A boron-coated ceramic gem film, its preparation method and application

Abstract

The present application relates to a boron-coated ceramic GEM film and a preparation method and application thereof, the boron-coated ceramic GEM film comprising a ceramic GEM film substrate lower layer, a Ti primer intermediate layer and a B4C neutron conversion upper layer. 10 The boron-coated ceramic GEM film is prepared by the following method: (1) Ti target material is sputtered onto the surface of the ceramic GEM film by magnetron sputtering to obtain a ceramic GEM film plated with a Ti primer intermediate layer; (2) boron carbide target material is sputtered onto the surface of the obtained Ti primer intermediate layer by magnetron sputtering, and then the target product is obtained through mechanical punching, chemical etching and cleaning. The boron-coated ceramic GEM film can be applied to a boron-coated GEM neutron detector. Compared with the prior art, the boron-coated ceramic GEM film prepared by the method of "coating film first and then punching" will not have boron carbide deposited in the holes. By using a nanoscale thickness Ti layer as a primer, the adhesion of the boron carbide film to the surface of the ceramic GEM film is increased, so that the film will not fall off in the subsequent processing process.

Description

Technical Field

[0001] The invention belongs to the technical field of particle detection and relates to a boron-coated ceramic GEM film and a preparation method and application thereof. Background Art

[0002] 3 He has a large cross section for thermal neutron reactions and is a good neutron absorbing material. 3 He reserves are very limited and expensive, so the development of alternative 3 The He tube solution is under continuous research. Among them, the method of using boron carbide film as the neutron conversion layer has become one of the popular solutions. 10 The B element undergoes a nuclear reaction, and secondary charged ions are generated, which escape from the conversion layer film and enter the working gas. The detection efficiency depends on the neutrons being 10 The product of the efficiency of B absorption and the probability of charged ions being ejected from the boron layer. 10 B4C thin film is a key component of boron-based neutron detectors. With the advent of gas electron multiplier (GEM) detectors, the stability requirements for B4C have increased further. Indirect detection of particles or radiation occurs through their interaction with matter. Gas detectors use gas as the detection medium. As particles pass through the gas, electrons and ions are generated. The detectors collect these electrons and ions to measure the particles. Magnetron sputtering technology can deposit large, highly uniform thin films, meeting the requirements for manufacturing boron-coated neutron detectors. 10 B4C or B4C is the preferred 10 B material is suitable for magnetron sputtering targets because of its high boron content, excellent wear resistance and thermochemical stability.

[0003] The traditional boron coating process for ceramic GEM membranes is "drilling first, then coating", that is, the hole structure on the surface of the ceramic GEM membrane is first processed, and then the surface is boron coated. However, this method easily deposits boron carbide into the holes on the surface of the ceramic GEM membrane during boron coating, resulting in conduction on both sides of the ceramic GEM membrane during actual detection, and then causing a short circuit when pressure is applied on both sides, seriously affecting the detection effect.

[0004] Therefore, for the surface boron coating process of ceramic GEM membrane, how to ensure that boron carbide does not enter the surface pore structure during the deposition process has become a key issue that needs to be solved urgently, and the need to develop a new preparation process is imminent. Summary of the Invention

[0005] The application aims to provide a boron-coated ceramic GEM film, a preparation method and application thereof, so as to overcome the following defects in the prior art: during the preparation of the boron-coated ceramic GEM film, boron carbide is easily deposited into the surface pores of the ceramic GEM film.

[0006] The application aims to provide a boron-coated ceramic GEM film, a preparation method and application thereof, so as to overcome the following defects in the prior art: during the preparation of the boron-coated ceramic GEM film, boron carbide is easily deposited into the surface pores of the ceramic GEM film.

[0007] The application aims to provide a boron-coated ceramic GEM film, a preparation method and application thereof, so as to overcome the following defects in the prior art: during the preparation of the boron-coated ceramic GEM film, boron carbide is easily deposited into the surface pores of the ceramic GEM film. 10 B4C neutron conversion upper layer, the method comprising the following steps:

[0008] (1) sputtering the target material Ti onto the surface of the ceramic GEM film by magnetron sputtering to obtain a ceramic GEM film coated with a Ti primer intermediate layer;

[0009] (2) sputtering the target material boron carbide onto the surface of the obtained Ti primer intermediate layer by magnetron sputtering, and then obtaining the target product through mechanical punching, chemical etching and cleaning.

[0010] Further, in step (1), the magnetron sputtering power is 500-1500 W, which can be 1000 W.

[0011] Further, in step (1), the purity of the target material Ti is ≥ 99.99%.

[0012] Further, in step (1), during the magnetron sputtering process, the base vacuum degree of the sputtering chamber is 1x10 -4 -2x10 -4 Pa, which can be 1x10 -4 Pa.

[0013] Further, in step (1), during the magnetron sputtering process, the working gas is argon with a purity of 99.999%, the argon flow rate is 10-20 sccm, and the gas pressure is 0.3-0.6 Pa.

[0014] Further, in step (1), the ceramic GEM film is also subjected to surface pretreatment before use, and the application does not have any special limitations on the pretreatment, which can be performed by using a pretreatment process well known to those skilled in the art.

[0015] Further, in step (2), the magnetron sputtering power is 2000-3000 W, which can be 2400 W.

[0016] Further, in step (2), during the magnetron sputtering process, the base vacuum degree of the sputtering chamber is 1x10 -4 -2x10 -4 Pa, which can be 1x10-4 Pa.

[0017] Furthermore, in step (2), during the magnetron sputtering process, the working gas is argon with a purity of 99.999%, an argon flow rate of 10 to 20 sccm, and a gas pressure of 0.3 to 0.6 Pa, optionally 0.4 Pa.

[0018] Furthermore, in step (2), the target boron carbide 10 The content of B is ≥96%.

[0019] Furthermore, in step (1) and step (2), the magnetron sputtering is DC magnetron sputtering.

[0020] Furthermore, the thickness of the Ti bottoming intermediate layer is 50-150 nm, and can be optionally 100 nm.

[0021] Furthermore, the 10 The thickness of the B4C neutron conversion upper layer is 1 to 3 μm, and can be optionally 1.2 μm.

[0022] The second technical solution of the present invention provides a boron-coated ceramic GEM membrane, which is prepared by the above-mentioned preparation method.

[0023] Furthermore, the size of the boron-coated ceramic GEM membrane is 50 mm×50 mm to 200 mm×200 mm.

[0024] The third technical solution of the present invention provides the application of the above-mentioned boron-coated ceramic GEM film, which is applied to a boron-coated GEM neutron detector.

[0025] The boron coating process for the ceramic GEM membrane of the present invention can be summarized as "film coating first, then drilling." Specifically, before the microscopic pore structure on the GEM membrane surface is formed, the thin film is first plated, followed by mechanical drilling and chemical etching in the factory. This ensures that the ceramic GEM membrane surface is free of pores during the thin film deposition process. The resulting boron-coated ceramic GEM membrane is free of boron carbide deposits in the pores, thus avoiding cross-conductivity issues during subsequent testing. Furthermore, the presence of the Ti primer layer significantly enhances the adhesion of the boron carbide film to the ceramic GEM membrane substrate, enabling the film to withstand subsequent drilling and etching processes without dislodging. Its mechanism of action is as follows:

[0026] The interface between the sputtered film and the ceramic GEM film substrate is a diffusion-like interface, and the adhesion is mainly derived from diffusion adhesion and mechanical locking. If a chemical reaction can occur between the sputtered film and the ceramic GEM film substrate, the chemical bond force has a great influence on the adhesion. The surface of the ceramic GEM film is Cu, and since the bonding force between boron carbide and Cu is smaller than the bonding force inside Cu, the boron carbide particles diffused into the inside of Cu still exist in the form of atoms, resulting in that the boron carbide film is easy to fall off. If a Ti layer is plated on the Cu surface in advance, since the bonding force between Ti and boron carbide is greater, and it is easy to oxidize, a chemical bond will be formed, and Ti and Cu interdiffuse and combine well, and the existence of the Ti layer enhances the adhesion between boron carbide and the substrate. The thickness of the Ti primer layer must be moderate, that is, 50-150 nm. If the thickness is too small, it will lead to uneven film formation and discontinuous film layer, and may cause the boron carbide film in the local area to fall off; if the thickness is too large, it will lead to the grain growth of the Ti layer, the interatomic force is increased, the formation of chemical bonds is affected, and the adhesion is reduced.

[0027] The selected magnetron sputtering power, background vacuum degree and gas pressure of the application are the optimal sputtering power, optimal working gas pressure and highest background vacuum of the experimental machine, and the process exploration proves that the film quality under this process is the best.

[0028] Compared with the prior art, the application has the following advantages:

[0029] (1) The application adopts the method of "coating film first and then punching holes", and the prepared boron-coated ceramic GEM film will not deposit boron carbide in the holes, solving the problem of conducting on both sides of the boron-coated ceramic GEM film in the prior art, and short circuit phenomenon will not occur during detection;

[0030] (2) The application uses a Ti layer with a nanoscale thickness as a primer, and uses the excellent adhesion of the Ti layer to boron carbide and Cu to connect the lower layer of the ceramic GEM film substrate and the upper layer of the B4C neutron conversion layer, increase the adhesion of the boron carbide film to the surface of the ceramic GEM film, and prevent the film from falling off during subsequent processing. 10 B4C BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The structure diagram of the boron-coated ceramic GEM film prepared in Example 1 is shown in the figure.

[0032] Figure 2 The microstructure diagram of the ceramic GEM film in Example 1 is shown in the figure.

[0033] Figure 3 The adhesive tape tearing test result diagram of the boron-coated ceramic GEM film prepared in Example 1 and Comparative Example 1 is shown in the figure.

[0034] MARKED DESCRIPTION IN THE FIGURE:

[0035] 1 - Ceramic GEM membrane substrate lower layer, 2 - Ti undercoating intermediate layer, 3 - 10 B4C neutron conversion upper layer. DETAILED DESCRIPTION

[0036] The application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0037] In the following embodiments, if no special raw materials or processing techniques are specified, it is indicated that the conventional commercially available raw material products or conventional processing techniques in the art are used.

[0038] In the following embodiments, the ceramic GEM membrane substrate lower layer 1 used is self-developed by the laboratory (China Spallation Neutron Source Gas Detector Group), and the model is 50x50mm, 100x100mm, and 200x200mm (Zhou Jianrong. Two-dimensional position-sensitive GEM neutron detector research[D]. Lanzhou University, 2020).

[0039] Embodiment 1:

[0040] The embodiment provides a boron-coated ceramic GEM membrane, which has the structure as shown in Figure 1 The boron-coated ceramic GEM membrane includes the following three-layer structure:

[0041] Ceramic GEM membrane substrate lower layer 1: an unperforated ceramic GEM membrane, Figure 2 is a microstructure diagram of the ceramic GEM membrane substrate lower layer 1, which is composed of three layers, i.e., the intermediate layer is a 168μm-thick Si, and the upper and lower layers are 16μm-thick Cu.

[0042] Ti undercoating intermediate layer 2: a Ti layer with a thickness of 50nm.

[0043] 10 B4C neutron conversion upper layer 3: a B4C layer with a thickness of 1.2μm. 10

[0044] The preparation process of the boron-coated ceramic GEM membrane is as follows:

[0045] The selected target materials are a Ti target with a purity of 99.99% and a concentrated boron carbide target with a B content of 96%. 10

[0046] First, the unperforated ceramic GEM membrane is pretreated to remove impurities on the surface; then, the target is sputtered in a vacuum chamber with a base vacuum of 1x10 -4 ​​Pa, the working gas (argon) with a purity of 99.999% was filled into the sputtering chamber at a flow rate of 12 sccm, the Ti base layer was sputtered at a power of 1000 W, and then the Ti base layer was sputtered at a power of 2400 W. 10 The B4C neutron conversion layer maintains a working gas pressure of 0.4 Pa throughout the sputtering process. The sputtering process adopts the form of glancing target, which is DC magnetron sputtering. Finally, the obtained sample is sent to Shenzhen Jinbaize Electronic Technology Co., Ltd. for subsequent processing of the surface structure (mechanical drilling, chemical etching, and cleaning) to obtain a boron-coated ceramic GEM film.

[0047] Comparative Example 1:

[0048] Compared with Example 1, most of the conditions are the same, except that the thickness of the Ti primer layer used in the boron-coated ceramic GEM membrane is 0 nm, that is, the boron-coated ceramic GEM membrane prepared in this comparative example has no Ti primer layer.

[0049] The adhesion of the boron-coated ceramic GEM films prepared in Example 1 and Comparative Example 1 was tested using 3M Scotch test tape. The test method was tape tearing. The test results are shown in Figure 2. Figure 3 As shown. Figure 3 It can be seen that the surface film of the sample of Example 1 did not fall off after the test, while the sample of Comparative Example 1 had a partial film fall off. 10 The adhesion of the B4C layer is greatly improved.

[0050] Comparative Example 2:

[0051] The targets used in this comparative example are Ti target with a purity of 99.99%, 10 Concentrated boron carbide target with a B content of 96%.

[0052] First, the perforated ceramic GEM membrane was pretreated to remove surface impurities; then the background vacuum was set at 1×10 -4 Pa, the working gas (argon) with a purity of 99.999% was filled into the sputtering chamber at a flow rate of 12 sccm, the Ti base layer was sputtered at a power of 1000 W, and then the Ti base layer was sputtered at a power of 2400 W. 10 For the B4C neutron conversion layer, the working gas pressure is maintained at 0.4 Pa throughout the sputtering process. The sputtering process adopts the form of glancing target, which is DC magnetron sputtering.

[0053] After the boron coating process, a large amount of boron carbide enters the microscopic pores on the surface of the ceramic GEM membrane, causing the two sides of the ceramic GEM membrane to be connected. During the detection process, applying pressure on both sides can cause a short circuit. This can cause sparks on the ceramic GEM membrane surface, seriously affecting the detection process. In contrast, in Example 1, the boron carbide-free pores of the resulting boron-coated ceramic GEM membrane are free of boron carbide, preventing short circuits during use.

[0054] Example 2:

[0055] Compared with Example 1, most of them are the same, except that in this embodiment, "sputtering Ti to form a base layer at a power of 1000 W" is changed to "sputtering Ti to form a base layer at a power of 500 W".

[0056] Example 3:

[0057] Compared with Example 1, most of them are the same, except that in this embodiment, "sputtering Ti to form a base layer at a power of 1000 W" is changed to "sputtering Ti to form a base layer at a power of 1500 W".

[0058] Example 4:

[0059] Compared with Example 1, most of the above are the same, except that in this embodiment, the sputtering power of 2400W is used. 10 B4C neutron conversion layer" was changed to "sputtering at a power of 2000W 10 B4C Neutron Conversion Layer".

[0060] Example 5:

[0061] Compared with Example 1, most of the above are the same, except that in this embodiment, the sputtering power is 2400W. 10 B4C neutron conversion layer" was changed to "sputtering at a power of 3000W 10 B4C Neutron Conversion Layer".

[0062] Example 6:

[0063] Compared with Example 1, most of the above are the same, except that in this example, the background vacuum degree is set to 1×10 -4 Pa" was changed to "the background vacuum degree is 2×10 -4 Pa”.

[0064] Example 7:

[0065] Compared with Example 1, most of the above are the same, except that in this example, the background vacuum degree is set to 1×10 -4 Pa" was changed to "the background vacuum degree is 1.5×10 -4 Pa”.

[0066] Example 8:

[0067] Except that in this example, "argon gas at a pressure of 0.4 Pa" is changed to "argon gas at a pressure of 0.3 Pa", the rest is substantially the same as in Example 1.

[0068] Example 9:

[0069] Except that in this example, "argon gas at a pressure of 0.4 Pa" is changed to "argon gas at a pressure of 0.6 Pa", the rest is substantially the same as in Example 1.

[0070] The above description of the embodiments is to enable a person of ordinary skill in the art to understand and use the present application. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A method for preparing a boron-coated ceramic GEM membrane, characterized in that: The boron-coated ceramic GEM membrane comprises a ceramic GEM membrane base lower layer, a Ti bottoming middle layer and 10 B4C neutron conversion upper layer, the method comprises the following steps: (1) Sputtering the target material Ti onto the surface of the ceramic GEM film by magnetron sputtering to obtain a ceramic GEM film coated with a Ti bottoming intermediate layer; (2) sputtering the target material boron carbide onto the surface of the obtained Ti primer intermediate layer by magnetron sputtering, and then mechanically drilling, chemically etching, and cleaning to obtain the target product; Wherein, the thickness of the Ti bottoming intermediate layer is 50 to 150 nm; In step (1), the magnetron sputtering power is 500-1500W; the purity of the target material Ti is ≥99.99%; during the magnetron sputtering process, the background vacuum of the sputtering chamber is 1×10 -4 ~2×10 -4 Pa; During the magnetron sputtering process, the working gas is argon with a purity of 99.999%, an argon flow rate of 10 to 20 sccm, and a gas pressure of 0.3 to 0.6 Pa; In step (2), the magnetron sputtering power is 2000-3000W; during the magnetron sputtering process, the background vacuum of the sputtering chamber is 1×10 -4 ~2×10 -4 Pa; In the magnetron sputtering process, the working gas is argon with a purity of 99.999%, an argon flow rate of 10 to 20 sccm, and a gas pressure of 0.3 to 0.6 Pa; The target material is boron carbide 10 B content ≥96%; In step (1) and step (2), the magnetron sputtering is DC magnetron sputtering; described 10 The thickness of the B4C neutron conversion upper layer is 1 to 3 μm.

2. A boron-coated ceramic GEM membrane, characterized in that: The boron-coated ceramic GEM membrane is prepared by the preparation method as claimed in claim 1.

3. The use of a boron-coated ceramic GEM membrane according to claim 2, characterized in that: The boron-coated ceramic GEM film is applied to a boron-coated GEM neutron detector.

Images