Gamma radioactive source

Abstract

The utility model relates to the field of precision measurement, in particular to a gamma radioactive source. The gamma radioactive source comprises a source shell and a source core, and the source core is arranged in the source shell; the source core comprises a support body made of an inorganic adsorption material and radionuclides, adsorption holes are formed in the support body, and the radionuclides are adsorbed in the adsorption holes; the specific surface area of the support body is 200-350m < 2 >. G <-1 >, and the pore volume is 0.1-0.4 cm < 2 >. G <-1 >; and the average pore size of the adsorption pores is 2.5-4.5 nm. Radionuclides in the gamma radioactive source are not easy to seep, the scattering of the gamma radioactive source is small, and the performance is excellent. The preparation method of the gamma radioactive source is simple, high in safety and environment-friendly.

Description

Technical Field

[0001] The invention relates to the field of precision measurement, and in particular to a gamma radiation source and a preparation method thereof. Background Art

[0002] Gamma-ray densitometers are widely used in mining, coal, food, steel, cement, electricity and other industries. The measurement of gamma-ray densitometers is non-contact and is not affected by the chemical properties of the measured medium and the physical properties such as temperature, pressure, viscosity, etc. There is no need to open holes, drill holes or make modifications on the measured equipment during installation. It only needs to be fixed on both sides of the pipeline with a clamp, which is very convenient to install. Since the measuring probe does not contact the measured medium, the gamma-ray densitometer basically does not require maintenance after it is put into use. Gamma-ray densitometers are particularly suitable for measuring the density of liquids with high temperature, high pressure, strong corrosion, high viscosity, severe toxicity, deep cold, and containing a large number of suspended particles. Under these harsh conditions, conventional measuring instruments are difficult to handle, which effectively solves the difficulties of high-standard precision detection and problems encountered in actual detection. The working principle of the gamma-ray densitometer is that the gamma rays emitted by the gamma radiation source pass through the medium being measured, a part of the rays are absorbed by the medium, and the remaining part is received by the receiver control. The more gamma rays received, the smaller the density of the object being measured, and vice versa. According to the attenuation degree of the gamma rays, the data processing module calculates the change of the ionizing radiation flux, thereby measuring the density of the medium being measured.

[0003] The gamma radiation source is the core component of the gamma-ray density meter. The conventional preparation method is to seal the ceramic block adsorbing the radioactive nuclide in a stainless steel shell. The conventional preparation method faces the following problems: (1) The conventional source core is produced by the ceramic method. First, the source core is obtained by cold pressing, sintered in a muffle furnace, and then adsorbed with a radioactive solution. Finally, it is sintered at a temperature of 1200°C. During the sintering process, the radioactive nuclides will form aerosols, which brings difficulties to the production and post-processing of the radiation source. Therefore, the conventional method is complex and polluting. (2) Due to process limitations, the diameter of the source core prepared by the ceramic method cannot be less than 6mm, which increases the scattering of the radiation source and is not conducive to improving the sensitivity of the instrument. (3) The nuclides used in the radiation source of the traditional density meter are 60 Co. 137 Cs, the activity range is generally 1 to 20 mCi. With the rapid development of the economy, the number of γ-ray densitometers has increased year by year. Only by improving the process and preparing environmentally friendly and high-performance γ-radiation sources can the growing market demand be met. Summary of the invention

[0004] The invention provides a gamma radiation source and a preparation method and application thereof, so as to solve the problems of the existing gamma radiation source preparation method, such as complex process, high pollution, and high scattering of the radiation source.

[0005] According to a first aspect of the present invention, the present invention provides a gamma radiation source, comprising:

[0006] Source Shell;

[0007] The source core is arranged in the source shell; the source core comprises a support body made of an inorganic adsorption material and a radioactive nuclide, the support body has adsorption holes inside, and the radioactive nuclide is adsorbed in the adsorption holes; the specific surface area of ​​the support body is 200-350m 2 ·g -1 , pore volume is 0.1-0.4cm 2 ·g -1 ; The average pore size of the adsorption pores is 2.5-4.5nm.

[0008] Furthermore, the specific surface area of ​​the support is 250-300m 2 ·g -1 , pore volume is 0.2-0.3cm 2 ·g -1 ; The average pore size of the adsorption pores is 3-4nm.

[0009] Furthermore, the source core is cylindrical; the diameter of the source core is 1-6 mm, and the height is greater than or equal to 1 mm; preferably, the diameter of the source core is 2-4 mm, and the height is 1-3 mm.

[0010] Furthermore, it also includes:

[0011] A protective shell made of high temperature glue is coated on the outer surface of the source core; preferably, the thickness of the protective shell is 0.5-1.5 mm.

[0012] Furthermore, the source shell is made of stainless steel; and the support body is made of cerium oxide material.

[0013] Furthermore, the source shell includes a source bottom and a source cover, and the source bottom and the source cover are connected together by laser welding; the source core is arranged in the source bottom.

[0014] Furthermore, a placement hole is opened in the source bottom; the source core is arranged in the placement hole; preferably, the distance a between the bottom of the placement hole and the bottom of the source core is 0.5-1 mm.

[0015] Furthermore, a mounting groove is provided in the source bottom, and the source cover is arranged in the mounting groove.

[0016] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned gamma radiation source, comprising the following steps:

[0017] Pressing the inorganic adsorption material into a shape to prepare a support body;

[0018] placing the support body into a liquid containing radioactive nuclides and allowing it to stand for a period of time for adsorption to obtain the source core;

[0019] Applying high temperature glue on the outer surface of the obtained source core;

[0020] The source core coated with high temperature glue is placed in the source bottom of the source shell, and the source cover of the source shell is covered. The source bottom and the source cover are welded together by laser welding, and the high temperature glue is cured to form a protective shell of the gamma radiation source.

[0021] Furthermore, the compression molding pressure is 4-6 MPa and the time is 4-6 min;

[0022] and / or, the radionuclide 22 Na and / or 152 Eu; the activity range of the radionuclide is 20 to 25 μCi;

[0023] And / or, the static adsorption time is 0.5-1.5h;

[0024] And / or, the welding is performed under argon protection; the welding energy is 20-40%, the weld width is 1-3 mm, the welding distance is 1-3 cm, the welding table speed is 20-50 r / min, and the welding angle is 365°.

[0025] According to the third aspect of the present invention, the present invention also provides the application of the above-mentioned gamma radiation source, which can be applied to devices or equipment that require a gamma radiation source, such as a gamma radiation source densitometer.

[0026] The technical solution provided by the present invention has the following beneficial effects:

[0027] A gamma radiation source of the present invention comprises a source shell and a source core, wherein the source core is arranged in the source shell, and the source shell plays a protective role on the source core to prevent the radioactive nuclides in the source core from leaking out. The source core comprises a support body made of an inorganic adsorption material and a radioactive nuclide, wherein the support body has adsorption holes inside, and the radioactive nuclides are adsorbed in the adsorption holes. The present invention can play a role in firmly adsorbing the radioactive nuclides by limiting the specific surface area and pore volume of the support body within a reasonable range value, and at the same time, limiting the average pore size of the adsorption holes in the support body within a reasonable range value, so that the pore size of the adsorption holes is close to the size of the radioactive nuclide ions, thereby effectively limiting the movement of the nuclide ions, so that the radioactive nuclides are more stably adsorbed in the support body, and the radioactive nuclides are not easy to leak out.

[0028] The source core of a γ radiation source of the present invention has three safety guarantees. The first is that the inorganic adsorption material with a large specific surface area can firmly adsorb radioactive nuclides; the second is that the high-temperature glue on the surface of the source core will solidify during the welding process to prevent the leakage of radioactive nuclides. The third is that the source shell is laser welded, which is the third safety barrier to prevent the leakage of radioactive nuclides. The source core of the γ radiation source can be made closer to a point source, which can reduce the scattering of the radiation source. The radioactive nuclides in the source core of the present invention are 22 Na, 152 Eu, the activity range is 20-25μCi, which is lower than the national exemption value, more environmentally friendly, and beneficial to the development of the entire industry.

[0029] The preparation method of a gamma radiation source of the present invention is simple, highly safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of the three-dimensional structure of a gamma radiation source provided in Example 1 of the present invention;

[0032] Figure 2 A schematic diagram of the internal structure of a gamma radiation source provided in Example 1 of the present invention;

[0033] Figure 3 This is an XRD diagram of a support in a gamma radiation source provided in Example 1 of the present invention;

[0034] Figure 4 This is a scanning electron microscope image of a support body in a gamma radiation source provided in Example 1 of the present invention.

[0035] Description of the drawings: 1: source shell; 11: source bottom; 12: source cover; 120: groove; 2: source core; 3: protective shell. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the present invention, if the specific technology or conditions are not specified in the examples, the technology or conditions described in the literature in the field or the product instructions are used. If the manufacturer of the instruments is not specified, they are all conventional products that can be purchased through regular channels. The raw materials used in the present invention can be easily purchased in the domestic market.

[0038] The embodiment of the present invention provides a gamma radiation source, such as Figure 1 and Figure 2 As shown, the gamma radiation source comprises a source shell 1 and a source core 2, wherein the source core 2 is arranged in the source shell 1; the source core 2 comprises a support body made of an inorganic adsorption material and a radioactive nuclide, wherein the support body has adsorption holes inside, and the radioactive nuclide is adsorbed in the adsorption holes; the specific surface area of ​​the support body is 200-350m 2 ·g -1 , pore volume is 0.1-0.4cm 2 ·g -1 ; The average pore size of the adsorption pores is 2.5-4.5nm.

[0039] The cross section of the source shell 1 can be square, circular, etc. The cross section of the source core 2 can be square, circular, etc. The cross sections of the source shell 1 and the source core 2 can be set according to different usage requirements.

[0040] Optionally, the specific surface area of ​​the support can be 200m 2 ·g -1 、210m 2 ·g -1 、220m 2 ·g -1 、230m 2 ·g -1 、240m 2 ·g -1 、250m 2 ·g -1 、260m 2 ·g -1 、270m 2 ·g -1 、280m 2 ·g -1 、290m 2 ·g -1 、300m 2 ·g -1 、310m 2 ·g -1 、320m 2 ·g -1 、330m 2 ·g -1 、340m 2 ·g -1 or 350m2 ·g -1 The pore volume can be 0.1 cm 2 ·g -1 、0.15cm 2 ·g -1 , 0.2cm 2 ·g -1 、0.25cm 2 ·g -1 、0.3cm 2 ·g -1 、0.35cm 2 ·g -1 or 0.4cm 2 ·g -1 The average pore size of the adsorption pores may be 2.5 nm, 3 nm, 3.5 nm, 4 nm or 4.5 nm, and of course, it may be other values ​​within the above range, which is not limited here.

[0041] In the above embodiment, the gamma radiation source of the present invention comprises a source shell 1 and a source core 2, wherein the source core 2 is arranged in the source shell 1, and the source shell 1 protects the source core 2 to prevent the radioactive nuclides in the source core 2 from leaking out. The source core 2 comprises a support body made of an inorganic adsorption material and a radioactive nuclide, wherein the support body has adsorption holes inside, and the radioactive nuclides are adsorbed in the adsorption holes. The present invention can play a role in firmly adsorbing the radioactive nuclides by limiting the specific surface area and pore volume of the support body within a reasonable range value, and at the same time, limiting the average pore size of the adsorption holes in the support body within a reasonable range value, so that the pore size of the adsorption holes is close to the size of the radioactive nuclide ions, thereby effectively limiting the movement of the nuclide ions, so that the radioactive nuclides are more stably adsorbed in the support body, and the radioactive nuclides are not easy to leak out.

[0042] In order to more firmly adsorb radionuclides, according to some specific embodiments of the present invention, the specific surface area of ​​the support is 250-300m 2 ·g -1 , pore volume is 0.2-0.3cm 2 ·g -1 ; The average pore size of the adsorption pores is 3-4nm.

[0043] According to some specific embodiments of the present invention, Figure 2As shown, the source core 2 is cylindrical; the diameter of the source core 2 is 1-6mm, and the height is greater than or equal to 1mm; optionally, the diameter of the source core 2 can be 1mm, 2mm, 3mm, 4mm, 5mm or 6mm, etc., and of course it can also be other values ​​within the above range, which is not limited here. The height can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, etc., and of course it can also be other values ​​within the above range, which is not limited here. Preferably, the diameter of the source core 2 is 2-4mm, and the height is 1-3mm.

[0044] In the above embodiment, by limiting the source core 2 to a cylindrical shape and limiting its diameter and height within a reasonable range, it is made closer to a point source, which can effectively reduce the scattering of the radiation source.

[0045] According to some specific embodiments of the present invention, Figure 2 As shown, gamma radiation sources also include:

[0046] A protective shell 3 made of high-temperature glue is coated on the outer surface of the source core 2; preferably, the thickness of the protective shell 3 is 0.5-1.5 mm. Optionally, the thickness of the protective shell 3 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm, etc., and of course it can also be other values ​​within the above range, which is not limited here, and is preferably 0.5-1 mm.

[0047] In the above embodiment, the gamma radiation source of the present invention includes a protective shell 3 made of high temperature glue, which will solidify during the welding process, and spontaneously generate a layer of protective shell 3 formed on the outer surface of the source core 2, which protects the source core 2 and prevents the leakage of radioactive nuclides. Furthermore, by limiting the thickness of the protective shell 3 to a reasonable range, it is more conducive to the protection of the source core 2.

[0048] According to some specific embodiments of the present invention, the source shell 1 is a source shell made of stainless steel; and the support body is a support body made of cerium oxide material.

[0049] According to some specific embodiments of the present invention, Figure 1 and Figure 2 As shown, the source shell 1 includes a source bottom 11 and a source cover 12, and the source bottom 11 and the source cover 12 are connected together by laser welding. The source core 2 is arranged in the source bottom 11.

[0050] In the above embodiment, the source shell 1 includes a source bottom 11 and a source cover 12, and the source bottom 11 and the source cover 12 are connected together by laser welding. The source bottom 11 and the source cover 12 are connected together by laser welding without undergoing high-temperature sintering in a conventional γ radiation source preparation method. The heat generated during the welding process is sufficient to solidify the high-temperature glue and spontaneously generate a layer of protective shell 3, which can avoid the generation of radioactive aerosols.

[0051] According to some specific embodiments of the present invention, a placement hole is provided in the source bottom 11; the source core 2 is disposed in the placement hole; preferably, the distance a between the bottom of the placement hole and the bottom of the source core 2 is 0.5-1 mm. The distance a can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm, etc.

[0052] In the above embodiment, by opening a placement hole in the source bottom 11 and placing the source core 2 in the placement hole, the source core 2 can be restricted to prevent displacement and affect use. Furthermore, by limiting the distance a between the bottom of the placement hole and the bottom of the source core 2 to a reasonable range, the gamma radiation source can fully emit gamma rays, thereby improving the performance of the gamma radiation source.

[0053] According to some specific embodiments of the present invention, Figure 1 and Figure 2 As shown, a mounting groove is provided in the source bottom 11, and the source cover 12 is provided in the mounting groove. In some specific embodiments, the longitudinal section of the mounting groove is U-shaped.

[0054] In the above solution, by providing a mounting groove in the source bottom 11 and arranging the source cover 12 in the mounting groove, the source core 2 can be stably fixed in the source shell 1 without affecting the overall size of the source shell 1 .

[0055] According to some specific embodiments of the present invention, Figure 2 As shown, a groove 120 is provided on the source cover 12. Through the provision of the groove 120, information such as the manufacturer and product model of the gamma radiation source can be etched or pasted into the groove 120, so that it is not easy to be worn during transportation.

[0056] The embodiment of the present invention also provides a method for preparing the above-mentioned gamma radiation source, comprising the following steps:

[0057] Pressing the inorganic adsorption material into a shape to prepare a support body;

[0058] The support is placed in a liquid containing radioactive nuclides and allowed to stand for a period of time for adsorption to obtain a source core 2;

[0059] Apply high temperature glue to the outer surface of the obtained source core 2;

[0060] The source core 2 coated with high temperature glue is placed into the source bottom 11 of the source shell 1, and the source cover 12 of the source shell 1 is covered. The source bottom 11 and the source cover 12 are welded together by laser welding, and the high temperature glue is cured to form the protective shell 3 of the γ radiation source.

[0061] In the above embodiment, the preparation method of the present invention first presses the inorganic adsorption material layer to form an adsorption support body, which adsorbs radioactive nuclides to form a source core 2, and then puts the source shell 1 into the source core 2. The source core 2 is coated with high-temperature glue, and then the source shell 1 is laser welded. The high temperature generated during the welding process will solidify the high-temperature glue to form a protective shell to avoid the generation of radioactive aerosols. Finally, the activity test and leakage test of the radioactive source are performed. The preparation method of the present invention has the following advantages: (1) The innovative structural design makes the source core 2 have a triple safety guarantee. The first is that the inorganic adsorption material with a large specific surface area can firmly adsorb radioactive nuclides; the second is that the high-temperature glue on the surface of the source core 2 will solidify during the welding process to prevent the leakage of radioactive nuclides. The third is that the source shell 1 is laser welded, which is the third safety barrier to prevent the leakage of radioactive nuclides. The preparation method of the γ radiation source of the present invention has the advantages of simple process, high safety, environmental protection, and small scattering.

[0062] According to some specific embodiments of the present invention, the pressure of the pressing molding is 4-6 MPa and the time is 4-6 min.

[0063] In the above embodiment, by limiting the pressure and time of the pressing molding within a reasonable range, it is beneficial to form a support body with a stable structure, not easy to disperse and suitable size, which is beneficial to the stable and effective adsorption of radionuclides.

[0064] According to some specific embodiments of the present invention, the radionuclide 22 Na and / or 152 Eu; the activity range of radionuclides is 20 to 25 μCi.

[0065] According to some specific embodiments of the present invention, the material of the high temperature adhesive may be silicate and inorganic polymer, or copper oxide and inorganic polymer.

[0066] According to some specific embodiments of the present invention, the static adsorption time is 0.5-1.5h.

[0067] In the above embodiment, by limiting the static adsorption time within a reasonable range, it is beneficial to fully adsorb the radioactive nuclides, thereby ensuring the radioactivity of the gamma radiation source.

[0068] According to some specific embodiments of the present invention, welding is performed under argon protection; the welding energy is 20-40%, the weld width is 1-3 mm, the welding distance is 1-3 cm, the welding table speed is 20-50 r / min, and the welding angle is 365°.

[0069] In the above embodiments, the welding efficiency can be improved by limiting the process parameters in the welding process to a reasonable range of values.

[0070] The main equipment and main reagents used in the following examples and comparative examples are shown in Tables 1 and 2 below.

[0071] Table 1 Main equipment

[0072]

[0073] Table 2 Main reagents

[0074]

[0075]

[0076] Example 1

[0077] This embodiment provides a gamma radiation source, such as Figure 1 and Figure 2 As shown, the gamma radiation source includes a source shell 1, a source core 2 and a protective shell 3 made of high-temperature glue. The source shell 1 is made of stainless steel and includes a source bottom 11 and a source cover 12. The source bottom 11 and the source cover 12 are connected together by laser welding. A placement hole is provided in the source bottom 11, and the source core 2 is arranged in the placement hole. The distance a between the bottom of the placement hole and the bottom of the source core 2 is 0.5 mm. A U-shaped mounting groove is provided in the source bottom 11, and the source cover 12 is arranged in the U-shaped mounting groove. The source cover 12 is also provided with a U-shaped groove, which is convenient for engraving product information such as company name and model in the U-shaped groove. The protective shell 3 is coated on the outer surface of the source core 2, and its thickness is 1 mm. A groove 120 is provided on the source cover 12.

[0078] The source core 2 includes a support made of an inorganic adsorption material and a radioactive nuclide 22Na, activity is 25μCi, the support has adsorption pores inside, and the radioactive nuclides are adsorbed in the adsorption pores; the support is cerium oxide synthesized by hydrothermal method, and the specific synthesis method is: CeCl3 (0.04mol) and sodium borohydride are mixed in a certain molar ratio of 1:8, CeCl3 is first dissolved in 80mL of chromatographic pure anhydrous ethanol, and then sodium borohydride is dissolved in 80mL of deionized water, and after sodium borohydride is fully dissolved, the two solutions are quickly added to the colloid mill and fully stirred. Stir for 5 minutes, and then put the solution after the reaction into 80mL polytetrafluoroethylene liner, and hydrothermally crystallize it in an autoclave at 160℃ oven for 15h, and finally centrifuge it, wash it with deionized water until it is neutral, and dry it in an oven at 70℃ overnight. The dried sample is fully ground in a mortar to obtain metal oxide CeO2, and its characteristic XRD peaks are (111), (200), (220), (311), (400), (331), (420) as shown in Figure 2. Figure 3 Scanning electron microscopy shows that CeO2 synthesized by hydrothermal method is petal-shaped. Figure 4 As shown in Figure 2, the fluffy structure is conducive to the adsorption of nuclides. The BET test results show that the specific surface area of ​​CeO2 synthesized by hydrothermal method is 289.1m 2 ·g -1 As shown in Table 3, the specific surface area of ​​commercially available CeO2 is much larger than 51.5 m 2 ·g -1 The large specific surface area is conducive to the adsorption of radionuclides. It can also be seen that the average pore size is 3.6nm, which is close to the size of the nuclide ions and limits the movement of the radionuclides. The source core 2 has a diameter of 2mm and a height of 1mm.

[0079] Table 3 BET test results

[0080]

[0081] Example 2

[0082] The method for preparing the gamma radiation source of Example 1 comprises the following steps:

[0083] (1) Cold pressing of the source core

[0084] Take 0.53g of cerium oxide powder and put it into the tablet press mold. Gently shake the mold back and forth on the table for 6 times to spread the powder evenly on the bottom of the mold. Set the tablet press pressure to 5MPa and the pressing time to 5min. Finally, take out the pressed adsorption column from the mold. The diameter of the adsorption column is 2mm and the height is 1mm.

[0085] (2) Preparation of source shell

[0086] Prepare the source shell and use a laser marker to engrave the company name, nuclide, source number, and source shell structure of the radioactive source.

[0087] (3) Liquid preparation

[0088] According to production needs, use a micro sampler to take samples from the raw material bottle. 22 10 μL of NaCl stock solution (specific activity 1 mCi / mL) was added to a measuring bottle, and the activity A0 (background subtracted) (Bq) was measured using a gamma spectrometer.

[0089] The required activity of the product is A1, and after calculation, V1 = 10 × A1 / A0. V1 is the volume of the radioactive raw material liquid required for source core adsorption.

[0090] (4) Source core preparation

[0091] Use tweezers to pick up the source core and place it in a measuring bottle. Let it stand for adsorption for 1 hour. After the adsorption is completed, place it in a culture dish and dry it with an infrared heat lamp.

[0092] Use tweezers to pick up the dried source core and apply high-temperature glue on its surface, then put the source core into the source shell and cover it with a source cover.

[0093] (5) Welding of source shell

[0094] Use a laser welder to weld the source shell. The specific steps of welding are: open the argon valve and adjust the argon flow rate (15L / min); turn on the power of the laser welder, adjust the welding energy of the laser welder to 30%, the weld width to 2mm, the welding distance to 2cm, the welding table speed to (30r / min), and the welding angle to 365°; wear welding goggles, turn on the welding switch for automatic welding, turn off the machine after the welding gun returns to its original position, and observe whether the weld is complete. After welding, close the argon valve and check the number of radioactive sources.

[0095] (6) Activity measurement

[0096] Place the welded radioactive source on the measuring stand and measure it with a multi-channel gamma spectrometer (the area of ​​the main peak should reach more than 10,000 counts). If the activity meets the requirements, it will be recorded; if it does not meet the requirements, it will be treated as waste.

[0097] (7) Decontamination

[0098] Wipe the surface of the source with an alcohol cotton ball to remove contamination, check with a contamination meter to ensure that there is no radioactive contamination on the surface, and then dry it.

[0099] (8) Appearance inspection

[0100] Observe the weld and the surface of the source body, and it is considered qualified if there is no collapse or hole.

[0101] (9) Leakage test

[0102] Place the radioactive source in a beaker, add 50 mL of deionized water, and then place it in an ultrasonic cleaning machine with an ultrasonic frequency of 40 kHz and an ultrasonic time of 5 minutes. After the ultrasonication is completed, use a high-purity germanium gamma spectrometer to measure the activity of the water sample. After deducting the background, if the total activity is 0, it is qualified.

[0103] The prepared source core was subjected to the following test experiments:

[0104] 1. Source core leaching rate experiment

[0105] Ten CeO2 supports and zeolite molecular sieve supports of the present invention with a diameter of 2 mm and a height of 1 mm were pressed by a tablet press. The pressed CeO2 supports were numbered 1 to 10 and the molecular sieve supports were numbered 11 to 20. They were placed in 20 measuring bottles (the radionuclide of each measuring bottle was 22 The activity of Na is known to be A1, and the volume of the solution is the same) and allowed to stand for adsorption for 1 hour to obtain the source core, and then the source core is taken out and placed in a culture dish to dry. The activity of the solution in the measuring bottle after adsorption is A2, and then the dried source core is placed in a measuring bottle with 5mL of deionized water. After standing for 5 hours, the source core is taken out and the activity of the leachate in the measuring bottle is A3. The leaching rate = A3 / (A1-A2)*100%. 10 data are obtained for each source core, and the leaching rate is calculated as shown in Table 4.

[0106] Table 4

[0107]

[0108] It can be seen from the experimental data in Table 4 that compared with molecular sieves, the use of CeO2 inorganic adsorption material as the support of the source core has a better leaching rate, indicating that CeO2 inorganic adsorption material as the support of the source core can better and more firmly adsorb radioactive nuclides.

[0109] 2. Source core vibration experiment

[0110] Use a tablet press to press 10 CeO2 source cores and zeolite molecular sieve source cores of the present invention with a diameter of 2 mm and a height of 1 mm. The pressed CeO2 source cores are numbered 1 to 10, and the zeolite molecular sieve source cores are numbered 11 to 20. They are placed in 20 source shells respectively, and each source shell is sealed with tape. Then each sample is placed in a plastic bottle respectively, and the bottle is vibrated 50 times while maintaining the same posture. The source core is taken out and visually judged whether the source core is intact. 10 data are obtained for each source core. The integrity rate = number of source cores with intact structure / 10*100%, as shown in Table 5.

[0111] Table 5 Vibration test of source core

[0112] Source Core Materials Source core size Completeness <![CDATA[CeO2]]> Cylinder with a diameter of 2 mm and a height of 1 mm 100％ Molecular sieve Cylinder with a diameter of 2 mm and a height of 1 mm 40％

[0113] It can be seen from the experimental data in Table 5 that compared with molecular sieves, using CeO2 inorganic adsorption material as the support of the source core has better stability.

[0114] 3. Blockage rate experiment

[0115] Take 5 source cores after adsorbing radionuclides according to the present invention, numbered 1 to 5, and the source cores adsorb radionuclides. 22 The activity measured after Na is B1, and the activity measured after loading into the source shell is B2. The blocking rate = (B1-B2) / B1*100%, as shown in Table 6. After calculation, the blocking rate of the source shell to the source core is 5.28%.

[0116] Table 6 Activity blocking experiment of γ radiation source

[0117]

[0118] 4. Leakage test

[0119] Ten gamma radiation sources of Example 1 were prepared and numbered 1 to 10. The activity of each gamma radiation source was measured using a high-purity germanium gamma spectrometer (the count was to reach 10,000 or more). Each gamma radiation source was then placed in a 100 mL beaker, 50 mL of deionized water was added, and the beaker was placed in an ultrasonic cleaning machine with an ultrasonic frequency of 40 kHz and an ultrasonic time of 5 min. After the ultrasonic cleaning was completed, the radiation source was taken out of the beaker and placed in a culture dish under an infrared lamp for drying. The activity of each gamma radiation source in the deionized water was then measured using a high-purity germanium gamma spectrometer. 22 The activity of Na (the count must reach 10,000 or more). If the activity is zero, it is qualified. The leakage test results are shown in Table 7 below.

[0120] Table 7 Leakage experiment of γ radiation source

[0121]

[0122]

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gamma radiation source, characterized in that: include: Source Shell; The source core is arranged in the source shell; the source core comprises a support body made of an inorganic adsorption material and a radioactive nuclide, the support body has adsorption holes inside, and the radioactive nuclide is adsorbed in the adsorption holes; the specific surface area of ​​the support body is 200-350m 2 ·g -1 , pore volume is 0.1-0.4cm 2 ·g -1 ; The average pore size of the adsorption pores is 2.5-4.5nm.

2. The gamma radiation source according to claim 1, characterized in that: The specific surface area of ​​the support is 250-300m 2 ·g -1 , pore volume is 0.2-0.3cm 2 ·g -1 ; The average pore size of the adsorption pores is 3-4nm.

3. The gamma radiation source according to claim 1, characterized in that: The source core is cylindrical; the diameter of the source core is 1-6 mm, and the height is greater than or equal to 1 mm.

4. The gamma radiation source according to claim 3, characterized in that: The source core has a diameter of 2-4 mm and a height of 1-3 mm.

5. The gamma radiation source according to claim 1, characterized in that: Also includes: A protective shell made of high temperature glue is coated on the outer surface of the source core.

6. The gamma radiation source according to claim 1, characterized in that: The source shell is made of stainless steel; the support body is made of cerium oxide material.

7. The gamma radiation source according to claim 1, characterized in that: The source shell comprises a source bottom and a source cover, wherein the source bottom and the source cover are connected together by laser welding; the source core is arranged in the source bottom.

8. The gamma radiation source according to claim 7, characterized in that: A placement hole is provided in the source bottom; the source core is arranged in the placement hole.

9. The gamma radiation source according to claim 8, characterized in that: The distance a between the bottom of the placement hole and the bottom of the source core is 0.5-1 mm.

10. The gamma radiation source according to claim 7, characterized in that: The source bottom is provided with a mounting groove, and the source cover is arranged in the mounting groove.

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