposition solution was considered to be approximately 5.

[0144] Radioactivity was measured using a germanium semiconductor detector manufactured by ERISYS MESURES, thereby determining the radioactivity in the obtained electrodeposition solution. 226 Ra content. The results are shown in Table 6.

[0145] Using the prepared electrodeposition solution, a φ10mm gold-plated silver plate (conical shape, 5mm thickness) was used as the substrate. The electrodeposition time was changed to 3 hours. Otherwise, the electrodeposition process was performed in the same manner as in Experimental Example 1, and a gold-plated silver plate containing [missing information] was electrodeposited on the substrate. 226 Ra substance.

[0146] The substrate contained in the electrodeposited material 226 Determining the Ra content itself is not easy; therefore, a pulsed current was applied for 3 hours, and radioactivity was measured using a germanium semiconductor detector manufactured by EURISYS MESURES. This allowed for the determination of the Ra content in the electrodeposition solution after the substrate was removed. 226 Ra content, the amount of Ra in the electrodeposition solution before and after electrodeposition. 226 The difference in Ra content is used as the basis for electrodeposition on the substrate. 226 Ra content (electrodeposited Ra amount). The results are shown in Table 6.

[0147] It should be noted that, for experimental examples 30-32, except for those that were completed after proton irradiation... 226 Ra targets were used for different purposes. 226 The same test was conducted outside of the Ra target.

[0148] [Table 6]

[0149]

Claims

1. 225 The manufacturing method of Ac, wherein... Through processes including electrodeposition 226 The manufacturing method of Ra target 226 Ra target, in the electrodeposition process, using a target containing... 226 Electrodeposition solution containing Ra ions and pH buffer, so that... 226 Ra material is electrodeposited onto a substrate, wherein the electrodeposition solution contains acetate as a pH buffer. 225 The method of manufacturing Ac includes feeding the... 226 Ra target irradiation is an irradiation process selected from at least one of charged particles, photons, and neutrons, wherein the electrodeposition solution substantially does not contain alcohol.

2. As described in claim 1 225 The manufacturing method of Ac, wherein... The electrodeposition solution used at the beginning of the electrodeposition process is acidic.

3. As described in claim 1 or 2 225 The manufacturing method of Ac, wherein... The pH of the electrodeposition solution in the electrodeposition process is 4-9.

4. As described in claim 1 or 2 225 The manufacturing method of Ac, relative to the above 226 The amount of pH buffer used is 0.2~11.0 mol / L for Ra ions 0.02 mol / L.

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