A hyperbolic single crystal graphite neutron analyzer and preparation method thereof

Abstract

The present invention relates to the technical field of neutron scattering, and in particular to a hyperbolic single crystal graphite analyzer used in a secondary spectrometer of a neutron spectrometer, which improves the energy resolution and detection efficiency of the neutron spectrometer by optimizing the geometric shape of the analyzer; the analyzer comprises a substrate, and both the horizontal (x) and vertical (y) directions of the substrate are designed into a hyperbolic trapezoidal structure according to a fourth-order polynomial, which determines the overall geometric shape of the analyzer; the present invention effectively solves the problems existing in the prior art through an innovative design of a hyperbolic single crystal graphite analyzer, significantly improves the performance of the neutron spectrometer, and has important value for neutron scattering research and applications in related fields.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron scattering, and in particular to a hyperbolic single crystal graphite analyzer used in a secondary spectrometer of a neutron spectrometer, which improves the energy resolution and detection efficiency of the neutron spectrometer by optimizing the geometric shape of the analyzer. Background Art

[0002] Neutron spectrometer is an important tool for studying the microstructure of matter, and its performance directly affects the depth and breadth of scientific research. In the secondary spectrometer of the neutron spectrometer, the analyzer plays a key role in energy analysis of neutrons scattered by the sample. However, there are many problems with the planar single crystal analyzer in the prior art, such as large uncertainty in neutron flight time, wide spatial distribution of neutrons at the detector, and small sample solid angle coverage. These problems directly lead to low energy resolution of neutron spectrometers, limiting their application in high-precision scientific research.

[0003] Specifically, due to design limitations, the planar single crystal analyzer cannot effectively focus neutrons in time and space, resulting in large differences in neutron flight paths and increased uncertainty in flight time. At the same time, the neutrons are widely distributed in space on the detector, reducing the detection signal-to-noise ratio. In addition, the small sample solid angle coverage also limits the neutron detection efficiency. Therefore, a new analyzer design is urgently needed to solve the above problems and improve the overall performance of the neutron spectrometer. Summary of the invention

[0004] The present invention aims to solve the problems of low energy resolution, poor detection signal-to-noise ratio and low detection efficiency existing in existing planar single crystal analyzers in neutron spectrometers, and provides a hyperbolic single crystal graphite analyzer. By optimizing the geometric shape of the analyzer, effective focusing of neutrons in time and space is achieved, thereby improving the energy resolution and detection efficiency of the neutron spectrometer.

[0005] The technical solution adopted by the present invention is: a hyperbolic single crystal graphite neutron analyzer, the analyzer includes a substrate, and the horizontal (x) and vertical (y) directions of the substrate are designed into a hyperbolic trapezoidal structure according to a fourth-order polynomial, which determines the overall geometric shape of the analyzer.

[0006] A method for preparing a hyperbolic single-crystal graphite neutron analyzer comprises the following steps:

[0007] Step 1: According to a preset fourth-order polynomial function, an analyzer substrate having a hyperbolic trapezoidal structure is formed to ensure the accuracy and consistency of the substrate shape;

[0008] Step 2: Prepare highly oriented pyrolytic graphite (HOPG) material and cut it into single pieces using cutting technology. These single pieces serve as neutron reflection surfaces.

[0009] Step 3: According to the fourth-order polynomial design of the substrate, use a precision positioning tool to determine the pasting position and angle of the graphite, ensure that the geometric center of the graphite is located on the polynomial function, and that the graphite is aligned with the substrate in the horizontal and vertical directions to achieve the best neutron focusing effect;

[0010] Step 4: Use specially selected glue to stick the graphite sheets on the substrate, ensuring that the glue is firmly attached and the gap between adjacent graphites is large. The number of graphite sheets in each row is based on actual needs to meet different neutron detection requirements;

[0011] Step 5: Conduct strict inspection on the prepared analyzer to ensure that the graphite is pasted in the correct position without falling off or misalignment, and that the overall structure meets the design requirements to ensure the performance and stability of the analyzer.

[0012] The analyzer substrate is made of boron-aluminum alloy material, which can effectively absorb neutrons that pass through single crystal graphite.

[0013] The neutron-reflecting material is highly oriented pyrolytic graphite (HOPG) glued to the substrate by glue, and has a size of 12 mm×12 mm×2 mm.

[0014] The graphite sticking position and angle are determined according to the fourth-order polynomials in the horizontal and vertical directions, and each graphite sheet is inscribed in the fourth-order polynomials in the horizontal and vertical directions.

[0015] When the graphite is pasted on the substrate, the geometric center of the graphite is located on the fourth-order polynomial function that determines the analyzer substrate to ensure the focusing effect of neutrons.

[0016] The graphites are aligned horizontally and vertically, and the gap between adjacent graphites is less than 0.5 mm. The number of graphites in each row can be 5-21 sheets as required.

[0017] The analyzer curved surface design realizes the focusing of neutrons in two dimensions, time and space, and improves the coverage of the sample solid angle, thereby improving the energy resolution of the spectrometer.

[0018] In step 4, through the curved surface design, the analyzer can make the flight paths of neutrons with different incident angles θ in the secondary spectrometer approximate, that is, L1≈L2≈L3, thereby achieving neutron focusing in the time dimension.

[0019] In step five, the hyperbolic surface design is used to spatially focus neutrons on the detector, thereby improving the signal-to-noise ratio of neutron detection and expanding the solid angle coverage of the sample, thereby completing the preparation of the hyperbolic single crystal graphite neutron analyzer.

[0020] The beneficial effects of the present invention are as follows: the present invention effectively solves the problems existing in the prior art through the innovative design of the hyperbolic single crystal graphite analyzer, significantly improves the performance of the neutron spectrometer, and has important value for neutron scattering research and applications in related fields. Compared with the existing planar analyzer, the present invention shows significant beneficial effects in many aspects, which are specifically shown as follows:

[0021] (I) Improved the focusing of neutron flight time: The hyperbolic design effectively reduces the difference in neutron flight distance in the secondary spectrometer, achieves the focusing of neutron flight time, reduces the uncertainty of flight time, and thus improves the time resolution of the neutron spectrometer.

[0022] (ii) Optimized neutron spatial distribution: The hyperbolic design enables neutrons to be focused onto the detector in the spatial dimension, improving the signal-to-noise ratio of neutron detection and reducing the demand for the detector's effective detection area, which helps save the construction cost of the spectrometer.

[0023] (iii) Expanded sample solid angle coverage: Compared with a planar analyzer, a hyperbolic analyzer provides a larger solid angle coverage, improves the neutron detection efficiency, and thus enhances the overall performance of the neutron spectrometer.

[0024] (IV) Improved energy resolution: Combining the advantages of time focusing, space focusing and solid angle coverage mentioned above, the neutron spectrometer using a hyperbolic analyzer has achieved a significant improvement in energy resolution, providing more accurate data support for neutron scattering experiments.

[0025] (V) Innovation in structural design: The analyzer base is made of boron-aluminum alloy material, which effectively absorbs neutrons that pass through graphite and reduces background interference. The hyperbolic trapezoidal structure design of the base is precisely controlled according to a fourth-order polynomial, ensuring that the geometric shape of the analyzer is optimized for neutron focusing. The precise pasting position and angle design of graphite, as well as the small gaps between adjacent graphites, further ensure the focusing effect and detection efficiency of neutrons. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a neutron path diagram of the present invention applied to a secondary spectrometer.

[0027] Figure 2 It is a schematic structural diagram of the substrate in the present invention.

[0028] Figure 3 It is a schematic diagram of the structure of highly oriented pyrolyzed graphite in the present invention.

[0029] Figure 4 It is a schematic diagram of the assembly result of the analyzer in the present invention.

[0030] Description of the drawings: 1-substrate, 2-graphite. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings:

[0032] like Figure 1-4 As shown, the present invention proposes a hyperbolic single crystal graphite analyzer, which aims to solve the problems of uncertainty of neutron secondary time of flight (TOF) focusing effect, wide spatial distribution of neutrons on the detector and small solid angle (Ω) coverage caused by the geometric shape of the analyzer when the secondary spectrometer of the neutron spectrometer analyzes neutrons scattered by the sample. Specific implementation method:

[0033] (I) Analyzer substrate material and design: Boron aluminum alloy is selected as the material of the analyzer substrate 1, which can effectively absorb neutrons passing through single crystal graphite and reduce background interference. The substrate 1 is designed into a hyperbolic trapezoidal structure, and its horizontal (x) and vertical (y) directions are designed according to fourth-order polynomials to determine the overall geometry of the analyzer.

[0034] (ii) Selection and pasting of reflective materials: Highly oriented pyrolytic graphite 2 (HOPG) is selected as the material for reflecting neutrons, and its size is 12mm×12mm×2mm. The graphite is pasted on the substrate 1 with specially selected glue. The pasting position and angle are determined by the fourth-order polynomials in the horizontal and vertical directions to ensure that each graphite is inscribed with the fourth-order polynomial of the substrate 1. When pasting, the geometric center of the graphite is required to be located on the fourth-order polynomial function that determines the analyzer substrate 1 to ensure the focusing effect of the neutrons. The graphite needs to be aligned horizontally and vertically on the substrate 1, and the gap between adjacent graphites should be less than 0.5mm to reduce neutron leakage and scattering. The number of graphite in each row can be 5-21 pieces according to actual needs to meet different neutron detection needs.

[0035] (III) Focusing principle and implementation of the analyzer: To achieve secondary flight time focusing of neutrons, the analyzer adopts a curved surface design so that the flight paths of neutrons with different incident angles θ in the secondary spectrometer are similar, that is, L1≈L2≈L3. The hyperbolic design can not only achieve neutron focusing in the time dimension and reduce the uncertainty of the flight time, but also focus neutrons on the detector in the spatial dimension and improve the signal-to-noise ratio of neutron detection. Through the hyperbolic design, the analyzer has a larger solid angle coverage of the sample than a planar analyzer, thereby improving the detection efficiency of neutrons.

[0036] (IV) Effects and advantages of the analyzer: The hyperbolic analyzer can effectively reduce the difference in the flight distance of neutrons in the secondary spectrometer and achieve the focusing of neutrons in both time and space. Compared with the planar analyzer, the hyperbolic analyzer can significantly improve the energy resolution of the neutron spectrometer.

[0037] The hyperbolic analyzer can also reduce the demand for the effective detection area of ​​the detector, thereby saving the cost of spectrometer construction.

[0038] The following is further described by specific embodiments:

[0039] Embodiment 1:

[0040] like Figure 1-4 As shown, this embodiment proposes a hyperbolic single crystal graphite analyzer for a secondary spectrometer of a neutron spectrometer, and the specific implementation method is as follows:

[0041] Analyzer substrate design and material selection: Boron aluminum alloy is selected as the material of the analyzer substrate 1, which has good neutron absorption performance and can effectively reduce background interference. The substrate 1 is designed as a hyperbolic trapezoidal structure, and both the horizontal (x) and vertical (y) directions are designed according to specific fourth-order polynomials to ensure that the overall geometry of the analyzer meets the requirements of neutron focusing.

[0042] Selection and pasting of reflective materials: Highly oriented pyrolytic graphite 2 (HOPG) is selected as the neutron reflective material. Its size is 12mm×12mm×2mm and it has good neutron reflection performance. Use specially selected glue to paste the HOPG graphite sheet on the substrate 1. The pasting position and angle are determined by the fourth-order polynomials in the horizontal and vertical directions. Ensure that each graphite sheet is inscribed in the fourth-order polynomial of the substrate 1 to achieve the best neutron focusing effect. When pasting, ensure that the geometric center of the graphite sheet is located on the fourth-order polynomial function that determines the analyzer substrate 1. The graphite sheets are aligned horizontally and vertically, and the gap between adjacent graphite sheets is controlled to be less than 0.5mm to reduce neutron leakage and scattering. According to actual needs, 5-21 sheets of graphite can be pasted in each row to adapt to different neutron detection scenarios.

[0043] Focusing effect and advantages of the analyzer: The hyperbolic design enables the analyzer to reduce the difference in the flight distance of neutrons in the secondary spectrometer, achieve the focusing of neutrons in the time dimension, and reduce the uncertainty of the flight time. At the same time, the hyperbolic design can also focus neutrons on the detector in the spatial dimension, improve the signal-to-noise ratio of neutron detection, and reduce the demand for the effective detection area of ​​the detector, thereby saving the cost of spectrometer construction. Compared with the planar analyzer, the hyperbolic analyzer has a larger solid angle coverage of the sample, which improves the detection efficiency of neutrons.

[0044] Embodiment 2:

[0045] like Figure 1-4 As shown, this embodiment is based on the hyperbolic single crystal graphite analyzer for the secondary spectrometer of the neutron spectrometer proposed by the present invention, and further specific implementation methods are as follows:

[0046] Innovative design of the analyzer substrate 1: The boron aluminum alloy substrate 1 not only has good neutron absorption performance, but also optimizes the flight path and focusing effect of neutrons through the hyperbolic trapezoidal structure design.

[0047] Both the horizontal (x) and vertical (y) dimensions are designed according to sophisticated fourth-order polynomials to ensure that the analyzer geometry minimizes the uncertainty in the neutron flight time.

[0048] Precise pasting and layout of reflective materials: High-quality HOPG graphite sheets are selected as neutron reflective materials and fixed on the substrate 1 through a precise pasting process. The pasting position and angle are precisely calculated to ensure that each graphite sheet is inscribed with the fourth-order polynomial of the substrate 1 to achieve the best neutron focusing effect. The gap between the graphite sheets is controlled to be less than 0.5mm to reduce the impact of neutron leakage and scattering on the detection results. The number of graphite sheets in each row (5-21 sheets) can be flexibly adjusted according to actual needs to meet different neutron detection needs.

[0049] Comprehensive performance and advantages of the analyzer: The hyperbolic design enables the analyzer to focus neutrons in the time dimension, reducing the uncertainty of the flight time and improving the energy resolution of the neutron spectrometer. At the same time, the neutrons are also focused on the detector in the spatial dimension, improving the signal-to-noise ratio of neutron detection and reducing the demand for the effective detection area of ​​the detector. Compared with the traditional planar analyzer, the hyperbolic analyzer has a larger solid angle coverage and improves the detection efficiency of neutrons.

[0050] In summary, the use of hyperbolic single crystal graphite analyzer can effectively improve the performance of neutron spectrometer, reduce construction costs and improve detection efficiency.

Claims

1. A hyperbolic single crystal graphite neutron analyzer, characterized in that: The analyzer includes a substrate, wherein both the horizontal (x) and vertical (y) directions of the substrate are designed into a hyperbolic trapezoidal structure according to a fourth-order polynomial, which determines the overall geometric shape of the analyzer; The method for preparing the hyperbolic single-crystal graphite neutron analyzer comprises the following steps: Step 1: According to a preset fourth-order polynomial, an analyzer substrate with a hyperbolic trapezoidal structure is formed. Both the horizontal (x) and vertical (y) directions are designed according to the preset fourth-order polynomial to ensure that the overall geometric shape of the analyzer meets the requirements of neutron focusing and ensure the accuracy and consistency of the substrate shape; Step 2: Prepare highly oriented pyrolytic graphite (HOPG) material and cut it into single pieces using cutting technology. These graphite single pieces serve as neutron reflection surfaces. Step 3: According to the fourth-order polynomial design of the substrate, a precision positioning tool is used to determine the pasting position and angle of the graphite single sheet, and the pasting position and angle of the graphite single sheet are determined according to the fourth-order polynomials in the horizontal and vertical directions, and each graphite single sheet is inscribed in the fourth-order polynomials in the horizontal and vertical directions; when the graphite single sheet is pasted on the substrate, the geometric center of the graphite single sheet is located on the fourth-order polynomial that determines the analyzer substrate to ensure the focusing effect of the neutrons, and the graphite single sheet is aligned with the substrate in the horizontal and vertical directions respectively to achieve the best neutron focusing effect; Step 4: Use glue to stick the graphite sheet to the substrate, making sure it is firmly glued; Step 5: Conduct strict inspection on the prepared analyzer to ensure that the graphite sheet is accurately pasted in the correct position without falling off or misalignment, and that the overall structure meets the design requirements to ensure the performance and stability of the analyzer.

2. A hyperbolic single crystal graphite neutron analyzer according to claim 1, characterized in that: The analyzer substrate is made of boron-aluminum alloy material, which can effectively absorb neutrons that pass through the graphite single sheet.

3. A hyperbolic single crystal graphite neutron analyzer according to claim 1, characterized in that: The neutron-reflecting material glued to the substrate is highly oriented pyrolytic graphite (HOPG) with a size of 12 mm × 12 mm × 2 mm.

4. A hyperbolic single crystal graphite neutron analyzer according to claim 1, characterized in that: The graphite sheets are aligned horizontally and vertically respectively, the gap between adjacent graphite sheets is less than 0.5 mm, and the number of graphite sheets in each row can be 5-21 sheets as required.

5. A hyperbolic single crystal graphite neutron analyzer according to claim 1, characterized in that: The analyzer curved surface design realizes the focusing of neutrons in two dimensions, time and space, and improves the coverage of the sample solid angle, thereby improving the energy resolution of the spectrometer.

6. A hyperbolic single crystal graphite neutron analyzer according to claim 1, characterized in that: Through the curved surface design, the analyzer can make the flight paths of neutrons with different incident angles θ in the secondary spectrometer approximate, that is, L1≈L2≈L3, thus achieving neutron focusing in the time dimension.

7. A hyperbolic single crystal graphite neutron analyzer according to claim 1, characterized in that: Through the hyperbolic design, neutrons are spatially focused on the detector, the signal-to-noise ratio of neutron detection is improved, and the solid angle coverage of the sample is expanded, thereby completing the preparation of the hyperbolic single crystal graphite neutron analyzer.

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