阅读说明：本技术 一种富集112Cd靶的制备方法 (Enrichment method112Preparation method of Cd target ) 是由 李飞泽 高靖 杨远友 刘宁 廖家莉 杨吉军 兰图 于 2020-07-02 设计创作，主要内容包括：本发明公开了一种富集<Sup>112</Sup>Cd靶的制备方法,基于硫酸盐电镀体系,采用电沉积法制备富集<Sup>112</Sup>Cd靶,电沉积液成分为：<Sup>112</Sup>Cd<Sup>2+</Sup>浓度为18-22g/L,H<Sup>+</Sup>浓度为2-3mol/L,C<Sub>6</Sub>H<Sub>5</Sub>OH浓度为4-5g/L,C<Sub>2</Sub>H<Sub>5</Sub>OH体积分数为20-30％；电沉积参数为：电流密度为2.5-5mA/cm<Sup>2</Sup>,电沉积时间为18-24h,阳极用于负载靶物质的表面具有面积为3.4㎝<Sup>2</Sup>的沉积区和非沉积区,所述非沉积区覆盖绝缘层。本发明通过优化电沉积液组分和电沉积参数,在低浓度下进行镉靶制备,同时核反应有效面积控制在电沉积面积内,使每个靶片的镀镉量由传统的1-1.5g减少至0.2-0.3g,有效减少镉的用量,极大地降低了镉靶成本,填补了国内富集<Sup>112</Sup>Cd靶制备的空白。(The invention discloses enrichment 112 The method for preparing Cd target is based on sulfate electroplating system and adopts electrodeposition method to prepare enrichment 112 Cd target, electrodeposition liquid comprises the following components: 112 Cd 2+ the concentration is 18-22g/L, H + The concentration is 2-3mol/L, C 6 H 5 OH concentration of 4-5g/L, C 2 H 5 The volume fraction of OH is 20-30%; the electrodeposition parameters were: the current density is 2.5-5mA/cm 2 The electrodeposition time is 18-24h, and the surface of the anode for loading the target substance has an area of 3.4cm 2 And a non-deposition region covering the insulating layer. The invention optimizes the components of the electrodeposition liquid and electrodeposition parameters to prepare the cadmium target under low concentration, and simultaneously controls the effective area of nuclear reaction in the electrodeposition area to ensure that the effective area of each target sheetThe cadmium plating amount is reduced from 1-1.5g to 0.2-0.3g, the cadmium consumption is effectively reduced, the cadmium target cost is greatly reduced, and domestic enrichment is filled 112 Blank for Cd target preparation.)

1. Enrichment method¹¹²The preparation method of the Cd target is characterized by comprising the following steps: preparation of enrichment by electrodeposition based on sulfate system¹¹²A Cd target comprising the steps of:

(1) preparing an electrodeposition solution comprising¹¹²Uniformly mixing Cd compound, absolute ethyl alcohol, phenol, 5-10mol/L sulfuric acid solution and deionized water to prepare electrodeposition liquid, wherein the electrodeposition liquid contains Cd compound, absolute ethyl alcohol, phenol, 5-10mol/L sulfuric acid solution and deionized water¹¹²Cd²⁺The concentration is 10-25g/L, H⁺Concentration of 0.5-5.5mol/L, C₆H₅OH concentration of 3-6g/L, C₂H₅The volume fraction of OH is 20-40%;

(2) electrodeposition, namely, the prepared electrodeposition liquid is placed in an electrodeposition tank, an anode and a cathode are installed in parallel, and the surface for loading target substances is designed on the anode and has the area of 3.4cm²Deposition and non-deposition zones, protons and enrichment¹¹²The position of the nuclear reaction of Cd is a fast spot, the fast spot is positioned in the deposition area, and the non-deposition area is covered with an insulating layer; then carrying out electrodeposition under stirring conditions according to set electrodeposition parameters to obtain enriched Cd¹¹²Target, electrodeposition parameters were: the current density is 2.5-7.5mA/cm²The electrodeposition time is 12-24 h.

2. Enrichment according to claim 1¹¹²The preparation method of the Cd target is characterized by comprising the following steps: the components of the electrodeposition solution are as follows:¹¹²Cd²⁺the concentration is 18-22g/L, H⁺The concentration is 2-3mol/L, C₆H₅OH concentration of 4-5g/L, C₂H₅OH volume fraction20 to 30 percent.

3. Enrichment according to claim 1¹¹²The preparation method of the Cd target is characterized by comprising the following steps: the electrodeposition parameters were: the current density is 2.5-5mA/cm²The electrodeposition time is 18-24 h.

4. Enrichment according to any of claims 1 to 3¹¹²The preparation method of the Cd target is characterized by comprising the following steps: a copper target holder is used as a cathode, a platinum wire is used as an anode, and the anode is parallel to the cathode.

5. Enrichment according to any of claims 1 to 3¹¹²The preparation method of the Cd target is characterized by comprising the following steps: the copper target holds in the palm is the cuboid structure, and the opposite face of loading target material surface is provided with the recess that is used for passing through cooling water on the copper target holds in the palm.

Technical Field

The invention belongs to the technical field of targets, relates to preparation of a target for generating nuclear reaction, and particularly relates to enrichment¹¹²A method for preparing Cd targets.

Background

¹¹¹In is radionuclide produced by accelerator, and has physical half-life (T)_1/267h) d, which release 173keV and 247keV gamma rays during decay, have the best physical and chemical properties of radiopharmaceuticals, and are considered to be one of the superior radionuclides for medical use.¹¹¹In can form stable complexes with a number of organic ligands, e.g. tumor-avid¹¹¹In medicine¹¹¹InPAMINE、¹¹¹In-octree and¹¹¹in-labeled monoclonal antibodies, polypeptides and the like have important application values In medicine.

¹¹¹In can only be produced manually. Application of cadmium (Cd) target in accelerator for producing medical isotope¹¹¹In, the nuclear reaction of which is^NatCd(p，xn)¹¹¹In. Similar natural Cd target preparation is established in the national atomic energy institute, Beijing university and atomic high department¹¹¹In process flow, however¹¹¹The radioactive nuclear purity of In can reach 96%, while the radioactive chemical purity of radioactive drugs entering clinical use is required to be more than 90% and the nuclear purity of labeled nuclide is required to be more than 99% according to the radioactive drug production management standard (GRP) In China. At present, the natural Cd target in China is prepared¹¹¹In is In a low nuclear purity state, and the marking rate of a marking compound is low, so that the clinical medical requirements cannot be met.

Preparation of high purity¹¹¹In is a complex process, irradiating cadmium targets¹¹¹The In separation method and the cadmium target enrichment degree are¹¹¹The critical factors of In radionuclide purity and radiochemical purity. Cadmium (Cd)The target needs to be prepared into a flat, compact and firm thick target, so that the proton energy can be fully utilized, and the isotope yield is improved. Conventional electrodeposition methods use a large amount of complexing agents, buffers or cyanide-containing electrodepositing solutions in order to achieve the above-described requirements for the deposited layer. Cyanide is extremely toxic, and the introduction of a large amount of buffer and complexing agent increases salt content and impurity ions. In addition, the thicker the target, the less robust and dense it is, and the more likely it falls off during irradiation, which not only causes radioactive contamination, but also affects isotope yield.

Disclosure of Invention

Aiming at the technical difficulty of the preparation of the prior enriched cadmium target, the invention aims to provide enrichment¹¹²The Cd target preparation method can prepare a Cd target with a smooth, smooth and compact surface and a thickness of more than 50mg/cm²Is enriched in¹¹²The Cd target effectively reduces the cadmium consumption and greatly saves the cost.

In order to solve the technical problems, the basic idea of the invention is as follows: the natural cadmium target contains impurities such as Cu, Zn, Fe, Ni, Co and the like, and cadmium also has various isotopes, wherein the natural abundance of the cadmium is¹¹⁰Cd(12.5％)、¹¹¹Cd(12.8％)、¹¹²Cd(24.1％)、¹¹³Cd(12.3％)、¹¹⁴Cd (28.7%) and¹¹⁶cd (7.5%). Most isotopes of natural cadmium can produce (p, xn) under proton irradiation of 12-26MeV, generating a series of radioisotopes of In, among which¹⁰⁹In、¹¹¹In and^114mthe half-life period of In is longer and is respectively 4.3h, 2.83d and 49.5d, and the half-life period of the rest nuclides is very short. After the irradiated Cd target is cooled for 40h, the solution of the Cd target contains constant Cd, Zn, Ni, Cu, Fe, Co and other elements^114mIn and activated product⁵⁷Co、⁶⁵Zn and other radioactive impurities, and high nuclear purity¹¹¹In presents a great difficulty. The inventor of the invention researches and discovers that when the proton energy range is 12-30MeV, the proton irradiation is enriched¹¹²Cd generation of¹¹²Cd(p，2n)¹¹¹In reaction, compared with other isotopes of cadmium,¹¹¹the yield of In is the largest and can reach 1000 mu Ci/mu Ah, and^114mthe effect of radioactive impurities such as In is minimal. As shown in fig. 1Selecting the threshold energy of nuclear reaction and the excitation function of related reaction according to the performance index of the CS-30 cyclotron to obtain higher yield¹¹²Cd(p,2n)¹¹¹In reaction while obtaining a product of high nuclear purity¹¹¹In, selecting target nuclei for enrichment¹¹²Cd isotope to reduce the interference of other impurities. Thus, the present invention utilizes enrichment¹¹²And (5) carrying out target making by using Cd isotope.

The preparation process of natural cadmium target is mainly characterized by using electrodeposition, and mainly includes 3 electrodeposition systems, ① sulfate electroplating system, ② cyanide electroplating system and ③ acetate electroplating system, and for the preparation process of enriched cadmium target, Yarmohammadi, Mirzaii and others use KCN (potassium chloride) electroplating to prepare enriched cadmium target, and can effectively reduce the dose of enriched cadmium, but KCN is extremely toxic, and is easy to pollute environment, and comprehensively considers the recovery of enriched cadmium in later stage, environmental protection problem and process complexity, and said invention adopts sulfate system to make electrodeposition, and further in the traditional sulfate electroplating system the concentration of required cadmium is 52.5g/L, the area of cadmium target is 2cm 10cm, and the cadmium plating quantity on Cu substrate is 1.0-1.5g, but the cost of enriched cadmium is high, and the cadmium quantity must be reduced to reduce cost²) Much smaller than the area of target deposition (about 2 x 10 to 20 cm)²) Based on the method, the effective nuclear reaction electroplating area is deposited by controlling the corresponding electrodeposition conditions, and the deposition area is reduced so as to achieve the aim of reducing the cadmium consumption in the electroplating solution.

Based on the above inventive concept, the enrichment provided by the invention¹¹²The method for preparing Cd target is based on sulfate electroplating system and adopts electrodeposition method to prepare enrichment¹¹²A Cd target comprising the steps of:

(1) preparing electrodeposition liquid by using Cd¹¹²Uniformly mixing a compound, absolute ethyl alcohol, phenol, 5-10mol/L sulfuric acid solution and deionized water to prepare electrodeposition liquid, wherein the electrodeposition liquid contains¹¹²Cd²⁺The concentration is 10-25g/L, H⁺Concentration of 0.5-5.5mol/L, C₆H₅OH concentration of 3-6g/L, C₂H₅The volume fraction of OH is 20-40%;

(2) electrodeposition, namely placing the prepared electrodeposition liquid in an electrodeposition tank, installing an anode and a cathode in parallel, designing a deposition area and a non-deposition area with the area of 3.4cm < 2 > on the surface for loading target substances, and enriching protons¹¹²The position of nuclear reaction of Cd is a fast spot position, the fast spot is positioned in the precipitation zone, and the non-precipitation zone is covered with an insulating layer; then carrying out electrodeposition under stirring conditions according to set electrodeposition parameters to obtain enriched Cd¹¹²Target, electrodeposition parameters were: the current density is 2.5-7.5mA/cm²The electrodeposition time is 12-24 h.

The above enrichment¹¹²In the technical scheme of the preparation method of the Cd target, the deposition area deposits and enriches¹¹²Cd mainly used for nuclear reaction with the proton emitted from the accelerator¹¹²Cd(p，2n)¹¹¹In, proton and enrichment¹¹²The position of nuclear reaction of Cd is the fast spot position, and the target making work is meaningful only if the fast spot position is in the deposition area. The non-deposition region is covered with an insulating layer and is not deposited and enriched¹¹²Cd, the non-deposition area covers the insulating layer and can effectively reduce unnecessary deposition and reduce the waste of materials.

The above enrichment¹¹²In the technical scheme of the preparation method of the Cd target, the inventor pairs¹¹²Cd²⁺Concentration of H⁺Concentration and current density are subjected to cross experiment, and the following results are found:¹¹²Cd²⁺the surface of the cadmium target plated by the concentration which is too high (more than or equal to 25g/L) is rough, and the thickness of the cadmium target plated by the concentration which is too low (less than 20g/L) does not meet the requirement; h⁺The surface of the cadmium target plated by the plating with too high concentration (more than 3g/L) is rough, and the surface of the cadmium target plated by the plating with too low concentration (less than 0.5g/L) is also rough; the current density is preferably 2.5-7.5mA/cm²Too high a density (greater than 7.5 mA/cm)²) The surface of the cadmium target plated is rough, and the surface of the cadmium target plated by the. In addition, the electrodeposition bath composition is more preferably:¹¹²Cd²⁺the concentration is 18-22g/L, H⁺The concentration is 2-3mol/L, C₆H₅OH concentration of 4-5g/L, C₂H₅OH volume fraction of 20-30 percent. The electrodeposition parameters are preferably: the current density is 2.5-5mA/cm²The electrodeposition time is 18-24 h.

Further, the contents of phenol and alcohol in the electrodeposition liquid have an influence on the appearance quality and thickness of the target. When the concentration of the phenol is lower than 3g/L, the deposition of the cadmium target is uneven and rough, and when the content is higher than 6g/L, the electroplating solution becomes turbid. When the volume fraction of the alcohol is lower than 10%, the cadmium target is rough and not firm, and when the content is higher than 40%, the surface of the cadmium target is rough. On this basis, C is preferred₆H₅OH concentration of 4-5g/L, C₂H₅The OH volume fraction is 20-30%.

The above enrichment¹¹²In the technical scheme of the preparation method of the Cd target, a cathode generates a reduction reaction and loads a target substance, an anode generates an oxidation reaction, and the oxidation-reduction reaction specifically comprises the following steps: anode 4OH^--4e＝2H₂O+O²↓cathodeCd²⁺+2e ↓. The cathode/anode material for electrodeposition can be cathode/anode material commonly used in the field, and the copper (Cu) target holder is used as the cathode and platinum (Pt) wire is used as the anode in the invention. The copper target holder can be purchased or manufactured in the market, but the surface is smooth and flat to ensure¹¹²The Cd deposition layer is firmly attached. Further, the anode is parallel to the cathode to ensure¹¹²The thickness of the Cd deposition layer is uniform. The invention adopts a self-made copper target holder which is of a cuboid structure, a groove for passing cooling water is arranged on the opposite surface of the copper target holder for loading target substances, and the copper target holder enables the prepared enrichment to be enriched¹¹²The Cd target has good heat dissipation condition and is favorable for nuclear reaction¹¹¹And (3) preparing In.

The above enrichment¹¹²In the technical scheme of the preparation method of the Cd target, the area size of a precipitation zone is mainly determined by the technological parameters and the area of the precipitation zone. The effective nuclear reaction electroplating area is 3.4cm by controlling the corresponding electrodeposition conditions²On the one hand, to¹¹¹The effective area is matched In the In preparation, so that the waste of raw materials is avoided, and the production cost is reduced; on the other hand, the compactness of the prepared cadmium target can be improved by controlling the area of the deposition area, and a high-quality cadmium target product is obtained. In phaseThe elliptical area is smaller than the rectangular area under the condition of the same length and width, and finally the required enrichment of deposition¹¹²The mass of Cd is also correspondingly smaller, so we optimize the deposition zone to be elliptical.

The above enrichment¹¹²In the technical scheme of the preparation method of the Cd target, enrichment is carried out¹¹²In the process of preparing the Cd target, the electrodeposition liquid is stirred to prevent concentration polarization of the electrodeposition liquid, which is beneficial to improvement¹¹²Deposition rate of Cd and¹¹²uniformity of Cd deposition. The stirring speed is not specially limited, and the operation can be carried out according to the actual condition on the premise of achieving the purpose of preventing the concentration polarization of the electrodeposition liquid, and generally, the electrodeposition liquid can be manually stirred at intervals of 2-3 hours until the electrodeposition liquid has no concentration. In addition to the enrichment¹¹²During the preparation of Cd target, proper supplement is carried out¹¹²Cd²⁺To enrich the electrodeposition liquid¹¹²In the process of preparing Cd target, Cd²⁺The concentration is controlled to be 20-25g/L, which is beneficial to the preparation of cadmium target by repeatedly using the electrodeposition liquid.

The above enrichment¹¹²In the invention, the electro-deposition groove body material is polytetrafluoroethylene, the external dimension is 16 cm × 7 cm × 7 cm, and the internal dimension is 13 cm × 4.5.5 cm × 4.5.5 cm.

Enrichment provided by the invention¹¹²Compared with the prior art, the preparation method of the Cd target has the following beneficial effects:

1. according to the method, the cadmium target is prepared under low concentration by optimizing the components of the electrodeposition liquid and electrodeposition parameters, and meanwhile, the effective area of nuclear reaction is controlled within 3.4cm < 2 >, so that the cadmium plating amount of each target sheet is reduced to 0.2-0.3g from the traditional 1-1.5g, the cadmium consumption is effectively reduced, and the cadmium target cost is greatly reduced.

2. The present invention utilizes enrichment¹¹²Cd isotope target rather than other isotopes, prepared enrichment¹¹²The surface of the Cd target is flat, smooth and compact, and the thickness of the Cd target is more than 50mg/cm²For end products¹¹¹The In separation has great promotion effect, and is rich In production,Purity of radioactive nuclei is higher than 99%¹¹¹In lays a solid foundation and fills In the domestic enrichment¹¹²Blank for Cd target preparation.

3. The invention can be used for enriching¹¹²During the preparation of Cd target, supplement is performed¹¹²Cd²⁺Make Cd in the electrodeposition solution²⁺The concentration is controlled in a corresponding range, and the electrodeposition liquid is repeatedly used for preparing the cadmium target, so that the production cost is saved.

4. The enrichment prepared by the process of the invention¹¹²The Cd target is suitable for CS-30 cyclotron to prepare high-purity radioactive nuclide¹¹¹In provides necessary guarantee and has important application value In the field of clinical medicine.

Drawings

FIG. 1 is a computer simulation of proton beam bombardment according to the present invention¹¹²Excitation function of the main nuclear reaction generated by the Cd target;

FIG. 2 is a schematic view of the copper backing plate of the present invention, wherein FIG. (a) is a front view, FIG. (b) is a cross-sectional view, and FIG. (c) is a bottom view;

FIG. 3 is a schematic view of a deposition zone in the present invention;

FIG. 4 is a schematic diagram of the cathode (using a copper target holder) according to the present invention;

FIG. 5 shows enrichment prepared according to the present invention¹¹²A Cd target object graph;

FIG. 6 is a scanning electron microscope image of the present invention, wherein (a) is an overall view of the scanning electron microscope image, and (b) is an enlarged view of a white frame in (a);

FIG. 7 shows enrichment prepared according to the present invention¹¹²And (3) a Cd target energy spectrum component analysis diagram.

Detailed Description

The technical solutions of the present invention will be described in detail and fully with reference to the accompanying drawings, which are used for describing the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following examples, the materials selected for targeting were enriched for commercial supply¹¹²The electro-deposition groove body material for electro-deposition of the oxide of the Cd isotope (98.5%) is polytetrafluoroethylene, the external dimension is 16 cm × 7 cm × 7 cm, the internal dimension is 13 cm × 4.5.5 cm × 4.5.5 cm.Pt as an anode, the self-made Cu substrate target holder is a cathode, the self-made Cu substrate target holder is shown in figure 2 and integrally has a cuboid structure, the length of the cuboid structure is 11cm ×, the width of the cuboid structure is 2.8cm ×, the height of the cuboid structure is 0.5cm, the back surface of the cuboid structure is provided with an oval groove, the length of the oval groove is 9cm ×, the width of the oval groove is 1.8cm ×, and the height of the oval groove is 0.4cm, the front surface of the target holder is used for loading target substances through cooling water, the back surface of the target holder is covered with an insulating layer, and the oval through¹¹²Cd deposition area (area about 3.4cm 2). The insulating layer is made of butyl rubber material. In particular, as shown in FIG. 3, the spot velocity location is within the deposition zone.