Packaged 100Mo target sheet and < 99 > Mo isotope preparation structure

Abstract

The invention discloses a packaged 100Mo target sheet and a 99Mo isotope preparation structure, the packaged 100Mo target sheet comprises a base and an upper cover which are made of a corrosion-resistant material with high electron transmittance, the base is provided with a groove with the groove depth of 0.3-2mm and the groove diameter of 10-35mm, the upper cover is embedded in the groove and seals the groove, and the upper cover is embedded in the groove and seals the 99Mo isotope. And 100Mo powder is filled in the closed space of the groove. The packaged 100Mo target sheet can be matched with a minimum beam spot size required by a 150kW high-power electron beam and has relatively high isotope production capacity, and while the isotope yield is increased, corrosion of cooling water in a strong ionizing radiation environment can be tolerated in a sufficient irradiation period in a < 99 > Mo isotope preparation process; the packaged 100Mo target sheet enables 100Mo to form a compact whole with good thermal conductivity, so that heat generated by 100Mo can be effectively transmitted out through the shell during 99Mo isotope production and is taken away by cooling water; according to the < 99 > Mo isotope preparation structure, the isotope yield is increased and the corrosion resistance is enhanced by adopting a packaged < 100 > Mo target sheet.

Description

Technical Field

[0001] The present invention relates to 99 Mo isotope technology field, specifically relates to a packaged 100 Mo target and 99 Mo isotope preparation structure. Background Art

[0002] Currently, about 40 million people receive 99m Nuclear medicine examination with Tc-labeled diagnostic reagents, 99m Tc mainly comes from the molybdenum-technetium generator ( 99 Mo- 99m Tcgenerator). 99 Mo mainly comes from the separation and purification of fission products in fission reactors. 99 Mo production reactors have reached the end of their operating lifespans, and new reactors have a long construction period, face the risk of nuclear leakage, and require huge investment. 99 Mo international production capacity is insufficient. Proton cyclotron accelerator is used for production 99m Tc, produced by electron accelerator 99 Mo is a technology that is currently under great development.

[0003] The high-power electron beam at the end of the electron accelerator bombards the bremsstrahlung target to produce a large amount of high-energy X-rays. 100 Mo(γ,n) 99 Mo nuclear reaction produces the required 99 Mo isotope. How to optimize the design of the electron accelerator terminal target system and improve 99 The yield of Mo isotopes is the key to achieving electron accelerator production 99 The main way to make Mo nuclide economical.

[0004] Some designs known internationally use electron accelerators with an average power of 5-100kW and an electron energy of 20-45MeV to produce 99 Mo isotope, the target design uses an independent bremsstrahlung target (tantalum, tungsten, etc.) to convert the electron beam into high-energy X-rays, and then 4 to 30 pieces are placed downstream of the bremsstrahlung target. 100 Mo film, thereby undergoing a photonuclear reaction to convert it into the required 99 In this design, water is used as the target cooling medium to reduce the damage of water to the target in a strong ionizing radiation environment. 100 The corrosion of Mo target, in the area with the strongest ionizing radiation, use independent tantalum, tungsten and other materials of bremsstrahlung target to convert the radiation into X-rays, and place it after the ionizing radiation has been significantly attenuated at a certain distance downstream of the bremsstrahlung target. 100 Mo isotope production target, on the one hand100 Mo isotope production targets will still suffer from corrosion to a certain extent and the corrosion products will enter the cooling water, increasing the difficulty of environmental protection and radiation protection. 100 The Mo conversion target is far away from the bremsstrahlung target, i.e. the high energy X-ray source. 99 Mo yield is low.

[0005] An existing design method is that a 125kW 40MeV electron beam passes through a thin Inconel-718 vacuum window and then enters a total of 82 0.5mm thick 100 Mo film, 100 Mo acts as both a bremsstrahlung conversion target and an isotope production target, with approximately 70% of the power deposited in 100 In Mo wafers, in order to avoid the corrosion of cooling water on the target under strong ionizing radiation environment, high-pressure helium is used to cool the target. In this design, the vacuum window has a high risk of damage due to high temperature, and the high-pressure helium circulation system is expensive. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high-efficiency 99 Mo isotope and has strong tolerance packaging 100 Mo target and 99 Mo isotope preparation structure.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: a packaged 100 The Mo target sheet comprises a base and an upper cover made of a corrosion-resistant material with high electron transmittance, wherein the base is provided with a groove with a depth of 0.3-2 mm and a diameter of 10-35 mm, the upper cover is embedded in the groove and seals the groove, and the sealed space of the groove is filled with 100 Mo powder.

[0008] Furthermore, the base and the upper cover correspond to the 100 The thickness of the end surface where Mo powder contacts is between 0.03-0.2 mm.

[0009] A sort of 99 The Mo isotope preparation structure comprises an electron accelerator, and also comprises a vacuum window made of a corrosion-resistant material with excellent high-temperature mechanical properties, which is sequentially arranged at the emission end of the electron accelerator, and a vacuum window having 4 to 60 pieces of the package placed thereon. 100 The target frame of the Mo target is adjacent to the package 100 There are cooling water channels between Mo targets.

[0010] Furthermore, the cooling water channel gap is between 0.1-0.5 mm, and the cooling water inlet pressure in the cooling water channel is not less than 0.8 MPa.

[0011] Furthermore, the vacuum window is located at the electron accelerator and the package 100 The portion between the Mo target sheets is convex toward the cooling water side, and the central thickness of the vacuum window is between 0.3-1 mm.

[0012] Furthermore, during irradiation, the electron beam emitted by the electron accelerator is approximately uniformly distributed laterally, and when entering the vacuum window, the full width at half maximum of the electron beam is between 10 and 28 mm.

[0013] Furthermore, the average power of the single-sided electron beam emitted by the electron accelerator is between 50-150 kW, and the average power of the double-sided electron beam is between 100-300 kW.

[0014] Furthermore, the cooling water in the cooling water channel is circulated by an internal circulation cooling water system, and the internal circulation cooling water system is equipped with a deionizing resin, and a gamma spectrometer is used at the deionizing resin to monitor the corrosion degree of the target system.

[0015] Furthermore, the target rack can be remotely and automatically loaded and taken out through a hydraulic device, and the packaged 100 The Mo target piece is decomposed independently.

[0016] The beneficial effects of the present invention are embodied in:

[0017] 1. Encapsulated 100 Mo target, can match the minimum beam spot size required by 150kW high-power electron beam and has a higher isotope production. By controlling the thickness of the base and the upper cover end surface, while increasing the isotope yield, it also ensures that the base is packaged 100 The Mo target piece is not damaged during the pressing process. 99 The Mo isotope preparation process can withstand the corrosion of cooling water in a strong ionizing radiation environment during the irradiation period;

[0018] At the same time packaged 100 Mo target makes 100 Mo forms a dense and good thermal conductivity whole, making 99 Mo isotope production 100 The heat generated by Mo can be transferred very effectively through the shell and carried away by cooling water;

[0019] 2. 99 In the Mo isotope preparation structure, by using encapsulated 100 Mo targets increase isotope yield and enhance corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the base structure of the present invention;

[0021] Figure 2 The base filling of the present invention 100 Schematic diagram of Mo powder structure;

[0022] Figure 3 The base of the present invention and 100 Schematic diagram of the structure of Mo powder after pressing;

[0023] Figure 4 The base of the present invention and 100 Schematic diagram of the structure of Mo powder after sintering;

[0024] Figure 5 The present invention encapsulates 100 Mo target structure cross-sectional view;

[0025] Figure 6 The present invention 99 Schematic diagram of the Mo isotope preparation structure.

[0026] The components in the attached drawings are marked as follows: 1, base; 101, groove; 2, upper cover; 201,; 3, electron accelerator; 4, vacuum window; 5, target rack; 6, cooling water channel; A, 100 Mo powder. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] See also Figure 1 , Figure 5 .

[0029] The present invention encapsulates 100 The Mo target sheet comprises a base 1 and an upper cover 2 made of a corrosion-resistant material with high electron transmittance, wherein the base 1 is provided with a groove 101 with a groove depth of 0.3-2 mm and a groove diameter of 10-35 mm, the upper cover 2 is embedded in the groove 101 and seals the groove 101, and the sealed space of the groove 101 is filled with 100 Mo powder A. This design controls the diameter of the groove 101 and the depth of the groove to fill the groove.100 Mo target, which matches the minimum beam spot size required by a 150kW high-power electron beam and has a high isotope production capacity;

[0030] In this embodiment, preferably, the groove depth of the groove 101 is 0.7 mm, and the diameter of the groove 101 is 30 mm.

[0031] In this embodiment, preferably, the corrosion-resistant material with high electron transmittance is titanium or Inconel alloy.

[0032] In one embodiment, the base 1 and the upper cover 2 are respectively 100 The thickness of the end surface of Mo powder A is between 0.03-0.2mm. In this design, by controlling the thickness of the end surface of the base 1 and the upper cover 2, the thickness of the end surface of the Mo powder A is increased. 100 The proportion of Mo material in the entire target space is reduced by 100 The distance between the Mo targets increases the isotope yield while ensuring that the base 1 is packaged 100 The Mo target piece is not damaged during the pressing process. 99 The Mo isotope preparation process can withstand the corrosion of cooling water in a strong ionizing radiation environment during the irradiation period;

[0033] And in this embodiment, preferably, the end surface thickness of the base 1 and the upper cover 2 is 0.06 mm.

[0034] See also Figure 6 ,A sort of 99 The Mo isotope preparation structure includes an electron accelerator 3, a vacuum window 4 made of a corrosion-resistant material with excellent high-temperature mechanical properties, and a vacuum window 4 arranged at the emission end of the electron accelerator 3, and a vacuum window 4 having 4 to 60 pieces of the package placed thereon. 100 The target sheet frame 5 of the Mo target sheet and the adjacent package 100 There are cooling water channels 6 between Mo target sheets. 100 Mo target increases isotope yield and enhances corrosion resistance. It should also be noted that the package at both ends 100 Cooling water also flows through the outside of the Mo target, making each package 100 Cooling water flows through both end faces of the Mo target;

[0035] In this embodiment, preferably, the corrosion-resistant material with excellent high-temperature mechanical properties is titanium or Inconel alloy.

[0036] In one embodiment, the gap of the cooling water channel 6 is between 0.1-0.5mm, and the cooling water inlet pressure in the cooling water channel 6 is not less than 0.8MPa. This design ensures that the cooling water has a certain pressure in this area to increase the boiling point of the cooling water, and the cooling water inlet pressure is not less than 0.8MPa, which can increase the flow rate of the cooling water in the cooling water channel 6 and the contact with the package. 100 Heat transfer coefficient of Mo target.

[0037] In one embodiment, the vacuum window 4 is located between the electron accelerator 3 and the package. 100 The portion between the Mo target sheets is convex toward the cooling water side, and the central thickness of the vacuum window 4 is between 0.3-1 mm. This design can increase the cooling water pressure that the vacuum window 4 withstands.

[0038] In one embodiment, during irradiation, the electron beam emitted by the electron accelerator 3 is approximately uniformly distributed in the transverse direction, and the full width at half maximum of the electron beam when entering the vacuum window 4 is between 10 and 28 mm. 99 Typical spot values ​​for typical beam powers in Mo isotope production.

[0039] In one embodiment, the electron accelerator 3 emits an average power of 50-150kW for a single-sided electron beam and 100-300kW for a double-sided electron beam. It should be noted that, if cooling is allowed, the higher the beam power that the target is subjected to, the more conducive it is to the production of isotopes. Double-sided incidence is for the effective use of precious target materials, and 300kW is the typical value of the relative limit that the current accelerator and isotope target can withstand.

[0040] In one embodiment, the cooling water of the cooling water channel 6 is circulated by an internal circulation cooling water system, and the internal circulation cooling water system is equipped with a deionized resin, and a gamma spectrometer is used at the deionized resin to monitor the corrosion degree of the target system. With this design, the target area is cooled by the circulating cooling water system during irradiation, and the circulating water system exchanges heat with the external water cooling secondary circuit through heat exchange, so as to keep the circulating water temperature of the target area constant. At the same time, the ion exchange resin is used to absorb the extremely small amount of radioactive ions and particles that may exist in the cooling water of the target area. A gamma spectrometer is set near the ion exchange resin to monitor whether the target area has corrosion beyond expectations;

[0041] In this embodiment, the internal circulation cooling water system and the gamma spectrometer monitoring target system can be directly obtained through existing technologies, and will not be described in detail here.

[0042] In one embodiment, the target rack 5 can be remotely and automatically loaded and taken out by a hydraulic device, and the packaged 100Mo target pieces are separated independently. With this design, after irradiation, the target holder is automatically removed by hydraulic device and separated into independent packages. 100 Mo target, encapsulated 100 The Mo target is transported to the hot chamber through a special protective container for subsequent processing. First, the redundant base 1 and cover 2 materials outside the circumference of the precisely positioned packaged target are cut off by an automated hydraulic device, and then the remaining central part with a small amount of material is 100 Mo (after irradiation, it contains a certain 99 Mo) target material, using nitric acid solution to dissolve and remove the surface base 1 and upper cover 2 materials, retaining the solid high-purity molybdenum and washing it with pure water for subsequent treatment, and then dissolving the molybdenum and making it into a molybdenum-technetium generator according to the known molybdenum-technetium generator manufacturing procedure, and the hospital can use the molybdenum-technetium generator for subsequent clinical applications;

[0043] In this embodiment, the hydraulic device automatically loads and removes the target rack 5 and packages the 100 The independent decomposition of the Mo target pieces is achieved through existing technologies, which will not be elaborated here.

[0044] It should also be noted that see Figure 1-Figure 5 , the package of the present invention 100 The method for preparing a Mo target sheet comprises the following steps:

[0045] S1. A thin-walled base 1 having a groove 101 is made of a corrosion-resistant material with high electron transmittance;

[0046] S2. Filling into the groove 101 100 Mo powder A, and 100 Mo powder A fills the groove 101; and in this step, the powder 100 The particle size of Mo powder A should be less than 10 microns. 100 The mass of Mo powder A filled should be enough to fill the volume of groove 101 100 Mo powder A and 100 Mo powder A reaches a mass of 95% of the theoretical density;

[0047] S3. Using the base 1 as a mold 100 Mo powder A is pressed, and after the pressing is completed, it is sintered together with the base 1 in a vacuum furnace; and in this step, the pressing pressure is between 100-200 MPa, the holding time is 10-30 minutes, and the sintering temperature is 1300-1500 degrees Celsius;

[0048] S4. After sintering is completed, a thin-walled cover 2 made of a corrosion-resistant material with high electron transmittance is assembled, and after assembly, a hydraulic tool is used to press the surface so that the surface remains intact and smooth; and in this step, the pressing pressure is between 100-200MPa;

[0049] S5. After the pressing is completed, the base 1-upper cover 2 assembly is welded in an electron beam welding machine to discharge the internal gas; and in this step, the parts are first preheated to above 300 degrees Celsius and continued for more than 10 minutes during the welding process, so that the internal gas can be discharged to prevent the gas inside the target piece from expanding during the isotope production process and causing damage to the packaged target piece.

[0050] It should be understood that the examples and implementation modes described herein are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art may make various modifications or changes based on the examples and implementation modes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0051] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0052] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A package 100 Mo target sheet, characterized in that: The invention comprises a base (1) and an upper cover (2) made of a corrosion-resistant material with high electron transmittance, wherein the base (1) is provided with a groove (101) with a groove depth of 0.3-2 mm and a groove diameter of 10-35 mm, the upper cover (2) is embedded in the groove (101) and seals the groove (101), and the sealed space of the groove (101) is filled with 100 Mo powder (A).

2. The package according to claim 1 100 Mo target sheet, characterized in that: The base (1) and the upper cover (2) are respectively 100 The thickness of the end surface of Mo powder (A) in contact is between 0.03-0.2 mm.

3. A 99 The Mo isotope preparation structure comprises an electron accelerator (3), characterized in that: It also includes a vacuum window (4) made of a corrosion-resistant material with excellent high-temperature mechanical properties, which is sequentially arranged at the emission end of the electron accelerator (3), and a vacuum window (4) containing 4 to 60 pieces of the package according to any one of claims 1 to 2. 100 The target sheet frame (5) of the Mo target sheet is adjacent to the package 100 A cooling water channel (6) is provided between the Mo target pieces.

4. According to claim 3 99 Mo isotope preparation structure, characterized in that, The gap of the cooling water channel (6) is between 0.1 and 0.5 mm, and the cooling water inlet pressure in the cooling water channel (6) is not less than 0.8 MPa.

5. According to claim 3 99 Mo isotope preparation structure, characterized in that, The vacuum window (4) is located at the electron accelerator (3) and the package 100 The portion between the Mo target sheets is convex toward the cooling water side, and the central thickness of the vacuum window (4) is between 0.3 and 1 mm.

6. According to claim 3 99 Mo isotope preparation structure, characterized in that, During irradiation, the electron beam emitted by the electron accelerator (3) is approximately uniformly distributed in the transverse direction, and when entering the vacuum window (4), the full width at half maximum of the electron beam is between 10 and 28 mm.

7. According to claim 3 99 Mo isotope preparation structure, characterized in that, The average power of the single-sided electron beam emitted by the electron accelerator (3) is between 50-150 kW, and the average power of the double-sided electron beam is between 100-300 kW.

8. According to claim 3 99 Mo isotope preparation structure, characterized in that, The cooling water in the cooling water channel (6) is circulated by an internal circulation cooling water system, and the internal circulation cooling water system is equipped with a deionizing resin, and a gamma spectrometer is used at the deionizing resin to monitor the corrosion degree of the target system.

9. According to claim 3 99 Mo isotope preparation structure, characterized in that, The target sheet rack (5) can be remotely and automatically loaded and taken out through a hydraulic device, and the packaged 100 The Mo target pieces are decomposed independently.

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