Phosphate targets

Abstract

This invention relates to a phosphate-based glass target material, wherein the material comprises isotope-enriched elements or monoisotope elements.

Description

Technical Field

[0001] This invention relates to phosphate-based glass target materials, particularly those containing isotope-enriched elements or monoisotopic elements. The invention also relates to a method for producing radionuclides, comprising irradiating such phosphate-based glass targets with a high-energy particle beam. This method is particularly suitable for applications where the beam is provided by a cyclotron. The invention further relates to the use of phosphate-based glass targets in the production of radionuclides. Background Technology

[0002] In 2016, the global market valued at US$9.6 billion for nuclear medicine, with over 40 million surgeries performed annually. With the global market for radioisotopes growing at an annual rate of 5%, it is projected to reach US$17 billion by 2021. Medical radioisotopes account for 80% of the global market. They can be used as therapeutic agents or imaging agents in radiotherapy, or as part of biologically relevant molecules such as low molecular weight organic compounds, peptides, proteins, and antibodies.

[0003] Positron emission tomography (PET) technology offers the ability to provide functional and quantitative imaging. PET is a non-invasive medical imaging technique that can generate high-resolution images, such as those used in diagnostic applications in oncology, neurology, and cardiology. Single-photon emission computed tomography (SPECT) is another important imaging technique, primarily used in... 99m Tc is used in the field of nuclear cardiology. This radionuclide (made by...) 99 The relatively easy production of (Mo-based) nuclear medicine, coupled with its relatively low cost, has led to the adoption of this technology in approximately 80% of nuclear medicine procedures. In other applications, such as whole-body imaging, depth-independent quantitative imaging obtained via PET is preferred.

[0004] Due to the decommissioning of nuclear reactor production plants, it is expected that [resources] will be used in the coming years. 99m Tc generator 99 Mo supply will decrease significantly. In addition... 99m The limited versatility of Tc has spurred significant technological advancements in the PET radiopharmaceutical supply chain, including more efficient cyclotrons to improve the availability of PET isotopes. Consequently, more cost-effective PET radiopharmaceuticals are emerging, leading to an increase in PET facilities globally, particularly those equipped with cyclotrons for the in-house production of radionuclides.

[0005] The cyclotron accelerator portfolios recently launched by major suppliers have the potential to significantly increase the production of existing and new radionuclides, particularly from proton, deuteron, or alpha particle-mediated nuclear reactions. However, to fully utilize the production capacity of these high-power cyclotrons, mechanically and thermally stable targets need to be developed for the nuclear reactions in question. One limitation of current targets is the intensity of the accelerating particle flux that can be applied.

[0006] The most commonly used PET radionuclides are 18 F(t 1 / 2=109.7m), used for the production of [ 18 F]Fluorodeoxyglucose (FDG) is a radiopharmaceutical used in approximately 80% of all PET studies. 18 F is currently produced using an inefficient liquid target material. 18 F's solid target material has increased... 18 The concentration of O (produced through reaction with incident protons) 18 F) will represent the main steps to provide this radionuclide at a lower cost and with greater availability.

[0007] Most currently used metallic radionuclide targets are in the metallic form of the chemical elements under discussion. Furthermore, the target assembly (target material plus support) consists of chemical bonds between the target and its backing material (metallic target) or a dilute solution of a target isotope salt (liquid target).

[0008] The upper limit of particle flux, and the resulting desired yield of radionuclides, fundamentally depends on the physical properties of the target material, such as its heat capacity, heat transfer rate, and melting or boiling point, as well as the cooling properties provided by the target material support. Irradiating the target material with protons, for example, from a high-power cyclotron, will deposit a large amount of energy within the target, necessitating cooling with a liquid such as water, or a cooling gas such as helium, or a combination thereof.

[0009] The limitations of established targeting technologies are being compensated for by using significantly smaller particle beam currents over longer time intervals. This results in unsatisfactory schedules and significant pressure at radionuclide production centers. Therefore, the current problem of low radionuclide production capacity can only be addressed by building and operating more cyclotrons.

[0010] To fully utilize the potential of generating high beam currents from current and upcoming cyclotron operating parameters, improved target technology is needed.

[0011] Previous strategies have employed ceramic target materials, such as those described in WO 2020 / 048980. However, tests involving irradiated ceramic target materials in proton current rise studies have shown that higher energy deposition leads to material weakening. This weakening of the internal structure results in visual deformation of the material. Such deformation is clearly undesirable when exposed to the relatively high energy deposition encountered in production-related proton flows. Therefore, there remains a need to provide alternative target materials that avoid such problems.

[0012] The inventors have surprisingly discovered that phosphate-based glass target materials offer an attractive solution. In particular, phosphate-based glass materials expand upon heating (e.g., during irradiation with a high-energy particle beam), which is the opposite of the behavior of crystalline ceramic materials. Phosphate-based glass target materials remain in situ and effectively trap particle beams from accelerators, and also possess phase-transfer properties that allow exposure to production-related energy deposition from the particle beams. Summary of the Invention

[0013] Therefore, from a first aspect, the present invention provides a phosphate-based glass target material, wherein the material comprises isotope-enriched elements or monoisotope elements.

[0014] In another aspect, the present invention provides a method for preparing phosphate-based glass materials as defined above, the method comprising:

[0015] i. Mixing metal, metalloid, or nonmetal oxides with dilute phosphorous acid (H3PO4) to form phosphate compounds.

[0016] ii. The phosphate compound is melted with phosphorus pentoxide and / or oxides of isotopically enriched elements to produce phosphate-based glass materials.

[0017] In another respect, the present invention provides a method for producing radionuclides, comprising irradiating a phosphate glass target with a high-energy particle beam.

[0018] In one particular aspect, the present invention provides a method for producing a radionuclide as defined above, comprising the following steps:

[0019] Provides a plate with a recessed portion.

[0020] Place the target material in the recessed area;

[0021] The target material is covered with foil, so that the target material is encapsulated by the foil and the surface of the recessed portion.

[0022] The foil is fixed to the plate, so that the target material is fixed relative to the plate;

[0023] The melting point of the foil is higher than the glass transition temperature of the target material; and

[0024] The encapsulated target is irradiated with a high-energy particle beam.

[0025] On the other hand, the present invention provides the use of phosphate-based glass targets in a method for producing radionuclides.

[0026] In another respect, the present invention provides the use of phosphate glass materials as targets in a method for producing radionuclides.

[0027] definition

[0028] The terms "target material" and "target material" are used interchangeably herein, referring to materials that produce radionuclides upon irradiation with a high-energy particle beam. It is understood that by describing the phosphate-based glass materials of this invention as "target materials," it implies that they possess properties that make them suitable for this application.

[0029] The term "glass" defines a large class of materials with highly variable mechanical and optical properties that can solidify from a molten state without crystallizing. They are typically made from silicates fused with boron oxide, aluminum oxide, or phosphorus pentoxide, and are generally hard, brittle, and can be transparent or translucent. They can be considered supercooled liquids rather than true solids. In the context of this invention, the term "glass" should be distinguished from "ceramics." Ceramic materials typically contain a mixture of ionic and covalent bonds between atoms. The resulting material can be crystalline, semi-crystalline, or vitreous. In contrast, glass materials are amorphous.

[0030] "Phosphate glasses" consist of a random three-dimensional network of glass. This network is composed of tetrahedral phosphate anions and varying numbers of bridging oxygen ions (see...). Figure 1 The main component forming the network is phosphorus pentoxide (P₂O₅), which consists of tetrahedral phosphate anions and is therefore crucial to the structure and physicochemical properties of the glass. A given phosphate tetrahedron can both bridge oxygen and phosphorus atoms and form (POP) bonds, i.e., connections with adjacent tetrahedra, thus producing the glass structure.

[0031] Metal ions (M) can form (POM) bonds, thus becoming an integral part of phosphate glasses. The suitability of these structures for the production of radionuclides stems from the ability of phosphate glasses to coordinate with one of a group of target metal ions. Detailed Implementation

[0032] Detailed description of the invention

[0033] This invention relates to a method for producing radionuclides, comprising irradiating a phosphate-based glass target with a high-energy particle beam. The invention also relates to the phosphate-based glass target itself, wherein the target contains isotope-enriched elements or monoisotopic elements.

[0034] Phosphate glass target materials

[0035] Phosphate-based glass targets may include any suitable inorganic material containing phosphorus and oxygen, as well as metallic, metalloid, or nonmetallic elements, or mixtures thereof.

[0036] Phosphate-based glass targets may include all elements in their natural isotopic composition, or they may contain isotopically enriched elements or monoisotopic elements. Those skilled in the art will understand that appropriate isotopes can be selected based on the desired radionuclide product.

[0037] In a particular aspect of this invention, phosphate-based glass target materials themselves are always included in the form of isotope-enriched elements or monoisotope elements.

[0038] The presence of more than one (e.g., two) isotope-enriched elements or monoisotopic elements in the target material is within the scope of this invention, but the presence of only a single isotope-enriched element or monoisotopic element is preferred. In one embodiment, for example, additional isotope-enriched elements or monoisotopic elements may be added. This can lead to changes in the physical properties of the target material, such as an increase in the glass transition temperature. It should also be understood that phosphate-based glass targets may further contain other elements that can affect the physical properties of the target material.

[0039] Isotope-enriched elements or monoisotope elements can be selected from any suitable metallic, metallic, or nonmetallic element.

[0040] In a preferred aspect, the isotope-enriched element or monoisotope is selected from Mo, Ra, Y, Rb, Ca, Ni, Zn, Ga, O, Se, Te, Bi, Th, and Yb, with Mo, Y, and Zn being preferred. Particularly preferred isotope-enriched elements or monoisotopes are Mo and Zn.

[0041] In a particularly preferred embodiment, isotope selection is free. 100 Mo、 226 Ra、 89 Y、 85 Rb、 44 Ca, 64 Ni、 70 Zn, 67 Zn, 68 Zn, 69 Ga、 18 O、 76 Se、 77 Se、124 Te、 209 Bihe 176 The group consisting of Yb is preferred. 100 Mohe 68 Zn.

[0042] The phosphate-based glass target materials of the present invention typically have a glass transition temperature (Tg) in the range of 200 to 2000°C. In particular, when the target glass material contains Zn, the glass transition temperature of the material can be in the range of 800°C to 1000°C.

[0043] The density of phosphate-based glass target materials can range from 2 to 10 g / cm³. 3 For example, 2.5 to 5 g / cm³ 3 .

[0044] As previously mentioned, phosphate-based glass target materials comprise metallic, metallic-or nonmetallic elements, or mixtures thereof. The object of this invention is to maximize the content of these metallic, metallic-or nonmetallic elements in the material. Preferably, the content of these elements in the material is in the range of 10 to 50 wt% relative to the total weight of the material, more preferably in the range of 25 to 40 wt%. In particular, when the metallic, metallic-or nonmetallic element is zinc, the zinc content in the target material is preferably in the range of 20 to 40 wt% relative to the total weight of the material, for example, 30 to 40 wt%.

[0045] Phosphate-based glass target materials can be prepared by any suitable method known in the art. Phosphorus or phosphate functional groups can be introduced into the material in a variety of forms. Different forms, such as single-bonded or cross-bonded phosphorus groups, ( Figure 1 The target atoms are coordinated into different forms of target materials, ranging from crystalline phosphates to amorphous glassy states. The combination of different phosphorus substances with glass-forming modifiers determines the desired phosphate-based glass material.

[0046] Example methods include reacting a metal with a phosphorus substance to prepare a metal-containing phosphate material.

[0047] In one embodiment, the material is prepared by mixing a suitable metal, metalloid, or non-metal oxide with dilute phosphoric acid (H3PO4) to prepare a hydrated ceramic phosphate intermediate. The water of crystallization is typically removed from the salt by heating the intermediate. The structure of the phosphate ceramic can be further modified by continuous heat treatment to achieve a sintered, fused, or glassy structure through the addition of phosphorus pentoxide and / or glass modifiers.

[0048] Therefore, in one embodiment, the present invention covers a method for preparing phosphate-based glass materials as defined herein, the method comprising:

[0049] i. Mixing metal, metalloid, or nonmetal oxides with dilute phosphorous acid (H3PO4) to form phosphate compounds.

[0050] ii. The phosphate compound is melted with phosphorus pentoxide and / or oxides of isotopically enriched elements to produce phosphate-based glass materials.

[0051] Alternatively, phosphate glass materials can be produced by other methods, such as reacting a target element with a phosphate substance, such as anhydrous phosphoric acid or phosphorus pentoxide, and obtaining a melt by heating the material.

[0052] The methods of the present invention for preparing phosphate-based target materials generally do not include the addition of commonly used glass modifiers such as oxides of sodium, calcium, and magnesium. In other preparation methods, these elements are added to adjust the stability of the phosphate glass. However, in the context of the present invention, they may lead to the formation of unwanted radioactive or stable byproducts during irradiation.

[0053] The physicochemical properties of phosphate-based glass materials can be altered by changing characteristics such as density, heat transfer capacity, melting point or glass transition temperature, and solubility. This is achieved through the application of different stoichiometry of phosphate units, target elements, and / or the addition of non-target elements, as well as heat treatment. Once glass-forming components are added, such as enriched metal oxides, phosphate-based materials acquire glassy properties.

[0054] The phosphate-based glass materials described in this article are generally soluble in acid- and base-based solvents, which is a key step in the preparation of subsequent chromatographic methods for separating radionuclide products.

[0055] In embodiments requiring isotope enrichment of target materials, this is typically achieved by using appropriately enriched metal, metalloid, or nonmetal oxide reagents, although isotope-enriched phosphate (e.g., isotope-rich phosphate) can also be used. 18 O).

[0056] Target materials can be fabricated in various shapes. Typically, the target surface area should be greater than the extension of the particle beam intercept to maximize the utilization of the incident particles. Therefore, it is understood that the suitable shape and size of the target material will vary accordingly, being a function of beam propagation and the dimensions and construction of the target support in question. In one aspect, the target material is fabricated as a disk for use in the method of the present invention. In a preferred embodiment, the target is in the form of a disk with a diameter of 17 mm.

[0057] Preferably, the thickness of the disk is within a range to provide "thick target yield." "Thick target yield" refers to the thickness of the target that yields the maximum output of the nuclear reaction in question, given a given particle charge and its energy. It should be understood that this thickness will vary with different nuclear reactions, beam energies, and target densities.

[0058] The inventors have surprisingly discovered that phosphate-based glass target materials can withstand phase transfer caused by high-energy deposition. Naturally, the more heat the target material can withstand, the greater the usable beam intensity, thus achieving higher yields.

[0059] method

[0060] The method of this invention can be any suitable method known in the art for producing radionuclides, including irradiating a phosphate glass target with a high-energy particle beam. Those skilled in the art will be familiar with such methods and the instruments used therein.

[0061] Phosphate-based glass targets can be any of the targets described herein.

[0062] A "high-energy particle" beam refers to a beam of accelerated particles whose energy is typically sufficient to induce nuclear reactions with proton energies higher than 1 MeV. Therefore, beams are usually provided by particle accelerators, especially cyclotrons.

[0063] A high-energy particle beam can be any suitable beam known in the art and can include nuclear beams, such as protons, deuterons, alpha particles, etc. 3 He, carbon, or lithium. Typically, the beam is a proton beam, a deuterium beam, or an alpha particle beam.

[0064] When the beam is a proton beam, the energy levels of the proton beam are typically in the range of 1 MeV to 100 MeV, preferably in the range of 5 MeV to 70 MeV. The proton beam intensity (also referred to as "beam current") is preferably in the range of 10 to 5000 μA, more preferably 50 to 500 μA.

[0065] When the beam is a deuterium beam, the energy level of the deuterium beam is typically in the range of 1 MeV to 50 MeV, preferably 1 MeV to 35 MeV. The deuterium beam intensity (also referred to as "beam current") is preferably in the range of 10 to 1000 μA, more preferably 50 to 300 μA.

[0066] When the beam is an alpha particle beam, the energy level of the alpha beam is typically in the range of 1 MeV to 100 MeV, preferably in the range of 5 MeV to 70 MeV. The alpha beam intensity (also referred to as "beam current") is preferably in the range of 10 to 1000 μA, more preferably 50 to 300 μA.

[0067] The radionuclides produced by the method of the present invention can have activity in the range of 0.0001 to 10 TBq.

[0068] After irradiating a phosphate glass target and dissolving the target material in a suitable solvent, the radionuclide products are typically separated from the remaining target material and / or other byproducts by selective precipitation, electrolysis, chromatography, and preferably liquid chromatography.

[0069] The irradiation time depends on the reaction cross-section and the physical half-life of the product radionuclides, and is usually less than three times the half-life of the corresponding product radioisotopes.

[0070] In one particular aspect, the present invention provides a method as defined above, comprising:

[0071] Provide board,

[0072] Place the target material on the plate;

[0073] The target is fixed to the plate, so that the target is fixed relative to the plate;

[0074] And irradiating a plate with a target material using a high-energy particle beam.

[0075] In another particular aspect, the present invention provides a method as defined above, comprising:

[0076] Provides a plate with a recessed portion.

[0077] Place the target material in the recessed area;

[0078] The target material is covered with foil, so that the target material is encapsulated by the foil and the surface of the recessed portion.

[0079] The foil is fixed to the plate, so that the target material is fixed relative to the plate;

[0080] The melting temperature of the foil is higher than the glass transition temperature of the target material; and

[0081] The encapsulated target is irradiated with a high-energy particle beam.

[0082] The foil has a melting temperature higher than the glass transition temperature of the target material. The foil can have an average thickness from 5 μm to 5000 μm. The foil is typically a metallic foil. When present, the metal in the foil can be inert to the molten target material and has a suitably high melting point, such as a non-ferrous metal, niobium, tantalum, platinum, molybdenum, tungsten, vanadium, silver, gold, or an alloy.

[0083] The target material sheet can be a generally planar sheet of target material with dimensions adapted to the recessed portion. Preferably, the thickness of the generally planar sheet of target material is between 0.1 mm and 30 mm, and the maximum size of the generally planar sheet of target material is between 0.2 cm and 10 cm.

[0084] The plate may contain aluminum, non-ferrous metal, niobium, tantalum, platinum, molybdenum, tungsten, vanadium, silver, gold, or alloys.

[0085] The encapsulated target can be held in place relative to the plate by a cover having a hole. The size of the hole can be larger than the beam diameter of the high-energy particle beam used to irradiate the encapsulated target.

[0086] The plate can be cooled for part or all of the irradiation process. Cooling can be achieved by any suitable means, such as by using a constant flow rate of water, gas, CO2, or liquid nitrogen, or any cooling medium. Cooling of the target is preferably performed from both sides of the target. In current designs of target stations from commercial suppliers, the back of the target can be cooled with water, and the front can be cooled with helium. Alternative methods include using water on both sides of the target, or even immersing the target in one of the aforementioned liquids.

[0087] The following will refer to Figures 3 to 9 The preferred implementation scheme is described in more detail.

[0088] Figure 3 A lid 10 with a hole 12 is shown. The hole is preferably located at the center of the lid 10. The lid 10 may be made of metal. Preferably, the metal has a high melting point and high thermal conductivity, such as tantalum, aluminum, gold, or copper. Aluminum is described in more detail below due to its low cost, suitable mechanical properties, and short-lived activation products produced by accelerated particle irradiation.

[0089] Figure 3 The lid 10 can be approximated as a square (i.e. Figure 3 The length 24 (22) is equal to the length 22, and it has a mounting hole 16 at each corner. These mounting holes 16 are used to receive fasteners 15, such as screws or pins, to secure the cover 10 to the wall. Figure 4 On the plate 30 shown.

[0090] like Figure 4 As shown, plate 30 may be approximately square and has mounting holes 36 at each corner for attaching cover 10 to plate 30. When cover 10 is placed on top of plate 30, mounting holes 15 of cover 10 should align with mounting holes 36 on plate 30. The plate is preferably made of aluminum.

[0091] like Figure 6As shown, the plate 30 may have a recessed portion 32 at its center, such that when the cover 10 is attached to the plate 30, the center of the recessed portion 32 is coaxial with the center of the hole 12 of the cover 10. In one embodiment, the recessed portion 32 is circular and the hole 12 is circular. In this embodiment, the diameter 38 of the recessed portion 32 may be larger than the diameter 18 of the hole 12. Alternatively, the diameter 38 of the recessed portion 32 may be equal to or smaller than the diameter 18 of the hole 12. The recessed portion 32 does not extend through the entire thickness of the plate 30. That is, the recessed portion 32 may take the form of a blind hole in the plate 30.

[0092] Alternatively, plate 30 and / or recessed portion 32 can be made of other materials. Many materials are considered suitable. Furthermore, plate 30 and / or recessed portion 32 can be formed of a metal that is inert in the presence of the target material and the generated radioactive nuclide (at least at the melting temperature of the target material). The recessed portion can be the surface of aluminum oxide.

[0093] A sealing ring 14, such as an O-ring, may be provided within the cover 10. A sealing ring 34, such as an O-ring, may be provided within the plate 30. Preferably, the two sealing rings 14 and 34 are of the same size and are positioned coaxially when the cover is placed on top of and secured to the plate. The sealing rings 14 and 34 assist in gripping and sealing when the cover 10 is fastened to the plate 30. The sealing rings 14 and 34 may be made of rubber. Alternatively, the sealing rings 14 and 34 may be made of any other material that is inert, heat-resistant (to the extent of the target material temperature), and capable of being sufficiently compressed / sealed to prevent gas leakage when the cover 10 is fastened to the plate 30.

[0094] The target 50 can be placed in the recessed portion 32. For example... Figure 7 As shown, the target 50 can be in the shape of a coin with a diameter less than or equal to the diameter 38 of the recessed portion 32. Other shapes of the target 50 are also conceivable. Preferably, the shape of the target 50 matches the shape of the recessed portion 32. The target material can be inserted in coin size to fit the recessed portion, or inserted in multiple pieces, or inserted in powder form.

[0095] After the target 50 has been placed in the recessed portion 32 of the plate 30, the foil 52 can be placed on top of the target 50. The foil 52 may have a melting temperature higher than that of the target and is preferably made of a material that will not react with the target 50. Preferably, the foil will not interact with the proton beam, or will only interact with the proton beam to a minimal extent. For example, the foil 52 may be a platinum foil. Other suitable materials may be used for the foil 52, such as foils of niobium, tantalum, platinum, molybdenum, tungsten, vanadium, silver, gold, or alloys thereof. Furthermore, foils of different thicknesses may be used. The foil reduces the energy of the incident particle beam. Therefore, one criterion for controlling the selection of the foil material and thickness is based on the energy of the particle beam. Preferably, the foil material will have a combination of low stopping power and chemical inertness and physical stability in the presence of the heated target material.

[0096] The foil 52 can be sized such that it can cover the sealing rings 14, 34 of the plate 30 and contact the sealing rings at each point. That is, the foil 52 can be larger than the sealing ring boundaries. For example, Figure 7 The foil shown is square, with a side length greater than [missing information]. Figure 3-6 The sealing rings 14 and 34 shown have a diameter of 20. Preferably, the sealing rings are sufficiently compressible such that when the cover 10 is fastened to the plate 30, the foil 52 is in contact with and held by both the cover 10 and the plate 30.

[0097] Alternatively, the foil 52 may be integrally formed with the cover 10. In this embodiment, the hole 12 is formed by a thin portion of the cover, which is made of the same material as the cover 10 or by a separate material attached to the cover. This thin portion of the cover 10 is thin to limit energy loss of irradiation through the hole, so that the irradiation can interact with the target nuclide held in a recessed portion located below the thin portion of the hole 12 of the cover 10.

[0098] During assembly, target material 50 can be placed in recessed portion 32. Then, foil 52 can be placed on top of target material 50. Next, cap 10 can be placed on top of plate 30 and foil 52, such that sealing ring 14 of cap 10 presses foil 52 into sealing ring 34 of plate 30. Cap 10 can then be secured to plate 30.

[0099] The pressure from the cover 10 to the foil 52 and from the foil 52 to the target material 50 can hold the target material 50 in place within the recess 32 of the plate 30. The entire assembly can then be spatially oriented, and the target 50 will be held in place within the recess. That is, the target is encapsulated within the area defined by the foil and the recess. If the target 50 extends beyond the depth of the recess 32, then a portion of the plate between the recess 32 and the sealing ring 34 can also form part of the encapsulation area. For example, the plate 30 can be vertically oriented such that the normal starting from the bottom of the recess 32 points horizontally. Alternatively, the plate 30 can be laid flat such that the normal starting from the bottom of the recess 32 points vertically upwards or downwards. That is, the target can be used in any spatial orientation, which can increase the number of suitable cyclotrons that can be used with the target.

[0100] The aforementioned device can serve as the target output end of a cyclotron or other particle accelerator. In the following disclosure, this invention will refer to cyclotrons, but it should be understood that the invention is not limited thereto, and other particle accelerators can be suitably used.

[0101] Foil 52 can have a much higher melting temperature than the target material. Foil 52 can also prevent the release of radionuclides into the atmosphere. This is likely a useful safety feature inherent to this design.

[0102] After proton irradiation, the device can be removed from the cyclotron. Preferably, the foil 52 is selected to be inert relative to the target material. Furthermore, it is preferable that the foil is physically stable under the expected heating of the target material during irradiation. For example, the melting temperature of the foil may be higher than, preferably much higher than, the melting temperature of the target material. In this case, if it melts and resolidifies, the irradiated material can be easily separated from both the recessed portion 32 and the foil 52.

[0103] As a non-limiting example, plate 30 and cover 10 may each be 40x40mm, and the diameter 18 of the hole 12 in cover 10 may be 10-20mm, preferably 17mm. The recessed portion may have a diameter 38 of 20-22mm and a depth of 1.3mm. Target material 50 may be a cylinder with a diameter of 17mm and a thickness of 1.68mm. Foil 52 may be 25x25mm and have a thickness of 0.01mm. Thus, when the target material sheet 50 is placed in the recessed portion 32, it extends 0.38mm above the edge of the recess, and the thickness of foil 52 is additionally increased by 0.01mm. When cover 10 is secured to plate 30, the target material 50 is firmly held in the recessed portion 32 by pressure from cover 10, and cover 10 holds foil 52 on plate 30.

[0104] The invention will now be described with reference to the following non-limiting embodiments and accompanying drawings.

[0105] Figure 1 : Structural unit of phosphate glass materials.

[0106] Figure 2 The platinum crucible containing the phosphate and isotope-enriched melt is located in the outer area of ​​the furnace. A steel mold is placed outside. A flat metal scraper is also shown, used to level the liquid material after it has been poured into the mold.

[0107] Figure 3 : A plan view of a lid having a hole in one embodiment of the present invention.

[0108] Figure 4 : A plan view of a plate having a recessed portion in one embodiment of the present invention.

[0109] Figure 5 : Figure 3 Side view of the lid.

[0110] Figure 6 : Figure 4 Side view of the board.

[0111] Figure 7 Target sheet and foil sheet.

[0112] Figure 8 A side view and an enlarged side view of an apparatus formed from a lid, a plate, a target nuclide, and a foil, according to one embodiment of the present invention.

[0113] Figure 9 An exploded view of an apparatus formed from a lid, a sealing ring, a plate, a foil, and a target nuclide in one embodiment of the present invention.

[0114] Figure 10 The ceramic zinc target (middle) is shown between the bottom (left) and top (right) of the target holder.

[0115] Figure 11 The upper part of the figure shows the energy reduction of protons inside material #2 as a function of depth and linear energy transfer during the traversal process. The lower part shows the reaction cross-section (reaction probability) of the reaction of interest as a function of energy with increasing target depth. The yield reaches its maximum and flattens out at the optimal target thickness.

[0116] Figure 12 :like Figure 11 However, the proton energy is higher (13 MeV).

[0117] Example

[0118] Preparation of Glass Material with Zinc #1: Add 2.0 g Zn3(PO4)2, 1.47 g P2O5, and 0.85 g ZnO to a 10 ml platinum crucible. Homogenize the mixture before placing it in a preheated furnace at 330°C. Increase the temperature to 350°C within 10 minutes. Then, set the temperature to reach 1100°C within 20 minutes. After maintaining the temperature at 1100°C for 30 minutes, manipulate the crucible with tongs and remove it from the furnace. Quickly pour the melt into a mold, and simultaneously flatten the material into a disc with a scraper. Anneal the resulting molded glass disc by heating it in a furnace at 515°C for 15 minutes to eliminate the built-in tension caused by cold quenching. Finally, place the resulting disc in a support and refine it to the desired thickness, e.g., 400 μm.

[0119] In order to manufacture isotope enrichment target disks with Zn3(PO4) as part of the formulation, [ 68 Zn]Zn3(PO4)2 is prepared by the following reaction: before drying the precipitate, [ 68 ZnO reacts with dilute phosphoric acid, and the material is then granulated to produce powder in a mortar. Furthermore, the zinc oxide component in glass manufacturing is […]. 68 Zn]ZnO substitution.

[0120] Different compositions of zinc phosphate glass with and without Zn3(PO4)2, and with variable molar ratios of P2O5 and ZnO, were investigated (Table 1).

[0121] Table 1: Composition of the selected phosphate glass materials, showing the weight percentage of zinc and the density of the materials.

[0122]

[0123] Heating tests were conducted using discs made of different materials (from Table 1) in a slowly heated furnace. Within the transition temperature range of 600-700°C, the materials underwent a metamorphic process leading to crystallization. When the temperature was raised to 800-1100°C, the materials reformed into glass. After cold quenching, the discs could be molded.

[0124] To provide target material for gallium production using the GE MINITrace cyclotron (which accelerates protons to 9.6 MeV), we molded a 12 mm diameter disk suitable for the target holder.

[0125] The required target disk thickness is selected based on the following factors: i) capture from E 质子 9.6 MeV to the nuclear reaction threshold (E 质子A partial energy gap of <4MeV is used to ensure maximum product yield, while ii) avoiding the deposition of energy transfer peaks per unit length of protons (in the target material) (referred to as avoiding the capture of the "Bragg peak"); see Figure 11 (The red line in the image). The thickness of the target material is calculated based on the zinc content and density of each material being tested. Figure 11 The upper half shows the energy reduction of protons inside material #2 as a function of depth, and the linear energy transfer during the traversal process. The lower half shows the reaction cross section (reaction probability) of the reaction of interest as a function of energy with increasing target depth. Productivity reaches its maximum and flattens out at the optimal target thickness. Here, the molded disk of material #2 is granulated and polished to a thickness of approximately 400 μm using a grinding and sanding machine (optimal thickness shown in the figure below).

[0126] Figure 11 The calculations are for material #2 with 9.6 MeV protons and take into account... 68 Zn(p,n) 68 Cross-sectional nuclear data of the Ga reaction. In preparation for operation with a more powerful cyclotron, such as GE PETtrace, E... 质子,最大 =16.5 MeV. As mentioned above, the same calculations were performed for the same material, and the proton energy has been studied. The proton energy was first adjusted from 16.5 MeV to E. 质子 =13MeV( Figure 12 The study revealed that the optimal thickness is approximately 800 μm, and that the productivity (GBq / μAh) could potentially double compared to the data we have obtained to date.

Claims

1. A phosphate-based glass target material, wherein, The material includes one or more selected from... 100 Mo、 226 Ra、 89 Y、 44 Ca, 64 Ni、 70 Zn, 67 Zn, 68 Zn, 69 Ga、 18 O、 85 Rb、 76 Se、 77 Se、 124 Te、 209 Bihe 176 Isotopes of Yb; The phosphate-based glass target material has a glass transition temperature in the range of 200°C to 2000°C. Furthermore, the isotopes are present in an amount of 10 to 50 wt% relative to the total weight of the material as a whole.

2. The phosphate-based glass target material according to claim 1, wherein, The isotopes are selected from 68 Zn, 89 Y and 100 Mo.

3. The phosphate-based glass target material according to claim 1 or 2, wherein, Phosphate-based glass target materials have a strength of 2 to 10 g / cm³. 3 Density within the range.

4. A method for preparing the phosphate-based glass target material according to any one of claims 1 to 3, the method comprising: i. Mixing an oxide containing an isotope with dilute phosphoric acid (H3PO4) to form a phosphate compound, wherein the dilute phosphoric acid is diluted phosphoric acid; ii. The phosphate compound is melted with phosphorus pentoxide and / or oxides of isotope-enriched elements to produce phosphate-based glass target materials.

Images