Large-size curved surface type thin-wall neutron beam window structure

Abstract

The utility model provides a large-size curved-surface thin-wall neutron beam window structure, which is applied to a high-resolution neutron diffractometer and aims to provide a high-vacuum environment for an experimental sample and a scattered neutron channel and ensure high transmittance of neutrons and mechanical strength and stability of a device at the same time. The neutron beam window structure is an integrated curved surface type structure, and the thickness of the beam window is 1.5 mm. According to the technical scheme, through strict quality detection and fatigue test, the stability and durability of the neutron beam window in actual use are ensured. In addition, potential problems can be found and processed in time through regular performance state monitoring, so that the service life of the beam window is prolonged, the maintenance cost is reduced, and more reliable and efficient support is provided for scientific research activities such as neutron diffraction experiments.

Description

Technical Field

[0001] The present invention relates to a key component of a neutron diffractometer, and particularly to a large-sized curved thin-walled neutron beam window structure. Background Art

[0002] In neutron diffraction experiments, in order to provide a stable high-vacuum environment and ensure the effective transmission of neutrons, the design of the neutron beam window is particularly important. Traditional large-sized planar neutron beam windows often face a trade-off between thickness and transmission rate: if the thickness is too large, the neutron transmission rate will be reduced; if the thickness is too thin, significant vacuum deformation, plastic deformation may occur after being stressed, and fatigue fracture may occur in the stress concentration area, posing a potential threat to the surrounding detectors. Currently, the research on small-sized beam windows at home and abroad has been relatively mature, and spherical shapes are mostly used to enhance the structural strength. However, for large-sized beam windows, considering processing costs, time, and difficulty, planar beam windows are more common. But these planar beam windows often undergo large deformations and stress concentrations after evacuation, reducing their service life and reliability. Summary of the Invention

[0003] In view of the above problems, the present invention proposes a large-sized curved thin-walled neutron beam window structure, which is applied to a high-resolution neutron diffractometer, aiming to provide a high-vacuum environment for experimental samples and scattering neutron channels, while ensuring high neutron transmission rate and the mechanical strength and stability of the device.

[0004] The technical solution adopted by the present invention is: a large-sized curved thin-walled neutron beam window structure, which is an integral curved structure, and the thickness of the beam window is 1.5 mm.

[0005] At least one transverse rib is provided in the middle of the neutron beam window to enhance the structural stability without affecting neutron transmission.

[0006] Two transverse ribs are provided in the middle of the neutron beam window, dividing the beam window into upper, middle, and lower three windows.

[0007] The neutron beam window is made of 7075-T651 aluminum alloy.

[0008] The cross-sectional size of each window is 620 mm x 465 mm.

[0009] The aluminum alloy is an aluminum alloy plate.

[0010] The thickness of the aluminum alloy plate is 30 mm.

[0011] The beneficial effects of the present invention are as follows: The beneficial effects of this technical solution are mainly reflected in the following aspects: (1) Improving neutron transmittance: By designing it as a thin-walled curved surface structure, the thickness of the material is reduced, thereby effectively improving the neutron transmittance. This is crucial for neutron diffraction experiments because it means that more neutrons can penetrate the beam window and be used in the experiments, thus improving the accuracy and efficiency of the experiments; (2) Enhancing mechanical stability: Compared with the traditional planar structure, the curved surface design has a more uniform stress distribution, which helps to reduce the stress concentration phenomenon. This design enables the neutron beam window to have better stability when bearing the internal and external pressure differences, reducing the risk of deformation and rupture, and thus extending the service life of the beam window; (3) Optimizing material selection: Selecting 7075-T651 aluminum alloy as the manufacturing material not only ensures that the neutron beam window has high neutron transmittance, but also this material has excellent mechanical strength. The selection of this material achieves the balance between neutron transmittance and mechanical strength, meeting the requirements of the neutron diffraction experiment for the performance of the beam window. The technical solution of the present invention has passed strict quality inspections and fatigue tests to ensure the stability and durability of the neutron beam window in actual use. In addition, regular performance monitoring can detect and handle potential problems in a timely manner, thereby extending the service life of the beam window and reducing maintenance costs, providing more reliable and efficient support for scientific research activities such as neutron diffraction experiments. Brief Description of the Drawings

[0012] Figure 1 is a schematic structural diagram of the present invention when used on the vacuum scattering cavity of the CSNS high-resolution neutron diffractometer.

[0013] Figure 2 is a schematic structural diagram of the large-size curved surface type thin-walled neutron beam window of the present invention.

[0014] Figure 3 is a partial external shape structural diagram of the planar neutron beam window in the prior art.

[0015] Figure 4 is a partial external shape structural diagram of the curved surface type neutron beam window of the present invention.

[0016] Explanation of the reference numerals in the drawings: 1 - Curved surface beam window, 2 - Scattering cavity, 3 - Inside the cavity, 4 - Transverse rib. Detailed Description of the Invention

[0017] The following details the specific embodiments of the present invention with reference to the drawings in the specification:

[0018] As Figures 1-4As shown in the figure, this embodiment provides a large-size curved thin-walled neutron beam window structure and its manufacturing method. This neutron beam window is mainly applied to a high-resolution neutron diffractometer, which provides a high-vacuum environment for the experimental sample and the scattered neutron channel. More specifically, it is the vacuum chamber 1 with a cavity volume of about 10m 3 . The inner part 3 of the cavity of the vacuum chamber 1 serves as the scattering chamber 2. A large-area detector is arranged around the scattering chamber 2. Therefore, a relatively large neutron scattering window is required. The corresponding curved beam window 1 is large in size, which brings great difficulties to the design. It is necessary to meet the physical requirement of being thin to ensure good neutron transmittance, and at the same time ensure that the curved beam window 1 has sufficient pressure-bearing capacity to ensure the safe and stable operation of the entire device. The following will elaborate on the solution from the neutron beam window structure design and manufacturing method.

[0019] I. Neutron Beam Window Structure Design

[0020] Overall structure: The neutron beam window of this embodiment adopts an integrated curved design, presenting a gentle arc as a whole. Such a design is not only beautiful and generous, but more importantly, it can effectively disperse stress and improve the stability of the structure. The thickness of the beam window is 1.5 mm. The selection of this thickness finds a balance between ensuring neutron transmittance and mechanical strength.

[0021] Horizontal rib design: In order to further enhance the stability of the structure without affecting neutron transmission, two horizontal ribs 4 are designed in the middle of the neutron beam window. These two horizontal ribs divide the beam window into upper, middle, and lower three windows, and the size of each window is 620 mm x 465 mm. The design of the horizontal ribs not only enhances the load-bearing capacity of the beam window, but also effectively disperses stress and extends the service life of the beam window.

[0022] Material selection: The neutron beam window is made of 7075-T651 aluminum alloy. This material not only has good neutron transmittance, but also has excellent mechanical strength, and can meet the high requirements of the neutron diffraction experiment for the performance of the beam window.

[0023] II. Neutron Beam Window Manufacturing Method

[0024] Material selection and rough machining: First, a 30-mm-thick 7075 aluminum alloy plate is selected as the raw material. Through rough machining, the raw material is initially processed to be close to the target thickness. In this process, special attention is paid to maintaining the flatness and roughness of the processing surface to ensure the smooth progress of subsequent processing.

[0025] Stress relief treatment: After rough machining, a secondary aging treatment is carried out to eliminate the internal stress in the material. This step is crucial for improving the mechanical stability of the beam window and extending its service life.

[0026] Semi-finishing and finishing: Next, we use a high-speed milling machine for semi-finishing and finishing. During the machining process, we strictly control the cutting parameters to ensure the machining accuracy and quality. At the same time, we also use special concave-convex die pads to prevent deformation and vibration during the machining process.

[0027] Quality inspection and fatigue test: After machining, we conduct quality inspections on the beam window for indicators such as dimensional accuracy and surface roughness. In addition, to verify the fatigue life of the beam window, we also conduct at least 10,000 vacuum pumping cycle tests. Only by passing these strict tests can the beam window be recognized as a good product.

[0028] Final treatment and application: Finally, we perform necessary surface treatments on the beam window that has passed the test, such as cleaning and anodizing, to improve its corrosion resistance and aesthetics. After the treatment is completed, we install the beam window into the vacuum scattering chamber of a high-resolution neutron diffractometer to prepare for neutron diffraction experiments.

[0029] The large-size curved thin-walled neutron beam window structure and its manufacturing method provided in this embodiment not only improve the neutron transmission rate and mechanical stability, but also optimize the material selection and processing technology, providing more reliable and efficient equipment support for neutron diffraction experiments.

Claims

1. A large-size curved thin-walled neutron beam window structure, characterized in that: The neutron beam window structure is an integrated curved structure, and the thickness of the beam window is 1.5 mm; at least one transverse rib is provided in the middle of the neutron beam window to enhance the structural stability without affecting the neutron transmission; the neutron beam window is made of 7075-T651 aluminum alloy; the cross-sectional size of each window is 620 mm x 465 mm.

2. The large-size curved thin-walled neutron beam window structure according to claim 1, characterized in that: Two horizontal ribs are provided in the middle of the neutron beam window, dividing the beam window into three windows: upper, middle and lower.

3. The large-size curved thin-walled neutron beam window structure according to claim 1, characterized in that: The aluminum alloy is an aluminum alloy plate.

4. The large-size curved thin-walled neutron beam window structure according to claim 3, characterized in that: The thickness of the aluminum alloy plate is 30 mm.

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