A radioactive source core based on a waste Strontium-90 patch and its preparation method

Abstract

This invention relates to the field of radioactive source core technology, and provides a radioactive source core based on a waste Strontium-90 applicator source sheet and its preparation method. The radioactive source core based on the waste Strontium-90 applicator source sheet includes: a first Au layer, a first Pd layer, a second Au layer, and so on, connected sequentially from top to bottom. 90 The structure comprises an Sr active layer, a first Ag layer, a second Pd layer, and an organic sealing layer, wherein the organic sealing layer covers the Sr active layer, a first Ag layer, a second Pd layer, and an organic sealing layer. 90 The exposed portion of the Sr active layer. The radioactive source core and its preparation method based on waste Sr-90 applicator source sheets provided by this invention realize the reuse of radioactive waste, obtain a low-activity β radioactive source core, recycle radionuclides, reduce the environmental pressure of radioactive waste, and practice the concept of green development.

Description

Technical Field

[0001] This invention belongs to the field of radioactive source core technology, and particularly relates to a radioactive source core based on a waste strontium-90 applicator source sheet and its preparation method. Background Technology

[0002] The domestically produced Strontium-90 dermatological dressing was successfully developed in 1988 by Cai Shanyu and others from the Institute of Isotopes, China Institute of Atomic Energy, and subsequently put into the market. More than 200 hospitals have since used nearly a thousand Strontium-90 dermatological dressings of various specifications. The domestically produced Strontium-90 dermatological dressing is square in shape, with sizes including 25×25mm and 30×40mm, and activity levels of 20mCi and 40mCi, with a recommended service life of 10 years. The dressing contains radioactive nuclides. 90 Sr has a half-life of 28.9 years. After reaching its recommended lifespan, due to wear and oxidation, the radionuclide's sealing performance will no longer meet requirements, and its use is no longer recommended. It needs to be decommissioned and returned to local municipal waste repositories or the manufacturer. Research has found that most domestically produced applicators have far exceeded the recommended lifespan, reaching 20 or even 30 years. It is estimated that nearly a thousand applicators have been put into the market. Even using the most conservative estimate of 500 applicators, each with 20 mCi and a maximum decay time of 34 years, the market includes decommissioned applicators. 90 Sr radionuclides with an activity of at least 4.4 Ci should be decommissioned to local municipal radioactive waste repositories according to current policies. 90 Sr has a long half-life, taking 300 years to completely decay, and the large amount of radioactive waste inevitably puts pressure on the environment. There is an urgent need to reuse the radioactive waste from spent Sr-90 patch source sheets, recycling its radionuclides to reduce the environmental pressure caused by radioactive waste. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a radioactive source core based on a waste Strontium-90 applicator source sheet and its preparation method. The radioactive source core based on a waste Strontium-90 applicator source sheet and its preparation method provided by this invention facilitate the stretching of the waste Strontium-90 applicator source sheet to obtain a low-activity β-radioactive source core with excellent properties such as ductility, sealing performance, and uniformity. This better enables the reuse of radioactive waste, the recycling of radionuclides, and reduces the environmental pressure of radioactive waste, thus practicing the concept of green development.

[0004] In a first aspect, the radioactive source core based on a waste strontium-90 applicator source sheet provided by the present invention comprises: a first Au layer, a first Pd layer, a second Au layer, and so on, connected sequentially from top to bottom. 90 The 90Sr active layer comprises a first Ag layer, a second Pd layer, and a second Ag layer, and an organic sealing layer, wherein the organic sealing layer covers the exposed portion of the 90Sr active layer.

[0005] Preferably, the organic sealing layer covers a first Pd layer, a second Au layer, and 90 The Sr active layer, the first Ag layer, the second Pd layer, and the exposed portions of the second Ag layer; the organic sealing layer also covers the side of the first Au layer and exposes the upper surface of the first Au layer.

[0006] More preferably, the organic sealing layer is an epoxy resin sealant.

[0007] Preferably, the thickness of the organic sealing layer is 0.01 to 0.1 mm.

[0008] Preferably, the thickness of the first Au layer is 0.2–20 μm, the thickness of the first Pd layer is 0.02–0.4 μm, and the thickness of the second Au layer is 0.5–10 μm. 90 The thickness of the Sr active layer is 0.001–0.1 mm, the thickness of the first Ag layer is 0.005–0.2 mm, the thickness of the second Pd layer is 0.02–0.4 μm, and the thickness of the second Ag layer is 0.05 mm–1 mm.

[0009] Further preferably, in the radioactive source core, the first Au layer, the first Pd layer, the second Au layer, and the... 90 The sum of the thicknesses of the Sr active layer, the first Ag layer, the second Pd layer, and the second Ag layer is approximately 0.08 mm to 1.3 mm.

[0010] Preferably, the activity of the radioactive source core is 0.01–100 μCi; the activity per unit area of ​​the radioactive source core is 0.01–20 μCi / mm². 2 .

[0011] Secondly, the method for preparing the radioactive source core provided by the present invention includes the following steps: pre-treating and stamping the waste source sheet of the Strontium-90 applicator to obtain a small-sized waste source sheet; placing the stamped waste source sheet on a silver block, covering the waste source sheet with a gold strip, positioning it with the silver strip, and then hot-pressing it to obtain a composite film; performing double-track rolling on the composite film to extend it to the target multiple, stamping out the source core, and immersing or spraying an organic sealing layer to obtain the radioactive source core.

[0012] Preferably, the impregnation of the inorganic sealing layer includes: applying a layer of epoxy resin sealant to the surface of the release paper, placing the stamped source core with the silver layer facing down on the epoxy resin sealant layer, and allowing the source core to sink under gravity, with the upward-facing epoxy resin sealant layer covering it. 90 The exposed portion of the Sr active layer is cured; the sprayed organic sealing layer includes: placing the stamped source core with the gold layer facing down and the silver layer facing up on the perforated plate, and spraying epoxy resin sealant.

[0013] Further preferably, the pretreatment includes: ultrasonically cleaning the waste source sheet of the Strontium-90 applicator in an ethanol solution, and then removing and drying it; the hot pressing includes: heating the block after the silver strip is positioned, and hot pressing it under a preset pressure to form a composite film; the heating is performed by heating the block with an alcohol torch or an induction heater until it turns red all over, and maintaining it for a set time.

[0014] The beneficial effects of this invention are at least as follows: the radioactive source core based on waste strontium-90 patch source sheet and its preparation method provided by this invention, through the arrangement of each layer... 90 The combination and coating of the Sr active layer yields a low-activity β-radioactive source core with excellent ductility and sealing performance. This is beneficial for the comprehensive performance of the waste source sheet after stretching and coating, better realizing the reuse of radioactive waste, recycling of radionuclides, reducing the environmental pressure of radioactive waste, and practicing the concept of green development. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the radioactive source core provided by the present invention;

[0017] Figure 2 A schematic diagram of the powder metallurgy strontium-90 applicator source sheet provided by the present invention;

[0018] Figure 3 This is a schematic diagram of the assembly of the membrane body provided by the present invention.

[0019] Figure label:

[0020] 1: First Au layer; 2: First Pd layer; 3: Second Au layer; 4: 90 5: Sr active layer; 6: First Ag layer; 7: Second Pd layer; 8: Second Ag layer; 9: Organic sealing layer. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] In the description of the embodiments of the present invention, it should be noted that the terms "top," "bottom," "inner," "outer," "upper," and "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0024] The following is combined Figures 1 to 3 This invention describes a radioactive source core based on a waste strontium-90 patch and its preparation method.

[0025] like Figure 1 As shown in the figure, the radiation source core based on the waste Strontium-90 applicator source sheet in this embodiment includes: a first Au layer 1, a first Pd layer 2, and a second Au layer 3 connected sequentially from top to bottom. 90 The structure comprises an Sr active layer 4, a first Ag layer 5, a second Pd layer 6, a second Ag layer 7, and an organic sealing layer 8, wherein the organic sealing layer 8 covers the Sr active layer 4, the first Ag layer 5, the second Pd layer 6, the second Ag layer 7, and an organic sealing layer 8. 90 The exposed portion of the Sr active layer 4.

[0026] Specifically, the radioactive source core based on the waste Strontium-90 applicator source sheet shown in this embodiment can be prepared from the waste Strontium-90 applicator source sheet prepared by powder metallurgy. By adding each layer of covering active layer, a low-activity β radioactive source core can be prepared, realizing the reuse of radioactive waste, recycling of radionuclides, reducing the environmental pressure of radioactive waste, and practicing the concept of green development. The combination of each layer and the organic sealing layer 8, and the epoxy resin and other sealants have good radiation resistance properties, can withstand the radiation of the low-activity source core, and maintain long-term sealing.

[0027] In this embodiment of the invention, the waste source sheet of the Strontium-90 applicator can be selected from the Strontium-90 applicator source sheet that has reached the recommended service life, or it can be selected from the scrap material of the Strontium-90 applicator source sheet; in this embodiment of the invention, all layers except the organic sealing layer 8 are obtained through stretching treatment, including the first Pd layer 2, the second Au layer 3, and the...90 The Sr active layer 4, the first Ag layer 5, and the second Pd layer 6 were obtained from the waste source sheet of the Sr-90 applicator through an extension process.

[0028] In some embodiments, the organic sealing layer 8 covers the first Pd layer 2 and the second Au layer 3. 90 The exposed portions of the Sr active layer 4, the first Ag layer 5, the second Pd layer 6, and the second Ag layer 7; the organic sealing layer 8 also covers the side of the first Au layer 1 and exposes the upper surface of the first Au layer 1.

[0029] In some embodiments, the organic sealing layer 8 is an epoxy resin sealant.

[0030] Specifically, the present invention uses epoxy resin sealant, especially an epoxy resin sealant layer with optimized thickness, which has better radiation resistance and can further enhance the ability to withstand the radiation of the low-activity source core of the present invention, and maintain a longer-term seal.

[0031] In a preferred embodiment, the thickness of the organic sealing layer 8 is 0.01 to 0.1 mm.

[0032] In a further preferred embodiment, the thickness of the first Au layer 1 is 0.2–20 μm, the thickness of the first Pd layer 2 is 0.02–0.4 μm, and the thickness of the second Au layer 3 is 0.5–10 μm. 90 The thickness of the Sr active layer 4 is 0.001–0.1 mm, the thickness of the first Ag layer 5 is 0.005–0.2 mm, the thickness of the second Pd layer 6 is 0.02–0.4 μm, and the thickness of the second Ag layer 7 is 0.05 mm–1 mm.

[0033] Specifically, the radioactive source core provided by this invention extends to a specific thickness through the combination of various layers, realizing the reuse of radioactive waste, reducing the environmental pressure of radioactive waste, practicing the concept of green development, while better reducing radioactivity, and obtaining a low-activity β instrument source core with excellent ductility and mechanical properties.

[0034] In a further preferred embodiment, the first Au layer 1, the first Pd layer 2, the second Au layer 3, and the... 90 The sum of the thicknesses of the Sr active layer 4, the first Ag layer 5, the second Pd layer 6, and the second Ag layer 7 is approximately 0.08 mm to 1.3 mm.

[0035] In a preferred embodiment, the activity of the radioactive source core is 0.01–100 μCi; the activity per unit area of ​​the radioactive source core is 0.01–20 μCi / mm². 2 .

[0036] This invention also provides a method for preparing the radioactive source core as described above, comprising the following steps: pre-treating and stamping a waste source sheet from a Strontium-90 applicator to obtain a small-sized waste source sheet; placing the stamped waste source sheet on a silver block, covering the waste source sheet with a gold strip for positioning, and then hot-pressing it to obtain a composite film; performing double-track rolling on the composite film to extend it to the target multiple, stamping out the source core, and immersing or spraying an organic sealing layer 8 to obtain the radioactive source core.

[0037] Specifically, the method for preparing a radioactive source core provided in this embodiment of the invention is based on a waste strontium-90 applicator source sheet prepared by powder metallurgy. Through specific processing technology, the waste source sheet is processed and an extended coating layer is added. It is then coated with epoxy resin to prepare a high-performance low-activity β radioactive source core, realizing the reuse of radioactive waste, recycling of radionuclides, reducing the environmental pressure of radioactive waste, and practicing the concept of green development.

[0038] As a preferred embodiment, the impregnation of the inorganic sealing layer 8 includes: scraping a layer of epoxy resin sealant onto the surface of the release paper, placing the silver layer side of the stamped source core facing down on the epoxy resin sealant layer, and curing it; the spraying of the organic sealing layer 8 includes: placing the gold layer side of the stamped source core facing down on the perforated plate, and uniformly spraying epoxy resin sealant.

[0039] In a preferred embodiment, the pretreatment includes: ultrasonically cleaning the waste source sheet of the Strontium-90 applicator in an ethanol solution, and then removing and drying it; the hot pressing includes: heating the block after the silver strip is positioned, and hot pressing it under a preset pressure to form a composite film; the heating is performed by heating the block with an alcohol torch or an induction heater until it turns red all over, and maintaining it for a set time.

[0040] In some embodiments of this invention, the source sheet of the Strontium-90 applicator is manufactured using powder metallurgy, consisting of gold and silver coated nuclides, and requires stretching to produce a low-activity source core. However, as a long-term used waste source sheet, its surface is oxidized and cracked, making it unsuitable for direct stretching. In this embodiment of the invention, after pretreatment such as cleaning, a gold surface and a silver base are coated. The waste source sheet is stamped into a size of 3mm, placed in the middle of a silver block, and positioned with thin gold and silver strips. After high-temperature heating, it is hot-pressed into a single piece. After using double-track rolling and stretching to the target multiple, it is stamped to produce the required β-radiation source core. The active layer at the edge of the stamped source core is exposed, and there are metal burrs, which is not conducive to the sealing of the electroplated layer. This invention uses immersion or spraying of an organic sealing layer 8 for sealing, improving the mechanical properties and ductility of the source core. At the same time, epoxy resin and other sealants also have good radiation resistance, which can withstand the radiation of the low-activity source core and maintain long-term sealing.

[0041] In some embodiments of the present invention, the pretreatment includes: ultrasonically cleaning the waste source sheet of the Strontium-90 applicator twice in a 95% ethanol solution, each ultrasonic cleaning lasting 8-15 minutes, preferably 10 minutes, and then removing and air-drying it; the hot pressing includes: heating the block after the silver strip is positioned, and hot-pressing it for 10-30 seconds under a pressure of 5-10 MPa to form a composite film; preferably, the heating is performed by heating the block until it glows red throughout using an alcohol torch or an induction heater, and maintaining this temperature for at least 1 minute. In the embodiments of the present invention, the use of specific and preferred process parameters helps to better prepare low-activity β-radioactive source cores with excellent performance.

[0042] In some embodiments of the present invention, the specifications of the waste source sheet of the Strontium-90 applicator are not limited. However, in order to better prepare a high-performance, low-activity, small-size β-radiation source core, the preferred specification is 10mCi.

[0043] In some embodiments of the present invention, the waste source sheet of the 10mCi Strontium-90 applicator preferably has an actual activity of 4-5mCi and a unit area activity of 4.2-7.1μCi / mm². 2 .

[0044] In some embodiments of the present invention, the size of the silver block can be 10-15mm × 10-15mm × 3-8mm, and the size of the gold strip can be 8-15mm × 8-15mm × 20-100μm.

[0045] In some embodiments of the present invention, the waste source sheet after cleaning is stamped into a small size to better make full use of the waste source sheet. The preferred shapes are square, rectangular, regular polygonal, or circular, such as a circle with a diameter of 3mm.

[0046] In some embodiments of the present invention, the waste strontium-90 applicator source sheet is originally manufactured by powder metallurgy process, which incorporates strontium carbonate [ 90 Sr] and silver powder are mixed and molded into an active layer, which is then covered and extended with a gold overlay and a silver base layer. Finally, a layer of palladium is electroplated. The structural layers are shown in the figure. Figure 2 The outer surface has a 2-3 μm Pd coating, the Au surface layer is about 50 μm thick, and the middle layer contains... 90 The active layer of Sr has silver at the bottom, and the total thickness of the source wafer is 1-2 mm.

[0047] In specific embodiments provided by this invention, the main experimental equipment and materials are shown in Tables 1 and 2:

[0048] Table 1 Main experimental equipment in the embodiments of the present invention

[0049] Equipment Name quantity Model / Specification β activity meter One RM905A Activity meter One CRC-55tR Dual-track film press one C3385 stamping dies set custom made hydraulic press set UP-45SVG-8SA ultrasonic cleaner One KQ-100E

[0050] Table 2 Main materials in the embodiments of the present invention

[0051] Material Name Purity / Specifications Waste Strontium-90 Applicator Source Sheet 10mCi ethanol AR (95%) Silver ingot 99.9% (12×12×5mm) Gold belt 99.9% (5mm × 20μm) Silver belt 99.9% (13mm x 1mm, homemade)

[0052] In some embodiments of the present invention, by using various metal composite films combined with the waste strontium-90 applicator source sheet, it is possible to produce a low-activity small-size β-radiation source core with better extensibility. At the same time, the direction of extensibility can be changed, such as by using vertical staggered extensibility to prepare a square low-activity source core.

[0053] In some embodiments of the present invention, a low-activity radioactive source core based on a waste strontium-90 applicator source sheet and its preparation method are specifically provided. The radioactive source core provided by the embodiments of the present invention has excellent ductility, low activity, small size, good activity uniformity, and superior sealing and mechanical properties. Radioactive source cores with other activities can refer to the following examples, with the steps as follows:

[0054] 1. Source wafer cleaning and measurement

[0055] The experimental material was scraps of Strontium-90 applicator source sheets left over from the production site. Except for the size difference from the finished product, the other processes were the same. The waste source sheets were placed in a beaker of 95% ethanol and ultrasonically cleaned twice, 10 minutes each time. After cleaning, they were removed with tweezers and allowed to air dry naturally.

[0056] The radioactivity of the waste source sheet was measured using a beta activity meter, and the size of the active region was determined. The specific activity per unit area of ​​the active region was calculated. The waste source sheet used in the experiment had an activity of 5 mCi and a density of 4.2 μCi / mm². 2 and 4mCi, 7.1μCi / mm 2 .

[0057] 2. Closure

[0058] After cleaning, the waste source sheets are stamped into smaller sizes, such as squares, rectangles, regular polygons, and circles, to better utilize the waste source sheets. In this embodiment, circles with a diameter of 3mm are used.

[0059] Place the stamped (scrap) source chip in the center of a silver block (12mm×12mm×5mm). Cover the source chip with a gold strip (12mm×12mm×20μm) and press the gold strip to adhere to the silver block, protruding from the shape of the source chip. Take a silver strip and make a hole in the center of the silver strip according to the size of the stamped source chip. Cover the hole of the silver strip with the protruding source chip, exposing the gold surface, and assemble them together; see the assembly diagram. Figure 3 Hold the block with tweezers and heat it over an alcohol torch (or induction heater) until it glows red all over. Hold this position for at least 1 minute. While it is still hot, place the block under a hydraulic press and heat it at 5-10 MPa for 10-30 seconds to form a composite film. At this point, the gold and silver active layers (stamped source sheet) and the silver block are fully fused together under high temperature and pressure. The gold area on the surface indicates the active area.

[0060] 3. Source chip preparation

[0061] The composite film is repeatedly stretched into a source strip in the same direction on a dual-track rolling mill, with a unit area of... 90 Sr activity also decreases accordingly, and the reduction factor of source core activity can be estimated by measuring the extension factor. After reaching the target factor, the source core is stamped into a circular, regular polygonal (in order to make full use of the source strip, a regular hexagon can be used instead of a circular one if the usage requirements are met), or a source core of a specified size, according to the required dimensions.

[0062] The active layer at the edge of the stamped source core is exposed, with a small amount of radioactive leakage and metal burrs, which is not conducive to sealing the electroplated layer. To address this, an organic sealing layer is applied by immersion or spraying. Specifically, a layer of epoxy resin sealant is evenly applied to the release paper surface. The stamped source core is then placed on the sealant layer with its back facing down. Under gravity, the source core sinks into the sealant layer, while the sealant layer at the edges folds up, covering the exposed active layer. After curing, a seal is achieved. Alternatively, the source core is placed on a perforated plate with the window facing down and its back facing up. A thin layer of sealant is then evenly sprayed, achieving the same sealing effect. Because epoxy resin and other sealants have good radiation resistance, they can withstand the radiation from low-activity source cores, maintaining long-term sealing.

[0063] 4.1 Preparation of source cores with a diameter of 5 mm and an activity of 2.5 ± 0.5 μCi

[0064] The waste source chip used has a strength of 4.2 μCi / mm. 2 The calculated activity per unit area of ​​the target source core is 0.1 μCi / mm². 2 The stretching factor was 42.4. Actual stretching was performed at 35, 40, 45, and 50 times, with activity measured using a 5mm diameter source core. The experimental results are shown in Table 3. The experiment shows that a stretching of 50 times is sufficient to meet the requirements. The difference may be due to the thinner size, which reduces the self-absorption of the active layer and increases the output per unit area, thus increasing the stretching factor.

[0065] Table 3. Experimental results of preparing samples with a diameter of 5 mm and an activity of 2.5 ± 0.5 μCi.

[0066]

[0067] The embodiment of the present invention prepares a 5mm diameter, 2.5uCi activity, and approximately 0.1mm total thickness, wherein the thickness of the first Au layer is 0.4μm, the thickness of the first Pd layer is 0.04μm, and the thickness of the second Au layer is 1μm. 90 The thickness of the Sr active layer is 0.005 mm, the thickness of the first Ag layer is 0.01 mm, the thickness of the second Pd layer is 0.04 μm, and the thickness of the second Ag layer is 0.1 mm.

[0068] 4.2 Preparation of source cores with a diameter of 5 mm and an activity of 10 ± 0.5 μCi

[0069] The waste source chip used has a strength of 7.1 μCi / mm. 2 0.51 μCi / mm 2 The elongation factor is 13.7 times. Actual experiments were conducted with elongations of 5 times, 10 times, 15 times, 20 times, and 25 times. The activity was measured by stamping the source cores with a diameter of 5 mm. The experimental results are shown in Table 4. The experiment shows that the elongation factor of 10 times meets the requirements.

[0070] Table 4. Experimental results of preparing 5mm samples with an activity of 10 ± 0.5 μCi.

[0071]

[0072] The sample prepared in this embodiment of the invention has a diameter of 5 mm, an activity of 10 μCi, and a total thickness of approximately 0.5 mm. The first Au layer has a thickness of 2 μm, the first Pd layer has a thickness of 0.2 μm, and the second Au layer has a thickness of 5 μm. 90 The thickness of the Sr active layer is 0.025 mm, the thickness of the first Ag layer is 0.05 mm, the thickness of the second Pd layer is 0.2 μm, and the thickness of the second Ag layer is 0.5 mm.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radioactive source core based on a waste Strontium-90 patch source sheet, characterized in that, include: The first Au layer, the first Pd layer, the second Au layer, and the third Au layer are connected sequentially from top to bottom. 90 The structure comprises an Sr active layer, a first Ag layer, a second Pd layer, and an organic sealing layer, wherein the organic sealing layer covers the first Pd layer and the second Au layer. 90 The Sr active layer, the first Ag layer, the second Pd layer, and the exposed portions of the second Ag layer; the organic sealing layer also covers the side surface of the first Au layer and exposes the upper surface of the first Au layer, the organic sealing layer is an epoxy resin sealant, the thickness of the organic sealing layer is 0.01~0.1mm, the thickness of the first Au layer is 0.2~20μm, the thickness of the first Pd layer is 0.02~0.4μm, and the thickness of the second Au layer is 0.5~10μm. 90 The thickness of the Sr active layer is 0.001~0.1mm, the thickness of the first Ag layer is 0.005~0.2mm, the thickness of the second Pd layer is 0.02~0.4μm, and the thickness of the second Ag layer is 0.05mm~1mm. In the radioactive source core, the first Au layer, the first Pd layer, the second Au layer, and the... 90 The sum of the thicknesses of the Sr active layer, the first Ag layer, the second Pd layer, and the second Ag layer is 0.08~1.3mm; the radioactive source core based on the waste Sr-90 applicator source sheet is prepared by the following method: the waste source sheet of the Sr-90 applicator is pretreated and stamped to obtain a small-sized waste source sheet; the stamped waste source sheet is placed on a silver block, a gold strip is covered on the waste source sheet and positioned by the silver strip, and then hot-pressed to obtain a composite film; the composite film is double-tracked and stretched to the target multiple, the source core is stamped out, and an organic sealing layer is immersed or sprayed to obtain the radioactive source core.

2. The radioactive source core based on the waste Strontium-90 applicator source sheet according to claim 1, characterized in that, The activity of the radioactive source core is 0.01~100 μCi; the activity per unit area of ​​the radioactive source core is 0.01~20 μCi / mm. 2 .

3. The method for preparing the radioactive source core based on the waste Strontium-90 patch source sheet as described in claim 1 or 2, characterized in that, Includes the following steps: The waste source sheet of the Strontium-90 applicator is pre-treated and stamped to obtain a small-sized waste source sheet; the stamped waste source sheet is placed on a silver block, and a gold strip is covered on the waste source sheet and positioned by the silver strip, and then hot-pressed to obtain a composite film; the composite film is double-tracked and stretched to the target multiple, and the source core is stamped out, and then immersed or sprayed with an organic sealing layer to obtain a radiation source core.

4. The method for preparing a radioactive source core based on a waste Strontium-90 patch source sheet according to claim 3, characterized in that, The impregnation of the inorganic sealing layer includes: applying a layer of epoxy resin sealant to the surface of the release paper; placing the stamped source core with the silver layer facing down on the epoxy resin sealant layer; the source core sinks into the sealant layer under gravity, and the upward-facing epoxy resin sealant layer covers it. 90 The exposed portion of the Sr active layer is cured; the sprayed organic sealing layer includes: placing the stamped source core with the gold layer facing down and spraying epoxy resin sealant.

5. The method for preparing a radioactive source core based on a waste strontium-90 patch source sheet according to claim 4, characterized in that, The pretreatment includes: ultrasonically cleaning the waste source sheet of the Strontium-90 applicator in an ethanol solution, and then removing and drying it; the hot pressing includes: heating the block after the silver strip is positioned, and hot pressing it under a preset pressure to form a composite film; the heating is to heat the block until it turns red all over and hold it for a set time.

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