A radial collimator for neutron diffractometer

Abstract

A radial collimator for a neutron diffraction spectrometer comprises a collimator frame, an absorbing film, and spacers. The collimator frame is square and horn-shaped, with both front and rear end faces being cylindrical, and their axes coinciding. The absorbing film is a trapezoidal thin film made of a strong neutron-absorbing material, and the spacers are long, deformed thin plates of variable thickness. Several absorbing films and spacers are alternately stacked and arranged within the collimator frame. The absorbing films and spacers are arranged within the square and horn-shaped collimator frame. The collimator's coverage range includes that of the detector. The collimator is positioned between the sample center point and the detector of the neutron diffraction spectrometer. Compared to experiments without a radial collimator, the background noise of the spectrometer experiment is greatly reduced, and the data accuracy and spectrometer resolution are significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron collimators, and in particular to a radial collimator for a neutron diffraction spectrometer. 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. Neutron diffractometers are the experimental terminals of neutron sources. Their basic principle is that protons bombard a heavy metal target, generating a spallation reaction. The resulting 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 or react with non-sample components, resulting in the neutron signal becoming background noise. The signal-to-noise ratio is a crucial factor in determining the resolution and accuracy of a spectrometer experiment. Existing data demonstrates that placing a radial collimator between the sample and the neutron detector significantly reduces background noise, significantly improving data accuracy and spectrometer resolution. In summary, the radial collimator is a core device in neutron diffraction spectrometers, determining both the test signal quality and accuracy.

[0004] However, various types of collimators currently available on the market, such as cylindrical collimators, circular hole collimators or soller collimators, are all neutron collimators arranged on the incident neutron beam and are not suitable for the diffracted neutron direction of the neutron diffractometer. Summary of the Invention

[0005] In order to solve the above technical problems, the present application proposes a radial collimator for a neutron diffraction spectrometer.

[0006] According to a first aspect, an embodiment provides a radial collimator for a neutron diffractometer, comprising:

[0007] A collimator frame, wherein the front end face and the rear end face of the collimator frame are both cylindrical surfaces, the axes of the front end face and the rear end face of the collimator frame coincide with each other, and the area of the front end face of the collimator frame is smaller than the area of the rear end face of the collimator frame;

[0008] An absorption film, wherein the absorption film is a trapezoidal thin film, and the absorption film material is a strong neutron absorption material;

[0009] Spacer bar, the spacer bar is a long thin plate with variable thickness;

[0010] A plurality of the absorption films and a plurality of the spacer bars are alternately stacked and arranged in the collimator frame;

[0011] The horizontal coverage angle of the absorption film is greater than or equal to the horizontal coverage angle of the neutron diffraction spectrometer detector, and the vertical coverage angle of the absorption film is greater than or equal to the vertical coverage angle of the neutron diffraction spectrometer detector.

[0012] In one embodiment, the collimator frame includes a front upper beam, a front lower beam, a rear upper beam, a rear lower beam and two symmetrically arranged side panels, the front upper beam, the front lower beam, the rear upper beam and the rear lower beam are arc-shaped, the side panels are trapezoidal panels, the two ends of the front upper beam, the front lower beam, the rear upper beam and the rear lower beam are respectively connected to the side panels on both sides, and the four corners of the absorption film and the spacer are respectively connected to the front upper beam, the front lower beam, the rear upper beam and the rear lower beam.

[0013] In one embodiment, L-shaped slots are provided at the four corners of the absorption film and the spacer strips; a through slot is provided on the front end upper beam, and a plurality of front end L-shaped buckles are provided in the through slot of the front end upper beam, and the front end L-shaped buckles are buckled with the corresponding arrays of L-shaped slots of the absorption film and the spacer strips; a through slot is provided on the rear end upper beam, and a plurality of rear end L-shaped buckles are provided in the through slot of the rear end upper beam, and the rear end L-shaped buckles are buckled with the corresponding arrays of L-shaped slots of the absorption film and the spacer strips; L-shaped buckles are provided on the front end lower beam and the rear end lower beam, and the L-shaped buckles are buckled with the L-shaped slots of the absorption film and the spacer strips.

[0014] In one embodiment, the side panel includes a fixed side panel and a stretching side panel, the stretching side panel is arranged above the fixed side panel, and the stretching side panel can move in the vertical direction relative to the fixed side panel, the stretching side panel is connected to the front end upper beam and the rear end upper beam, and the fixed side panel is connected to the front end lower beam and the rear end lower beam.

[0015] In one embodiment, a plurality of vertical jack screw bolts are provided between the tension side plate and the fixed side plate, and the jack screw bolts pass through the tension side plate.

[0016] In one embodiment, a plurality of blind hole pins are provided on the fixed side plate, and the blind hole pins are arranged opposite to the top screw bolts.

[0017] In one embodiment, a positioning guide pin is provided between the stretching side plate and the fixed side plate.

[0018] In one embodiment, it also includes: a stretching stud, which is an arc-shaped double-headed stud, and several of the stretching studs pass through all the absorption films and the spacer strips and the side panels on both sides. The side panels are provided with countersunk holes, and nuts are provided in the countersunk holes. The nuts are connected to the stretching studs, and the stretching side panels and the fixed side panels are both penetrated by the stretching studs.

[0019] In one embodiment, straight hole grooves are provided at both ends of the front end upper beam, the front end lower beam, the rear end upper beam and the rear end lower beam, and the front end upper beam, the front end lower beam, the rear end upper beam and the rear end lower beam are connected to the side plate by bolts, and the bolts pass through the straight hole grooves.

[0020] In one embodiment, threaded through holes are provided on the front end L-shaped buckle and the rear end L-shaped buckle, and the threaded through holes are communicated with the through groove. An auxiliary stretching cover is provided above the rear end L-shaped buckle, and the auxiliary stretching cover is provided with a plurality of through holes corresponding to the positions of the threaded through holes on the rear end L-shaped buckle.

[0021] According to the radial collimator for a neutron diffraction spectrometer of the above-mentioned embodiment, an absorption film and spacer strips are arranged in a square horn-shaped collimator frame. The coverage range of the collimator includes the coverage range of the detector. The collimator is arranged between the sample center point and the detector of the neutron diffraction spectrometer. Compared with not setting a radial collimator, the background noise of the spectrometer experiment is greatly reduced, and the data accuracy and spectrometer resolution are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a schematic structural diagram of a radial collimator for a neutron diffraction spectrometer in one embodiment;

[0023] Figure 2 is a partial cross-sectional schematic diagram of a side plate of a radial collimator for a neutron diffractometer in one embodiment;

[0024] Figure 3 Schematic diagram of the connection state of the front end L-shaped buckle of a radial collimator for a neutron diffractometer in one embodiment.

[0025] Explanation of the accompanying drawings: 1. Collimator frame; 2. Absorption film; 3. Spacer; 41. Front upper beam; 411. Front L-shaped buckle; 42. Front lower beam; 51. Rear upper beam; 511. Rear L-shaped buckle; 512. Auxiliary stretching cover; 52. Rear lower beam; 61. Stretching side plate; 62. Fixed side plate; 63. Top screw bolt; 64. Blind hole pin; 7. Stretching stud; 71. Countersunk hole; 72. Nut; 10. L-shaped slot; 20. Through slot; 30. Straight hole slot; 40. Bolt; 50. Threaded through hole. DETAILED DESCRIPTION

[0026] 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.

[0027] 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.

[0028] 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).

[0029] Broadly speaking, the radial collimator described in the present invention is a type of precision optical device. Unlike collimators used in optical devices such as visible light and X-rays, the radial collimator described in the present invention primarily functions to collimate a neutron beamline, and its core material is a strong neutron-absorbing material. Unlike various neutron collimators placed on the incident neutron beam, such as cylindrical or circular-hole collimators or soller collimators, the radial collimator described in the present invention is placed in the direction of diffracted neutrons, i.e., the radial direction, hence the name radial collimator, which requires higher precision.

[0030] For the neutron diffractometer, the center point of the sample is a point in space. It is the end of the neutron beam and the center point of the reaction between the neutron beam and the sample. The neutron detector envelopes the center point of the sample at a certain spatial coverage angle. The distance between the detector and the sample center point varies from several hundred millimeters to several meters (the second flight distance). The radial collimator is set in the space between the center point of the sample and the detector. Its shape is a square horn with a small front end and a large rear end. The front focus is the center point of the sample, and the rear end faces the neutron detector. The opening angles of the left and right planes correspond to the horizontal coverage angles of the neutron detector. Similarly, the opening angles of the upper and lower planes correspond to the vertical coverage angles of the neutron detector. The core component of the radial collimator is the absorption film. The absorption film contains strong neutron absorption material and needs to be precisely fixed in the frame at a certain angle.

[0031] In an embodiment of the present application, a radial collimator for a neutron diffraction spectrometer includes a collimator frame, an absorption film, and spacer bars. The collimator frame is square and horn-shaped, with both front and rear end faces being cylindrical, and the axes of the front and rear end faces coinciding. The absorption film is a trapezoidal thin film made of a strong neutron-absorbing material, and the spacer bars are long, thin plates of variable thickness. Several absorption films and spacer bars are alternately stacked and arranged within the collimator frame. The absorption film and spacer bars are arranged within the square and horn-shaped collimator frame. The coverage range of the collimator includes the coverage range of the detector. The collimator is arranged between the sample center point and the detector of the neutron diffraction spectrometer. Compared with the case where no radial collimator is provided, the background noise of the spectrometer experiment is greatly reduced, and the data accuracy and spectrometer resolution are significantly improved.

[0032] The present application is described below through specific embodiments.

[0033] Example 1:

[0034] like Figures 1 to 3As shown, in one embodiment of the present application, a radial collimator for a neutron diffraction spectrometer is provided, comprising: a collimator frame 1, an absorption film 2 and a spacer 3. The front end face and the rear end face of the collimator frame 1 are both cylindrical surfaces, and the axes of the front end face and the rear end face of the collimator frame 1 coincide with each other. The area of the front end face of the collimator frame 1 is smaller than the area of the rear end face of the collimator frame 1 and the collimator frame is in the shape of a square trumpet. When the radial collimator is in use, the axes of the front end face and the rear end face of the collimator frame 1 pass through the center point of the sample, that is, the focus of the front end face of the collimator frame 1 is the center point of the sample. The absorption film 2 is a trapezoidal thin film, and the material of the absorption film 2 is a strong neutron absorption material. The spacer 3 is a long strip of variable thickness thin plate. Preferably, the spacer 3 is thinner at the front end and thicker at the rear end, and the thickness increases evenly. Several absorber films 2 and spacer bars 3 are alternately stacked in the collimator frame 1. The performance of the absorber film 2 is related to its thickness. The thinner the thickness, the better the performance. Preferably, the thickness of the absorber film 2 is 0.05-0.1 mm. The spacer bars 3 are used to separate the absorber films 2. The gap between adjacent absorber films 2 is one of the core technical indicators of the radial collimator. This technology is related to the thickness of the spacer bars 3. Therefore, the thickness of the front and rear ends of the spacer bars 3 must be highly accurate. The thickness of the spacer bars is obtained by physical calculation and is not limited in this application. The front and rear end surfaces of the several absorption films 2 arranged in the collimator frame 1 can form a discontinuous coverage surface with a certain angle. The horizontal coverage angle of the absorption film 2 is greater than or equal to the horizontal coverage angle of the neutron diffraction spectrometer detector, and the vertical coverage angle of the absorption film 2 is greater than or equal to the vertical coverage angle of the neutron diffraction spectrometer detector, that is, the coverage range of the radial collimator is greater than or equal to the coverage range of the neutron diffraction spectrometer detector to ensure the effective operation of the radial collimator. Preferably, the opening angles of the left and right planes of the radial collimator correspond to the horizontal coverage angle of the neutron diffraction spectrometer detector. Similarly, the opening angles of the upper and lower planes of the radial collimator correspond to the vertical coverage angles of the neutron diffraction spectrometer detector.

[0035] In one embodiment, the collimator frame 1 includes a front upper beam 41, a front lower beam 42, a rear upper beam 51, a rear lower beam 52, and two symmetrically arranged side panels. The front upper beam 41, the front lower beam 42, the rear upper beam 51, and the rear lower beam 52 are arc-shaped, and the side panels are trapezoidal plates. The ends of the front upper beam 41, the front lower beam 42, the rear upper beam 51, and the rear lower beam 52 are respectively connected to the side panels on both sides. The four corners of the absorbent film 2 and the spacer 3 are respectively connected to the front upper beam 41, the front lower beam 42, the rear upper beam 51, and the rear lower beam 52. The side panels should be thick to ensure sufficient rigidity.

[0036] In one embodiment, L-shaped slots 10 are provided at the four corners of the absorbent film 2 and the spacer bars 3. A through slot 20 is provided on the front upper beam 41. Several front L-shaped buckles 411 are positioned within the through slot 20 of the front upper beam 41. These buckles 411 engage with the corresponding sets of L-shaped slots 10 of the absorbent film 2 and the spacer bars 3. A through slot 20 is provided on the rear upper beam 51. Several rear L-shaped buckles 511 are positioned within the through slot 20 of the rear upper beam 51. These buckles engage with the corresponding sets of L-shaped slots 10 of the absorbent film 2 and the spacer bars 3. L-shaped buckles are provided on the front end lower beam 42 and the rear end lower beam 52, and the L-shaped buckles on the front end lower beam 42 and the rear end lower beam 52 are buckled with the L-shaped slots 10 of the absorption film 2 and the spacer strip 3. Preferably, the L-shaped buckle on the front end lower beam 42 is arranged on the outer side of the arc of the front end lower beam 42, and the L-shaped buckle on the rear end lower beam 52 is arranged on the inner side of the arc of the rear end lower beam 52.

[0037] In one embodiment, the side panels include a stretching side panel 61 and a fixed side panel 62. The stretching side panel 61 is positioned above the fixed side panel 62 and can move vertically relative to the fixed side panel 62. The stretching side panel 61 is connected to the front upper beam 41 and the rear upper beam 51, while the fixed side panel 62 is connected to the front lower beam 42 and the rear lower beam 52. When the stretching side panel 61 moves upward, it drives the front upper beam 41 and the rear upper beam 51 upward, thereby driving the front L-shaped buckles 411 and the rear L-shaped buckles 422 upward, stretching the absorbent film 2 and the spacer bars 3. This flattens the absorbent film 2 and creates a uniform gap, thereby improving the accuracy of the radial collimator. The L-shaped buckles on the front lower beam 42 and the rear lower beam 52 secure the absorbent film 2 and the spacer bars 3. The front and rear end surfaces of the absorbent film 2 are curved, ensuring that the tension along the curved section of the absorbent film 2 is uniform during stretching, thus preventing wrinkles and cracks during stretching.

[0038] In one embodiment, a plurality of vertical jackscrews 63 are provided between the tension side plate 61 and the fixed side plate 62. The jackscrews 63 penetrate the tension side plate 61. When the tension side plate 61 needs to be moved upward, a torque is applied to the jackscrews 63, which is converted into an axial force to separate the tension side plate 61 from the fixed side plate 62.

[0039] In one embodiment, as the torque applied to the jack bolt 63 increases, the axial force of the jack bolt 63 gradually increases. Due to the interaction of forces, the bottom surface of the jack bolt 63 inevitably applies the same force to the upper surface of the fixed side plate 62. To prevent the upper end surface of the fixed side plate 62 from being damaged by the jack bolt 63, the fixed side plate 62 is provided with a plurality of blind hole pins 64. The blind hole pins 64 are arranged below the jack bolts 63, and the blind hole pins 64 are arranged in a one-to-one correspondence with the jack bolts 63. The rigidity of the material of the blind hole pins 63 should be greater than the rigidity of the material of the jack bolt 63 and the fixed side plate 62. The contact surface between the blind hole pins 63 and the jack bolt 64 can be lubricated with oil to reduce resistance during tension.

[0040] In one embodiment, in order to ensure that the movement direction of the stretching side plate 61 remains vertical when the stretching side plate 61 is separated from the fixed side plate 62, a positioning guide pin is provided between the stretching side plate 61 and the fixed side plate 62 to play a positioning and guiding role, thereby ensuring the smooth stretching of the stretching side plate 61.

[0041] In one embodiment, the radial collimator further includes a stretching stud 7, which is an arc-shaped double-headed stud. Several stretching studs 7 penetrate all the absorption films 2 and the spacer bars 3 as well as the side panels on both sides. A countersunk hole 71 is provided on the side panel, and a nut 72 is provided in the countersunk hole. The nut 72 is connected to the stretching stud 7. The stretching side panel 61 and the fixed side panel 62 are both penetrated by the stretching stud 72. The arc length of the stretching stud 7 corresponds to an angle greater than the horizontal coverage angle of the radial collimator. The arc radius and length of each stretching stud 7 are calculated based on the position. When the stretching side panel 61 moves upward, the stretching stud 7 passed through the stretching side panel 61 moves upward, stretching the absorption film 2 and the spacer bars 3. The stretching stud 72 passed through the fixed side panel 62 plays the role of fixing the absorption film 2 and the spacer bars 3. Preferably, a number of stretching studs 7 with gradually increasing radius and arc length are evenly arranged on the stretching side plate 61 from the front end to the rear end, and the same number of stretching studs 7 with gradually increasing radius and arc length are evenly arranged on the lower edge of the fixed side plate 62 from the front end to the rear end. In some embodiments, the cross-sectional shape of the portion of the stretching stud 7 that penetrates the absorbent film 2 and the spacer bar 3 can be non-circular, and the two ends of the stretching stud 7 need to be connected to the nut 72, so the cross-sectional shape of the threaded section at both ends of the stretching stud 7 needs to be circular. For example, the cross-sectional shape of the portion of the stretching stud 7 that penetrates the absorbent film 2 and the spacer bar 3 can be rectangular, and the cross-sectional shape of the threaded section at both ends is circular. With such a structural design, when the absorbent film 2 and the spacer bar 3 are stretched, the stretching stud 7 has a larger contact area with the absorbent film 2 and the spacer bar 3, and the stretching force is more uniform. However, the processing technology of the stretching stud is more complicated. The style of the stretching stud 7 can be selected according to actual experimental needs and conditions.

[0042] In one embodiment, straight holes 30 are provided at both ends of the front upper beam 41, the front lower beam 42, the rear upper beam 51, and the rear lower beam 52. The front upper beam 41, the front lower beam 42, the rear upper beam 51, and the rear lower beam 52 are connected to the side panels via bolts 40, which pass through the straight holes 30. When assembling the radial collimator, the nuts 72 at both ends of the tension stud 7 are tightened. At this time, the two side panels will close together to compress all the absorbent films 2 and spacer bars 3. During the compression of the side panels, the bolts 40 will automatically adjust to the correct position in the straight holes 30, and the bolts 40 will then be tightened. During the tightening of the nuts 72 and the stretching process, the tension stud 7 may twist, which will affect the flatness of the local absorbent film 2. Therefore, anti-twist pins are provided at both ends of the tension stud 7 and embedded in the side panels.

[0043] In one embodiment, threaded through-holes 50 are provided on the front L-shaped buckle 411 and the rear L-shaped buckle 511. The threaded through-holes 50 communicate with the through-slot 20. An auxiliary stretching cover plate 512 is provided above the rear L-shaped buckle 511. The auxiliary stretching cover plate 512 has a plurality of through-holes corresponding to the threaded through-holes 50 on the rear L-shaped buckle 511. By screwing a jackscrew 63 into the threaded through-holes of the front L-shaped buckle 411 or the through-holes of the auxiliary stretching cover plate 512, the absorbent film 2 and the spacer strip 3 connected to the corresponding front L-shaped buckle 411 or rear L-shaped buckle 511 can be stretched a second time.

[0044] The above is the radial collimator for neutron diffraction spectrometer disclosed in this application, which is described below with an example.

[0045] In one example, the neutron diffractometer detector has a horizontal coverage angle of 30° and a vertical coverage angle of 40°. The distance between the detector and the sample center is 2 meters, and the radial collimator is placed within this 2-meter space. To provide sufficient sample space, the front face of the radial collimator is a cylindrical surface with a radius of 600 mm. Due to the manufacturing process, the maximum length of the radial collimator is 600 mm. Therefore, the rear face of the radial collimator is calculated to be a cylindrical surface with a radius of 1200 mm. The focus of the front cylindrical surface strictly coincides with the sample center. Combined with the horizontal and vertical coverage angles of the detector, this creates a square horn spatial profile with a small front end and a large rear end. When the measurement length is 4 mm, physical and optical path calculations show that the angle between the absorber films within the radial collimator is 0.191°, with a deviation of no more than ±0.005°. The total number of absorber films is 164, made of trapezoidal metal foil with a thickness of 0.06 mm and a strong neutron absorber. The spacer bars are over 600mm long, with thicknesses of 1.94mm at the thin end and 3.94mm at the thick end, with a thickness deviation of no more than 50 microns. The radial collimator side panels are constructed from trapezoidal aluminum alloy sheets, optimized for a thickness of 40mm through finite element analysis. Ten set screws separate the tensioning side panels from the fixed side panels. Two positioning guide pins provide positioning and guidance. Blind pins made of high-strength alloy steel are located beneath the set screw studs. The contact surfaces between the set screw studs and the blind pins are lubricated to reduce resistance during tensioning. The radial collimator features 18 curved tension studs, nine each on the bottom edge of the tensioning side panels and the fixed side panels. The arc radius of the tension studs increases from the front to the rear, with the arc length corresponding to an angle greater than 30° of the radial collimator's horizontal coverage angle. Accordingly, nine circular holes are located on the upper and lower edges of the absorber film and spacer bars, and nine countersunk holes are provided on both the tensioning side panels and the fixed side panels for the tension studs and nuts.

[0046] According to the radial collimator for a neutron diffraction spectrometer in the above-described embodiment, an absorption film and spacers are arranged within the square horn-shaped collimator frame. The collimator's coverage area includes the detector's coverage area. The collimator is positioned between the sample center point and the detector of the neutron diffraction spectrometer. Compared to experiments without a radial collimator, the background noise of the spectrometer experiment is greatly reduced, and data accuracy and spectrometer resolution are significantly improved. Simultaneously, relying on the mounting relationship between the various components, the absorption film can be stretched in whole or in part by stretching the side panels, front L-shaped clips, and rear L-shaped clips, resulting in a smooth absorption film with uniform gaps. The front and rear end surfaces of the absorption film are curved, ensuring that the tension along the arc of the absorption film during stretching is uniform, thus preventing wrinkles and ruptures during the stretching process.

[0047] 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 radial collimator for a neutron diffractometer, characterized in that: include: A collimator frame, wherein the front end face and the rear end face of the collimator frame are both cylindrical surfaces, the axes of the front end face and the rear end face of the collimator frame coincide with each other, the area of the front end face of the collimator frame is smaller than the area of the rear end face of the collimator frame, and the collimator frame is in the shape of a square trumpet; An absorption film, wherein the absorption film is a trapezoidal thin film, and the absorption film material is a strong neutron absorbing material; a spacer, wherein the spacer is a long thin plate with variable thickness; A plurality of the absorption films and a plurality of the spacer bars are alternately stacked and arranged in the collimator frame; The horizontal coverage angle of the absorption film is greater than or equal to the horizontal coverage angle of the neutron diffraction spectrometer detector, and the vertical coverage angle of the absorption film is greater than or equal to the vertical coverage angle of the neutron diffraction spectrometer detector; The collimator frame includes a front upper beam, a front lower beam, a rear upper beam, a rear lower beam and two symmetrically arranged side plates, the front upper beam, the front lower beam, the rear upper beam and the rear lower beam are arc-shaped, the side plates are trapezoidal plates, the ends of the front upper beam, the front lower beam, the rear upper beam and the rear lower beam are respectively connected to the side plates on both sides, and the four corners of the absorption film and the spacer are respectively connected to the front upper beam, the front lower beam, the rear upper beam and the rear lower beam; The side panels include fixed side panels and stretching side panels, the stretching side panels are arranged above the fixed side panels, the stretching side panels can move in the vertical direction relative to the fixed side panels, the stretching side panels are connected to the front end upper beam and the rear end upper beam, and the fixed side panels are connected to the front end lower beam and the rear end lower beam.

2. The radial collimator for a neutron diffractometer according to claim 1, wherein: The four corners of the absorption film and the spacer are provided with L-shaped slots; the front end upper beam is provided with a through slot, and a plurality of front end L-shaped buckles are provided in the through slot of the front end upper beam, and the front end L-shaped buckles are buckled with the corresponding arrays of L-shaped slots of the absorption film and the spacer; the rear end upper beam is provided with a through slot, and a plurality of rear end L-shaped buckles are provided in the through slot of the rear end upper beam, and the rear end L-shaped buckles are buckled with the corresponding arrays of L-shaped slots of the absorption film and the spacer; the front end lower beam and the rear end lower beam are provided with L-shaped buckles, and the L-shaped buckles are buckled with the L-shaped slots of the absorption film and the spacer.

3. The radial collimator for a neutron diffractometer according to claim 2, wherein: A plurality of vertical top screw bolts are provided between the stretching side plate and the fixed side plate, and the top screw bolts pass through the stretching side plate.

4. The radial collimator for a neutron diffractometer according to claim 3, wherein: A plurality of blind hole pins are provided on the fixed side plate, and the blind hole pins are arranged opposite to the top screw bolts.

5. The radial collimator for a neutron diffractometer according to claim 4, wherein: Positioning guide pins are provided between the stretching side plate and the fixed side plate.

6. The radial collimator for a neutron diffractometer according to claim 5, wherein: Also includes: The stretching stud is an arc-shaped double-headed stud. Several of the stretching studs pass through all the absorption films, the spacer strips and the side panels on both sides. Countersunk holes are provided on the side panels, and nuts are provided in the countersunk holes. The nuts are connected to the stretching studs. The stretching side panels and the fixed side panels are both penetrated by the stretching studs.

7. The radial collimator for a neutron diffractometer according to claim 6, wherein: Both ends of the front end upper beam, the front end lower beam, the rear end upper beam and the rear end lower beam are provided with straight hole grooves, and the front end upper beam, the front end lower beam, the rear end upper beam and the rear end lower beam are connected to the side plate by bolts, and the bolts pass through the straight hole grooves.

8. The radial collimator for a neutron diffractometer according to claim 7, wherein: The front end L-shaped buckle and the rear end L-shaped buckle are provided with threaded through holes, and the threaded through holes are communicated with the through groove. An auxiliary stretching cover is provided above the rear end L-shaped buckle, and the auxiliary stretching cover is provided with a plurality of through holes corresponding to the positions of the threaded through holes on the rear end L-shaped buckle.

Images