A neutron spectrometer collimator system

Abstract

A neutron spectrometer collimator system includes a first collimator, a first mounting frame, and a position adjustment device. The first collimator is arranged between the center point of the sample and the neutron detector, and the first collimator is mounted on the first mounting frame, and the first mounting frame is mounted on the position adjustment device. The first collimator is used to collimate the diffracted neutron beam to effectively reduce the entry of stray neutrons into the neutron detector. At the same time, the position adjustment device can adjust the position of the first collimator to find the position with the largest flux of the diffracted neutron beam, so as to reduce the background noise, enhance the effective signal, increase the signal-to-noise ratio, and improve the experimental resolution and accuracy of the spectrometer.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron collimators, and in particular to a neutron spectrometer collimator system. Background Art

[0002] Neutrons and X-rays are both powerful tools for exploring the microstructure of matter. Neutron sources are large scientific facilities that produce neutrons. Depending on how the neutron beam is generated, neutron sources can be divided into reactor neutron sources and accelerator-based pulsed neutron sources. A neutron spectrometer is the experimental terminal of a neutron source. Its basic principle is that protons bombard a heavy metal target, causing spallation reactions. The generated neutrons travel through transport lines to the sample, react with the sample, and then disperse again. Neutron detectors collect neutron signals at specific angles, allowing the sample's microstructure to be inferred.

[0003] Due to the unique characteristics of the neutron beam, a portion of the neutron beam will diverge. These stray neutrons may react with other non-sample components, and the signal from these stray neutrons becomes background noise. The signal-to-noise ratio is a key factor in determining the resolution and accuracy of a spectrometer experiment. The higher the signal-to-noise ratio, the higher the resolution and accuracy of the spectrometer experiment. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a neutron spectrometer collimator system.

[0005] According to a first aspect, an embodiment provides a neutron spectrometer collimator system, comprising:

[0006] a first collimator, the first collimator being arranged between the center point of the sample and the neutron detector, and being used for collimating the diffracted neutron beam;

[0007] a first mounting frame, wherein the first collimator is mounted on the first mounting frame;

[0008] A posture adjustment device, wherein the first mounting frame is installed on the posture adjustment device, and the posture adjustment device is used to adjust the spatial posture of the first collimator.

[0009] In one embodiment, the first collimator is in the shape of a square horn with a small front end face and a large rear end face, and the focus of the first collimator is the center point of the sample. The coverage angle of the rear end face of the first collimator is greater than or equal to the coverage angle of the neutron detector.

[0010] In one embodiment, the first mounting frame has a first collimator mounting cavity, the first collimator mounting cavity is in the shape of a square trumpet, the first collimator mounting cavity is formed by two oppositely arranged side walls and a bottom support plate, the first collimator is arranged in the first collimator mounting cavity and there is a gap between the first collimator and the side walls and the bottom support plate.

[0011] In one embodiment, a plurality of adjustment bolts are provided on the side wall and the bottom support plate, and the adjustment bolts are used to fine-tune the spatial position of the first collimator.

[0012] In one embodiment, the posture adjustment device includes: a first motion axis, a second motion axis and a third motion axis; the second motion axis is arranged on the first motion axis, and the second motion axis can perform reciprocating linear motion along the direction of the first motion axis; the third motion axis is arranged on the second motion axis, and the third motion axis can perform reciprocating linear motion along the direction of the second motion axis; the third motion axis can rotate; the direction of the first motion axis is perpendicular to the direction of the incident neutron beam, the direction of the second motion axis is perpendicular to the direction of the first motion axis, and the rotation axis of the third motion axis is perpendicular to both the direction of the first motion axis and the direction of the second motion axis; the first mounting bracket is installed on the third motion axis.

[0013] In one embodiment, the first mounting frame has a posture adjustment device connection portion, the posture adjustment device connection portion is provided with a plurality of wedge-shaped connecting blocks, the third motion axis is provided with a rectangular connecting block, the side surface of the rectangular connecting block is an inclined surface, and the upper inclined surface of the wedge-shaped connecting block is connected to the upper inclined surface of the rectangular connecting block.

[0014] In one embodiment, it also includes: a second collimator and a second mounting bracket; the second collimator is arranged between the first collimator and the neutron detector, the second collimator is in the shape of a square horn and the focus of the second collimator is the center point of the sample, the front end face shape of the second collimator is the same as the rear end face shape of the first collimator, the rear end face shape of the second collimator is the same as the shape of the neutron detector and the rear end face of the second collimator is close to the surface of the neutron detector; the second collimator is mounted on the second mounting bracket.

[0015] In one embodiment, a transition plate is provided between the first collimator and the second collimator, and the transition plate is used to close the gap between the first collimator and the second collimator.

[0016] In one embodiment, the second collimator is provided with a plurality of adjustment hinges, the adjustment hinges are used to adjust the pitch attitude of the second collimator, and the adjustment hinges are slidably connected to the second mounting frame.

[0017] In one embodiment, a top platform and a counterweight are provided on the second mounting frame, the posture adjustment device is installed at one end of the top platform, and the counterweight is installed at the other end of the top platform.

[0018] According to the neutron spectrometer collimator system of the above embodiment, since a first collimator is provided between the center point of the sample and the neutron detector, stray neutrons entering the neutron detector are effectively reduced. At the same time, the position adjustment device can adjust the position of the first collimator to find the position where the flux of the diffracted neutron beam is the largest, thereby reducing the background noise, enhancing the effective signal, increasing the signal-to-noise ratio, and improving the experimental resolution and accuracy of the spectrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the overall structure of a neutron spectrometer collimator system in one embodiment;

[0020] Figure 2 1 is a schematic diagram of the overall structure of a first collimator and a first mounting bracket of a neutron spectrometer collimator system in one embodiment;

[0021] Figure 3 for Figure 2 A schematic structural diagram of the first collimator and the first mounting bracket as a whole from another angle;

[0022] Figure 4 Schematic diagram of the structure of the connection part of the posture adjustment device of the neutron spectrometer collimator system in one embodiment;

[0023] Figure 5 Schematic diagram of the structure of a posture adjustment device of a neutron spectrometer collimator system in one embodiment;

[0024] Figure 6 1 is a schematic diagram of the overall structure of a second collimator and a second mounting bracket of a neutron spectrometer collimator system in one embodiment;

[0025] Figure 7 is a schematic structural diagram of a second collimator of a neutron spectrometer collimator system in an embodiment;

[0026] Figure 8 for Figure 7 Schematic diagram of the structure of the second collimator at another angle.

[0027] Explanation of the accompanying drawings: 1. First collimator; 2. First mounting bracket; 21. First collimator mounting cavity; 211. Side wall; 212. Bottom support plate; 213. Limit block; 214. Anti-flip beam; 22. Position adjustment device connection part; 221. Wedge-shaped connecting block; 23. Lifting ear; 3. Position adjustment device; 31. First movement axis; 32. Second movement axis; 33. Third movement axis; 331. Rectangular connecting block; 332. Guide pin; 4. Second collimator; 41. First transition plate; 411. Handle; 42. Second transition plate; 43. Shelf; 44. Adjustment hinge; 5. Second mounting bracket; 51. Mounting beam; 52. Reinforcement tie rod; 53. Top platform; 54. Counterweight; 55. Column; 56. Mounting plate; 561. Anchor rod; 100. Adjustment bolt; 200. Connecting waist groove. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions, and for those skilled in the art, it is not necessary to describe these related operations in detail. They will fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0029] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0030] The serial numbers assigned to components herein, such as "first," "second," etc., are used solely to distinguish the objects being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings).

[0031] Definitions of some terms used in this application:

[0032] Sample center point: The sample center point is a point in space. It is the end of the incident neutron beam and the center point where the neutron beam reacts with the sample.

[0033] Neutron detector: The neutron detector covers the sample center point in a spatial coverage angle envelope and is used to collect neutron signals at a specific angle.

[0034] Diffracted neutron beam: A neutron beam that scatters after reacting with the sample.

[0035] In an embodiment of the present invention, the neutron spectrometer collimator system includes a first collimator, a first mounting bracket and a posture adjustment device. The first collimator is arranged between the center point of the sample and the neutron detector. The first collimator is mounted on the first mounting bracket, and the first mounting bracket is mounted on the posture adjustment device. The first collimator is used to collimate the diffracted neutron beam, effectively reducing the entry of stray neutrons into the neutron detector. At the same time, the posture adjustment device can adjust the posture of the first collimator to find the position where the flux of the diffracted neutron beam is the largest, so that the background noise is reduced, the effective signal is enhanced, the signal-to-noise ratio is increased, and the experimental resolution and accuracy of the spectrometer are improved.

[0036] The present application is described below by way of examples.

[0037] Example 1:

[0038] like Figures 1 to 8 As shown, in one embodiment of the present application, a neutron spectrometer collimator system is provided, comprising: a first collimator 1, a first mounting bracket 2 and a posture adjustment device 3. The first collimator 1 is arranged between the center point of the sample and the neutron detector. The diffracted neutron beam passes through the first collimator 1 from the center point of the sample and reaches the neutron detector after being collimated, which can effectively reduce the number of stray neutrons reaching the neutron detector and reduce the background noise. The first collimator 1 is mounted on the first mounting bracket 2. The first mounting bracket 2 is mounted on the posture adjustment device 3, and the posture adjustment device 3 is used to adjust the spatial posture of the first collimator 1 to find the position where the flux of the diffracted neutron beam is the largest, increase the number of neutrons that react with the sample and reach the neutron detector, and enhance the effective signal. The background noise is reduced, the effective signal is enhanced, the signal-to-noise ratio is increased, and the experimental resolution and accuracy of the spectrometer are improved.

[0039] During the neutron spectrometer experiment, the incident neutron beam reacts with the sample and then scatters again to form a diffracted neutron beam. The neutron detector covers the center of the sample at a certain spatial coverage angle according to the experimental requirements to collect diffracted neutron signals at a specific angle for inferring the microstructure of the sample. The diffracted neutron beam is radially emitted from the center of the sample or the area near the center of the sample to the neutron detector, and the direction of the stray neutrons that react with non-sample parts to the neutron detector is generally different from the direction of the diffracted neutron beam to the neutron detector. The purpose of setting the first collimator 1 is to collimate the diffracted neutron beam and prevent external stray neutrons from entering the neutron detector. For this purpose, the shape of the first collimator 1 should be the front end (close to the The collimator 1 is shaped like a trumpet with a small front end (near the center point of the sample) and a large rear end (near the neutron detector). The front and rear facets of the first collimator 1 should be cylindrical or spherical. The outer contour of the first collimator 1 should envelop the radial area of the diffracted neutron beam from the center point of the sample to the neutron detector, and the focus of the trumpet-shaped outer contour of the first collimator 1 is the center point of the sample. With this arrangement, the diffracted neutron beam is collimated by the first collimator 1 and then emitted to the neutron detector. Stray neutrons cannot enter the first collimator 1 or cannot pass through the first collimator 1 due to a large difference between the direction of entering the first collimator 1 and the direction of the diffracted neutron beam. The neutrons that pass through the first collimator 1 and reach the neutron detector can only come from the sample within the measurement field of view, thereby reducing background noise.

[0040] In one embodiment, the first collimator 1 is shaped like a square horn with a small front end and a large rear end. The focal point of the horn-shaped outer contour of the first collimator 1 is the center point of the sample. The coverage angle of the rear end of the first collimator 1 is greater than or equal to the coverage angle of the neutron detector. This ensures that neutrons that pass through the first collimator 1 and reach the neutron detector originate only from the sample, thereby reducing background noise. The square horn shape of the first collimator 1, with its outer contour formed of flat plates, facilitates installation and fine-tuning of the spatial position of the first collimator 1.

[0041] According to the above records, the first collimator 1 should be trumpet-shaped, so it is difficult to directly install the first collimator 1 on the posture adjustment device 3. The first collimator 1 needs to be installed on the first mounting bracket 2, and then the first mounting bracket 2 is installed on the posture adjustment device 3, so that the posture adjustment device 3 can be used to adjust the spatial posture of the first collimator 1.

[0042] In one embodiment, the first mounting frame 2 has a first collimator mounting cavity 21, and an opening is provided above the first collimator mounting cavity 21. The first collimator 1 is placed into the first collimator mounting cavity 21 through the opening. The first collimator mounting cavity 21 is trumpet-shaped and its overall shape is similar to that of the first collimator 1. There is a gap between the first collimator 1 and the inner wall of the first collimator mounting cavity 21 to provide space for fine-tuning the first collimator 1.

[0043] In one embodiment, the first collimator mounting cavity 21 is in the shape of a square horn. The first collimator mounting cavity 21 is formed by two relatively arranged side walls 211 and a bottom support plate 212. The upper end has an opening for the first collimator 1 to be placed in. There is a gap between the first collimator 1 and the side walls 211 and the bottom support plate 212 for fine-tuning the spatial posture of the first collimator 1. The first collimator mounting cavity 21 adopts a split design. On the one hand, it is convenient for the disassembly and assembly of the first collimator 1. On the other hand, it avoids deformation caused by integral forming processes such as welding or stamping, which causes the installation accuracy of the entire collimator system to decrease. In one embodiment, slots are symmetrically provided on the two side walls 211, and the bottom support plate 212 is inserted into the slots. The connection between the side walls 211 and the bottom support plate 212 is achieved by fixing pins, connecting bolts, limiting structures, etc., and the installation and positioning accuracy is high.

[0044] In one embodiment, a jack structure is provided on the side wall 211 and the bottom support plate 212, and the top of the jack is connected to the first collimator 1. When the spatial position of the first collimator 1 needs to be fine-tuned, the spatial position of the first collimator 1 can be fine-tuned in the gap between the first collimator 1 and the first collimator mounting cavity 21 through the coordinated action of the jacks, thereby achieving precise installation and positioning of the first collimator 1.

[0045] In one embodiment, a plurality of adjusting bolts 100 are provided on the side wall 211 and the bottom support plate 212, and the top of the adjusting bolt 100 is connected to the first collimator 1. When the spatial position of the first collimator 1 needs to be fine-tuned, the spatial position of the first collimator 1 can be fine-tuned in the gap between the first collimator 1 and the first collimator mounting cavity 21 through the coordinated action of the adjusting bolts 100, thereby achieving precise installation and positioning of the first collimator 1. The adjusting bolts 100 are small in size and easy to install. The provision of multiple adjusting bolts 100 will not affect the overall strength of the side wall 211 and the bottom support plate 212. The multiple adjusting bolts 100 can also fine-tune the spatial position of the first collimator more finely and jointly share the pressure of the first collimator 1, resulting in higher overall accuracy and reliability.

[0046] In one embodiment, a limit block 213 is provided at the rear end of the first collimator mounting cavity 21, which blocks the first collimator 1 to prevent it from sliding out of the first collimator mounting cavity 21. An anti-flip beam 214 is provided on the front side of the upper end of the first collimator mounting cavity 21, and the anti-flip beam 214 is used to prevent the first collimator 1 from flipping backward and falling out of the first collimator mounting cavity 21.

[0047] For some neutron spectrometers, several first collimators 1 of different specifications are configured, corresponding to different spatial resolutions, to meet different experimental requirements. Generally speaking, as the spatial resolution increases, the inner diameter of the first collimator 1 gradually increases. Since the focus of the first collimator 1 coincides with the center point of the sample, the increase in the inner diameter of the first collimator 1 means that the spatial position needs to be further away from the center point of the sample. Before conducting the experiment, the operator selects a suitable first collimator 1 according to the spatial resolution required by the experiment, and uses the first mounting bracket 2 to hang the first collimator 1 on the posture adjustment device 3. The posture adjustment device 3 adjusts the spatial posture of the first collimator 1 to a suitable position and records the posture data of the posture adjustment device 3, which can be used as calibration data for the first collimator 1 of the corresponding specification. When the first collimator 1 of the same specification is used again, the posture adjustment device 3 can be directly adjusted according to the calibration data. In one embodiment, the posture adjustment device 3 is controlled by an external control platform, and the working posture data of the posture adjustment device 3 is recorded by the external control platform.

[0048] In one embodiment, the first mounting bracket 2 comprises an upper and lower portion. The upper portion is connected to the posture adjustment device 3, and the lower portion comprises a first collimator mounting cavity 21 for mounting the first collimator 1. Due to the large size of the first mounting bracket 2, the upper and lower portions are separate structures to facilitate assembly and disassembly. Each specification of the first collimator 1 has a corresponding first mounting bracket 2. When a first collimator 1 of a different specification is required, the first collimator 1 and the first mounting bracket 2 can be replaced as a whole from the posture adjustment device 3.

[0049] In one embodiment, the posture adjustment device 3 includes a first motion axis 31, a second motion axis 32 and a third motion axis 33. The second motion axis 32 is provided on the first motion axis 31, and the second motion axis 32 can perform reciprocating linear motion along the direction of the first motion axis 31. The third motion axis 33 is provided on the second motion axis 32, and the third motion axis 33 can perform reciprocating linear motion along the direction of the second motion axis 32. The third motion axis 33 can rotate. The first mounting bracket 2 is mounted on the third motion axis 33. The direction of the first motion axis 31 is perpendicular to the direction of the incident beam. Adjusting the position of the first collimator 1 along the direction of the first motion axis 31 can make the distance between the first collimator 1 and the center point of the sample gradually closer or farther. After replacing the first collimator 1 with a different spatial resolution, it is necessary to adjust the distance between the first collimator 1 and the center point of the sample to meet the experimental requirements. Those skilled in the art will appreciate that the orientation of the first motion axis 31 is related to the position of the collimator system in this application. For example, in this embodiment, the collimator system is positioned to one side of the incident neutron beam, and the line connecting the sample center and the neutron detector center is perpendicular to the direction of the incident neutron beam. Therefore, the orientation of the first motion axis 31 should be perpendicular to the direction of the incident neutron beam. In some embodiments, the line connecting the sample center and the neutron detector center forms a certain angle with the direction of the incident neutron beam. In this case, the orientation of the first motion axis 31 should be set at a corresponding angle to the direction of the incident neutron beam to ensure proper operation of the collimator system. The direction of the second movement axis 32 is perpendicular to the direction of the first movement axis 31. Adjusting the first collimator 1 along the direction of the second movement axis 32 can make the first collimator 1 move left and right, so that the first collimator 1 scans left and right. The rotation axis of the third movement axis 33 is perpendicular to the directions of the first movement axis 31 and the second movement axis 32. The rotation of the third movement axis 33 can make the first collimator 1 rotate and scan. Through the left and right and rotational scanning of the first collimator 1, the first collimator 1 finds the position with the maximum neutron flux, thereby improving the signal-to-noise ratio.

[0050] Since the spatial posture accuracy of the first collimator 1 is very high, the installation stability of the first mounting frame 2 and the posture adjustment device 3 must be very high. The upper portion of the first mounting frame 2 is used to connect to the posture adjustment device 3. The upper portion of the first mounting frame 2 is provided with a posture adjustment device connecting portion 22, which is connected to the posture adjustment device 3.

[0051] In one embodiment, a connecting disk is provided on the third moving shaft 33, and a plurality of positioning columns or positioning holes are correspondingly provided on the connecting disk and the connection part 22 of the posture adjustment device. When the first mounting frame 2 is connected to the posture adjustment device 3, the positioning columns and the positioning holes are matched in pairs, and the gravity of the first mounting frame 2 and the first collimator 1 presses the first mounting frame 2 tightly against the connecting disk, thereby realizing a stable connection between the first mounting frame 2 and the posture adjustment device 3.

[0052] In one embodiment, the posture adjustment device connection portion 22 is provided with a plurality of wedge-shaped connection blocks 221, and a rectangular connection block 331 is provided on the third motion axis 33. The side surface of the rectangular connection block 331 is an inclined surface, and the upper inclined surface of the wedge-shaped connection block 221 is connected to the upper inclined surface of the rectangular connection block 331. The gravity of the first mounting frame 2 and the first collimator 1 presses the first mounting frame 2 tightly against the upper surface of the rectangular connection block 331. The wedge-shaped connection block 221 presses against the rectangular connection block 331 to prevent the first mounting frame 2 from shaking, and the connection between the two is stable.

[0053] In one embodiment, a plurality of guide pins 332 are provided on the rectangular connecting block 331, and corresponding guide pin holes are provided on the posture adjustment device connecting portion 22. The guide pins 332 cooperate with the guide pin holes to assist the first mounting frame 2 in being installed on the posture adjustment device 3. In order to make the guiding effect of the guide pins 332 stronger, the top of the guide pins 332 is conical, which facilitates the insertion of the guide pins 332 into the guide pin holes, thereby reducing the difficulty of installation and improving the installation accuracy.

[0054] In one embodiment, an elastic member is provided on the connection portion 22 of the posture adjustment device, and the elastic member acts on the wedge-shaped connection block 221, so that the wedge-shaped connection block 221 can tightly press against the rectangular connection block 331, ensuring the stability of the connection between the two.

[0055] In one embodiment, an adjusting bolt 100 is provided on the connection portion 22 of the posture adjustment device, and the adjusting bolt 100 acts on the wedge-shaped connecting block 221. The wedge-shaped connecting block 221 is fine-tuned by the adjusting bolt 100, thereby adjusting the fitting clearance between the inclined surface of the wedge-shaped connecting block 221 and the inclined surface of the rectangular connecting block 331, controlling the tightness of the installation, ensuring a high repeatability positioning accuracy, and at the same time being easy to disassemble and assemble, thereby facilitating the replacement and use of first collimators 1 of different specifications.

[0056] In one embodiment, a lifting lug 26 is provided on the upper end of the first mounting frame 2. When the first mounting frame 2 and the first collimator 1 of corresponding specifications are idle, the first mounting frame 2 and the first collimator 1 can be hoisted as a whole by the lifting lug 26 for standby use.

[0057] In order to improve the signal-to-noise ratio, the range of the first collimator 1 that envelops the diffracted neutron beam should be as large as possible, that is, the closer the rear end face of the first collimator 1 is to the neutron detector, the better. However, if the first collimator 1 is too large, the production cost and installation cost will increase significantly, and such a large first collimator 1 is not necessary to perform fine collimation of the neutron beam.

[0058] In one embodiment, the neutron spectrometer collimator system further includes a second collimator 4, which is disposed between the first collimator 1 and the neutron detector. The second collimator 4 is also used to collimate the diffracted neutron beam and prevent stray neutrons from reaching the neutron detector. Because the diffracted neutron beam has already been finely collimated by the first collimator 1, the collimation accuracy of the second collimator 4 does not need to be too high, thereby saving costs. Based on the aforementioned description, it can be seen that the second collimator 4 should also be horn-shaped with a small front end and a large rear end. The focus of the second collimator 4 is the center point of the sample. The shape of the front end face of the second collimator 4 should be the same as the shape of the rear end face of the first collimator 1, and the shape of the rear end face of the second collimator 4 should be the same as the shape of the neutron detector. The rear end face of the second collimator 4 is in close proximity to the neutron detector, and the coverage angle of the rear end face of the second collimator 4 is greater than the coverage angle of the neutron detector. Accordingly, the neutron spectrometer collimator system further includes a second mounting bracket 5 for mounting the second collimator 4.

[0059] As can be seen from the previous records, some neutron spectrometers are equipped with several first collimators 1 of different specifications. The smaller first collimator 1 is close to the center point of the sample, and the gap between it and the second collimator 4 is larger. The larger first collimator 1 is close to the second collimator 4, and the gap between it and the second collimator 4 is smaller. The gap between the two always exists. In order to prevent stray neutrons from entering the second collimator 4 from the gap between the first collimator 1 and the second collimator 4, the gap between the first collimator 1 and the second collimator 4 should be closed.

[0060] In one embodiment, a transition plate is provided between the first collimator 1 and the second collimator 4. The transition plate is made of neutron absorbing material. The transition plate closes the gap between the first collimator 1 and the second collimator 4 to prevent stray neutrons from entering the second collimator 4 and then reaching the neutron detector to cause background noise.

[0061] In one embodiment, the transition plate is trumpet-shaped, with the front end connected to the first collimator 1 and the rear end connected to the second collimator 4, closing the gap between the first collimator 1 and the second collimator 4 to prevent stray neutrons from entering the second collimator 4 and then reaching the neutron detector to cause background noise.

[0062] In one embodiment, the transition plate includes a first transition plate 41 and a second transition plate 42. The two first transition plates 41 are relatively arranged on the left and right sides of the second collimator 4. The first transition plate 41 is rotatably connected to the second collimator 4. The first transition plates 41 on the left and right sides can be opened to the left and right sides, and the two second transition plates 42 are relatively fixedly arranged on the upper and lower sides of the second collimator 4. The length of the first transition plate 41 is sufficient to cover the gap between the first collimator 1 and the second collimator 4 of the smallest size. The second transition plates 42 have different specifications and are matched with the first collimators 1 of different specifications. After the first collimator 1 is installed in place, the first transition plate 41 is first closed and fixedly connected to the first collimator 1. Then, the second transition plate 42 is selected according to the specifications of the selected first collimator 1 and installed to the upper and lower sides of the second collimator 4. The second transition plate 42 is fixedly connected to the first collimator 1 to complete the installation of the transition plate. The first transition plate 41 is connected to the second collimator 4 through a hinge. When a first collimator 1 of a different specification is selected, the first transition plate 41 does not need to be removed from the second collimator 4, which facilitates operation. The reason why this installation method is not used for the second transition plate 42 is to avoid interference between the second transition plate 42 and the first mounting frame 2.

[0063] In one embodiment, a handle 411 is provided on the first transition plate 41 to facilitate an operator to open and close the first transition plate 41 .

[0064] The second collimator 4 serves as an extension of the first collimator 1 and is used to further collimate the neutron beam.

[0065] In one embodiment, the second collimator 4 is internally mounted with several plates 43, which are arranged at a specific angle to further collimate the neutron beam in the vertical direction. The thickness and spatial angle of the plates 43 are calculated based on the spatial relationship between the second collimator 4 and the neutron detector. The plates 43 correspond one-to-one with the neutron detector's dead zone and do not obstruct the neutron detector's receiving surface. The plates 43 are made of a strong neutron-absorbing material. A neutron-absorbing layer is provided within the second collimator 4, also made of a strong neutron-absorbing material. The external frame of the second collimator 4 can be made of a metal material such as an aluminum alloy. The plates 43 are positioned on the neutron-absorbing layer within the second collimator 4. To reduce the amount of machining required for the neutron-absorbing layer and the plates 43 and ensure their effective function, the neutron-absorbing layer is provided with slots. The plates 43 are inserted into the slots and spliced onto the neutron-absorbing layer, completely eliminating the need for threaded holes in the neutron-absorbing layer and ensuring proper function of the plates 43 and the neutron-absorbing layer.

[0066] To ensure the working effect of the second collimator 4, there are strict requirements on the spatial positioning accuracy of the second collimator 4. The geometric focus of the second collimator 4 is strictly the center point of the sample, and the vertical neutral plane of the second collimator 4 must coincide with the vertical neutral plane of the neutron detector. Therefore, the installation of the second collimator 4 on the second mounting bracket 5 should be stable and adjustable.

[0067] In one embodiment, the second collimator 4 is provided with a plurality of adjustment hinges 44, which are mounted on the second mounting frame 5. The adjustment hinges 44 are used to adjust the pitch attitude of the second collimator 4. The adjustment hinges 44 are slidably connected to the second mounting frame 5 to further adjust the spatial attitude of the second collimator 4. In one embodiment, the second mounting frame 5 is provided with adjustment bolts 100 for fine-tuning the position of the adjustment hinges 44 and thereby adjusting the spatial attitude of the second collimator 4.

[0068] In one embodiment, a mounting beam 51 is provided on the second mounting frame 5 , an adjustment hinge 44 is provided on the mounting beam 51 , and a plurality of adjustment bolts 100 are provided at both ends of the mounting beam 51 for adjusting the horizontality of the mounting beam 51 , thereby providing an installation reference for the second collimator 4 .

[0069] In one embodiment, the second mounting frame 5 is provided with reinforcing ribs 52. Two reinforcing ribs 52 are located on either side of the second collimator 4 and are connected to the respective sides of the second collimator 4, thereby holding the second collimator 4 in place and reducing the pressure on the adjustment hinge 44. A connecting groove 200 is provided on the reinforcing ribs 52. A connecting member passes through the connecting groove 200 to connect to the second collimator 4. A gap is provided between the connecting member and the inner wall of the connecting groove 200. When the second collimator 4 is adjusted in space, the connecting member moves within the connecting groove 200.

[0070] In one embodiment, the posture adjustment device 3 is installed on the second mounting frame 5, which saves installation space and makes the spatial structure of the neutron spectrometer collimator system more compact.

[0071] In one embodiment, a top platform 53 is provided on the second mounting frame 5, and the posture adjustment device 3 is mounted on the top platform 53. Because the first collimator 1 is mounted forward and the second collimator 4 is mounted backward, the top platform 53 has a protruding cantilever portion for mounting the posture adjustment device 3. Due to the relatively large combined weight of the first collimator 1 and the first mounting frame 2, a counterweight 54 is mounted on the other end of the top platform 53 to balance the torque generated by the cantilever load of the top platform 53 and ensure the overall rigidity of the neutron spectrometer collimator system.

[0072] The second mounting frame 5 is a supporting component of the entire neutron spectrometer collimator system, and needs to ensure the rigidity and operational stability of the neutron spectrometer collimator system.

[0073] In one embodiment, the second mounting frame 5 is a gantry steel structure. It mounts a crossbeam 51, reinforcing bars 52, a top platform 53, a counterweight 54, and two side columns 55. Bolts connect these components, facilitating adjustment of the gaps between them to ensure accurate installation of the components. This also prevents welding-induced deformation that could reduce the accuracy of the neutron spectrometer collimator system installation. The columns 55 are square steel structures, reducing weight while providing excellent mechanical rigidity. The bottom of the column 55 is connected to the ground through the mounting plate 56. The installation position of the mounting plate 56 is the basis of the installation accuracy of the neutron spectrometer collimator system. Therefore, the positioning point of the mounting plate 56 is required to be extremely high. The positioning point of the mounting plate 56 is obtained by theoretical calculation with the help of high-precision measuring equipment (such as laser trackers, etc.). Due to the cantilever structure in the neutron spectrometer collimator system, the mounting plate 56 (especially the rear end of the mounting plate 56) is subjected to a large tensile force. Therefore, the mounting plate 56 is fixed to the ground with a high-strength anchor rod 561 and an embedded steel bar glue to ensure the installation strength and reliability of the neutron spectrometer collimator system and ensure long-term stable operation. An adjusting bolt 100 is provided between the column 55 and the mounting plate 56 for indirectly adjusting the horizontality and position of the mounting beam 51 and the top platform 53. The mounting beam 51 is mounted between two columns 55. Adjustment bolts 100 are installed on both sides of the mounting beam 51 to further adjust the horizontality and position of the mounting beam 51. Two reinforcing bars 52 are symmetrically mounted on the two columns 55 and located above the mounting beam 51. The mounting beam 51 and the two reinforcing bars 52 provide a mounting base for the second collimator 4. The top platform 53 is mounted on the top of the two columns 55. Adjustment bolts 100 are installed between the top platform 53 and the columns 55 to further adjust the horizontality and position of the top platform 53, providing a mounting base for the posture adjustment device 3. Adjustment bolts 100 are also installed between the posture adjustment device 3 and the top platform, allowing the posture adjustment device 3 to be fine-tuned horizontally within the mounting surface of the top platform 53, ensuring the positional relationship between the motion axis of the posture adjustment device 3 and the neutron beam. A counterweight 54 can be installed at the other end of the top platform 53 to balance the torque generated by the cantilever load of the top platform 53 and ensure the overall rigidity of the neutron spectrometer collimator system.

[0074] The above is the neutron spectrometer collimator system disclosed in this application, which is described below with an example.

[0075] In one example, the neutron detector of an engineering neutron spectrometer has a horizontal coverage angle of 30° and a vertical coverage angle of 40°. The distance between the neutron detector's detection surface and the sample center is 2 meters. The neutron spectrometer collimator system is located within this 2-meter space. In addition to the sample space, the neutron spectrometer collimator system will cover as much of the 2-meter radial space of the diffracted neutron beam as possible, preventing external stray neutrons from entering the neutron detector through this space, thereby reducing the noise floor and improving the signal-to-noise ratio.

[0076] In this example, the engineering neutron spectrometer is equipped with four sets of first collimators 1 of varying specifications. Both the front and rear surfaces of these four sets of first collimators 1 are cylindrical. The smallest first collimator 1 has an inner diameter of approximately 400 mm, while the largest has an outer diameter of approximately 1300 mm. The second collimator 4 in the neutron spectrometer collimator system accommodates all sizes of first collimators 1. Each first collimator 1 comes standard with a separate first mounting bracket 2, customized to the dimensions of the first collimator 1. The position adjustment device 3 has a travel range along the first axis 31 that covers the center of gravity of all sizes of first collimators 1, with a certain allowance. The travel range along the second axis 32 and the rotation angle range along the third axis 33 are relatively small, resulting in high accuracy and resolution, allowing for fine-tuning of the position of the first collimator 1. The second collimator 4 is installed between the first collimator 1 and the neutron detector. The internal space of the second collimator 4 has a horizontal coverage angle greater than 30° and a vertical coverage angle greater than 40°. The front end face of the second collimator 4 is a cylindrical surface with a radius of 1310mm, which cooperates with the rear end face of the largest first collimator 1, minimizing the gap while ensuring installation feasibility. The rear end face of the second collimator 4 is a spherical surface, which cooperates with the spherical detection surface of the neutron detector. Six layers 43 are installed inside the second collimator 4, dividing its internal space into seven spaces with the same coverage angle, corresponding to the seven detection modules of the neutron detector. All layers 43 are enclosed in the dead zone between the detection modules and do not block the receiving surface of the neutron detector detection module.

[0077] The functions and working principles of the neutron spectrometer collimator system in this example are mainly reflected in the following aspects: 1) Through a strictly controllable installation process, the posture adjustment device 3 and the second collimator 4 are installed with high precision, which is the basis for the high-precision spatial positioning of the first collimator 1; 2) The first collimator 1 is installed on the posture adjustment device 3 through the first mounting bracket 2, and all specifications of the first collimators 1 are adjusted and calibrated with high precision during the first installation; 3) First collimators 1 of different specifications can be quickly replaced and accurately positioned repeatedly, and the online position fine-tuning of the first collimator 1 can be achieved through remote motion control of the posture adjustment device 3 and combined with the neutron data processing system to maximize the neutron signal intensity. The following are explained separately:

[0078] 1) Through a strictly controlled installation process, the posture adjustment device 3 and the second collimator 4 are installed with high precision. This is the basis for the high-precision spatial positioning of the first collimator 1. The main steps are as follows:

[0079] 1a) Secure mounting plate 56 to the ground. The precise positioning of mounting plate 56 is crucial for the precise installation of the neutron spectrometer collimator system. Therefore, the positioning of mounting plate 56 is determined through theoretical calculations using a laser tracker. Because the neutron spectrometer collimator system has a cantilever structure, mounting plate 56 (particularly its rear end) is subject to significant tensile forces. Therefore, high-strength anchor rods 561 combined with rebar adhesive are used to secure it to the ground, replacing conventional expansion bolts. This significantly improves the overall strength and reliability of the neutron spectrometer collimator system, ensuring its long-term stable operation.

[0080] 1b) Install the columns 55 on both sides, the mounting beam 51, and the reinforcing bars 52 to establish a base for the installation of the second collimator 4. The levelness and position of the mounting beam 51 are roughly adjusted by adjusting the height and position of the adjustment bolts 100 between the columns 55 and the mounting plate 56. The levelness of the mounting beam 51 can be fine-tuned using the adjustment bolts 100 at both ends of the mounting beam 51.

[0081] 1c) Install the second collimator 4. Use the adjustment hinge 44 and the adjustment bolt 100 to fine-tune the spatial position of the second collimator 4 so that its vertical neutral plane is perpendicular to the beam direction and the focus coincides with the center of the sample.

[0082] 1d) Assemble the posture adjustment device 3, counterweight 54, and top platform 53 into a single unit and install them above the two side columns 55. Adjust the height and position of the adjustment bolts 100 between the top platform 53 and the columns 55 to coarsely adjust the horizontality and position of the posture adjustment device 3. Then, fine-tune the posture adjustment device 3 using the adjustment bolts between the posture adjustment device 3 and the top platform 53, ensuring that its motion trajectory is horizontal and that the direction of the first motion axis 31 is perpendicular to the direction of the incident neutron beam and passes directly above the center of the sample.

[0083] 2) The first collimator 1 is mounted on the posture adjustment device 3 via the first mounting bracket 2. During the first installation, high-precision adjustment and calibration are performed on all specifications of the first collimator 1. The main steps are as follows:

[0084] 2a) Place the bottom support plate 212 of the first mounting frame 2 firmly on the table, and install the first collimator 1 on the bottom support plate 212 so that the lower edge of the rear end of the first collimator 1 contacts the limit block 213 on the bottom support plate 212 without sliding.

[0085] 2b) Assemble the other components of the first mounting frame 1 so that they form a complete unit with the first collimator 1. The lower rear edge of the first collimator 1 contacts the stop block 213, and a flexible gasket is placed between the upper front edge and the anti-flip beam 214 of the first mounting frame 2 to prevent damage to the first collimator 1. This ensures that the twelve adjustment bolts 100 on the bottom support plate 212 and side walls 211 can operate smoothly.

[0086] 2c) Calibrate the initial position of the first collimator 1. Hoist the first collimator 1 onto the posture adjustment device 3 through the first mounting frame 2, adjust the 8 wedge-shaped connecting blocks 221 on the top of the aforementioned first mounting frame 2, control the tightness of the installation, ensure high repeatability accuracy, and facilitate installation and disassembly. The posture adjustment device 3 drives the first collimator 1 to move along the first motion axis 31 so that the center of gravity of the first collimator 1 of this specification is located at the corresponding theoretical calculation point, and is located at the initial zero position in the rotation space in the direction of the second motion axis 32 and the third motion axis 33. Use the 12 adjustment bolts 100 around the aforementioned first collimator 1 to fine-tune the spatial posture of the first collimator 1 so that the vertical neutral plane of the first collimator 1 is perpendicular to the beam direction and the focus coincides with the center point of the sample. If necessary, the first collimator 1 can be driven to move along the first motion axis 31 again, and the position data is finally recorded in the external control system.

[0087] 2d) Repeat steps 2a through 2c above to sequentially install and calibrate all specifications of the first collimator 1. Record the position data of the posture adjustment device 1 along the first motion axis 31 in the control software. This completes the initial installation and calibration of the neutron spectrometer collimator system.

[0088] 3) The first collimators 1 of different specifications can be quickly replaced and accurately repositioned. Through remote motion control of the posture adjustment device 3 and in combination with the neutron data processing system, the online position fine adjustment of the first collimator 1 is achieved to maximize the neutron signal intensity. This is the normal operation procedure of the neutron spectrometer collimator system, which is as follows:

[0089] 3a) Select the first collimator 1. Select a first collimator 1 of appropriate specifications based on the requirements of the neutron diffraction experiment. Hoist the first mounting frame 2 and the first collimator 1 onto the posture adjustment device 3.

[0090] 3b) Online adjustment of the spatial position of the first collimator 1. The position adjustment device 3 is driven to bring the first collimator 1 to the calibrated initial position, and neutron signal acquisition begins. The scanning process is initiated: the first mounting frame 2 is driven to reciprocate along the second motion axis 32 for a certain distance, the position with the highest neutron signal intensity is recorded, and the position is moved to that position; the first mounting frame 2 is driven to rotate back and forth through an angle, the angle with the highest neutron signal intensity is recorded, and the position is moved to that angle.

[0091] 3c) Close the first transition plates 41 on the left and right of the second collimator 4, install the second transition plate 42 corresponding to the first collimator 1 of the same specification, and start the experiment.

[0092] The neutron spectrometer collimator system of the aforementioned embodiment, comprising a first collimator, a second collimator, a first mounting bracket, a second mounting bracket, and a position adjustment device, can achieve high-precision installation of the neutron spectrometer collimator system through a strictly controllable assembly process for each component. This allows for rapid replacement and accurate, repeatable positioning of first collimators of varying specifications, as well as the ability to locate the location with the highest flux of the diffracted neutron beam, thereby maximizing neutron signal intensity. This reduces background noise, enhances the effective signal, increases the signal-to-noise ratio, and improves the experimental resolution and accuracy of the spectrometer.

[0093] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A neutron spectrometer collimator system, characterized in that: include: a first collimator, the first collimator being arranged between the center point of the sample and the neutron detector, and being used for collimating the diffracted neutron beam; a first mounting frame, wherein the first collimator is mounted on the first mounting frame; A posture adjustment device, the first mounting frame is mounted on the posture adjustment device, and the posture adjustment device is used to adjust the spatial posture of the first collimator; The first collimator is in the shape of a square horn with a small front face and a large rear face, and the focus of the first collimator is the center point of the sample. The coverage angle of the rear face of the first collimator is greater than or equal to the coverage angle of the neutron detector. The front face is cylindrical or spherical, and the rear face is cylindrical or spherical. a second collimator and a second mounting bracket; the second collimator is arranged between the first collimator and the neutron detector, the second collimator is in the shape of a square horn and the focus of the second collimator is the center point of the sample, the front end face shape of the second collimator is the same as the rear end face shape of the first collimator, the rear end face shape of the second collimator is the same as the shape of the neutron detector and the rear end face of the second collimator is close to the surface of the neutron detector; the second collimator is mounted on the second mounting bracket; the second collimator serves as an extension of the first collimator and is used to further collimate the diffracted neutron beam collimated by the first collimator.

2. The neutron spectrometer collimator system according to claim 1, characterized in that: The first mounting frame has a first collimator mounting cavity, which is in the shape of a square horn. The first collimator mounting cavity is formed by two oppositely arranged side walls and a bottom support plate. The first collimator is arranged in the first collimator mounting cavity and there is a gap between the first collimator and the side walls and the bottom support plate.

3. The neutron spectrometer collimator system according to claim 2, characterized in that: A plurality of adjusting bolts are provided on the side wall and the bottom supporting plate, and the adjusting bolts are used to fine-tune the spatial posture of the first collimator.

4. The neutron spectrometer collimator system according to claim 3, characterized in that: The posture adjustment device includes: a first motion axis, a second motion axis and a third motion axis; the second motion axis is arranged on the first motion axis, and the second motion axis can perform reciprocating linear motion along the direction of the first motion axis; the third motion axis is arranged on the second motion axis, and the third motion axis can perform reciprocating linear motion along the direction of the second motion axis; the third motion axis can rotate; the direction of the first motion axis is perpendicular to the direction of the incident neutron beam, the direction of the second motion axis is perpendicular to the direction of the first motion axis, and the rotation axis of the third motion axis is perpendicular to both the direction of the first motion axis and the direction of the second motion axis; the first mounting bracket is installed on the third motion axis.

5. The neutron spectrometer collimator system according to claim 4, characterized in that: The first mounting frame has a posture adjustment device connection part, and the posture adjustment device connection part is provided with several wedge-shaped connecting blocks. The third motion axis is provided with a rectangular connecting block, and the side surface of the rectangular connecting block is an inclined surface. The upper inclined surface of the wedge-shaped connecting block is connected to the upper inclined surface of the rectangular connecting block.

6. The neutron spectrometer collimator system according to claim 1, wherein: A transition plate is provided between the first collimator and the second collimator, and the transition plate is used to close the gap between the first collimator and the second collimator.

7. The neutron spectrometer collimator system according to claim 6, characterized in that: The second collimator is provided with a plurality of adjustment hinges, which are used to adjust the pitch attitude of the second collimator. The adjustment hinges are slidably connected to the second mounting frame.

8. The neutron spectrometer collimator system according to claim 7, characterized in that: The second mounting frame is provided with a top platform and a counterweight block, the posture adjustment device is installed at one end of the top platform, and the counterweight block is installed at the other end of the top platform.

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