Preparation method of self-supporting Hf isotope target
The preparation of self-supporting Hf isotope targets by magnetic deflection electron gun melting and focused heavy ion sputtering solves the problem of low material utilization in existing technologies and achieves the effect of efficient preparation of self-supporting Hf targets.
Patent Information
- Application Number
- CN202411194562.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-28
- Publication Date
- 2025-01-14
AI Technical Summary
Existing technologies struggle to efficiently prepare self-supporting Hf isotope targets, especially in low-energy nuclear physics, laser nuclear physics, atomic and molecular physics, astrophysical nuclear physics, and nuclear chemistry experiments, where existing methods suffer from low material utilization and high loss rates.
Hf isotope powder material was melted into metal spheres using a magnetic deflection electron gun. An Hf film was deposited on Cu foil by focused heavy ion sputtering. The Cu foil was then gradually removed by combining etching solution and Ar plasma bombardment to obtain a self-supporting Hf target.
This significantly improved the utilization rate of Hf isotope materials, reduced the loss rate during the preparation process, and ensured the quality and integrity of the self-supporting Hf target.
Smart Images
Figure CN119307869A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of nuclear technology application, and in particular relates to a method for preparing a self-supporting Hf isotope target. Background Art
[0002] Self-supporting targets refer to targets that are not supported by carriers during use, and their thickness ranges from tens of nanometers to tens of microns. In many nuclear science studies, especially in low-energy nuclear physics, laser nuclear physics, atomic and molecular physics, astro-nuclear physics and nuclear chemistry experiments, self-supporting targets are needed as target films, peeling films, X-ray reflectors or X-ray filters, etc.
[0003] Metal hafnium Hf has excellent welding performance, processing performance, high temperature resistance and corrosion resistance, and has become an important material in the atomic energy industry. Hafnium has a large thermal neutron capture cross section and is an ideal neutron absorber. It can be used as a control rod and protective device for atomic reactors. 181 Hf(n,g) 182 In the Hf cross-section experiment, a self-supporting Hf isotope target is required as the target material. Summary of the invention
[0004] The purpose of the present invention is to provide a method for preparing a self-supporting Hf isotope target with a mass thickness of 100 to 5000 μg / cm 2 Self-supporting 178 Hf and 180 Hf isotope target, as a basis for ( 18 O, 16 O) Indirect measurement of nuclear astrophysical reactions using the double neutron transfer substitution ratio method 181 Hf(n,g) 182 Target material required for Hf cross-section experiments.
[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a self-supporting Hf isotope target, the method comprising the following steps:
[0006] S1. 178 Hf or 180 Hf isotope powder material is melted into the corresponding 178 Hf or 180 Hf isotope metal pellets;
[0007] S2, preparing Cu foil;
[0008] S3, sputtering deposition on the Cu foil 178 Hf or 180 Hf film, and the corresponding Cu-based 178 Hf film or Cu base 180 Hf film;
[0009] S4, etching and stripping: using an etching solution to remove the Cu-based 178 Hf film or Cu base 180 The Hf film is corroded and stripped, and the Cu foil therein is corroded to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film;
[0010] S5, the unlined 178 Hf film or no liner 180 The Hf membrane was transferred to the deionized water surface for rinsing, and then scooped out with the experimental target frame and dried to obtain the corresponding self-supporting 178 Hf target or self-supporting 180 Hf target.
[0011] Further, step S1 includes the following specific steps: 178 Hf or 180 The Hf isotope powder material is placed in a two-stage stepped truncated cone-shaped water-cooled oxygen-free copper crucible and a magnetic deflection electron beam generated by a magnetic deflection electron gun is used to 178 Hf or 180 Hf isotope powder metal material is sintered and melted into corresponding 178 Hf or 180 Hf isotope metal pellets.
[0012] Further, the inner cavity of the two-stage stepped truncated cone type water-cooled oxygen-free copper crucible is a two-stage stepped truncated cone, including a first-stage truncated cone and a second-stage truncated cone, wherein the first-stage truncated cone includes a first-stage truncated cone bottom surface, a first-stage truncated cone slope surface, and a first-stage truncated cone top surface, and the second-stage truncated cone includes a second-stage truncated cone bottom surface, a second-stage truncated cone slope surface, and a second-stage truncated cone top surface, and the first-stage truncated cone top surface coincides with the second-stage truncated cone bottom surface;
[0013] The first-level truncated cone bottom surface is the inner cavity bottom surface of the second-level stepped truncated cone type water-cooled oxygen-free copper crucible, and the first-level truncated cone slope surface and the second-level truncated cone slope surface constitute the inner cavity side wall of the second-level stepped truncated cone type water-cooled oxygen-free copper crucible.
[0014] Furthermore, the diameter of the bottom surface of the first-level truncated cone is Φ3mm, the diameter of the top surface of the first-level truncated cone is Φ15mm, and the slope angle of the first-level truncated cone is 60°; the diameter of the bottom surface of the second-level truncated cone is Φ15mm, the diameter of the top surface of the second-level truncated cone is Φ30mm, and the slope angle of the second-level truncated cone is 20°.
[0015] Furthermore, in step S1, the melting parameters of the magnetically deflected electron beam generated by the magnetically deflected electron gun are: 270° deflection, high voltage 8kV, beam current 80-150mA; filament current 0.7-0.85A, filament voltage 80-110V, beam spot ~Φ5mm.
[0016] Furthermore, in step S2, the Cu foil is a high-purity Cu foil with a thickness of 10 to 15 μm.
[0017] Further, in step S3, the Cu foil is used as a substrate, the Cu foil is fixed by a target frame and then mounted on a target bracket, and a focused heavy ion sputtering method is used to bombard the Cu foil with a high-energy ion beam. 178 Hf or 180 Hf isotope metal beads are sputtered and deposited on the Cu foil with a mass thickness of 100 to 5000 μg / cm 2 of 178 Hf or 180 Hf film, and the corresponding Cu-based 178 Hf film or Cu base 180 Hf film.
[0018] Further, the etching solution is CCl 3 CO 2 NH 4 Solution.
[0019] Further, in step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 100~300μg / cm 2 When the Cu-based 178 Hf film or Cu base 180 Hf film, directly the Cu-based 178 Hf film or Cu base 180 The Hf film is placed in the etching solution to be corroded and removed to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film.
[0020] Further, in step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 300~800μg / cm 2 When the Cu substrate is etched with an etching solution 178 Hf film or Cu base 180 Before the Hf film is corroded and stripped, the following steps are also included: taking out the Cu-based 178 Hf film or Cu base 180 After Hf film, the Cu-based 178 Hf film or Cu base 180 The entire Hf film is subjected to high vacuum annealing treatment.
[0021] Furthermore, the process condition parameters of the high vacuum annealing treatment are: vacuum is less than 5×
[0022] 10 -4 Pa, annealing temperature 600℃, lasting 30 to 60 minutes.
[0023] Further, in step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 800~5000μg / cm 2 When the Cu substrate is etched with an etching solution 178 Hf film or Cu base 180 Before the Hf film is corroded and stripped, the following steps are also included: sputtering and depositing a mass thickness of 800 to 5000 μg / cm on the Cu foil. 2 of 178 Hf film or 180 Hf film, sandwiching the Cu substrate 178 Hf film or Cu base 180 The target frame of the Hf film was taken out as a whole and installed just below the substrate of another vacuum chamber. The Cu substrate was bombarded by Ar plasma. 178 Hf film or Cu base 180 Hf film.
[0024] Further, the process condition parameters for generating the Ar plasma are as follows: when the local vacuum of the other vacuum chamber is evacuated to less than 5×10 -4 After the pressure of Ar in the other vacuum chamber reaches 2 Pa, Ar is introduced into the other vacuum chamber at a flow rate of 80-90 sccm, corresponding to a pressure of Ar in the other vacuum chamber of 2 Pa and maintained, and a negative high voltage of 800-1000 V is applied to the substrate in the other vacuum chamber to generate glow discharge to form Ar plasma, and the Cu substrate is 178 Hf film or Cu base 180 The Hf film was bombarded for 10 to 20 minutes.
[0025] The beneficial effect of the present invention is that: a method for preparing a self-supporting Hf isotope target provided by the present invention is adopted, through the following steps: 178 Hf or 180 Hf isotope powder material is melted into the corresponding 178 Hf or 180 Hf isotope metal beads are used to prepare Cu foil; sputtering and depositing a mass thickness of 100 to 5000 μg / cm on the Cu foil 2 of 178 Hf or 180 Hf film, and the corresponding Cu-based 178Hf film or Cu base 180 Hf film; using an etching solution to the Cu base 178 Hf film or Cu base 180 The Hf film is corroded and stripped, and the Cu foil therein is corroded to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film; the unlined 178 Hf film or no liner 180 The Hf membrane was transferred to the deionized water surface for rinsing, and then scooped out with the experimental target frame and dried to obtain the corresponding self-supporting 178 Hf target or self-supporting 180 Hf target. The specific beneficial effects of the present invention are mainly reflected in:
[0026] (1) The method first 178 Hf or 180 The Hf isotope powder material is melted by means of a magnetic deflection electron gun and a two-stage stepped frustum-shaped water-cooled oxygen-free copper crucible to form the corresponding 178 Hf or 180 The Hf isotope metal pellets are then bombarded by a high-energy ion beam using a focused heavy ion sputtering method. 178 Hf or 180 Hf isotope metal pellets 178 Hf or 180 Hf isotope sputtering deposition on Cu foil significantly improves 178 Hf or 180 The utilization rate of Hf isotope powder materials has greatly reduced 178 Hf or 180 Loss rate of Hf isotope powder material during the preparation process.
[0027] (2) For different thicknesses 178 Hf film or 180 The internal stress of Hf film is different. The thicker the film, the 178 Hf film or 180 The more difficult it is to directly remove the Hf film by etching, the more difficult it is to obtain the Cu-based 178 Hf film or Cu base 180 The thickness of the Hf film is determined by direct etching, high vacuum annealing followed by etching, or Ar plasma bombardment followed by etching. 178 Hf film or no liner 180 After the Hf membrane is transferred to the deionized water surface for rinsing and finally picked up with the experimental target frame and dried, the corresponding self-supporting 178 Hf target or self-supporting 180 Hf target. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1It is a schematic flow chart of a method for preparing a self-supporting Hf isotope target according to an embodiment of the present invention;
[0029] Figure 2 It is a two-stage stepped truncated cone-shaped water-cooled oxygen-free copper crucible described in this embodiment of the present invention. DETAILED DESCRIPTION
[0030] The technical solutions in the embodiments of the present invention will be further clearly and completely described below in conjunction with the drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0031] In the embodiment of the present invention, a method for preparing a material having a mass thickness of 100 to 5000 μg / cm 2 Self-supporting 178 Hf and 180 Hf isotope target, used as a 18 O, 16 O) Indirect measurement of nuclear astrophysical reactions using the double neutron transfer substitution ratio method 181 Hf(n,g) 182 Target material in Hf cross-section experiment.
[0032] The inventors found in their research that when a high-energy ion beam is used to directly bombard Hf isotope powder material in the focused heavy ion sputtering method, the Hf isotope is sputtered and deposited on the Cu foil, 178 Hf or 180 Hf isotope powder material will be lost in large quantities due to scattering and splashing during the sputtering process. Considering that Hf isotope material is expensive and in small quantities (200 mg, about $100 / mg), in order to improve the material utilization rate in the target making process, the inventors first 178 Hf or 180 Hf isotope powder material is melted into the corresponding 178 Hf or 180 The Hf isotope metal pellets are then bombarded by a high-energy ion beam using a focused heavy ion sputtering method. 178 Hf or 180 Hf isotope metal pellets 178 Hf or 180 Hf isotope sputtering is deposited on Cu foil. 178 Hf or 180 Hf isotope powder material is placed in Figure 2 In the two-stage stepped truncated cone-shaped water-cooled oxygen-free copper crucible shown in the figure, the electron beam generated by the magnetic deflection electron gun is used to 178 Hf or 180Hf isotope powder metal material is sintered and melted into corresponding 178 Hf or 180 The Hf isotope metal pellets are then focused heavy ion sputtering to 178 Hf or 180 Hf isotope metal pellets were sputter-deposited on Cu foil.
[0033] With direct 178 Hf or 180 Compared with the sputtering deposition of Hf isotope powder material on Cu foil, the method provided by this embodiment significantly improves 178 Hf or 180 Utilization rate of Hf isotope powder material ( 178 Hf or 180 The utilization rate of Hf isotope powder materials has been increased by more than 50%), which has greatly reduced 178 Hf or 180 The loss rate of the Hf isotope powder material during the preparation process is about 6.5% in the method provided in this embodiment.
[0034] like Figures 1-2 As shown, this embodiment provides a method for preparing a self-supporting Hf isotope target, the method comprising the following steps:
[0035] S1. 178 Hf or 180 Hf isotope powder material is melted into the corresponding 178 Hf or 180 Hf isotope metal pellets;
[0036] Specifically, step S1 includes the following specific steps: 178 Hf or 180 Hf isotope powder material is placed in Figure 2 In the two-stage stepped truncated cone-shaped water-cooled oxygen-free copper crucible shown in FIG. 1 , a magnetic deflection electron beam generated by a magnetic deflection electron gun is used to 178 Hf or 180 Hf isotope powder metal material is sintered and melted into corresponding 178 Hf or 180 Hf isotope metal pellets.
[0037] The inner cavity of the two-stage stepped truncated cone type water-cooled oxygen-free copper crucible is designed and processed into a two-stage stepped truncated cone shape, including a first-stage truncated cone and a second-stage truncated cone, wherein the first-stage truncated cone includes a first-stage truncated cone bottom surface, a first-stage truncated cone slope surface, and a first-stage truncated cone top surface, and the second-stage truncated cone includes a second-stage truncated cone bottom surface, a second-stage truncated cone slope surface, and a second-stage truncated cone top surface, and the first-stage truncated cone top surface coincides with the second-stage truncated cone bottom surface; the first-stage truncated cone bottom surface is the inner cavity bottom surface of the two-stage stepped truncated cone type water-cooled oxygen-free copper crucible, and the first-stage truncated cone slope surface and the second-stage truncated cone slope surface constitute the inner cavity side wall of the two-stage stepped truncated cone type water-cooled oxygen-free copper crucible. In such as Figure 2 In the embodiment shown, the diameter of the bottom surface of the first-level cone is Φ3mm, the diameter of the top surface of the first-level cone is Φ15mm, and the slope angle of the first-level cone is 60°; the diameter of the bottom surface of the second-level cone is Φ15mm, the diameter of the top surface of the second-level cone is Φ30mm, and the slope angle of the second-level cone is 20°.
[0038] In the two-stage stepped truncated cone type water-cooled oxygen-free copper crucible, a smaller Φ3mm first-stage truncated cone bottom surface and a first-stage truncated cone slope angle of 60° are used to transfer the molten 178 Hf or 180 The Hf isotope powder metal material automatically gathers on the bottom surface of the first-stage truncated cone to form a corresponding 178 Hf or 180 Hf isotope metal pellets are used to avoid the melting of the large bottom surface of the commonly used crucible. 178 Hf or 180 The Hf isotope powder metal material is scattered and cannot be gathered together to form metal balls; the top surface of the secondary truncated cone is Φ30mm and the slope angle of the secondary truncated cone is 20°, which can 178 Hf or 180 Hf isotope powder metal materials are automatically collected back to the bottom of the first stage frustum, and try to avoid 178 Hf or 180 Loss of Hf isotope powder metal material.
[0039] In a specific embodiment, in step S1, the melting parameters of the magnetically deflected electron beam generated by the magnetically deflected electron gun are: 270° deflection, high voltage 8kV, beam current 80-150mA; filament current 0.7-0.85A, filament voltage 80-110V, beam spot ~Φ5mm.
[0040] S2, preparing Cu foil;
[0041] Optionally, in step S2, the Cu foil is a fresh high-purity Cu foil with a thickness of 10 to 15 μm, wherein the Cu content in the high-purity Cu foil is not less than 99.95%; fresh means that the surface of the high-purity Cu foil is almost not oxidized and is a high-purity Cu foil that has just been rolled.
[0042] Specifically, in step S2, the fresh high-purity Cu foil with a thickness of 10 to 15 μm is rolled by a double-roll cold rolling mill.
[0043] The inventors found in this embodiment that if the high-purity Cu foil rolled by a double-roll cold rolling mill is not used, but is left for a few days before use, since some oxides exist on the surface of the Cu foil after being left for a period of time, the corresponding linerless Cu foil obtained in the subsequent step S4 of etching and stripping will be 178 Hf film or without liner 180 Hf film may be difficult to remove and may have pinholes or sand spots on the surface.
[0044] S3, sputtering deposition mass thickness on the Cu foil is 100-5000 μg / cm 2 of 178 Hf or 180 Hf film, and the corresponding Cu-based 178 Hf film or Cu base 180 Hf film;
[0045] Specifically, in step S3, the Cu foil is used as a substrate, the Cu foil is fixed by a target frame and then mounted on a target bracket, and a focused heavy ion sputtering method is used to bombard the Cu foil with a high-energy ion beam. 178 Hf or 180 Hf isotope metal beads are sputtered and deposited on the Cu foil (the substrate) with a mass thickness of 100 to 5000 μg / cm 2 of 178 Hf or 180 Hf film, and the corresponding Cu-based 178 Hf film or Cu base 180 Hf film.
[0046] In a specific embodiment, step S3 adopts a focused heavy ion sputtering method, wherein the Cu foil (substrate) is fixed by a target frame and then mounted on a target support, and bombarded by a high energy ion beam. 178 Hf or 180 Hf isotope metal beads are sputtered and deposited on the substrate (the Cu foil) with a mass thickness of 100 to 5000 μg / cm 2 of 178 Hf or 180 When sputtering Hf film, the relevant sputtering process parameters used are: sputtering ion Ar + , acceleration voltage -10KV, focusing voltage 300~700V, discharge voltage 900~1200V, magnetic field voltage 8.8~9.5V, discharge pressure 5.5~6.5Pa, vacuum chamber background vacuum 6.3×10 -4 Pa.
[0047] S4, etching and stripping: using an etching solution to remove the Cu-based 178 Hf film or Cu base 180 The Hf film is corroded and stripped, and the Cu foil therein is corroded to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film.
[0048] Specifically, the etching solution is CCl 3 CO 2 NH 4 Solution (ammonium trichloroacetate solution), which is prepared from trichloroacetic acid, ammonia and deionized water. In a specific embodiment, CCl 3 CO 2 NH 4 The raw material composition of the solution is: 9gCCl 3 CO 2 H+45ml NH 4 OH+45ml H 2 O.
[0049] Optionally, in step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 100~300μg / cm 2 When the Cu-based 178 Hf film or Cu base 180 Hf film, the Cu-based 178 Hf film or Cu base 180 The Hf film is placed in the etching solution to be corroded and removed to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film.
[0050] Optionally, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 300~800μg / cm 2 When 178 Hf film or 180 The internal stress of Hf film is large, and directly placing it in the etching solution to corrode and remove the film will result in a linerless 178 Hf film or no liner 180 The Hf film curls up and sinks into the etching solution, eventually resulting in a linerless 178 Hf film or no liner 180 The Hf film cannot be flattened and cannot be fixed by floating, and may even break.178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 300~800μg / cm 2 When the Cu substrate is etched with an etching solution 178 Hf film or Cu base 180 Before the Hf film is corroded and stripped, the following steps are also included: taking out the Cu-based 178 Hf film or Cu base 180 After Hf film, the Cu-based 178 Hf film or Cu base 180 The entire Hf film is subjected to high vacuum annealing treatment.
[0051] In a specific embodiment, the process condition parameters of the high vacuum annealing treatment are: the vacuum is less than 5×10 -4 Pa, annealing temperature is about 600℃, and lasts for 30 to 60 minutes.
[0052] When the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 800~5000μg / cm 2 When 178 Hf film or 180 The internal stress of Hf film is very large, and the Cu-based 178 Hf film or Cu base 180 When the Hf film is taken out of the target frame, it is severely curled as a whole. If it is directly placed in the etching solution for etching and film removal, it will result in a linerless 178 Hf film or no liner 180 The Hf film curls up and sinks into the etching solution, eventually resulting in a linerless 178 Hf film or no liner 180 The Hf film cannot be flattened and floated and fixed, and may even break; it also cannot be flattened for the high vacuum annealing treatment.
[0053] Therefore, optionally, in step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 800~5000μg / cm 2 When the Cu substrate is etched with an etching solution 178 Hf film or Cu base 180 Before the Hf film is corroded and stripped, the following steps are also included: sputtering and depositing a mass thickness of 800 to 5000 μg / cm on the Cu foil. 2of 178 Hf film or 180 Hf film, sandwiching the Cu substrate 178 Hf film or Cu base 180 The target frame of the Hf film was taken out as a whole and installed just below the substrate of another vacuum chamber. The Cu substrate was bombarded by Ar plasma. 178 Hf film or Cu base 180 Hf film, remove 178 Hf film or 180 Stress inside the Hf film.
[0054] In a specific embodiment, the process condition parameters for the Ar plasma generation are: when the local vacuum of the other vacuum chamber is evacuated to less than 5×10 -4 After the pressure of Ar in the other vacuum chamber reaches 2 Pa, Ar is introduced into the other vacuum chamber at a flow rate of 80-90 sccm, corresponding to a pressure of Ar in the other vacuum chamber of 2 Pa and maintained, and a negative high voltage of 800-1000 V is applied to the substrate in the other vacuum chamber to generate glow discharge to form Ar plasma, and the Cu substrate is 178 Hf film or Cu base 180 The Hf film was bombarded for 10 to 20 minutes.
[0055] S5, the unlined 178 Hf film or no liner 180 The Hf membrane was transferred to the deionized water surface for rinsing, and then scooped out with the experimental target frame and dried to obtain the corresponding self-supporting 178 Hf target or self-supporting 180 Hf target.
[0056] Specifically, a glass slide is used to place the unlined substrate floating on the etching solution. 178 Hf film or 180 The Hf membrane was transferred to deionized water for rinsing.
[0057] The method described in the present invention is not limited to the specific embodiments described. The above embodiments are only examples of the present invention. The present invention can also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present invention. Therefore, the described embodiments should be regarded as illustrative rather than restrictive in any respect. The scope of the present invention should be described by the attached claims, and any changes equivalent to the intent and scope of the claims should also be included in the scope of the present invention.
Claims
1. A method for preparing a self-supporting Hf isotope target, characterized in that: The method comprises the following steps: S1. 178 Hf or 180 Hf isotope powder material is melted into the corresponding 178 Hf or 180 Hf isotope metal pellets; S2, preparing Cu foil; S3, sputtering deposition on the Cu foil 178 Hf or 180 Hf film, and the corresponding Cu-based 178 Hf film or Cu base 180 Hf film; S4, etching and stripping: using an etching solution to remove the Cu-based 178 Hf film or Cu base 180 The Hf film is corroded and stripped, and the Cu foil therein is corroded to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film; S5, the unlined 178 Hf film or no liner 180 The Hf membrane was transferred to the deionized water surface for rinsing, and then scooped out with the experimental target frame and dried to obtain the corresponding self-supporting 178 Hf target or self-supporting 180 Hf target.
2. The method for preparing a self-supporting Hf isotope target according to claim 1, characterized in that: Step S1 includes the following specific steps: 178 Hf or 180 The Hf isotope powder material is placed in a two-stage stepped truncated cone-shaped water-cooled oxygen-free copper crucible and a magnetic deflection electron beam generated by a magnetic deflection electron gun is used to 178 Hf or 180 Hf isotope powder metal material is sintered and melted into corresponding 178 Hf or 180 Hf isotope metal pellets.
3. The method for preparing a self-supporting Hf isotope target according to claim 2, characterized in that: The inner cavity of the two-stage stepped truncated cone type water-cooled oxygen-free copper crucible is a two-stage stepped truncated cone, including a first-stage truncated cone and a second-stage truncated cone, wherein the first-stage truncated cone includes a first-stage truncated cone bottom surface, a first-stage truncated cone slope surface, and a first-stage truncated cone top surface, and the second-stage truncated cone includes a second-stage truncated cone bottom surface, a second-stage truncated cone slope surface, and a second-stage truncated cone top surface, and the first-stage truncated cone top surface coincides with the second-stage truncated cone bottom surface; The first-level truncated cone bottom surface is the inner cavity bottom surface of the second-level stepped truncated cone type water-cooled oxygen-free copper crucible, and the first-level truncated cone slope surface and the second-level truncated cone slope surface constitute the inner cavity side wall of the second-level stepped truncated cone type water-cooled oxygen-free copper crucible.
4. The method for preparing a self-supporting Hf isotope target according to claim 3, characterized in that: The diameter of the bottom surface of the first-level truncated cone is Φ3mm, the diameter of the top surface of the first-level truncated cone is Φ15mm, and the slope angle of the first-level truncated cone is 60°. The diameter of the bottom surface of the second-level truncated cone is Φ15mm, the diameter of the top surface of the second-level truncated cone is Φ30mm, and the slope angle of the second-level truncated cone is 20°.
5. The method for preparing a self-supporting Hf isotope target according to claim 1, characterized in that: In step S1, the melting parameters of the magnetically deflected electron beam generated by the magnetically deflected electron gun are: 270° deflection, high voltage 8kV, beam current 80-150mA; filament current 0.7-0.85A, filament voltage 80-110V, beam spot ≈Φ5mm.
6. The method for preparing a self-supporting Hf isotope target according to claim 1, characterized in that: In step S2, the Cu foil is a high-purity Cu foil with a thickness of 10 to 15 μm.
7. The method for preparing a self-supporting Hf isotope target according to claim 1, characterized in that: In step S3, the Cu foil is used as a substrate, the Cu foil is fixed by a target frame and then mounted on a target bracket, and a focused heavy ion sputtering method is used to bombard the Cu foil with a high-energy ion beam. 178 Hf or 180 Hf isotope metal beads are sputtered and deposited on the Cu foil with a mass thickness of 100 to 5000 μg / cm 2 of 178 Hf or 180 Hf film, and the corresponding Cu-based 178 Hf film or Cu base 180 Hf film.
8. The method for preparing a self-supporting Hf isotope target according to claim 1, characterized in that: The etching solution is CCl3CO2NH4 solution.
9. The method for preparing a self-supporting Hf isotope target according to claim 8, characterized in that: In step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 100~300μg / cm 2 When the Cu-based 178 Hf film or Cu base 180 Hf film, directly the Cu-based 178 Hf film or Cu base 180 The Hf film is placed in the etching solution to be corroded and removed to obtain the corresponding liner-free 178 Hf film or no liner 180 Hf film.
10. The method for preparing a self-supporting Hf isotope target according to claim 8, characterized in that: In step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 300~800μg / cm 2 When the Cu substrate is etched with an etching solution 178 Hf film or Cu base 180 Before the Hf film is corroded and stripped, the following steps are also included: taking out the Cu-based 178 Hf film or Cu base 180 After Hf film, the Cu-based 178 Hf film or Cu base 180 The entire Hf film is subjected to high vacuum annealing treatment.
11. The method for preparing a self-supporting Hf isotope target according to claim 10, characterized in that: The process condition parameters of the high vacuum annealing treatment are: vacuum is less than 5× 10 -4 Pa, annealing temperature 600℃, lasting 30 to 60 minutes.
12. The method for preparing a self-supporting Hf isotope target according to claim 8, characterized in that: In step S4, when the Cu-based 178 Hf film or Cu base 180 In Hf film, the corresponding 178 Hf film or 180 Hf film thickness is 800~5000μg / cm 2 When the Cu substrate is etched with an etching solution 178 Hf film or Cu base 180 Before the Hf film is corroded and stripped, the following steps are also included: sputtering and depositing a mass thickness of 800 to 5000 μg / cm on the Cu foil. 2 of 178 Hf film or 180 Hf film, sandwiching the Cu substrate 178 Hf film or Cu base 180 The target frame of the Hf film was taken out as a whole and installed just below the substrate of another vacuum chamber. The Cu substrate was bombarded by Ar plasma. 178 Hf film or Cu base 180 Hf film.
13. The method for preparing a self-supporting Hf isotope target according to claim 12, characterized in that: The process parameters for generating the Ar plasma are as follows: when the local vacuum of the other vacuum chamber is evacuated to less than 5×10 -4 After the pressure of Ar in the other vacuum chamber reaches 2 Pa, Ar is introduced into the other vacuum chamber at a flow rate of 80-90 sccm, corresponding to a pressure of Ar in the other vacuum chamber of 2 Pa and maintained, and a negative high voltage of 800-1000 V is applied to the substrate in the other vacuum chamber to generate glow discharge to form Ar plasma, and the Cu substrate is 178 Hf film or Cu base 180 The Hf film was bombarded for 10 to 20 minutes.