Rotary switching mechanism for neutron scattering spectrometer

Abstract

The present invention relates to the technical field of spallation neutron sources, and discloses a rotary switching mechanism for a neutron scattering spectrometer, comprising a main body seat, a rotating cylinder, and a drive assembly. The rotating cylinder is rotatably disposed in the mounting cavity of the main body seat, and the rotating cylinder is provided with three through holes that completely penetrate along its axial direction. The three through holes can respectively give the neutron beam different characteristics, one of which can allow the neutron beam to pass normally, the second through hole can polarize the neutron beam, and the third through hole is provided with a multi-slit aperture plate to cause the neutron beam to diffract. The drive assembly is used to drive the rotating cylinder to rotate so that one of the through holes rotates to a preset position. When the through hole rotates to the preset position, the neutron beam can pass through the through hole and have specific characteristics. The rotary switching mechanism can realize the switching of different working modes through a rotating action. Compared with the horizontal movement switching in the prior art, this method reduces the overall volume and weight of the equipment, saving costs.

Description

Technical Field

[0001] The present invention relates to the technical field of spallation neutron sources, and in particular to a rotary switching mechanism for a neutron scattering spectrometer. Background Art

[0002] Neutron scattering spectrometer is an experimental platform that uses the interaction between neutrons and atomic nuclei to study the microstructure and dynamics of matter. Among them, the small-angle neutron scattering spectrometer is an upgrade of the traditional small-angle neutron scattering spectrometer. It can study the internal microstructure of materials such as polymers, biomacromolecules, complex fluids, metal precipitation phases, and inorganic materials within the scale range of 1 to 1000 nm. It has a wide range of applications in new drug development, new energy, new materials, etc.

[0003] A small-angle neutron scattering spectrometer primarily consists of a target station, a neutron guide, a sample stage, and a detector. The neutron beam from the target station passes through the neutron guide and sample stage before being detected by the detector, which is then used to analyze the stress, structure, and other characteristics of the sample. Due to variations in sample shape, material, and other characteristics, as well as the required technical specifications, it is necessary to switch and adjust different guides to produce neutron beams with varying characteristics.

[0004] In existing technology, switching between different conduits typically involves horizontal movement. Specifically, multiple conduits are spaced side by side and driven by a horizontal movement mechanism. When a neutron beam with specific characteristics is required, the mechanism moves the conduits so that the opening of the desired conduit aligns with the incident direction of the neutron beam, allowing the neutron beam to pass through the conduit, thereby imparting the desired neutron beam characteristics. Because the entire process must take place within a sealed chamber, the chamber must be large to accommodate the conduits' movement. This results in a large device, heavy and bulky, requiring significant space and resulting in high costs.

[0005] Therefore, there is an urgent need to provide a rotation switching mechanism for a neutron scattering spectrometer to solve the above problems. Summary of the Invention

[0006] The object of the present invention is to provide a rotary switching mechanism for a neutron scattering spectrometer, which can realize switching between different working modes by rotation, thereby reducing the overall volume and weight of the equipment and saving costs.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A rotary switching mechanism for a neutron scattering spectrometer, comprising:

[0009] A main body seat, wherein a mounting cavity is provided;

[0010] A rotating cylinder is rotatably disposed in the mounting cavity, and the rotating cylinder is provided with three through holes that completely penetrate the rotating cylinder along its axial direction, and the three through holes are arranged at intervals along the circumference of the rotating cylinder;

[0011] a drive assembly, an output end of which is connected to the rotating cylinder, the drive assembly being used to drive the rotating cylinder to rotate so that one of the through holes rotates to a preset position, and when the through hole rotates to the preset position, the neutron beam can pass through the through hole;

[0012] One of the through holes can allow the neutron beam to pass normally, the second through hole can polarize the neutron beam, and a multi-slit aperture plate is provided in the third through hole to cause the neutron beam to diffract.

[0013] As an optional solution, the driving component includes:

[0014] driving parts;

[0015] A reducer connected to the output end of the driving member, wherein the reducer is fixed on the main body seat;

[0016] a first bevel gear connected to the output end of the output shaft of the reducer;

[0017] The second bevel gear is sleeved outside the rotating cylinder and fixed coaxially with the rotating cylinder. The second bevel gear is meshed with the first bevel gear for transmission.

[0018] As an optional solution, the second bevel gear is a backlash-eliminating bevel gear, which includes:

[0019] A gear outer ring, wherein an annular receiving groove is formed on the end surface of the gear outer ring, and three circular arc grooves spaced and evenly distributed along the circumferential direction are formed inside the gear outer ring, and the circular arc grooves are connected to the receiving groove;

[0020] The inner ring of the gear is accommodated in the accommodating groove, and three spaced and evenly arranged protrusions are formed on the end surface of the inner ring of the gear. The protrusions are accommodated in the circular arc groove and abut against one end surface of the circular arc groove;

[0021] a spring accommodated in the arc groove, one end of the spring abutting against the other end surface of the arc groove, and the other end of the spring abutting against the protrusion;

[0022] A pressure plate has a portion pressed onto the inner ring of the gear and another portion fixed onto the outer ring of the gear.

[0023] As an optional solution, it also includes a vacuum sealing component, which includes a magnetic fluid and a mounting seat. The mounting seat is sleeved on the output shaft and is fixed to the reducer on one side and the main body seat on the other side. The magnetic fluid is sleeved on the output shaft and fixed on the mounting seat.

[0024] As an optional solution, except for the three through holes, the rest of the rotating cylinder is a solid structure, and the rotating cylinder is made of stainless steel.

[0025] As an optional solution, along the axial direction of the rotating cylinder, the rotating cylinder includes a plurality of shaft segments with different outer diameters, and the outer diameters of the shaft segments at both ends are greater than the outer diameter of the shaft segment in the middle portion.

[0026] As an optional solution, the main seat includes a shell and a base, the shell is fixed on the base, the shell is constructed in a circular ring shape, and the shell is coaxially sleeved outside the rotating cylinder.

[0027] As an optional solution, the outer shell of the rotating cylinder is provided with at least two bearings, and the at least two bearings are arranged at intervals along the axial direction, the inner ring of the bearing is connected to the rotating cylinder, and the outer ring is connected to the housing.

[0028] As an optional solution, it further includes an insertion mechanism, wherein the insertion mechanism is fixed on the main body seat, and the main body seat is provided with an avoidance hole;

[0029] An insertion hole is provided on the side wall of the rotating cylinder, and the insertion hole is connected with the through hole for installing the multi-slit aperture plate. When the through hole for accommodating the multi-slit aperture plate is rotated to the preset position, the avoidance hole is connected with the insertion hole, and the insertion mechanism can insert the multi-slit aperture plate into the corresponding through hole through the avoidance hole and the insertion hole.

[0030] As an optional solution, a monitoring component is further included, which includes a circular grating scale and a matching reading head. The reading head is arranged on the main body seat, and the circular grating scale is coaxially fixed to the rotating cylinder.

[0031] The beneficial effects of the present invention are:

[0032] The rotary switching mechanism for a neutron scattering spectrometer provided by the present invention includes a main body, a rotating cylinder and a drive assembly. The main body serves to support the rotating cylinder. Three through holes are provided on the rotating cylinder. The three through holes can respectively give the neutron beam different characteristics. One through hole can allow the neutron beam to pass normally, the second through hole can polarize the neutron beam, and the third through hole is provided with a multi-slit aperture plate to cause the neutron beam to diffract. The drive assembly drives the rotating cylinder to rotate so that one of the through holes rotates to a preset position and faces the incident direction of the neutron beam, thereby allowing the neutron beam to pass through the through hole and have specific characteristics. When there are different experimental requirements, the drive assembly can drive the corresponding through hole to rotate to the preset position, and the operation is flexible and convenient. The rotary switching mechanism can realize the switching of different working modes through the rotation action. Compared with the horizontal movement switching in the prior art, this method reduces the overall volume and weight of the equipment and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly and easily illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 1 is a schematic diagram of the overall structure of a rotary switching mechanism for a neutron scattering spectrometer provided by an embodiment of the present invention;

[0035] Figure 2 This is a structural schematic diagram of a rotary switching mechanism for a neutron scattering spectrometer provided by an embodiment of the present invention with the main body seat hidden;

[0036] Figure 3 is a schematic structural diagram of a drive assembly provided by an embodiment of the present invention;

[0037] Figure 4 is an exploded view of a second bevel gear provided by an embodiment of the present invention;

[0038] Figure 5 1 is a schematic structural diagram of the outer ring of the second bevel gear provided by an embodiment of the present invention;

[0039] Figure 6 1 is a schematic structural diagram of the inner ring of the second bevel gear provided by an embodiment of the present invention;

[0040] Figure 7 is a side view of the mating of the first bevel gear and the second bevel gear provided by an embodiment of the present invention;

[0041] Figure 8 yes Figure 7Cross-sectional view at AA in the middle;

[0042] Figure 9 is an axonometric cross-sectional view of a drive assembly provided by an embodiment of the present invention;

[0043] Figure 10 is a schematic diagram of a rotation switching mechanism for a neutron scattering spectrometer provided by an embodiment of the present invention with some structures hidden;

[0044] Figure 11 It is a schematic diagram of the structure of the monitoring component provided by an embodiment of the present invention.

[0045] In the picture:

[0046] 1. Main body; 11. Shell; 111. Avoidance hole; 112. Bellows; 12. Base;

[0047] 2. Rotating cylinder; 21. Through hole; 22. Bearing; 23. Insertion hole;

[0048] 3. Drive assembly; 31. Drive member; 32. Reducer; 321. Output shaft; 33. First bevel gear; 34. Second bevel gear; 341. Gear outer ring; 3411. Accommodation groove; 3412. Arc groove; 342. Gear inner ring; 3421. Bump; 343. Spring; 344. Pressure plate;

[0049] 4. Vacuum sealing assembly; 41. Magnetic fluid; 42. Mounting seat;

[0050] 5. Insertion mechanism;

[0051] 6. Monitoring component; 61. Circular grating scale; 62. Reading head. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0053] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0054] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0055] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on those shown in the accompanying drawings. These terms are intended solely for ease of description and simplified operation, and are not intended to indicate or imply that the components or elements referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0056] like Figure 1 As shown, this embodiment provides a rotary switching mechanism for a neutron scattering spectrometer, hereinafter referred to as a rotary switching mechanism. This rotary switching mechanism is typically used in small-angle neutron scattering spectrometers. Neutron beams emitted from a target station pass through the rotary switching mechanism and are detected by the detector of the small-angle neutron scattering spectrometer, thereby analyzing the stress, structure, and other characteristics of the sample. The rotary switching mechanism's rotational motion enables the neutron beam to have different characteristics, thereby matching the shape, material, and other characteristics of the sample being tested, as well as the different detection technical indicators required.

[0057] Specifically, if Figure 1 As shown, the rotary switching mechanism includes a main seat 1, a rotating cylinder 2 and a driving assembly 3. A mounting cavity is provided in the main seat 1, and the rotating cylinder 2 is rotatably arranged in the mounting cavity. The rotating cylinder 2 is provided with three through holes 21 that completely penetrate along its axial direction. The three through holes 21 can serve as neutron conduits for the neutron beam to pass through, and the three through holes 21 are arranged at intervals along the circumference of the rotating cylinder 2, wherein the three through holes 21 can respectively make the neutron beam have different characteristics, one of the through holes 21 can make the neutron beam pass normally, the second through hole 21 can polarize the neutron beam, and the third through hole 21 is provided with a multi-slit aperture plate to make the neutron beam diffract, and the order of the three through holes 21 can be set at will. The output end of the driving assembly 3 is connected to the rotating cylinder 2, and the driving assembly 3 is used to drive the rotating cylinder 2 to rotate so that one of the through holes 21 rotates to a preset position. When the through hole 21 rotates to the preset position, the neutron beam can pass through the through hole 21. In this embodiment, the preset position refers to Figure 1The position of the through hole 21 located directly above is shown as the location where the neutron beam can only pass through. In other embodiments, the preset position can also be other positions, which are not specifically limited here.

[0058] Exemplarily, the three through holes 21 can respectively make the neutron beam have different characteristics, that is, each through hole 21 represents a working mode, the first mode is to only allow the neutron beam to pass normally, the second mode is to polarize the neutron beam, that is, to make the neutron beam magnetic. The third mode is to make the neutron beam diffract through a multi-slit aperture plate, wherein the multi-slit aperture plate includes a plurality of slits, and the spacing between the slits is equal. After the neutron beam passes through the multi-slit aperture plate, a plurality of bright lines can be formed. In order to meet different experimental needs, any working mode can be adaptively selected. When a specific working mode is required, the driving component 3 drives the rotating cylinder 2 to rotate so that the through hole 21 corresponding to the corresponding characteristic can be rotated to the preset position. After the neutron beam passes through the through hole 21, the required neutron beam spot can be formed, and the operation is flexible and convenient. The rotary switching mechanism provided in this embodiment is compact and practical. Three through-holes 21 are arranged within a limited overall space. Through rotation, the mechanism can meet the requirements of different neutron beam characteristics and switch between three different operating modes. Compared to the horizontal movement switching method used in the prior art, this method reduces the overall size and weight of the device, saving costs. In other embodiments, the number of through-holes 21 can be set to two, depending on actual needs, to achieve switching between any two modes.

[0059] Specifically, if Figure 1 As shown, the main base 1 includes a shell 11 and a base 12. The shell 11 is fixed to the base 12 and is constructed in a circular ring shape. The shell 11 is coaxially sleeved outside the rotating cylinder 2 to support the rotating cylinder 2. It is understandable that in actual use, multiple rotary switching mechanisms are usually required to be coaxially connected to form a combination of a certain length. When connecting, the shells 11 of two adjacent rotary switching mechanisms need to be fastened together. Preferably, the shell 11 has bellows 112 at opposite ends. The bellows 112 are retractable, so that design and assembly tolerances can be compensated during connection to facilitate assembly and connection.

[0060] Furthermore, if Figure 2As shown, except for the three through holes 21, the rest of the rotating cylinder 2 is a solid structure, and the rotating cylinder 2 is made of stainless steel to achieve a shielding effect. In other words, the neutron beam can only pass through the through hole 21 located at the preset position, and the other areas near the through hole 21 have a very good shielding effect, thereby preventing the gamma rays generated by the cascade reaction of neutrons from passing through and affecting the experimental results. In the prior art, the solid shielding of the horizontal movement switching method is very difficult to implement, and the shielding block needs to move with the switching of the catheter, and the shielding effect is not good. The rotary switching mechanism of this embodiment integrates the through-hole neutron catheter and the steel shield. During the switching of the working mode, the steel shield as a whole also rotates and switches accordingly, which is easy to implement and has a good shielding effect.

[0061] Preferably, if Figure 2 As shown, along the axial direction of the rotating cylinder 2, the rotating cylinder 2 includes a plurality of shaft segments with different outer diameters and coaxially arranged. The plurality of shaft segments are passed through the same central axis and connected by bolts or other fasteners, thereby forming a complete rotating cylinder 2. The total length of the rotating cylinder 2 is 1.5 meters and the weight is 2 tons. In other words, the outer surface of the rotating cylinder 2 has a plurality of stepped surfaces, and the inner surface of the shell 11 can be processed into a step structure that matches the outer surface of the rotating cylinder 2. The outer diameter of the shaft segments at both ends is greater than the outer diameter of the shaft segments in the middle part. After the shell 11 is fitted with the rotating cylinder 2, there is no horizontal straight seam running through the shell 11 and the rotating cylinder 2 in the axial direction, and the shaft segments at both ends have a shielding effect on the shaft segments in the middle part, thereby increasing the shielding area, thereby achieving the effect of shielding ionizing radiation and further improving the shielding effect.

[0062] Furthermore, if Figure 2 As shown, at least two bearings 22 are provided on the outer surface of the rotating cylinder 2. These bearings 22 are spaced axially and positioned near each end of the rotating cylinder 2. The inner ring of the bearings 22 is connected to the rotating cylinder 2, and the outer ring is connected to the housing 11. This supports the rotating cylinder 2 and ensures stable rotation. Specifically, the bearings 22 are large thrust roller bearings that bear the weight of the entire rotating cylinder 2, enabling coaxial motion of the rotating cylinder 2 and ensuring reliable rotation.

[0063] Furthermore, if Figures 1 to 3As shown, the drive assembly 3 includes a drive member 31, a reducer 32, a first bevel gear 33 and a second bevel gear 34. The reducer 32 is connected to the output end of the drive member 31, and the reducer 32 is fixed to the flange protruding from the housing 11. The first bevel gear 33 is connected to the output end of the output shaft 321 of the reducer 32. The second bevel gear 34 is sleeved outside the rotating cylinder 2 and fixed coaxially with the rotating cylinder 2. The second bevel gear 34 is meshed with the first bevel gear 33 for transmission. Among them, the drive member 31 is a motor, and the reducer 32 is a worm gear reducer, which plays the role of matching the speed and transmitting torque between the motor and the first bevel gear 33. Figure 3 The driving member 31 rotates the output shaft 321 of the drive reducer 32, thereby driving the first bevel gear 33 to rotate. The first bevel gear 33 drives the second bevel gear 34 to rotate, thereby driving the entire rotating cylinder 2 to rotate, ensuring the repeatable positioning accuracy of the rotating cylinder 2. The bevel gear transmission method can withstand large torque, has smooth and low noise transmission, and a constant transmission ratio. It can be used for both deceleration and acceleration, and has high transmission efficiency.

[0064] Specifically, if Figures 3 to 8 As shown, the second bevel gear 34 is a clearance-eliminating bevel gear, which includes a gear outer ring 341, a gear inner ring 342, a spring 343 and a pressure plate 344. The gear outer ring 341 and the gear inner ring 342 are coaxially arranged. An annular receiving groove 3411 is provided on the end face of the gear outer ring 341. After the gear inner ring 342 is received in the receiving groove 3411, the gear teeth of the gear outer ring 341 and the gear teeth of the gear inner ring 342 are in the same plane and mesh with the first bevel gear 33. The pressure plate 344 is a circular ring structure and is coaxially arranged with the two bevel gears. The outer ring portion of the pressure plate 344 is pressed onto the gear inner ring 342, and the inner ring portion is fixed to the gear outer ring 341, thereby connecting the gear inner ring 342 and the gear outer ring 341 into a whole. Figure 5 As shown, the gear outer ring 341 is provided with three circular arc grooves 3412 spaced apart and evenly distributed along the circumferential direction. The circular arc grooves 3412 are connected to the accommodating groove 3411. That is, the circular arc grooves 3412 are formed by the bottom surface of the accommodating groove 3411 continuing to be concave along the axial direction. Figure 6 As shown, three spaced and evenly arranged protrusions 3421 are formed on the end face of the gear inner ring 342, and the protrusions 3421 are accommodated in the arc groove 3412 and abut against one end face of the arc groove 3412; the spring 343 is accommodated in the arc groove 3412, one end of the spring 343 abuts against the other end face of the arc groove 3412, and the other end of the spring 343 abuts against the protrusion 3421.

[0065] The working principle of the backlash-eliminating bevel gears is as follows: the outer ring 341 and the inner ring 342 are two thin-slice gears with exactly the same number of teeth. The sum of the tooth widths of the inner ring 342 and the outer ring 341 is the same as the tooth width of the first bevel gear 33. They mesh with the first bevel gear 33, and the inner and outer ring gears can rotate relative to each other. The elastic force or tension of the spring 343 causes the bevel teeth of the inner and outer ring gears to misalign, that is, the left and right tooth flanks of each tooth of the inner and outer ring gears respectively contact the left and right tooth flanks of the corresponding teeth of the first bevel gear 33, thereby meshing with the first bevel gear 33 and achieving the effect of eliminating backlash. Since there is no backlash between the first bevel gear 33 and the second bevel gear 34, the positioning accuracy of the rotation is improved.

[0066] Furthermore, if Figure 11 As shown, the rotation switching mechanism also includes a monitoring assembly 6, which includes a circular grating scale 61 and a matching reading head 62. The reading head 62 is mounted on the main body 1, and the circular grating scale 61 is coaxially fixed to the rotating cylinder 2. When the rotating cylinder 2 rotates, it drives the circular grating scale 61 to rotate. The reading head 62 obtains the angular position of the rotating cylinder 2 around its axis by reading the values ​​on the circular grating scale 61 passing through its identification area in real time. The monitoring assembly 6, in conjunction with the drive element 31 and a high-precision worm gear reducer, can achieve high motion control accuracy and repeatable positioning accuracy. Through research and testing, the rotational positioning accuracy of the rotating cylinder 2 can reach 0.5 degrees.

[0067] Furthermore, if Figure 9 As shown, the rotary switch also includes a vacuum sealing assembly 4, which includes a magnetic fluid 41 and a mounting seat 42. The mounting seat 42 is sleeved on the output shaft 321, and one side is fixed to the reducer 32, and the other side is fixed to the raised flange on the housing 11. The magnetic fluid 41 is located outside the mounting cavity, sleeved on the output shaft 321 and fixed to the mounting seat 42. The magnetic fluid 41 can achieve a seal between the output shaft 321 and the housing 11, so that the first bevel gear 33 located in the mounting cavity can be in a vacuum environment.

[0068] Further, combined with Figure 1 and Figure 10The rotation switch also includes an insertion mechanism 5, the outer shell of which is fixed to the protruding connecting flange on the shell 11. The main base 1 is provided with an avoidance hole 111, and the side wall of the rotating cylinder 2 is provided with an insertion hole 23. The insertion hole 23 is connected to the through hole 21 for installing the multi-slit aperture plate. When the through hole 21 for accommodating the multi-slit aperture plate is rotated to a preset position, the avoidance hole 111 is connected to the insertion hole 23. The insertion mechanism 5 can insert the multi-slit aperture plate into the corresponding through hole 21 through the avoidance hole 111 and the insertion hole 23, thus solving the problem of the inconvenience of installing the multi-slit aperture plate in the rotating cylinder 2. It should be noted that in this embodiment, the insertion mechanism 5 can select any linear drive structure such as a cylinder, an electric push rod, or a motor screw nut according to actual needs, and there is no need to limit the specific type of the insertion mechanism 5.

[0069] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A rotary switching mechanism for a neutron scattering spectrometer, characterized in that: include: A main body seat (1) having a mounting cavity therein; A rotating cylinder (2) is rotatably disposed in the mounting cavity, and the rotating cylinder (2) is provided with three through holes (21) that completely penetrate the rotating cylinder along its axial direction, and the three through holes (21) are arranged at intervals along the circumference of the rotating cylinder (2); A drive assembly (3), the output end of which is connected to the rotating cylinder (2), the drive assembly (3) being used to drive the rotating cylinder (2) to rotate so that one of the through holes (21) rotates to a preset position, and when the through hole (21) rotates to the preset position, the neutron beam can pass through the through hole (21); One of the through holes (21) can allow the neutron beam to pass normally, the second through hole (21) can polarize the neutron beam, and a multi-slit aperture plate is provided in the third through hole (21) to cause the neutron beam to diffract; The driving assembly (3) comprises: A driving member (31); A reducer (32) is connected to the output end of the driving member (31), and the reducer (32) is fixed on the main body (1); A first bevel gear (33) connected to an output end of an output shaft (321) of the reducer (32); a second bevel gear (34) sleeved outside the rotating cylinder (2) and coaxially fixed to the rotating cylinder (2), the second bevel gear (34) meshing with the first bevel gear (33) for transmission; The second bevel gear (34) is a backlash-eliminating bevel gear, comprising: A gear outer ring (341), wherein an annular receiving groove (3411) is provided on the end surface of the gear outer ring (341), and three circular arc grooves (3412) spaced apart and evenly distributed along the circumferential direction are provided in the gear outer ring (341), and the circular arc grooves (3412) are communicated with the receiving groove (3411); The gear inner ring (342) is accommodated in the accommodating groove (3411), and three spaced and evenly arranged protrusions (3421) are formed on the end surface of the gear inner ring (342), and the protrusions (3421) are accommodated in the circular arc groove (3412) and abut against one end surface of the circular arc groove (3412); A spring (343) is accommodated in the circular arc groove (3412), one end of the spring (343) abuts against the other end surface of the circular arc groove (3412), and the other end of the spring (343) abuts against the protrusion (3421); A pressure plate (344), a portion of which is pressed onto the gear inner ring (342), and another portion of which is fixed onto the gear outer ring (341); The invention also includes a vacuum sealing component (4), the vacuum sealing component (4) including a magnetic fluid (41) and a mounting seat (42), the mounting seat (42) being sleeved on the output shaft (321), and having one side fixed to the reducer (32) and the other side fixed to the main body seat (1), the magnetic fluid (41) being sleeved on the output shaft (321) and fixed to the mounting seat (42).

2. The rotary switching mechanism for a neutron scattering spectrometer according to claim 1, characterized in that: Except for the three through holes (21), the rest of the rotating cylinder (2) is a solid structure, and the rotating cylinder (2) is made of stainless steel.

3. The rotary switching mechanism for a neutron scattering spectrometer according to claim 1, characterized in that: Along the axial direction of the rotating cylinder (2), the rotating cylinder (2) comprises a plurality of shaft segments with different outer diameters, and the outer diameters of the shaft segments at both ends are larger than the outer diameter of the shaft segment in the middle portion.

4. The rotary switching mechanism for a neutron scattering spectrometer according to claim 1, characterized in that: The main body seat (1) comprises a shell (11) and a base (12), wherein the shell (11) is fixed on the base (12), the shell (11) is constructed in a circular ring shape, and the shell (11) is coaxially sleeved outside the rotating cylinder (2).

5. The rotary switching mechanism for a neutron scattering spectrometer according to claim 4, characterized in that: The outer sleeve of the rotating cylinder (2) is provided with at least two bearings (22), and the at least two bearings (22) are arranged at intervals along the axial direction. The inner ring of the bearing (22) is connected to the rotating cylinder (2), and the outer ring is connected to the housing (11).

6. The rotary switching mechanism for a neutron scattering spectrometer according to claim 1, characterized in that: It also includes an insertion mechanism (5), the insertion mechanism (5) is fixed on the main body seat (1), and the main body seat (1) is provided with an avoidance hole (111); An insertion hole (23) is provided on the side wall of the rotating cylinder (2), and the insertion hole (23) is communicated with the through hole (21) for installing the multi-slit aperture plate. When the through hole (21) for accommodating the multi-slit aperture plate is rotated to the preset position, the avoidance hole (111) is communicated with the insertion hole (23), and the insertion mechanism (5) can insert the multi-slit aperture plate into the corresponding through hole (21) through the avoidance hole (111) and the insertion hole (23).

7. The rotary switching mechanism for a neutron scattering spectrometer according to claim 1, characterized in that: The apparatus further comprises a monitoring assembly (6), wherein the monitoring assembly (6) comprises a circular grating ruler (61) and a matching reading head (62), wherein the reading head (62) is arranged on the main body seat (1), and the circular grating ruler (61) is coaxially fixed to the rotating cylinder (2).

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