A production 225 Closed cycle of Ac 226 Ra solution target system

Abstract

The present invention relates to a production 225 Closed cycle of Ac 226 Ra solution target system. The closed cycle 226 Ra solution target system includes solution type 226 Ra target, isotope target chamber, valve, 226 Ra solution circulation structure, radium-actinium separation structure, radium-lead separation structure, photon detection system I, photon detection system II, heat exchange system, vacuum radon evaporator and radon treatment system, among which, solution type 226 The Ra target includes a solution circulation pipeline and a radium-containing solution, and the radium-containing solution is contained in a closed solution circulation pipeline; the solution circulation pipeline includes a main loop pipeline and two branch pipelines; the photon detection system I, 226 The Ra solution circulation structure, vacuum radon evaporator, heat exchange system, valve and photon detection system II are sequentially arranged on the main loop pipeline; the radium-actinium separation structure and the radium-lead separation structure are respectively arranged on the two branch pipelines. 225 Preparation efficiency and yield of Ac.

Description

Technical Field

[0001] The present invention relates to an accelerator for producing medical 225 Ac isotope target system technology field, specifically relates to a production 225 Closed cycle of Ac 226 Ra solution target system. Background Art

[0002] Targeted α therapy is a cancer treatment method characterized by high precision, significant efficacy, and relatively few side effects. This method achieves its therapeutic purpose by injecting drugs loaded with short-lived α radionuclides into the human body and allowing them to accumulate in the tumor, irradiating and killing cancer cells with α particles. The key to targeted α therapy is the development of suitable α radioisotopes. Currently, several candidate isotopes are undergoing clinical and preclinical evaluation, including 149 Tb, 211 At 212 Bi, 212 Pb, 213 Bi, 223 Ra, 224 Ra, 227 Th and 225 Ac etc. Among them, 225 Ac is one of the α-radionuclides with medical prospects due to its advantages such as short half-life (about 10 days), ability to effectively combine with a variety of chelating agents, and efficient irradiation through four α decays and two β decays.

[0003] 225 There are several main ways to produce Ac: (1) through the thorium-actinium generator. 229 Th decays naturally 225 Ac; (2) Thorium target high energy proton preparation, the nuclear reaction formula is 232 Th(p, x) 225 Ra→ 225 Ac; (3) Preparation by low-energy proton reaction in radium target, the nuclear reaction formula is 226 Ra(p,2n)→ 225 Ac; (4) Preparation of radium target photonuclear reaction, the nuclear reaction formula is 226 Ra(γ, n) 225 Ra→ 225 Ac; (5) Based on fast reactor and neutron source preparation, the nuclear reaction formula based on the fast reactor scheme is 226 Ra(μ-, nv) 225 Fr→ 225 Ac, the nuclear reaction equation based on the neutron source scheme is 226 Ra(n,2n) 225 Ra→ 225 Ac. Among them, radium target photonuclear reaction preparation 225Ac is a method of bombarding heavy metal conversion targets with medium and high energy electrons generated by an electron linear accelerator to produce a large number of γ photons. 226 Ra target obtains product through photonuclear interaction 225 Ra, then 225 Ra decays to produce 225 Ac, the photonuclear reaction produces 225 The lower limit of photon energy of Ra is 6.4MeV. 225 The feasibility of Ac's technical route was confirmed in 2005, and then the international community began to develop this technical route.

[0004] Prepared by electron linear accelerator with radium target photonuclear reaction 225 The technical route of Ac is to increase the 226 Ra target surface area to improve the utilization of target material, but there is still 226 Ra raw material supply difficulties and 226 Ra will continue to decay and release harmful radioactive gas radon-222 (i.e. 222 Rn) and other issues, so recycling and reuse 226 Ra and proper handling of radon and its daughter nuclides are very important. At the same time, the electron linear accelerator is used to prepare radium target photonuclear reaction. 225 The Ac technology route will also produce another medical isotope with application prospects. 212 Pb. Due to 212 The half-life of Pb is short (T 1 / 2 = 10.6 hours), compared to 225 The longer half-life of Ac (T 1 / 2 = 9.9 days), 212 Pb needs to be separated and extracted quickly after production, otherwise it will decay and become unextractable; 225 Ac can be separated and processed after the target material is deposited for a period of time. 212 Pb and 225 One of Ac, or simultaneous separation and extraction 212 Pb and 225 Ac, this operation has low extraction efficiency and will also lead to large and uncontrollable losses, resulting in low yield of medical isotopes.

[0005] The prior art patent document with publication number CN112885495B discloses a method for producing Ac-225 from Ra-226. Its main purpose is to propose an electrodeposition method to solve the problem of chemical separation and extraction of Ac-225 after irradiation, and to avoid the risks arising from the subsequent recovery process of Ra-226. However, the process of separating and extracting Ac-225 requires the cathode after deposition to be removed for separate separation and purification, which still poses a radioactive risk. In addition, the electrodeposition method will produce electrolytic waste gas such as chlorine or nitrogen oxides, which also poses a safety hazard. Prior art patent document CN112366020B discloses a method for producing actinium by liquefying radium, and relates to an apparatus for producing actinium by using liquefied radium, the main purpose of which is to minimize the loss of Ra-226 generated during the reaction process. The invention carries out gas treatment, Ra raw material treatment, and separation and purification of radium and actinium in multiple steps in additional containers (vials), which is an online irradiation and offline processing method, and the entire process is not completed in a single loop. The separation and purification of radium and actinium requires the interruption of irradiation to produce actinium. In addition, the invention only collects the harmful radioactive gas radon and does not process it. Summary of the Invention

[0006] The present invention aims to prepare the 225 In the technical route of Ac, the radon produced by the decay of radium target and its decay daughters are difficult to handle. A production 225 Closed cycle of Ac 226 Ra solution target system. The closed cycle 226 Ra solution target system can effectively reduce 225 Ac extraction step, improve 225 Ac preparation efficiency, and can also separate another medical isotope produced during the preparation process 212 Pb; and the closed cycle structure designed by the present invention can effectively treat gaseous radon and its daughters. In addition, the closed cycle 226 The Ra solution target system is combined with an electron linear accelerator with an energy of 35MeV and a current of 2mA, which can make 225 The annual output of Ac reaches 12.33 Ci.

[0007] The technical solution adopted in the present invention is as follows:

[0008] A production 225 Closed cycle of Ac 226 Ra solution target system, including solution type 226 Ra target, isotope target chamber, valve, 226Ra solution circulation structure, radium-actinium separation structure, radium-lead separation structure, photon detection system I, photon detection system II, heat exchange system, vacuum radon evaporator and radon treatment system, among which, solution type 226 The Ra target comprises a solution circulation pipe and a radium-containing solution, wherein the radium-containing solution is contained in the closed solution circulation pipe;

[0009] The solution circulation pipeline includes a main loop pipeline, a first branch pipeline and a second branch pipeline. A section of the main loop pipeline passes through the isotope target chamber and is fixed by the isotope target chamber. A section of the main loop pipeline located in the isotope target chamber serves as an irradiated section for cooperating with the electron beam to irradiate and produce 225 Ac; the first branch pipe and the second branch pipe are located outside the isotope target chamber, and both ends of the first branch pipe and the second branch pipe can be connected to the main loop pipe;

[0010] The photon detection system I, 226 The Ra solution circulation structure, the reduced pressure radon evaporator, the heat exchange system, the valve and the photon detection system II are sequentially arranged on the main loop pipeline of the solution circulation pipeline, and the valve is arranged at the first connection point between the main loop pipeline and the two branch pipelines, and the photon detection system II is arranged behind the second connection point between the main loop pipeline and the two branch pipelines; the valve is electrically connected to the photon detection system I; the photon detection system I is used to detect the target nuclides generated after irradiation 225 Ac, 212 Pb and the impurity nuclides generated during the reaction emit photons of specific energy, which are converted into electrical signals and transmitted to the valve; the valve is a four-way solenoid valve used to adjust the connection direction; the heat exchange system is used to cool the radium-containing solution in the solution circulation pipeline; 226 The Ra solution circulation structure is a power pump, which is used to provide driving force for the circulation of the radium-containing solution and control the flow rate of the radium-containing solution in the solution circulation pipeline; the radon treatment system is connected to the vacuum radon evaporator, which is used to evaporate the radon and its daughters generated in the radium-containing solution after irradiation into the radon treatment system;

[0011] The radium-actinium separation structure is arranged on the first branch pipe of the solution circulation pipe, and is used to separate and collect the radium-containing solution generated after being irradiated. 225 The radium-lead separation structure is provided on the second branch pipe of the solution circulation pipe, and is used to separate and collect the radium-containing solution generated after being irradiated. 212 Pb; Photon detection system II is used to detect target nuclides after radium-actinium separation or radium-lead separation 225 Ac, 212 Photons of specific energy emitted by Pb and impurity nuclides.

[0012] Furthermore, the radon treatment system includes a sealed container in which activated carbon is placed for absorbing radon and its daughters generated after the radium-containing solution is irradiated.

[0013] Furthermore, the heat exchange system is a plate heat exchanger.

[0014] Furthermore, the radium-containing solution is 226 RaCl2 solution.

[0015] Furthermore, the photon detection system I and the photon detection system II are both photon detectors.

[0016] The beneficial effects of the present invention are as follows:

[0017] (1) Compared with solid isotope targets, the closed-circulation solution type 226 Ra target can directly avoid 226 The poor physical properties of Ra single-element materials lead to problems such as target breakage, target melting and leakage.

[0018] (2) The closed cycle adopted by the present invention 226 Ra solution target system can effectively target solution type through the structural design of solution circulation 226 The Ra target is cooled and can be 226 Decay daughter nuclei of Ra 222 Rn is effectively recycled to avoid 222 Rn leakage problem; and separate collection 225 Ac, 212 There is no need to interrupt irradiation production during the separation and treatment of Pb and radon and its daughters 225 Ac and 212 The work of Pb improves the preparation efficiency.

[0019] (3) The photon detection system I used in the present invention detects the target nuclides generated after irradiation. 225 Ac, 212 Photons of specific energy released in the decay chain of Pb are converted into electrical signals to control the steering of the four-way solenoid valve to select the separation target, thereby improving the separation and extraction efficiency of the target nuclide.

[0020] (4) The photon detection system II used in the present invention detects the target nuclide in the radium-containing solution after separation. 225 Ac, 212 Photons of specific energy released in the decay chain of Pb can be used to infer the activity of the target nuclide; combined with Photon Detection System I, the yield of the target nuclide and the corresponding separation efficiency can be inferred. At the same time, the content of impurity nuclides in the radium-containing solution that will continue to be irradiated after the target nuclide is separated can be monitored. When the impurity nuclides accumulate to a certain level, the radium-containing solution needs to be replaced.

[0021] (5) Using the closed cycle adopted by the present invention 226 Ra solution target system is used in electron linear accelerator with energy of 35MeV and current of 2mA, which can achieve 225 The annual output of Ac is more than 12.33 times. 212 The annual output of Pb reaches 15.09 Ci.

[0022] (6) Using the solution type used in the present invention 226 Compared with the traditional solid radium target, Ra target is more suitable for separation. 225 The Ac process does not require the initial step of dissolving the solid radium isotope sample, and the target preparation process does not require solidification drying, pressing or electrodeposition operations, which greatly simplifies the 225 Preparation process of Ac. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the solution type in the present invention 226 Schematic diagram of the working of Ra target in the terminal target area of ​​the electron beam.

[0024] Figure 2 The present invention produces 225 Closed cycle of Ac 226 Schematic diagram of the structure of the Ra solution target system.

[0025] Figure 3 It is the solution type in the present invention 226 Longitudinal cross-section of the Ra target.

[0026] Figure 4 The solution type of the present invention 226 After 10 days of irradiation of the Ra target in an electron linear accelerator with an energy of 35 MeV and a current of 2 mA, 225 Ra and 225 Ac, 212 Pb production over time.

[0027] In the figure: 1. Electron beam; 2. Conversion target chamber; 3. Tungsten conversion target; 4. Solution type 226 Ra target; 41, 226 RaCl2 solution; 5. Isotope target chamber; 6. Solution circulation pipeline; 7. Valve; 8. 226 Ra solution circulation structure; 9. Radium and actinium separation structure; 10. Heat exchange system; 11. Vacuum radon evaporator; 12. Radon treatment system; 13. Radium and lead separation structure; 14. Photon detection system I; 15. Photon detection system II. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Produced by photonuclear reaction of radium target 225 Ac isotope process, for effective protection 226 Decay daughter nuclei of Ra 222 Leakage of Rn, and to simplify 225 Ac isotope preparation process, the present invention provides a circulating solution type 226 Ra target system.

[0030] like Figures 1 to 3 A production method for an electron linear accelerator is shown. 225 Closed cycle of Ac 226 Ra solution target system, including solution type 226 Ra target 4, isotope target chamber 5, valve 7, 226 Ra solution circulation structure 8, radium-actinium separation structure 9, heat exchange system 10, radium-lead separation structure 13, photon detection system I 14, photon detection system II 15, among which, solution type 226 The Ra target 4 includes a solution circulation pipe 6 and a radium-containing solution. In this embodiment, the radium-containing solution is 226 RaCl2 solution 41, 226 The RaCl2 solution 41 is contained in a closed solution circulation pipe 6; the solution circulation pipe 6 includes a main loop pipe, a first branch pipe and a second branch pipe. A section of the main loop pipe of the solution circulation pipe 6 passes through the isotope target chamber 5 and is fixed by the isotope target chamber 5. A section of the main loop pipe located in the isotope target chamber 5 serves as an irradiated section, which is used to cooperate with the electron beam 1 for irradiation to produce 225 Ac; The first branch pipeline and the second branch pipeline are located outside the isotope target chamber 5, and both ends of the first branch pipeline and the second branch pipeline can be connected to the main loop pipeline. Photon detection system I 14, 226The Ra solution circulation structure 8, heat exchange system 10, valve 7 and photon detection system II 15 are sequentially arranged on the main loop pipeline of the solution circulation pipeline 6, and the valve 7 is arranged at the first connection point between the main loop pipeline and the two branch pipelines of the solution circulation pipeline 6; the photon detection system II 15 is arranged behind the second connection point between the main loop pipeline and the two branch pipelines, that is, the photon detection system I 14 and the photon detection system II 15 are respectively arranged at the two ends of the irradiated section of the main loop pipeline. Among them, the photon detection system I 14 and the photon detection system II 15 are both photon detectors, such as: high-purity germanium detectors, sodium iodide detectors and selenium iodide detectors. A photon detector is a precision instrument used to detect light signals (such as visible light, ultraviolet light, X-rays, gamma rays, etc.) and convert them into measurable electrical signals. The photon detection system I 14 is used to detect target nuclides after irradiation. 225 Ac, 212 The photons of specific energy released by Pb in the decay chain are converted into electrical signals and transmitted to valve 7, thereby controlling the direction of valve 7, separating and purifying the target nuclides, and being able to monitor impurity nuclides in the radium-containing solution; 226 The Ra solution circulation structure 8 is a power pump, such as a peristaltic pump of model YZ1525. The material of the internal delivery tube of the peristaltic pump is silicone. 226 The Ra solution circulation structure 8 is used to provide driving force for the circulation of the radium-containing solution in the solution circulation pipeline 6, and can accurately control the flow rate of the radium-containing solution in the solution circulation pipeline 6; the heat exchange system 10 is used to heat the solution circulation pipeline 6. 226 The RaCl2 solution 41 is cooled; the valve 7 is a four-way solenoid valve with adjustable connection direction, and the material of the valve 7 can be aluminum or aluminum alloy; the valve 7 is electrically connected to the photon detection system I 14, and the valve 7 is used to receive the signal from the photon detection system I 14, thereby adjusting the connection direction between the main loop pipeline of the solution circulation pipeline 6 and the first branch pipeline and the second branch pipeline; the radium-actinium separation structure 9 is provided on the first branch pipeline of the solution circulation pipeline 6; the radium-actinium separation structure 9 is a radium-actinium separation system, which specifically includes a radium-actinium separation resin and a leaching container structure for separating and collecting the radium-containing solution generated after being irradiated. 225 Ac, wherein the radium-actinium separation resin is used to 225 Ac is separated from the radium-containing solution, and the elution container structure is used to separate the radium from the solution through the acid solution. 225 Ac is extracted from the resin; the radium-lead separation structure 13 is provided on the second branch pipe of the solution circulation pipe 6; the radium-lead separation structure 13 is a radium-lead separation system, specifically including a radium-lead separation resin and a washing container structure, which is used to separate and collect the radium-containing solution generated after being irradiated. 212 Pb, among which radium-lead separation resin is used to 212Pb is separated from the radium-containing solution, and the elution container structure is used to separate the radium from the solution through the acid solution. 212 Pb is extracted from the resin. The radium-actinium separation resin uses separation adsorption materials known in the art, such as Ln resin, DGA resin or MnO2 resin; the radium-lead separation resin can use Sr resin or Pb resin known in the art, both of which are very effective in separating Pb; the resin can directionally absorb the radium-containing solution generated after irradiation through different molecular structures. 225 Ac or 212 Pb is adsorbed and separated separately. Photon detection system II 15 is used to detect the target nuclide in the radium solution after separation. 225 Ac, 212 Photons of specific energy released by Pb during the decay chain can be combined with photon detection system I 14 to infer the yield and separation efficiency of the target nuclide. In this embodiment, photon detection system I 14 and photon detection system II 15 are connected to a remote server via signals to display yield changes. Photon detection system I 14 and photon detection system II 15 monitor photons of specific energy and transmit signals to an existing remote server, forming a photon energy spectrum that reflects yield changes.

[0031] The heat exchange system 10 used in this embodiment is a multi-plane plate heat exchanger. The plate heat exchanger is an existing high-efficiency heat exchanger made of a series of metal sheets with a certain corrugated shape. Thin rectangular channels are formed between the various plates. The high-temperature fluid and the low-temperature fluid flow through different channels respectively without mixing with each other, and heat is exchanged through the plates; the solution circulation pipe 6 226 The temperature of the RaCl2 solution 41 rises after passing through the irradiated section. When passing through the heat exchange system 10, it flows out from the high-temperature fluid channel of the heat exchange system 10. During the process, it exchanges heat with the coolant in the low-temperature fluid channel of the heat exchange system 10, thereby achieving cooling. 226 The purpose of the RaCl2 solution 41. The coolant in the heat exchange system 10 can be deionized water.

[0032] In this embodiment, the production 225 Closed cycle of Ac 226 The Ra solution target system also includes a vacuum radon evaporator 11 and a radon treatment system 12. The vacuum radon evaporator 11 is arranged at 226The radon treatment system 12 is connected to a vacuum radon evaporator 11 on the main loop of the solution circulation pipeline 6 between the Ra solution circulation structure 8 and the heat exchange system 10. The vacuum radon evaporator 11 is a vacuum evaporator that reduces the system pressure to evaporate the liquid at a lower temperature, evaporating the radon and its daughters produced in the radium-containing solution after irradiation into the radon treatment system 12. Because the radium-containing solution and the radon and its daughters have different evaporation temperatures, the vacuum evaporator can prevent thermal decomposition of the radium-containing solution and changes in its properties, thereby separating the radon and its daughters with a lower evaporation temperature from the radium-containing solution. The radon treatment system 12 is a sealed container that contains a radon-absorbing material, such as activated carbon. In a more preferred embodiment, the sealed container of the radon treatment system 12 is provided with a maintenance door that can be opened periodically to replace the activated carbon in the radon treatment system 12 to ensure effective radon treatment. After irradiation, the radium-containing solution will continuously decay to produce radioactive gas radon and its daughters. The heat generated by irradiation will cause part of the radon and its daughters to evaporate into gaseous state. In order to prevent the radon and its daughters in the radium-containing solution from being completely evaporated, the radon evaporator 11 can further utilize the principle of reduced pressure evaporation to further reduce the radon in the solution circulation pipe 6. 226 All harmful substances radon and its daughters produced in RaCl2 solution 41 222 All Rn is separated and transported to the radon treatment system 12 for absorption treatment.

[0033] In nuclide analysis, a parent nuclide transforms into another daughter nuclide during radioactive decay, often accompanied by the release of characteristic photons, such as gamma rays or X-rays. These photons have specific energies, corresponding to transitions between nuclear energy levels during the decay process. By using a photon detector to measure the energy and intensity of these photons, it is possible to identify which nuclide has decayed. Furthermore, by counting photons of a specific energy and combining parameters such as detector efficiency, the decay constant of the nuclide, and the measurement time, the activity of the parent nuclide can be quantitatively calculated, thereby inferring its yield (this is the existing calculation method in this field). In an electron linear accelerator, radium target photonuclear reaction is used to prepare 225 In Ac's technical route, through detection 225 In the Ac decay chain, 221 The number of photons with an energy of 218 KeV emitted by Fr, and 213 The number of photons emitted by Bi with an energy of 440 KeV is estimated to be 225 Ac yield; by detection 212 In the Pb decay chain, 212 The number of photons with energy of 238KeV emitted by Pb, 212 The number of photons with an energy of 727 KeV emitted by Bi, and 208 The number of photons emitted by Ti with an energy of 2.6 MeV is estimated to be 212The yield of Pb; 227 Ra, 223 The photons of specific energy generated in the decay chain of Ra and other radionuclides are used to monitor the impurity nuclides ( 227 Ra, 223 Ra) and its decay daughters ( 227 Ac, 227 Th and 210 Po) activity.

[0034] The production 225 Closed cycle of Ac 226 The working principle of Ra solution target system is: the main loop pipe of solution circulation pipe 6 is connected to photon detection system I 14, 226 The Ra solution circulation structure 8, the vacuum radon evaporator 11, the heat exchange system 10, the valve 7, and the photon detection system II 15 are connected. The valve 7 is initially closed. The valve 7 is connected to the radium-actinium separation structure 9 through the first branch pipe of the solution circulation pipeline 6. At the same time, the valve 7 is connected to the radium-lead separation structure 13 through the second branch pipe. The solution output ends of the radium-actinium separation structure 9 and the radium-lead separation structure 13 are connected to the main loop pipeline through the first branch pipe and the second branch pipe respectively. When only irradiation is performed, start 226 Ra solution circulation structure 8, and the valve 7 is directly connected to the irradiated section of the main loop pipeline of the solution circulation pipeline 6 fixed at the isotope target chamber 5, and the irradiated section, photon detection system I 14, 226 The Ra solution circulation structure 8, the reduced pressure radon evaporator 11, the heat exchange system 10 and the photon detection system II 15 are connected in sequence. 226 Ra solution circulation structure 8 provides power for solution circulation flow, so that the solution circulation pipe 6 226 After passing through the irradiated section, the RaCl2 solution 41 flows through the photon detection system I 14, the reduced pressure radon evaporator 11, the heat exchange system 10, the valve 7, the photon detection system II 15, and then flows back to the irradiated section. 226 The RaCl2 solution 41 circulates continuously in the main loop pipeline of the solution circulation pipeline 6; 226 When the RaCl2 solution 41 flows through the irradiated section, it is irradiated by the electron beam 1 and produces 225 Ac and 212 Pb; 226 When the RaCl2 solution 41 flows through the reduced-pressure radon evaporator 11, the radon and its daughters generated in the solution are separated and transported to the radon treatment system 12 for absorption treatment.

[0035] The photon detection system I 14 can detect the 226 The photons in the RaCl2 solution 41 are monitored in real time by monitoring 226 RaCl2 solution 41 exists221 Fr, 213 The specific energy photons released by Bi are inferred 225 Ac yield, when 225 When the Ac yield accumulates to a certain level (which can be a preset threshold value, which can be set or changed according to the separation requirements, such as 10mCi), the photon detection system I 14 transmits an electrical signal to the valve 7, which adjusts the direction of the valve 7, so that the heat exchange system 10 is connected to the radium-actinium separation structure 9, so that 226 The RaCl2 solution 41 flows through the first branch pipe of the solution circulation pipe 6 and then returns to the main loop pipe, and circulates continuously, thereby separating the radium and actinium through the radium and actinium separation structure 9. 226 RaCl2 solution 41 produced 225 Ac is separated and collected; when it is detected 226 RaCl2 solution 41 exists 212 Bi, 212 Pb and 208 Ti releases photons of specific energy and prompts 212 When Pb accumulates to a certain level (which can be a preset threshold value, which can be set or changed according to the separation requirements, such as 10mCi), the photon detection system I 14 transmits an electrical signal to the valve 7, which adjusts the direction of the valve 7, so that the heat exchange system 10 is connected to the radium-lead separation structure 13, so that 226 The RaCl2 solution 41 flows through the second branch pipe of the solution circulation pipe 6 and then returns to the main loop pipe, and circulates continuously, thereby separating the RaCl2 solution 41 from the lead radium through the radium-lead separation structure 13. 226 RaCl2 solution 41 produced 212 Pb is separated and collected. 226 The RaCl2 solution 41 will first pass through the photon detection system II 15 and then return to the irradiated section. At this time, the photon detection system II 15 can detect 226 The number of photons of specific energy in the RaCl2 solution 41 can be used to infer the separation efficiency of the nuclides, so as to adjust the separation frequency according to the separation efficiency; at the same time, the 226 The content of impurity nuclides in the RaCl2 solution 41 is such that when the impurity nuclides accumulate to a certain level, the radium-containing solution in the solution circulation pipe 6 is replaced.

[0036] During the production process, the power pump can be adjusted 226 The output flow of Ra solution circulation structure 8 is adjusted 226 The speed of RaCl2 solution 41 flowing in the solution circulation pipe 6 is beneficial to improve 225 Ac collection efficiency and radon and its daughter separation efficiency; at the same time, the collection 225 Ac, collection 212The process of separating Pb and radon and its daughters does not affect the irradiation of the irradiated section of the main loop pipeline at the isotope target chamber 5, and there is no need to interrupt the irradiation production. 225 Ac and production 212 The operation of Pb does not affect the continuous operation of the reduced pressure radon evaporator 11 and the heat exchange system 10.

[0037] Thus, the closed cycle of the present invention 226 Ra solution target system can be closed for processing 226 Decay daughter nuclei of Ra 222 Rn, you can also 226 The RaCl2 solution 41 circulates in the solution circulation pipe 6, the reduced pressure radon evaporator 11, the heat exchange system 10, the radium-actinium separation structure 9, and the radium-lead separation structure 13 in the form of a solution, simplifying the separation and purification in the solid radium target production method. 225 The steps of dissolving the solid radium target in the early stage of Ac and the solid 226 The preliminary preparation process of Ra isotope target, etc.

[0038] In this embodiment, 226 The mass percentage concentration of RaCl2 solution 41 is 0.83%, 226 RaCl2 solution 41 is contained in the closed solution circulation pipe 6, 226 RaCl2 solution 41 can be circulated in the solution circulation pipeline 6; Figure 3 As shown, the solution circulation pipe 6 has an inner diameter of 25 mm, a wall thickness of 10 mm, and is made of S316 stainless steel. Figure 1 As shown, a section of the main loop of the solution circulation pipe 6 is fixed by the isotope target chamber 5 as the irradiated section, which is placed in the conversion target chamber 2 and irradiated by the electron beam 1 emitted by the electron linear accelerator to produce 225 Ac, another medical isotope is also produced in the process 212 The length of the irradiated section of the solution circulation pipe 6 is 138.8 mm. The isotope target chamber 5 is made of S316 stainless steel and has a size of 56 mm × 56 mm × 90 mm. Figure 2 As shown, 226 RaCl2 solution 41 is directed to valve 7 through solution circulation pipe 6, and valve 7 can control 226 The flow direction of the RaCl2 solution 41, during the irradiation process, the reduced pressure radon evaporator 11 and the radon treatment system 12 can 222 When only irradiation is required, adjust valve 7 to connect directly with the irradiated section of the main loop of solution circulation pipeline 6 to complete the cycle; 225 When separating and purifying Ac, adjust the connection guide of valve 7 to 226The RaCl2 solution 41 is directed to the first branch pipe and the radium-actinium separation structure 9; 212 When separating and purifying Pb, adjust the connection guide of valve 7 to 226 The RaCl2 solution 41 is directed to the second branch pipe and the radium-lead separation structure 13; and then the separated RaCl2 solution 41 is directed to the second branch pipe and the radium-lead separation structure 13; 226 The RaCl2 solution 41 is directed to the irradiated section of the main loop of the solution circulation pipeline 6 to complete the 226 Circulation of RaCl2 solution 41.

[0039] The present invention provides a production method 225 Closed cycle of Ac 226 The schematic diagram of the irradiation of the Ra solution target system in an electron linear accelerator with an energy of 35 MeV and a current of 2 mA is shown in the figure. Figure 1 Solution type 226 The irradiated section of the main loop pipeline of the solution circulation pipeline 6 in the Ra target 4 is fixed in the isotope target chamber 5, which is placed in the conversion target chamber 2. The conversion target chamber 2 also contains a tungsten conversion target 3. The isotope target chamber 5 is aligned with the center lines of the conversion target chamber 2, the tungsten conversion target 3 and the electron beam 1. The electron beam 1 emitted by the electron linear accelerator passes through the conversion target chamber 2 and hits the tungsten conversion target 3. The tungsten conversion target 3 is used to convert the electrons emitted by the electron linear accelerator into photons and pass through the isotope target chamber 5 to hit the solution type accelerator. 226 The irradiated section of Ra target 4 is irradiated, thereby 226 The RaCl2 solution 41 is irradiated. The energy of the electron beam 1 is 35 MeV, the current intensity is 2 mA, the beam spot spatial distribution of the electron beam 1 is Gaussian, and the beam spot half-height width is 15 mm. The size of the conversion target chamber 2 is 70 mm × 70 mm × 138.8 mm, and the material is Al (aluminum). The size of the tungsten conversion target 3 is 56 mm × 56 mm × 2 mm, and the material is tungsten. There are three tungsten conversion targets 3, and the spacing between adjacent tungsten conversion targets 3 is 1.5 mm. The distance between the isotope target chamber 5 and the nearest tungsten conversion target 3 is 10 mm. 225 Closed cycle of Ac 226 The Ra solution target system was irradiated with an electron beam with an energy of 35 MeV and a current of 2 mA for 10 days using an electron linear accelerator. 226 RaCl2 solution 41 contains 225 Ac, 212 Pb and 225 Ra changes with cooling time as shown in Figure 4 As shown, according to the stage extraction method known in the art, the solution type 226 After the Ra target 4 is irradiated by the electron beam 1 for 10 days, the electron beam is irradiated once every 15 days. 225Ac separation and extraction, if the efficiency of each extraction is 100% theoretical value, the extraction efficiency of three consecutive extractions is 100%. 225 The total activity of Ac is related to the 225 The total activity of Ra is equivalent. Figure 4 As shown, after 10 days of irradiation with electron beam 1, cooling begins. 226 RaCl2 solution 41 contains 225 The total activity of Ra is 0.411 Ci. If the effective irradiation time of the electron linear accelerator is 300 days per year, 12.33 Ci of Ra can be produced per year. 225 Ac. At the end of irradiation 212 The total activity of Pb is 212 The maximum total extractable activity of Pb is Figure 4 As shown, after 10 days of irradiation with electron beam 1, cooling begins. 226 RaCl2 solution 41 contains 212 The total activity of Pb is 0.503 Ci. If the effective irradiation time of the electron linear accelerator is 300 days per year, 15.09 Ci of Pb can be produced each year. 212 Pb.

[0040] The invention is designed to be suitable for producing by photonuclear reaction 225 Closed cycle of Ac 226 Ra solution target system can effectively reduce the preparation of radium target photonuclear reaction 225 Ac separation and purification steps to improve 225 Ac preparation efficiency, and can also separate another medical isotope produced during the preparation process 212 Pb, and can be used in the preparation process 226 Radon (Ra decay daughter nuclei 222 The radon) gas is effectively treated to prevent the decay of radon and its toxic daughter polonium from leaking into the environment.

Claims

1. A production 225 Closed cycle of Ac 226 Ra solution target system, characterized in that Including solution type 226 Ra target, isotope target chamber, valve, 226 Ra solution circulation structure, radium-actinium separation structure, radium-lead separation structure, photon detection system I, photon detection system II, heat exchange system, vacuum radon evaporator and radon treatment system, among which, solution type 226 The Ra target comprises a solution circulation pipe and a radium-containing solution, wherein the radium-containing solution is contained in the closed solution circulation pipe; The solution circulation pipeline includes a main loop pipeline, a first branch pipeline and a second branch pipeline. A section of the main loop pipeline passes through the isotope target chamber and is fixed by the isotope target chamber. A section of the main loop pipeline located in the isotope target chamber serves as an irradiated section for cooperating with the electron beam to irradiate and produce 225 Ac; the first branch pipe and the second branch pipe are located outside the isotope target chamber, and both ends of the first branch pipe and the second branch pipe can be connected to the main loop pipe; The photon detection system I, 226 The Ra solution circulation structure, the reduced pressure radon evaporator, the heat exchange system, the valve and the photon detection system II are sequentially arranged on the main loop pipeline of the solution circulation pipeline, and the valve is arranged at the first connection point between the main loop pipeline and the two branch pipelines, and the photon detection system II is arranged behind the second connection point between the main loop pipeline and the two branch pipelines; the valve is electrically connected to the photon detection system I; the photon detection system I is used to detect the target nuclides generated after irradiation 225 Ac, 212 Pb and the impurity nuclides generated during the reaction emit photons of specific energy, which are converted into electrical signals and transmitted to the valve; the valve is a four-way solenoid valve used to adjust the connection direction; the heat exchange system is used to cool the radium-containing solution in the solution circulation pipeline; 226 The Ra solution circulation structure is a power pump, which is used to provide driving force for the circulation of the radium-containing solution and control the flow rate of the radium-containing solution in the solution circulation pipeline; the radon treatment system is connected to the vacuum radon evaporator, which is used to evaporate the radon and its daughters generated in the radium-containing solution after irradiation into the radon treatment system; The radium-actinium separation structure is arranged on the first branch pipe of the solution circulation pipe, and is used to separate and collect the radium-containing solution generated after being irradiated. 225 The radium-lead separation structure is provided on the second branch pipe of the solution circulation pipe, and is used to separate and collect the radium-containing solution generated after being irradiated. 212 Pb; Photon detection system II is used to detect target nuclides after radium-actinium separation or radium-lead separation 225 Ac, 212 Photons of specific energy emitted by Pb and impurity nuclides.

2. The production according to claim 1 225 Closed cycle of Ac 226 Ra solution target system, characterized in that The radon treatment system comprises a sealed container in which activated carbon is placed for absorbing radon and its daughters generated after the radium-containing solution is irradiated.

3. The production according to claim 1 225 Closed cycle of Ac 226 Ra solution target system, characterized in that The heat exchange system is a plate heat exchanger.

4. The production according to claim 1 225 Closed cycle of Ac 226 Ra solution target system, characterized in that The radium-containing solution is 226 RaCl2 solution.

5. The production according to claim 1 225 Closed cycle of Ac 226 Ra solution target system, characterized in that The photon detection system I and the photon detection system II are both photon detectors.

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