Medical radioisotope irradiation target welding and handling apparatus and method

Abstract

The application belongs to the technical field of target welding and sealing, and aims to solve the technical problems of complicated operation, harsh environment requirement, low production efficiency and insufficient safety in the existing target packaging process. A medical radioactive isotope irradiation target welding and sealing device and method are disclosed. The device comprises a box-type closed cavity and a front door thereof. The inner wall of the box-type closed cavity and the front door are provided with a metal shielding layer and a neutron and gamma ray shielding layer. The bottom of the box-type closed cavity is provided with a target placing base for fixing and placing the target. The device has a vacuum system, an inert gas filling system, an automatic control system, a semi-automatic process control system and a pressure recovery and safety release system. The method uses the device to perform medical radioactive isotope irradiation target welding and sealing processing. The application can automatically complete the two key processes of frit sealing of the quartz target bottle and welding of the metal shell in a controlled inert atmosphere and a closed shielding environment, and realizes the automation and integration of the preparation process.

Description

Technical Field

[0001] This application belongs to the field of target welding and sealing technology, and particularly relates to a device and method for welding and sealing medical radioisotope irradiated targets. Background Technology

[0002] In medical radioisotopes (e.g., lutetium-177) 177 Lu), Terbium-161 161 In reactor irradiation production (such as Tb), it is usually necessary to first irradiate the target material (e.g., high-purity Tb). 176 Yb2O3, 160 Gd₂O₃ is packed into a quartz target vial, which is then filled with an inert gas (such as helium) for thermal conductivity, buffering, and protection. The quartz target vial is then subjected to a high-temperature fusion sealing process to achieve a gaseous seal. The sealed quartz target vial is then placed inside a metal casing (such as a zirconium alloy or niobium alloy), which is also filled with helium and sealed by welding. The encapsulated target (comprising an inner quartz target vial and an outer metal casing) is then loaded into a specific carrier and placed in the irradiation channel of a nuclear reactor for neutron irradiation for a certain period to produce the desired radioactive isotope.

[0003] Current target fabrication typically requires separate sealing of the quartz target bottle and welding of the metal shell. This process often relies on manual operation of high-temperature flames or welding equipment in open or semi-open environments, which is not only inefficient and labor-intensive but also poses risks of oxidation contamination of the raw materials and safety hazards. For example, quartz sealing must be performed under helium or inert gas protection; otherwise, contact between quartz and oxygen at high temperatures can lead to oxidation defects, crystal structure damage, and even cracks at the sealing joint, directly affecting the sealing performance and subsequent irradiation. Simultaneously, high-temperature oxidation may introduce trace amounts of oxygen, increasing oxidation contamination of the target material and lining, adversely affecting the target's mechanical properties and thermal stability. Similarly, metal shell welding must be performed in a low-oxygen or inert protective atmosphere to ensure weld quality and material properties. Oxygen and nitrogen in the air can cause oxidation, nitriding, or porosity defects in the metal weld, affecting weld density and reliability under static / dynamic loads. In addition, because the welding process involves high-temperature heat radiation and potential exposure to radioactive materials, operators in traditional open environments may be exposed to heat radiation, welding arc light, and residual radioactive contamination (such as target activation products), increasing occupational health risks and potential environmental pollution hazards. Summary of the Invention

[0004] The main objective of this application is to provide a device and method for welding and sealing medical radioisotope irradiation targets, in order to solve the technical problems existing in the current target packaging process, such as complex operation, harsh environmental requirements, low production efficiency and insufficient safety.

[0005] Another objective of this application is to provide an apparatus and method for the welding and sealing of medical radioisotope irradiation targets, which improves the reliability and safety of the packaging process, reduces the stringent requirements on the operating environment, and alleviates the labor intensity and health risks of operators, thereby improving the overall production efficiency and quality of medical isotope irradiation target preparation.

[0006] Another objective of this application is to provide an apparatus and method for welding and sealing medical radioisotope irradiation targets, which can automatically complete the quartz target bottle welding and metal shell welding process in a controlled inert atmosphere and shielded environment, thereby overcoming the technical defects of the prior art such as complex target packaging operation, harsh environmental requirements, and insufficient safety.

[0007] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application provides a medical radioisotope irradiation target welding and sealing device, including a box-type sealed cavity and its front door. The inner wall of the box-type sealed cavity and the front door are provided with a metal shielding layer, a neutron and gamma-ray shielding layer, and the bottom of the box-type sealed cavity is provided with a target placement base for fixing and holding the target. The device has a vacuum system, an inert gas filling system, an automatic control system, a semi-automatic process control system, and a pressure recovery and safety release system.

[0008] In some embodiments, multiple heating nozzles or plasma generators are installed around the inside of the box-type enclosed cavity and are evenly distributed around the target in a 360° pattern.

[0009] In some embodiments, the heating nozzle is arranged at an elevation angle relative to the horizontal plane.

[0010] In some embodiments, the target includes a quartz target bottle and a metal housing disposed outside thereon. The target placement base is a rotatable support, which drives the quartz target bottle and the metal housing mounted thereon to rotate together via a built-in rotation drive mechanism.

[0011] In some embodiments, the automatic control system of the device is provided with multi-point temperature sensors for monitoring the temperature of the quartz target bottle and the surface of the metal housing, as well as the temperature of the target placement base.

[0012] In some embodiments, the box-type enclosed cavity is connected to a coarse vacuum pump and a high vacuum pump via a vacuum pipeline (or air extraction pipeline) and a vacuum valve to extract the air inside the box-type enclosed cavity to a low pressure.

[0013] In some embodiments, the device has an inert gas filling system, including a nitrogen or helium gas source connected in sequence to the box-type sealed cavity, and a valve assembly for controlling the gas inlet and outlet. When the box-type sealed cavity reaches a high vacuum, nitrogen is first filled in for cleaning and then evacuated, followed by filling in high-purity helium to a pressure slightly higher than atmospheric pressure to form an inert protective environment.

[0014] Secondly, this application provides a method for welding and sealing a medical radioisotope irradiation target, comprising: Step 1: Place the quartz target bottle containing the target material and the metal casing on the target placement base, close the front door and lock it; Step 2: Evacuate the box-type sealed cavity to the predetermined vacuum level, then introduce helium for pre-cleaning, exhaust the helium and evacuate again, then fill with high-purity helium to the set pressure to form an inert protective atmosphere. Step 3: Under helium protection, start the heating nozzle to synchronously heat the target until the quartz target bottle seal melts and closes and the metal shell opening is welded. Step 4: After stopping heating, maintain helium protection and allow it to cool naturally or with assistance to a safe temperature; Step 5: Release the gas inside the sealed chamber to restore normal pressure, and remove the target that has been welded and sealed.

[0015] In some embodiments, the quartz target bottle is flame-sealed under an inert atmosphere. The filled quartz target bottle is rotated and its neck heated to soften and melt the quartz, stretching it to seal the bottle opening. The flame-sealing is performed in an environment filled with inert gas. After the flame-sealing is completed, the contents of the quartz target bottle... 98 Mo2O3 powder is sealed in a small, enclosed space filled with inert gas, thus isolating it from external impurities and moisture.

[0016] In some embodiments, the metal casing is vacuumed and welded together. First, the metal casing and its surrounding space are evacuated to a high vacuum. Then, high-purity helium is introduced through the gas inlet to a pressure slightly higher than atmospheric pressure to form an inert protective atmosphere inside and outside the casing. Under this inert environment, the opening of the metal casing is sealed by a surrounding heating welding method.

[0017] Compared with the prior art, the medical radioisotope irradiation target welding and sealing device and method provided in this application have the following advantages: This application enables the automatic completion of two key processes—sealing the quartz target bottle and welding the metal shell—in a controlled inert atmosphere and a sealed environment, thereby achieving automation and integration of the preparation process and significantly improving the efficiency and quality of target preparation.

[0018] This application reduces oxidation pollution and environmental dependence by integrating the two processes of quartz target bottle sealing and metal shell welding into the same closed and controlled environment. By using inert gas protection and high vacuum conditions, it effectively prevents the influence of pollutants such as oxygen and moisture on the target material and weld during the sealing and welding process, improves the packaging quality, and reduces the stringent requirements on the operating environment.

[0019] This device adopts a box-type enclosed structure and integrates functions such as radiation shielding, anti-oxidation inert environment, high-efficiency heating and welding, and automatic control. It can complete the fusion welding and sealing process of quartz target bottle and metal shell in a single device, effectively improving the safety of the irradiation target welding and sealing process and the on-site protection level.

[0020] Furthermore, the lead / tungsten alloy shielding layer equipped in this device enhances the radiation safety protection level, ensuring personnel safety even when the equipment is near an irradiation facility, and meeting the stringent requirements for personnel safety and environmental protection in medical radioisotope production devices.

[0021] Furthermore, this application achieves full-process monitoring and automatic control of the packaging process through a PLC control system and comprehensive safety interlocking measures, making the entire welding and sealing process more stable, reliable and controllable, and significantly improving the automation level and operational safety of medical radioactive target preparation.

[0022] Furthermore, this application can achieve uniform heating and improve processing efficiency. This application adopts multi-nozzle surround synchronous heating technology, which makes the heat distribution more uniform, thereby improving the efficiency of heating and welding, helping to reduce thermal stress, reduce local overheating, improve overall processing stability, and significantly reduce manual operation intensity. Attached Figure Description

[0023] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0024] Figure 1 A schematic diagram of the structure of the medical radioisotope irradiation target welding and sealing device provided in this application; Figure 2 A top view of the medical radioisotope irradiation target welding and sealing device provided in this application; Figure 3 A flowchart of the welding and sealing method for medical radioisotope irradiation targets provided in this application.

[0025] Explanation of reference numerals in the attached figures: 1. Enclosed box-type cavity; 2. Front door; 3. Target placement base; 4. Quartz target bottle; 5. Metal casing; 6. Heating nozzle; 7. Metal shielding layer; 8. Neutron and gamma-ray shielding layer. Detailed Implementation

[0026] The following detailed description provides further details on specific implementation methods.

[0027] like Figure 1 and Figure 2 As shown, this application provides a medical radioisotope irradiation target welding and sealing device, including a box-type sealed cavity 1. The box-type sealed cavity 1 is provided with an openable front door 2. The inner wall of the cavity and the front door 2 are provided with a metal shielding layer 7 and a neutron and gamma-ray shielding layer 8. In addition to shielding neutrons, gamma rays and induced radioactive rays, the metal shielding layer 7 can also provide the cavity with the necessary mechanical strength to maintain the high vacuum environment inside and resist the high temperature thermal stress generated during welding. The neutron and gamma-ray shielding layer 8 is used to shield neutrons and gamma rays.

[0028] The bottom of the box-type enclosed cavity 1 is equipped with a high-temperature resistant target placement base 3 for fixing and supporting the quartz target bottle 4 and its external metal shell 5. The interior of the box-type enclosed cavity 1 is equipped with a heating system consisting of multiple equally spaced heating nozzles 6 or plasma heat sources arranged in a ring, with the nozzles pointing towards the central region of the target. The multiple heating nozzles 6 are distributed in a single or multiple layers in a horizontal plane perpendicular to the target axis, ensuring uniform heating of the target seal in both the vertical and circumferential directions. When using a plasma heat source, the energy output of each heat source is independently controlled by an automated system to achieve non-contact, high-energy-density, precise heating of the central region of the target. The geometric center lines of all nozzles intersect at a point on the vertical central axis of the target, and the height of this intersection point matches the weld position of the quartz target bottle's sealing neck or the metal shell.

[0029] Preferably, the target placement base 3 is equipped with a rotation drive mechanism to drive the target to rotate around its axis, thereby achieving 360-degree heating without dead angles in conjunction with the stationary surrounding nozzle; or, the heating nozzle 6 is mounted on a liftable ring bracket to adapt to the target packaging requirements of different heights.

[0030] This device is equipped with a vacuum system, an inert gas filling system, and an automatic control system. The vacuum system and the inert gas filling system are connected to the enclosed box-type cavity 1 via interfaces, and are used to evacuate the enclosed box-type cavity 1 and fill it with inert gases such as helium to form a protective atmosphere. The automatic control system is used to control the coordinated operation of the front door 2, the vacuum system, the gas filling, and the heating process to achieve the fusion welding and sealing treatment of the target.

[0031] The internal space of the box-type enclosed cavity 1 is used to accommodate the target assembly to be processed. The box-type enclosed cavity 1 consists of an outer shell made of thick steel plate and an inner lining of lead or tungsten alloy shielding layer, which can shield neutron and gamma-ray radiation.

[0032] The front door 2 has a shielding material (such as lead steel or tungsten steel) on its door panel and is equipped with an observation window for easy observation of the interior. The front door 2 adopts a vacuum sealing structure (such as a flange quick-opening door with a sealing ring or a multi-bolt locking structure) to ensure that the cavity can maintain a high vacuum environment after closing. The front door 2 facilitates the operator in placing the quartz target bottle 4 and the metal housing 5 into the cavity.

[0033] Alternatively, the vacuum sealing structure may be a flange quick-opening door with a sealing ring or a multi-bolt locking structure.

[0034] Optionally, the viewing window is made of lead glass.

[0035] The target placement base 3 is located at the center of the bottom of the cavity. It is a high-temperature heat-resistant base, such as made of graphite, refractory ceramic, or high-temperature alloy, and is used to support and fix the position of the target. This device uses the target placement base 3 to ensure that both the quartz target bottle 4 and the metal shell 5 are located in the center of the cavity.

[0036] The target component includes a quartz target bottle 4 and a metal shell 5 disposed outside it. The quartz target bottle 4 is placed inside the metal shell 5 and slightly lower than the opening of the shell, so that the quartz bottle can be completely sealed inside the metal shell 5 after it is melted and sealed.

[0037] Optionally, the metal casing 5 may be made of zirconium alloy / niobium alloy.

[0038] The target placement base 3 is designed as a rotatable fixed support. The built-in rotation drive mechanism drives the quartz target bottle 4 and the metal shell 5 mounted on it to rotate slowly together, while ensuring that they remain in the center of the cavity and withstand high temperatures without shifting or being damaged, thus achieving more uniform heating.

[0039] like Figure 2 As shown, the heating system of this device is arranged as follows: multiple heating nozzles 6 (or plasma generators) are installed around the inside of the box-type enclosed cavity 1, and are evenly distributed around the target at a 360° angle. Each heating nozzle 6 is connected to a gas or plasma generator, capable of producing a high-temperature flame or plasma jet aimed at the target. The heating nozzles 6 are arranged at an elevation angle relative to the horizontal plane, tilting downwards at approximately a 30° angle towards the center of the target. The installation height of the heating nozzles 6 is slightly higher than the top of the target (e.g., 100 mm to 150 mm from the top of the target) to ensure that the heating range covers the entire area around the target, thereby achieving uniform 360° heating around the target. This circumferential, oblique heating arrangement ensures that the quartz target bottle 4 and the metal shell 5 are heated uniformly, enabling the quartz material to melt and the opening of the metal shell 5 to be welded closed in a short time.

[0040] Preferably, the device employs nine heating nozzles 6 arranged at equal intervals around the target, distributed at equal angles within the cavity around the target, with adjacent heating nozzles 6 spaced 45° apart.

[0041] To further improve heating uniformity, the target placement base 3 and target assembly of this device are designed as rotatable structures. This means that the target rotates slowly during heating, while the heating nozzle 6 remains stationary, achieving a uniform heating effect through relative motion. The heating nozzle 6 is equipped with a cooling structure to prevent overheating during prolonged high-temperature operation, and the design and installation took into account thermal insulation distances and maintenance space.

[0042] The rotation of the target makes the heat flow from the fixed nozzle 6 more uniform, avoiding overheating in one direction, thereby further improving the consistency and reliability of the fusion seal welding. In the heating process, the annular nozzle heating and the rotating target placement base work together to achieve efficient synchronous welding of the inner fusion seal and the outer weld seal.

[0043] This device also includes a vacuum system, an inert gas filling system, an automatic control system, a semi-automatic process control system, and a pressure recovery and safety release system to provide a controlled inert protection environment. The enclosed box-type chamber 1 is connected to a rough vacuum pump and a high vacuum pump via vacuum piping (or evacuation piping) and vacuum valves, which can evacuate the internal air to a level such as 10⁻⁶. -5 mbar even 10 -8 The pressure is on the order of mbars. After vacuuming, the inert gas filling system can be pre-flushed with helium to remove residual oxygen and moisture from the cavity. Then, vacuuming is repeated or high-purity helium is introduced directly to fill the cavity to a helium protective environment slightly above atmospheric pressure. Helium, as an inert protective gas, ensures that no oxidation occurs during quartz sealing and metal welding. The semi-automated process control system is equipped with various valves and sensors to achieve automated process control and safety monitoring, including gas inlet valves, vacuum exhaust valves, and sensors for helium purity, residual oxygen content, and cavity pressure. Once the welding process is complete and the temperature decreases, the pressure recovery and safety release system vents the gas from the cavity to restore atmospheric pressure, allowing for safe opening and removal of the target.

[0044] This device integrates a vacuum pump interface and an inert gas supply interface, which can automatically evacuate and fill the box-type sealed cavity 1 with nitrogen or helium to form a low-oxygen inert protective atmosphere inside the cavity. Through the program setting of the automatic control system, it can sequentially execute operation steps such as vacuuming, gas replacement, heating and sealing, and cooling to realize a semi-automated process of target encapsulation.

[0045] The vacuum system includes a rough vacuum pump and a high vacuum pump, capable of pumping the pressure inside the chamber to 10. -5 mbar or lower.

[0046] The inert gas filling system includes a nitrogen gas source and a helium gas source connected in sequence to the box-type sealed cavity 1, as well as a valve assembly for controlling the gas inlet and outlet. After the box-type sealed cavity 1 reaches a high vacuum, nitrogen gas is first filled in for cleaning and then evacuated. Subsequently, high-purity helium gas is filled in to a pressure slightly higher than atmospheric pressure to form an inert protective environment.

[0047] Preferably, the inert gas filling system also includes a gas monitoring unit for monitoring the helium purity, residual oxygen content, and pressure parameters inside the cavity to ensure that a low oxygen content and appropriate gas pressure are maintained inside the cavity during quartz sealing and metal welding.

[0048] The automatic control system includes a programmable logic controller (PLC) and an operator panel with a human-machine interface (HMI) for setting parameters to preset and execute the automated process of target welding. The automatic control system is electrically connected to components such as the front door 2, vacuum pump, valves, and heating nozzles 6, and performs functions such as door interlocking, vacuuming time control, helium filling sequence and pressure control, heating power and time control, and cooling rate control during the process.

[0049] This device is equipped with an automatic control system consisting of a PLC, whose integrated semi-automatic process control program coordinates the actions of various subsystems. Especially during the heating stage, the system dynamically adjusts the output power of the heating nozzle 6 by receiving feedback signals from the temperature sensor, thereby achieving precise control of the sealing process.

[0050] It should be noted that the automated control system is not completely independent. If the systems operated independently, significant safety hazards would arise: if the vacuum system operated independently, an operator might accidentally open the front door while high-pressure gas still exists inside, causing radioactive powder to be ejected. For example, the automated control system incorporates interlocking functions. For instance, only when the "vacuum system" feedback pressure reaches 10... -5 The automatic control system will only allow the heating system to start after the helium purity meets the standard, provided that the "inert gas system" reports that the helium purity meets the standard.

[0051] The automatic control system is equipped with multiple temperature sensors to monitor the temperature of the quartz target bottle 4 and the surface of the metal shell 5, as well as the temperature of the target placement base 3. The automatic control system also has a safety interlock and alarm module, which can automatically stop the heating process and provide audible and visual alarm prompts when the system detects air leakage in the cavity, abnormal vacuum, malfunction of the heating nozzle 6, or excessive temperature.

[0052] The automatic control system is pre-programmed with a complete process flow. From the interlocking and closing of the front door 2, to the start and stop of the vacuum pump, valve switching, gas filling, heating initiation, and cooling time control, all are executed sequentially by the PLC. For example, users can set parameters such as the vacuuming duration, helium filling pressure, heating temperature or time, and cooling rate. The system is equipped with multiple sensors to monitor key indicators in real time, including multi-point temperature sensors monitoring the surface temperature of the quartz target bottle 4 and the metal casing 5, as well as the base temperature; and a gas monitoring module detecting the oxygen content, humidity, helium purity, and pressure within the chamber.

[0053] The safety interlock design ensures that the heating process can only begin after the front door 2 is fully sealed, and the door lock will not open under high temperature or vacuum conditions. Once an abnormality is detected (such as insufficient vacuum, gas leakage, excessive temperature, nozzle malfunction, etc.), the automatic control system will automatically stop the process and issue an alarm.

[0054] Preferably, a radiation monitoring probe is installed on this device to monitor the radiation level in the environment or near the equipment. Although the target itself is not radioactive before irradiation, this device can better monitor radiation measurements by installing a radiation monitoring probe.

[0055] In practice, the sealing of the quartz target bottle and the welding of the metal shell are both controlled by a PLC program, sequentially executing the process of vacuuming → nitrogen purging → re-vacuuming → helium purging for protection. For example, the cavity is first evacuated to 10... -5 A high vacuum of mbar is applied, followed by helium pre-purging to remove residual oxygen and moisture. After evacuation again, high-purity helium is introduced to a pressure slightly above atmospheric pressure. This maintains an inert environment within the cavity during target sealing and welding, preventing target oxidation at high temperatures and ensuring weld quality and target purity.

[0056] The process of using this device to perform welding and sealing on the target is as follows: First, the operator opens the front door 2, places the quartz target bottle 4 containing the target material in the center of the target placement base 3, and then places the corresponding metal casing 5 on the outside of the target bottle.

[0057] Afterwards, the front door 2 is closed and the door lock interlock device is activated. Subsequently, the semi-automatic control system starts the vacuum pump to evacuate the box-type sealed cavity 1 through the vacuum pump interface 7 until the pressure inside the cavity reaches a predetermined low-pressure level (e.g., 10). -8 mbar).

[0058] After the vacuum is achieved, helium is introduced into the cavity for pre-purification to remove residual oxygen and water vapor, and then the vacuum is evacuated again to remove the helium. Next, high-purity helium is introduced to a pressure slightly above atmospheric pressure to establish a helium-protected environment. Under this inert atmosphere, the automatic control system ignites or activates all heating nozzles 6. These nozzles work synchronously to heat the target, rapidly melting and sealing the quartz target bottle 4, while simultaneously welding the opening of the metal casing 5, thus sealing the target.

[0059] During the heating process, the semi-automatic process control system continuously monitors temperature and atmosphere parameters, ensuring that the target is held at the desired temperature for a period of time to allow for complete melting. Then, the heat source power is reduced according to a preset program to allow the target to cool slowly. Once the temperature drops to a safe level, all heating is stopped, and helium or argon gas is slowly introduced into the chamber to assist cooling and prevent oxygen from entering during the cooling process.

[0060] Finally, the exhaust valve is opened to restore the pressure of the sealed chamber 1 to normal, the front door is unlocked by interlock, and the operator opens the front door 2 to take out the sealed target.

[0061] The entire operation of this device is semi-automated. Except for the two steps of loading and unloading, which require manual operation, the rest of the process is completed automatically by the equipment, which greatly reduces the possibility of human intervention and misoperation.

[0062] This device integrates the two processes of quartz target bottle sealing and metal shell welding into the same controlled inert environment, significantly simplifying the operation process. Through the coordinated application of the aforementioned key structures, it achieves… 98 The high-quality and high-efficiency encapsulation of the Mo2O3 target provides a safe and reliable target for subsequent in-pile irradiation.

[0063] Furthermore, based on the aforementioned device, this application also provides a method for welding and sealing a medical radioisotope irradiation target, such as... Figure 3 As shown, this method includes the following steps: Step 1, Place the target and lock: Open the front door 2, place the quartz target bottle 4 containing the target material and the corresponding metal shell 5 together on the target placement base 3 at the bottom of the cavity, close the front door 2 and lock it. Step 2: Establish an inert atmosphere: Start the vacuum system to evacuate the box-type sealed cavity 1 to the predetermined vacuum level, then introduce helium for pre-cleaning, discharge the helium and evacuate again, then fill with high-purity helium to the set pressure to form an inert protective atmosphere. Step 3, Synchronous Heating and Sealing: In a helium-protected environment, start all heating nozzles 6 to synchronously heat the target until the quartz target bottle 4 is sealed and melted closed and the metal shell 5 is welded open. Step 4, Controlled Cooling: After heating is stopped, maintain helium protection and allow it to cool naturally or by introducing inert gas to cool it to a safe temperature; Step 5, restore normal pressure and remove: release the gas in the box-type sealed cavity 1 to restore normal pressure, open the front door 2 and remove the target that has been welded and sealed.

[0064] In one embodiment, 98 The Mo2O3 target uses a double-layer encapsulation system consisting of an inner quartz target bottle and an outer metal shell. The specific steps are as follows: (1) Filling: Fill with approximately 0.5 grams of... 98 Mo2O3 powder is packed into a clean, dry quartz target bottle (quartz target bottle 4). The powder should be loosely and evenly distributed, and a certain amount of space should be left at the bottle opening to accommodate inert gas. The size of quartz target bottle 4 can be selected according to the volume of powder, generally ranging from a few millimeters to one centimeter in inner diameter, to ensure that the powder height does not affect the sealing operation.

[0065] (2) Quartz Target Bottle Flame Sealing: The quartz target bottle is flame-sealed under an inert atmosphere. Specifically, the loaded target bottle is slowly rotated and its neck heated to soften and melt the quartz, then stretch and seal the bottle opening. To prevent oxidation defects caused by contact between the quartz and air at high temperatures, the flame sealing must be carried out in an environment filled with an inert gas (such as high-purity helium). After the flame sealing is completed, the contents of the target bottle... 98 Mo2O3 powder is sealed in a small, enclosed space filled with inert gas, thus isolating it from external impurities and moisture.

[0066] (3) Inserting the metal casing 5: Insert the fused quartz target bottle into the metal casing 5 of the corresponding size. The metal casing 5 is usually a cylindrical cup-shaped structure with one end closed and the other end open. Its inner diameter is slightly larger than the diameter of the quartz target bottle, and its length ensures that the entire target bottle is slightly lower than the opening of the casing. After the quartz target bottle is completely placed in the casing, check that the target bottle seal is below the opening of the casing and that a welding gap is left. Zirconium alloy / niobium alloy materials have high mechanical strength, corrosion resistance, and low neutron absorption cross section, making them suitable as outer casings to withstand the in-reactor irradiation environment.

[0067] (4) Metal casing welding and sealing: The metal casing 5 containing the target bottle is placed in a special welding and sealing device for vacuuming and welding. First, the vacuum system is connected to evacuate the casing and its surrounding space to a high vacuum. Then, high-purity helium is introduced through the gas filling port to a pressure slightly higher than atmospheric pressure, forming an inert protective atmosphere inside and outside the casing. In this inert environment, the opening of the metal casing is sealed by a surrounding heating welding method: multiple high-temperature heating nozzles 6 are simultaneously aimed at the casing opening and heated, rapidly melting the edge of the casing opening (usually equipped with a cover plate or solder) and welding it to the casing body to form a continuous weld. By precisely controlling the heating time and temperature, the weld is fully melted and then slowly cooled to finally form an airtight welded joint. After the welding and sealing is completed, the helium inside the metal casing 5 is sealed, and the inner quartz target bottle and target powder are doubly sealed and protected.

[0068] After the above packaging process is completed, the inner contents are obtained.98 A target encapsulated with Mo2O3 powder. A quartz target vial provides the first layer of sealing and chemical inertness, while an outer zirconium / niobium alloy shell provides a second layer of sealing and mechanical strength. Both layers are filled with inert gas for protection. This dual-layer structure ensures that the target material will not leak or become contaminated during subsequent neutron irradiation.

[0069] Therefore, this application improves the reliability and safety of the encapsulation process, reduces the stringent requirements on the operating environment, and alleviates the labor intensity and health risks of operators by providing an automated, controlled encapsulation processing apparatus and method, thereby improving the overall production efficiency and quality of medical isotope irradiation target preparation.

[0070] This application integrates the two processes of quartz target sealing and metal shell welding into the same closed and controlled environment. On the one hand, the inert gas protection and high vacuum conditions effectively prevent oxygen and moisture from contaminating the target and weld during the sealing and welding process; on the other hand, the multi-nozzle synchronous heating improves the uniformity of heat distribution and processing efficiency, and significantly reduces the intensity of manual operation.

[0071] In summary, this application effectively improves the efficiency of target preparation, packaging quality, and environmental safety by integrating the sealing of quartz target bottles and the welding of metal shells under inert atmosphere, protective shielding, and automated control conditions, providing a practical and feasible technical solution for the large-scale and standardized preparation of medical isotope irradiation targets.

[0072] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A device for welding and sealing medical radioactive isotope irradiation targets, characterized in that, It includes a box-type enclosed cavity (1) and its front door (2). The inner wall of the box-type enclosed cavity (1) and the front door (2) are provided with a metal shielding layer (7) and a neutron and gamma-ray shielding layer (8). The bottom of the box-type enclosed cavity (1) is provided with a target placement base (3) for fixing and holding the target.

2. The medical radioisotope irradiation target welding and sealing device according to claim 1, characterized in that, The box-type enclosed cavity (1) is equipped with multiple heating nozzles (6) or plasma generators, which are evenly distributed around the target in a 360° pattern.

3. The medical radioisotope irradiation target welding and sealing device according to claim 2, characterized in that, The heating nozzle (6) is arranged at an upward angle relative to the horizontal plane.

4. The medical radioisotope irradiation target welding and sealing device according to claim 1, characterized in that, The target includes a quartz target bottle (4) and a metal shell (5) disposed on its exterior. The target placement base (3) is a rotatable support, which drives the quartz target bottle (4) and the metal shell (5) mounted on it to rotate together through a built-in rotation drive mechanism.

5. The medical radioisotope irradiation target welding and sealing device according to claim 4, characterized in that, The device has an automatic control system, which is equipped with multi-point temperature sensors to monitor the temperature of the surface of the quartz target bottle (4) and the metal shell (5), as well as the temperature of the target placement base (3).

6. The medical radioisotope irradiation target welding and sealing device according to claim 1, characterized in that, The box-type enclosed cavity (1) is connected to a coarse vacuum pump and a high vacuum pump through a vacuum pipeline and a vacuum valve to pump the air inside the box-type enclosed cavity (1) to a low pressure.

7. The medical radioisotope irradiation target welding and sealing device according to claim 4, characterized in that, The device has an inert gas filling system, including a nitrogen or helium gas source connected in sequence to the box-type sealed cavity (1), and a valve assembly for controlling the gas inlet and outlet. When the box-type sealed cavity (1) reaches a high vacuum, nitrogen is first filled in for cleaning and then evacuated. Then, high-purity helium is filled in to a pressure slightly higher than atmospheric pressure to form an inert protective environment.

8. A method for welding and sealing a medical radioactive isotope irradiation target, characterized in that, include: Step 1: Place the quartz target bottle (4) containing the target material and the metal shell (5) on the target placement base (3), close the front door (2) and lock it; Step 2: Evacuate the box-type sealed cavity (1) to the predetermined vacuum level, then introduce helium for pre-cleaning, exhaust the helium and evacuate again, then fill with high-purity helium to the set pressure to form an inert protective atmosphere. Step 3: Start the heating nozzle (6) under helium protection to synchronously heat the target until the quartz target bottle (4) is sealed and melted closed and the metal shell (5) is opened and welded. Step 4: After stopping heating, maintain helium protection and allow it to cool naturally or with assistance to a safe temperature; Step 5: Release the gas in the box-type sealed cavity (1) to restore normal pressure, and take out the target that has been welded and sealed.

9. The method for sealing medical radioactive isotope irradiation targets according to claim 8, characterized in that, In step 3, the quartz target bottle (4) is flame-sealed under an inert atmosphere. The quartz target bottle (4) after being filled is rotated and its neck is heated to soften and melt the quartz, then stretch and seal the bottle mouth. The sealing is carried out in an environment filled with inert gas. After the sealing is completed, the contents of the quartz target bottle (4) are sealed. 98 Mo2O3 powder is sealed in a small, enclosed space filled with inert gas, thus isolating it from external impurities and moisture.

10. The method for sealing medical radioisotope irradiation targets according to claim 8, characterized in that, In step 2, the metal shell (5) is vacuumed and welded and sealed. First, the metal shell (5) and its surrounding space are vacuumed to a high vacuum. High-purity helium is filled through the gas filling port to a pressure slightly higher than atmospheric pressure to form an inert protective atmosphere inside and outside the shell. Under this inert environment, the opening of the metal shell is sealed by a surrounding heating welding method.

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