A spectrum measuring device under high pressure conditions

Abstract

The invention relates to the field of material research, and is a spectral measurement device under high pressure conditions, comprising an upper pressure plate, a lower pressure plate, a leveling screw, a pressure screw, an anvil limit screw, an upper support plate, a lower support plate, an upper anvil, a lower anvil, an annular gasket, a pressure medium, a sample, a limit screw, a light collection system and a laser. The spectral characteristics of the sample can be studied under high pressure conditions, and the signal of the anvil material can be suppressed as much as possible, so that the incident light and the reflected light on the sample surface enter and leave the anvil through the crown bevel of the anvil respectively, and the incident light is incident from the crown bevel of the diamond anvil, and the incident angle on the sample surface is large, so that the scattered light and fluorescence of the diamond can be better separated from the scattered light of the sample, the pressure device does not need a guide rail structure, and the pressure deviation caused by the looseness of the components is avoided, and the laser does not need to be focused on a very small area on the sample, and the local heat on the sample surface caused by the laser can be reduced.

Description

Technical Field

[0001] The invention relates to the field of material research, in particular to a spectrum measuring device under high pressure conditions for studying the spectrum characteristics of a sample under high pressure conditions. Background Art

[0002] It is of great significance to study how certain properties of materials change with applied pressure. High-pressure spectroscopy measurement technology is a typical research method. For example, inelastic scattering technology of visible light, including Raman scattering, is very suitable for studying the dependence of material properties on photon energy, magnetic interaction, plasma energy, electronic band structure and superconducting energy gap. Usually, pressure is applied by anvils and other pressure-applying devices to the sample of the material to be tested, and the material is measured in combination with spectral technology. In particular, high-pressure light scattering technology is widely used. Its advantages are that the solid angle of scattered light emitted from the sample that can be collected is large, and the scattered light signal of the sample is strong. However, the devices of the prior art also have the following defects. The first defect of the prior art: It is difficult to obtain clear Raman scattering spectra for some special materials that are opaque and have weak scattering signals in the prior art, especially for materials whose spectral range overlaps with the single-photon and two-photon Raman scattering spectrum range of the anvil material. Second defect of the prior art: High-pressure spectroscopy measurement in the prior art usually uses a support table combined with a diamond anvil, and the support table is pressed along a fixed guide rail to apply pressure to the sample. The relaxation of the guide rail will cause a slight deviation in the displacement, and the pressure of the support table on the bottom surface of the anvil is unevenly distributed, resulting in pressure deviation between the anvils. The spectroscopy measurement device under high-pressure conditions can solve the problem. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to suppress and filter the light scattering signal of the anvil material as much as possible. The design of the present invention allows the incident light and the light reflected from the sample surface to enter and leave the anvil through the crown bevel of the anvil respectively. In addition, the device for applying pressure to the sample of the present invention does not require a guide rail structure, thereby avoiding pressure deviation caused by loose components.

[0004] The technical solution adopted by the present invention is:

[0005] The spectral measurement device under high pressure conditions comprises an upper pressure plate, a lower pressure plate, a leveling screw, a pressure screw, an anvil limit screw, an upper support plate, a lower support plate, an upper anvil, a lower anvil, an annular gasket, a pressure medium, a sample, a limit screw, a light collection system and a laser, wherein xyz is a three-dimensional space coordinate system, and the corresponding names of the various parts of the diamond standard cut include table, crown, girdle, pavilion and bottom surface, the bottom surface of the upper anvil is downward, and the bottom surface of the lower anvil is upward, the annular gasket is located between the bottom surfaces of the upper anvil and the lower anvil, and a pressure medium is contained in the annular gasket, and the sample is located in the pressure medium. When high pressure is applied to the sample, the upper anvil and the lower anvil are close to each other and press the pressure The medium applies pressure to the sample, and the high pressure range is 5GPa to 30GPa. The area corresponding to the light that can be collected by the light collection system is called the light collection area; the upper pressure plate and the lower pressure plate are both steel rings with an outer diameter of ten centimeters and are elastic. The upper pressure plate and the lower pressure plate are coaxially arranged in the vertical y direction. The upper pressure plate has three evenly distributed M5 screw holes on a circumference three centimeters from the center, and the upper pressure plate has three evenly distributed M4 screw holes on a circumference four centimeters from the center. The side of each M4 screw hole has a limiting screw, and the lower pressure plate has three evenly distributed M5 screw holes, which correspond to the M5 screw holes of the upper pressure plate, and the lower pressure plate has three evenly distributed conical grooves, and Corresponding to the M4 screw hole of the upper pressure plate, the pressure screw is an M5 screw, and the pressure screw connects the lower pressure plate to the upper pressure plate through the M5 screw hole. The leveling screw is an M4 screw and its top end is conical. The leveling screw passes through the M4 screw hole of the upper pressure plate, and the top end is located in the conical groove of the lower pressure plate. Three evenly distributed anvil limit screws are installed on the upper surface of the lower pressure plate at a circumference of two centimeters from the center. The upper support plate and the lower support plate are both silicon carbide rings with an outer diameter of three centimeters. The light collection system is located directly above the center of the upper support plate. The upper support plate is nested in the upper pressure plate and connected and fixed. The lower support plate is nested in the lower pressure plate. The lower support plate can be fixed through three anvil limit screws To fine-tune, the relative position between the lower support plate and the lower pressure plate in the horizontal plane can be changed. The upper anvil and the lower anvil are both made of standard diamond cutting and have a table, a crown, a girdle, a pavilion and a bottom surface. The angle between the crown bevel and the table is 40 degrees. The inner lower part of the upper support plate has a bevel at 40 degrees to the horizontal direction, and the inner bevel of the upper support plate contacts the crown bevel of the upper anvil. The inner upper part of the lower support plate has a bevel at 40 degrees to the horizontal direction, and the inner bevel of the lower support plate contacts the crown bevel of the lower anvil. The laser emitted by the laser can be incident on the crown bevel of the upper anvil in a normal direction, and is incident on the sample through the upper anvil and the pressure medium in turn.

[0006] The steps of using the spectrum measuring device under high pressure to measure the scattered light spectrum are as follows:

[0007] Step 1, placing an annular gasket on the bottom surface of the lower anvil, placing a pressure medium in the annular gasket, and placing a sample in the pressure medium;

[0008] Step 2, adjusting three leveling screws and three pressure screws to change the distance between the upper pressure plate and the lower pressure plate until the distance between the bottom surface of the upper anvil and the pressure medium on the bottom surface of the lower anvil is 100 to 150 microns;

[0009] Step 3: Adjust the three leveling screws so that the upper pressure plate is parallel to the lower pressure plate, and the bottom surface of the upper anvil and the bottom surface of the lower anvil are also parallel to the upper pressure plate and the lower pressure plate respectively, and then use the limit screw to fix the position of the three leveling screws;

[0010] Step 4: Adjust the three pressure screws to make the central parts of the upper pressure plate and the lower pressure plate produce a slight elastic deflection bend, so that the upper anvil and the lower anvil continue to approach each other, until the pressure medium distance between the bottom surface of the upper anvil and the bottom surface of the lower anvil is 20 microns, and then adjust the three anvil limit screws to adjust the position of the lower anvil in the horizontal direction, so that the bottom surface of the upper anvil is aligned with the bottom surface of the lower anvil;

[0011] Step 5, adjusting the three pressure screws to make the upper pressure plate and the lower pressure plate further deflect and bend, so that the upper anvil can apply pressure to the sample through the pressure medium, and the pressure range is 5GPa to 30GPa;

[0012] Step 6, adjusting the light collection system so that its light collection area is an inverted cone with the sample as the vertex, and the solid angle range is typically 10 to 30 degrees;

[0013] Step 7, the laser emitted by the laser is incident from the crown bevel surface of the upper anvil in a normal direction, and is incident on the sample after being refracted at the interface between the upper anvil and the pressure medium;

[0014] Step 8, a portion of the scattered light generated by the sample under the action of the laser and located in the light collection area of ​​the light collection system enters the light collection system;

[0015] Step nine: Analyze the scattered light information of the sample collected by the light collection system for material property research.

[0016] The beneficial effects of the present invention are:

[0017] In the device of the present invention, the spatial separation between the scattered light of the anvil and the scattered light of the sample is relatively high, which can increase the signal-to-noise ratio of the sample scattering signal, thereby obtaining a sufficiently strong sample scattering signal without focusing the laser on a very small area on the sample, thereby reducing the local heat on the sample surface caused by the laser. In addition, the device of the present invention does not require movable structures such as guide rails to apply pressure to the anvil, thereby avoiding pressure deviations caused by aging and relaxation of movable parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further explanation below in conjunction with the graphics of the present invention:

[0019] Figure 1 It is a schematic diagram of the present invention;

[0020] Figure 2 is a schematic diagram of the upper pressure plate viewed from above;

[0021] Figure 3 is an enlarged schematic diagram of the upper anvil and the lower anvil;

[0022] Figure 4 This is a diagram of the standard cut of diamonds.

[0023] In the figure, 1. upper pressure plate, 2. lower pressure plate, 3. leveling screw, 4. pressure screw, 5. anvil limit screw, 6. upper support plate, 7. lower support plate, 8. upper anvil, 8-1. table, 8-2. crown, 8-3. waist, 8-4. pavilion, 8-5. bottom, 9. lower anvil, 10. ring gasket, 11. pressure medium, 12. sample, 13. limit screw, 14. light collection system, 15. laser. DETAILED DESCRIPTION

[0024] like Figure 1 It is a schematic diagram of the present invention, such as Figure 21 is a top view schematic diagram of an upper pressure plate, comprising an upper pressure plate (1), a lower pressure plate (2), a leveling screw (3), a pressure screw (4), an anvil limit screw (5), an upper support plate (6), a lower support plate (7), an upper anvil (8), a lower anvil (9), an annular gasket (10), a pressure medium (11), a sample (12), a limit screw (13), a light collection system (14) and a laser (15). xyz is a three-dimensional space coordinate system. The upper pressure plate (1) and the lower pressure plate (2) are both steel annular rings with an outer diameter of ten centimeters and are elastic. The upper pressure plate (1) and the lower pressure plate (2) are coaxially arranged in the vertical y direction. The upper pressure plate (1) has three evenly distributed M5 screw holes on a circumference three centimeters from the center. The plate (1) has three evenly distributed M4 screw holes on a circumference of four centimeters from the center, and each of the M4 screw holes has a limit screw (13) on the side. The lower pressure plate (2) has three evenly distributed M5 screw holes, which correspond to the M5 screw holes of the upper pressure plate (1). The lower pressure plate (2) has three evenly distributed conical grooves on the surface, which correspond to the M4 screw holes of the upper pressure plate (1). The pressure screw (4) is an M5 screw, and the pressure screw (4) connects the lower pressure plate (2) with the upper pressure plate (1) through the M5 screw hole. The leveling screw (3) is an M4 screw and its top end is conical. The leveling screw (3) passes through the M4 screw hole of the upper pressure plate (1), and the top end is located in the conical groove of the lower pressure plate (2). (2) is provided with three evenly spaced anvil limit screws (5) on the circumference of a circle two centimeters from the center. The upper support plate (6) and the lower support plate (7) are both silicon carbide rings with an outer diameter of three centimeters. The light collecting system (14) is located directly above the center of the upper support plate (6). The area corresponding to the light that can be collected by the light collecting system (14) is called the light collecting area. The upper support plate (6) is nested in the upper pressure plate (1) and connected and fixed. The lower support plate (7) is nested in the lower pressure plate (2). The lower support plate (7) can be fine-tuned by the three anvil limit screws (5) to change the relative position between the lower support plate (7) and the lower pressure plate (2) in the horizontal plane. The upper anvil (8) and the lower anvil (9) are both made of diamond standard cutting. The invention relates to a sample (12) having a table (8-1), a crown (8-2), a girdle (8-3), a pavilion (8-4) and a bottom (8-5); the included angle between the crown bevel and the table (8-1) is 40 degrees; the inner lower part of the upper support plate (6) has a bevel at a 40-degree angle to the horizontal direction; the inner bevel of the upper support plate (6) contacts the crown bevel of the upper anvil (8); the inner upper part of the lower support plate (7) has a bevel at a 40-degree angle to the horizontal direction; the inner bevel of the lower support plate (7) contacts the crown bevel of the lower anvil (9); the laser emitted by the laser (15) can be incident on the crown bevel of the upper anvil (8) in a normal direction, and then incident on the sample (12) through the upper anvil (8) and the pressure medium (11) in sequence.

[0025] like Figure 3 It is an enlarged schematic diagram of an upper anvil and a lower anvil. The bottom surface of the upper anvil (8) is downward, and the bottom surface of the lower anvil (9) is upward. The annular gasket (10) is located between the bottom surfaces of the upper anvil (8) and the lower anvil (9). The annular gasket (10) contains a pressure medium (11). The sample (12) is located in the pressure medium (11). When high pressure is applied to the sample (12), the upper anvil (8) and the lower anvil (9) are close to each other and pressure is applied to the sample (12) through the pressure medium (11). The high pressure range is 5 GPa to 30 GPa. The area corresponding to the light that can be collected by the light collection system (14) is called the light collection area.

[0026] like Figure 4 It is a schematic diagram of a standard diamond cut. The corresponding names of the various parts of the standard diamond cut are table (8-1), crown (8-2), girdle (8-3), pavilion (8-4) and bottom (8-5).

[0027] The principle of the device of the present invention for spatially separating the scattered light of the diamond anvil and the scattered light of the sample is:

[0028] The scattered light of the sample is mainly located within a solid angle range of about 45 degrees perpendicular to the sample surface, while the scattered light of the diamond anvil is mainly concentrated in the optical path of the laser incident on the anvil and near the optical path of the laser in the anvil after being reflected by the sample surface. The laser is incident from the beveled surface of the crown of the diamond anvil, and the incident angle on the sample surface is large, and the corresponding reflection angle is also large, so that the scattered light and fluorescence of the diamond can be better separated from the scattered light of the sample. In addition, the refractive index of the pressure medium between the anvil and the sample is lower than that of the diamond. The refraction of the laser beam in the process of leaving the anvil and entering the pressure medium is strong and the refraction angle is large. Figure 3 As shown, the spatial separation between the scattered light of the diamond and the scattered light of the sample can be further increased.

[0029] It should be noted that since the angle at which the laser beam enters the diamond anvil and hits the diamond-pressure medium interface is greater than the critical angle of the diamond-air interface, the refractive index of the pressure medium n p It cannot be too small, otherwise the laser beam will be completely reflected back into the anvil. On the other hand, in order to make the laser beam have a larger refraction angle when entering the pressure medium from the diamond, it is necessary to ensure that n p Cannot be too large, so we need to choose a suitable n p Value, n p A typical value is 1.4.

[0030] The spectral measurement device under high pressure conditions comprises an upper pressure plate (1), a lower pressure plate (2), a leveling screw (3), a pressure screw (4), an anvil limit screw (5), an upper support plate (6), a lower support plate (7), an upper anvil (8), a lower anvil (9), an annular gasket (10), a pressure medium (11), a sample (12), a limit screw (13), a light collection system (14) and a laser (15), wherein xyz is a three-dimensional space coordinate system, and the names corresponding to the various parts of the diamond standard cut include table (8-1), crown (8-2), girdle (8-3), pavilion (8-4), and the like. ) and a bottom surface (8-5), the bottom surface of the upper anvil (8) is downward, the bottom surface of the lower anvil (9) is upward, the annular gasket (10) is located between the bottom surface of the upper anvil (8) and the bottom surface of the lower anvil (9), the annular gasket (10) has a pressure medium (11), the sample (12) is located in the pressure medium (11), when high pressure is applied to the sample (12), the upper anvil (8) and the lower anvil (9) are close to each other, and pressure is applied to the sample (12) through the pressure medium (11), the high pressure range is 5GPa to 30GPa, and the area corresponding to the light that can be collected by the light collection system (14) is called the light collection area;The upper pressure plate (1) and the lower pressure plate (2) are both steel rings with an outer diameter of ten centimeters and are elastic. The upper pressure plate (1) and the lower pressure plate (2) are coaxially arranged in the vertical y direction. The upper pressure plate (1) has three evenly distributed M5 screw holes on a circumference three centimeters from the center. The upper pressure plate (1) has three evenly distributed M4 screw holes on a circumference four centimeters from the center. The side of each M4 screw hole has a limiting screw (13). The lower pressure plate (2) has three evenly distributed M5 screw holes corresponding to the M5 screw holes of the upper pressure plate (1). The lower pressure plate (2) has three evenly distributed circular screw holes. The pressure screw (4) is an M5 screw, and the pressure screw (4) connects the lower pressure plate (2) to the upper pressure plate (1) through the M5 screw hole. The leveling screw (3) is an M4 screw and its top end is conical. The leveling screw (3) passes through the M4 screw hole of the upper pressure plate (1) and its top end is located in the conical groove of the lower pressure plate (2). Three evenly distributed anvil limit screws (5) are installed on the upper surface of the lower pressure plate (2) at a circumference of two centimeters from the center. The upper support plate (6) and the lower support plate (7) are both carbon steel with an outer diameter of three centimeters. The silicon ring, the light collecting system (14) is located just above the center of the upper support plate (6), the upper support plate (6) is nested in the upper pressure plate (1) and connected and fixed, the lower support plate (7) is nested in the lower pressure plate (2), the lower support plate (7) can be fine-tuned by three anvil limit screws (5), and the relative position between the lower support plate (7) and the lower pressure plate (2) in the horizontal plane can be changed, the upper anvil (8) and the lower anvil (9) are both made of diamond standard cutting and have a table (8-1), a crown (8-2), a waist (8-3), a pavilion (8-4) and a bottom (8- 5), the included angle between the crown bevel and the table (8-1) is 40 degrees, the inner lower part of the upper support plate (6) has a bevel at a 40-degree angle to the horizontal direction, the inner bevel of the upper support plate (6) contacts the crown bevel of the upper anvil (8), the inner upper part of the lower support plate (7) has a bevel at a 40-degree angle to the horizontal direction, the inner bevel of the lower support plate (7) contacts the crown bevel of the lower anvil (9), and the laser emitted by the laser (15) can be incident on the crown bevel of the upper anvil (8) in a normal direction, and then incident on the sample (12) through the upper anvil (8) and the pressure medium (11) in sequence. ;

[0031] The incident light of the device of the present invention is incident from the beveled surface of the crown of the upper anvil, and the incident angle on the sample surface is relatively large, so that the scattered light of the anvil and the scattered light of the sample can be better separated, and the signal-to-noise ratio of the sample scattering signal is increased. In addition, the present invention does not require a guide rail structure, avoiding the deviation of the pressure applied to the sample due to loose components.

Claims

1. A spectral measurement device under high pressure conditions, comprising an upper pressure plate (1), a lower pressure plate (2), a leveling screw (3), a pressure screw (4), an anvil stop screw (5), an upper support plate (6), a lower support plate (7), an upper anvil (8), a lower anvil (9), an annular gasket (10), a pressure medium (11), a sample (12), a stop screw (13), a light collection system (14) and a laser (15), wherein xyz is a three-dimensional space coordinate system, the bottom surface of the upper anvil (8) is downward, and the bottom surface of the lower anvil (9) is downward. The bottom surface is upward, the annular gasket (10) is located between the bottom surface of the upper anvil (8) and the bottom surface of the lower anvil (9), the annular gasket (10) contains a pressure medium (11), and the sample (12) is located in the pressure medium (11). When high pressure is applied to the sample (12), the upper anvil (8) and the lower anvil (9) are close to each other, and pressure is applied to the sample (12) through the pressure medium (11). The high pressure range is 5 GPa to 30 GPa. The area corresponding to the light that can be collected by the light collection system (14) is called the light collection area. Its characteristics are: The upper pressure plate (1) and the lower pressure plate (2) are both steel rings with an outer diameter of ten centimeters and are elastic. The upper pressure plate (1) and the lower pressure plate (2) are coaxially arranged in the vertical y direction. The upper pressure plate (1) has three evenly distributed M5 screw holes on a circumference three centimeters from the center. The upper pressure plate (1) has three evenly distributed M4 screw holes on a circumference four centimeters from the center. The side of each M4 screw hole has a limiting screw (13). The lower pressure plate (2) has three evenly distributed M5 screw holes corresponding to the M5 screw holes of the upper pressure plate (1). The lower pressure plate (2) has three The pressure screw (4) connects the lower pressure plate (2) to the upper pressure plate (1) through the M5 screw hole. The top of the leveling screw (3) is conical. The leveling screw (3) passes through the M4 screw hole of the upper pressure plate (1) and the top is located in the conical groove of the lower pressure plate (2). Three evenly distributed anvil limit screws (5) are installed on the upper surface of the lower pressure plate (2) at a circumference of two centimeters from the center. The upper support plate (6) and the lower support plate (7) are both silicon carbide rings with an outer diameter of three centimeters. The light collection system The system (14) is located directly above the center of the upper support plate (6), the upper support plate (6) is nested in the upper pressure plate (1) and connected and fixed, the lower support plate (7) is nested in the lower pressure plate (2), the lower support plate (7) can be fine-tuned by three anvil limit screws (5), and the relative position between the lower support plate (7) and the lower pressure plate (2) in the horizontal plane can be changed, the upper anvil (8) and the lower anvil (9) are both made of diamond standard cutting, and have a table (8-1), a crown (8-2), a waist (8-3), a pavilion (8-4) and a bottom surface (8-5), the crown The angle between the upper bevel surface and the table (8-1) is 40 degrees, the inner lower part of the upper support plate (6) has a bevel surface that is 40 degrees to the horizontal direction, the inner bevel surface of the upper support plate (6) contacts the crown bevel surface of the upper anvil (8), the inner upper part of the lower support plate (7) has a bevel surface that is 40 degrees to the horizontal direction, the inner bevel surface of the lower support plate (7) contacts the crown bevel surface of the lower anvil (9), and the laser emitted by the laser (15) can be incident on the crown bevel surface of the upper anvil (8) in a normal direction, and then pass through the upper anvil (8) and the pressure medium (11) to be incident on the sample (12) in turn.

Images