A low-temperature ultrafast x-ray diffraction system

Abstract

The application belongs to the technical field of pump-probe ultrafast characterization, and mainly provides a low-temperature ultrafast X-ray diffraction system, which is arranged and connected from bottom to top in sequence with a connecting assembly, a five-axis motion mechanism, a sample vacuum piece and a low-temperature assembly, the connecting assembly is peripherally arranged with an ultrafast X-ray source device, a pumping unit and an X-ray detector, the X-ray detector is rotationally assembled on the connecting assembly and coaxial with the rotation center of the five-axis motion mechanism. The sample vacuum piece can accommodate a sample, the low-temperature assembly regulates the sample test temperature, the sample vacuum piece is separately provided with an optical transmission sheet and an X-ray transmission sheet, the pump light and the ultrafast X-ray irradiate the sample in a channel, and the X-ray detector collects a two-dimensional diffraction pattern; the five-axis motion mechanism can adjust the position and posture of the sample. The application has high overall integration and compact structure, and is suitable for short-distance experimental conditions of a laser plasma X-ray source.

Description

Technical Field

[0001] This invention belongs to the field of pump-probe ultrafast characterization technology, and in particular relates to a low-temperature ultrafast X-ray diffraction system. Background Technology

[0002] Pump-probe ultrafast X-ray diffraction is an important characterization method for studying the microscopic ultrafast dynamics of materials. Under laboratory conditions, TW-level femtosecond laser-driven laser-plasma X-ray sources are the mainstream approach for obtaining femtosecond X-ray pulses. These X-ray sources are point radiation sources, and the number of X-ray photons decreases inversely with the square of the propagation distance. Therefore, ultrafast diffraction experiments require a small distance between the sample and the X-ray source, placing stringent demands on the spatial compactness of the entire experimental setup.

[0003] When conducting ultrafast X-ray diffraction experiments under cryogenic conditions, the sample not only needs to be placed in a vacuum cryogenic environment, but also needs to have multi-degree-of-freedom motion adjustment capabilities: X, Y, and Z-axis translational motion is required to achieve matching adjustment of sample position and optical path height; rotational degree of freedom is required to adjust the diffraction angle; and oscillation degree of freedom is required to correct the sample attitude, thereby ensuring that the pump laser and detector X-rays can accurately irradiate the same test area of ​​the sample. How to integrate cryogenic temperature control, vacuum sample chamber, multi-degree-of-freedom sample adjustment mechanism, and X-ray diffraction acquisition components into a single unit within a confined space is a key challenge that needs to be solved for this type of experimental device.

[0004] In the prior art, patent document CN206223698U discloses an ultrafast time-resolved X-ray diffraction temperature-variable sample chamber. This device integrates a liquid nitrogen thermostat and a vacuum sample chamber, and uses a Mylar membrane window to simultaneously accommodate pump laser and X-ray transmission, enabling low-temperature testing of samples in a vacuum environment. However, this patent document only discloses the main structure of the sample chamber, without providing a multi-degree-of-freedom motion adjustment mechanism for the sample, nor does it design a coaxial match between the X-ray detector and the sample rotation center. The sample chamber and X-ray detection component are arranged independently, resulting in a large overall stack size. This makes it unsuitable for the confined experimental space of a laser plasma X-ray source, and it cannot achieve multi-dimensional precision adjustment of the sample position and orientation, failing to meet the requirements of compact ultrafast pump-detection experiments.

[0005] In summary, existing ultrafast cryogenic X-ray diffraction devices generally suffer from the drawbacks of separate component arrangements and large overall stacking volume. This makes it difficult to simultaneously integrate a vacuum cryogenic environment, multi-degree-of-freedom sample attitude adjustment, co-path incident pump light and X-rays, and coaxial rotational diffraction acquisition functions within a compact space. Furthermore, they are unsuitable for close-range experiments using laser plasma X-ray sources. Therefore, there is an urgent need to develop a highly integrated and compact cryogenic ultrafast X-ray diffraction system. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a low-temperature ultrafast X-ray diffraction system to solve the problems of the prior art, which has separate components, large stacking size, inability to integrate low temperature, vacuum, multi-degree-of-freedom sample adjustment, and coaxial rotation diffraction acquisition functions in a small space, and difficulty in adapting to compact installation requirements.

[0007] To achieve the above and other related objectives, the present invention provides a low-temperature ultrafast X-ray diffraction system, comprising a connecting assembly, a five-axis motion mechanism, a sample vacuum component, and a low-temperature component arranged sequentially from bottom to top. An ultrafast X-ray source device, a pump unit, and an X-ray detector are arranged around the connecting assembly. The X-ray detector is rotatably mounted on the connecting assembly, and the rotation axis of the X-ray detector is consistent with the rotation center of the five-axis motion mechanism.

[0008] The sample vacuum chamber is used to place and position the sample, the low temperature component is used to control the temperature of the sample during testing, the sample vacuum chamber is equipped with an optical transmissive plate and an X-ray transmissive plate, the ultrafast X-ray source device and the pump unit irradiate the sample through the X-ray transmissive plate and the optical transmissive plate respectively, and the X-ray detector is used to collect the two-dimensional X-ray diffraction pattern after the sample is diffracted.

[0009] The sample vacuum component is mounted on the five-axis motion mechanism, which is used to adjust the position and orientation of the sample.

[0010] In some embodiments of the present invention, the pumping unit can control the timing of the pump light reaching the sample by controlling the optical path length of the pump light.

[0011] In some embodiments of the present invention, the connecting assembly includes a base, a bearing, and a clamping member. The five-axis motion mechanism is mounted on the base. The inner ring of the bearing is interference-fitted with the base. The outer ring of the bearing is fixedly connected to the X-ray detector through the clamping member, so that the X-ray detector rotates synchronously with the bearing around the rotation center of the five-axis motion mechanism.

[0012] In some embodiments of the present invention, the bearing includes an end cap located above the inner ring and outer ring of the bearing.

[0013] In some embodiments of the present invention, the X-ray detector is slidably mounted on a track, the track is fixedly connected to the outer ring of the bearing, and the X-ray detector is provided with a set screw that can be pressed and locked onto the track.

[0014] In some embodiments of the present invention, the five-axis motion mechanism includes a rotary table, an XY-axis translation stage, a Z-axis translation stage, and a swing table. The rotary table is fixed on the base of the connecting assembly, and the rotation center of the X-ray detector coincides with the rotation center of the rotary table.

[0015] In some embodiments of the present invention, the cryogenic assembly includes a cryogenic head that extends into the sample vacuum component, and a sample stage is fixed on the cryogenic head for placing a sample.

[0016] In some embodiments of the present invention, the sample stage is made of pure copper, and the sample stage is fixed to the low-temperature head by screws and a low-temperature thermally conductive medium, and the sample is bonded to the surface of the sample stage by the low-temperature thermally conductive medium.

[0017] In some embodiments of the present invention, the sample vacuum component has two sets of opposing openings. One set of openings is used to assemble the optical transducer, and the other set of openings is used to assemble the X-ray transducer. Both the optical transducer and the X-ray transducer are provided with cover plates on their outer sides. The cover plates press the annular rubber ring through the optical transducer and the X-ray transducer to achieve the fixation of the optical transducer and the X-ray transducer on the sample vacuum component and the vacuum sealing of the sample vacuum component.

[0018] In some embodiments of the present invention, the optical transmissive sheet is made of quartz material, and the X-ray transmissive sheet is made of PET film.

[0019] In some embodiments of the present invention, the rotary table is a motor-driven turntable, and the XY two-axis translation stage is composed of two sets of single-axis translation stage bodies that realize X-axis and Y-axis displacement respectively, which are docked and stacked longitudinally and transversely.

[0020] In some embodiments of the present invention, the bearing is a deep groove ball bearing.

[0021] As described above, the present invention has the following beneficial effects:

[0022] This invention employs an integrated stacked structure with connecting components, a five-axis motion mechanism, a sample vacuum component, and a cryogenic component arranged in layers from bottom to top. On one hand, the X-ray detector is rotatably mounted on the connecting component, and the rotation axis of the X-ray detector is coaxially set with the rotation center of the rotary table in the five-axis motion mechanism. The detector rotates directly relying on the bearings of the connecting component, eliminating the need for an additional independent detector rotation support. On the other hand, the five-axis motion mechanism, which has rotation, translation, and swing angle adjustment functions, is integrated between the connecting component and the sample vacuum component. The sample vacuum component is directly mounted on the five-axis motion mechanism, and the cryogenic component is mounted on the upper part of the sample vacuum component. This stacks and integrates the sample's multi-degree-of-freedom attitude adjustment, the vacuum chamber, and the cryogenic temperature control component, avoiding the problem of excessive stacking volume caused by the separate arrangement of each component. This significantly reduces the overall space occupied by the entire system and solves the problem that it is difficult to integrate multiple components such as vacuum cryogenics, multi-dimensional sample adjustment, and diffraction acquisition in a small space. It is suitable for the confined experimental conditions of laser plasma X-ray sources at close range. Attached Figure Description

[0023] Figure 1 The image shown is a top view of the present invention.

[0024] Figure 2 The diagram shown is a structural schematic from a first perspective of the present invention.

[0025] Figure 3 The diagram shown is a structural schematic from a second perspective of the present invention.

[0026] Figure 4 Shown is a partial cross-sectional view of the present invention;

[0027] Figure 5 Displayed as Figure 4 Enlarged view of point A in the middle.

[0028] Explanation of icon numbers:

[0029] 1. Pump unit; 2. Ultrafast X-ray source device; 3. X-ray detector; 4. Connecting assembly; 5. Five-axis motion mechanism; 6. Sample vacuum component; 7. Cryogenic component; 8. Optical transmission plate; 9. X-ray transmission plate;

[0030] 31. Rail; 32. Mounting base; 33. Set screw;

[0031] 41. Clamping components;

[0032] 51. Rotary table; 52. XY-axis translation stage; 53. Z-axis translation stage; 54. Swivel table;

[0033] 61. Cover plate; 62. Gasket; 63. Opening; 64. Sample stage; 65. Annular rubber ring. Detailed Implementation

[0034] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] Please see Figures 1-5 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] like Figures 1-3As shown, the present invention discloses a low-temperature ultrafast X-ray diffraction system. The entire low-temperature ultrafast X-ray diffraction system is assembled in layers from bottom to top, including a connecting component 4, a five-axis motion mechanism 5, a sample vacuum component 6, and a low-temperature component 7. The ultrafast X-ray source device 2, a pump unit 1, and an X-ray detector 3 are arranged around the connecting component 4.

[0037] In this embodiment, the sample vacuum component 6 has a sealed cavity inside, used to place and position the sample to be tested, while providing a vacuum testing environment. The low-temperature component 7 is assembled above the sample vacuum component 6, which can control the sample testing temperature throughout the process to meet the requirements of low-temperature experiments.

[0038] like Figure 3 , Figure 4 , Figure 5 As shown, in this embodiment, two sets of opposing through openings 63 are opened on the side wall of the sample vacuum component 6. Optical transmitting sheet 8 and X-ray transmitting sheet 9 are respectively set at the two sets of openings 63. The pump laser output from the pump unit 1 irradiates the sample through the optical transmitting sheet 8. The femtosecond X-rays output from the ultrafast X-ray source device 2 irradiate the same position of the same sample through the X-ray transmitting sheet 9. The X-ray detector 3 is arranged at the end of the diffraction optical path to collect the two-dimensional X-ray diffraction pattern generated by the sample diffraction.

[0039] The sample vacuum component 6 is fixed to the upper end of the five-axis motion mechanism 5. The five-axis motion mechanism 5 can vertically adjust the sample height to compensate for the height difference between the plane where the sample is located and the radiation emission plane of the ultrafast X-ray source device 2, thereby matching the system's reference optical path height. At the same time, the five-axis motion mechanism 5 can precisely adjust the sample's attitude and position, allowing the pump laser and X-ray irradiation positions to be arbitrarily selected. In this embodiment, the pump unit 1 can precisely control the timing of the pump light reaching the sample by controlling the optical path of the pump light.

[0040] In this embodiment, the connecting component 4 includes a base, a bearing, and a clamping member 41. The five-axis motion mechanism 5 is integrally assembled on the upper surface of the base. The base has sufficient structural rigidity to stably bear the load of all components above it, and there is no deformation or offset during operation. The inner ring of the bearing is assembled with the base using an interference fit to eliminate assembly clearance and prevent circumferential sliding and axial movement of the inner ring when the bearing rotates. The inner ring remains stationary, while the outer ring of the bearing can rotate relative to the inner ring. The clamping member 41 is fixedly assembled on the outer ring of the bearing and is synchronously connected to the X-ray detector 3. When the outer ring of the bearing rotates, it drives the X-ray detector 3 to rotate synchronously and coaxially. In this embodiment, a deep groove ball bearing is selected, which can simultaneously bear radial loads and a small amount of axial load. In another embodiment, a cylindrical roller bearing can also be selected to adapt to equipment of different weight specifications. The clamping member 41 is a flexible clamping structure that can deform slightly to fit the cylindrical surface of the outer ring of the bearing, thereby uniformly clamping it on the outer ring of the bearing, ensuring that there is no relative sliding between the clamping member 41 and the outer ring of the bearing, and stably transmitting rotational torque.

[0041] In this embodiment, the bearing includes an end cap, which is located above the inner ring and the outer ring of the bearing.

[0042] In this embodiment, the X-ray detector 3 is equipped with a mounting base 32. The X-ray detector 3 is slidably mounted on the track 31 via the mounting base 32. The track 31 is fixedly connected to the clamping member 41, so that the track 31 can also rotate synchronously with the outer ring of the bearing. The mounting base 32 is machined with a threaded hole, and a set screw 33 is installed in the threaded hole. When the set screw 33 is tightened, the end of the set screw 33 presses against the outer wall of the track 31, and the X-ray detector 3 can be locked at any position on the track 31 by friction. When the set screw 33 is loosened in the opposite direction, the friction is released, and the X-ray detector 3 can slide freely along the track 31. The operator can continuously adjust the straight-line distance between the X-ray detector 3 and the sample as needed. In this embodiment, the track 31 and the mounting base 32 adopt a dovetail tenon structure sliding fit. The contact surface of the dovetail tenon structure sliding fit uses PTFE solid lubricant to ensure a clean environment in the optical laboratory. The dovetail tenon structure can limit the lateral displacement of the X-ray detector 3, ensuring that the acquisition surface is always facing the sample. In another embodiment, track 31 is a ball-bearing track made of low-dust, low-evaporation grease, which reduces sliding friction resistance and improves the smoothness of position adjustment. Both of the above-mentioned track 31 structures can realize continuous displacement adjustment of the X-ray detector 3.

[0043] like Figure 2 As shown, in this embodiment, the five-axis motion mechanism 5 includes, from bottom to top, a rotary table 51, an XY-axis translation stage 52, a Z-axis translation stage 53, and a swing table 54. The rotary table 51 is mounted at the center of the base of the connecting assembly 4. The rotation center of the X-ray detector 3 coincides with the rotation center of the rotary table 51. That is to say, the sample angle adjustment and the rotation of the X-ray detector 3 share the same reference center.

[0044] In this embodiment, the rotary table 51 is a turntable driven by a motor and a worm gear. The rotary table 51 integrates a worm gear and a worm. The motor is fixedly installed inside the housing of the rotary table 51. The output shaft of the motor is coaxially and fixedly connected to the worm. The worm and the worm wheel mesh with each other. The output end of the worm wheel is fixedly connected to the table surface of the rotary table 51. The table surface is used to support the XY two-axis translation stage 52 above. The motor drives the worm to rotate, and through the meshing transmission of the worm gear, it drives the worm wheel and the table surface of the rotary table 51 to perform indexing rotational motion. The worm gear transmission mechanism is integrated and housed inside the housing of the rotary table 51, eliminating the need for additional exposed transmission rods outside the rotary table, which helps to reduce the overall radial space occupied by the five-axis motion mechanism 5.

[0045] In this embodiment, the XY dual-axis translation stage 52 is formed by two sets of single-axis translation stages stacked together in a longitudinal and transverse manner. The single-axis translation stage is a translation stage that can only realize linear displacement adjustment in a single axis. The two sets of single-axis translation stages correspond to the X and Y directions respectively. The base body of the Y-axis single-axis translation stage is directly fixed to the motion slide of the X-axis single-axis translation stage, realizing integrated stacking in the longitudinal and transverse directions. There is no need to add an independent adapter plate between the two sets of single-axis translation stages, reducing the assembly and stacking thickness. The integrated structure reduces the overall stacking height, further ensuring the space compactness of the entire system.

[0046] In another embodiment, the XY two-axis translation stage 52 is a cross-roller manual translation stage or an electric translation stage. The cross-roller manual translation stage is equipped with a cross-roller group as a rolling guide pair. The two sets of single-axis translation stages are still stacked longitudinally and transversely. The cross-roller group constrains the movement trajectory of the translation stage, reducing lateral offset during the movement process, thereby improving the straightness of the translation. The electric translation stage is equipped with a drive motor and a displacement feedback component on the basis of the single-axis translation stage. The drive motor drives the single-axis translation stage to perform linear displacement, and the displacement feedback component collects displacement data and outputs it to the outside, thereby supporting remote program displacement control.

[0047] In this embodiment, the swing stage 54 is a worm gear manual swing stage. The swing stage 54 is internally equipped with a meshing worm gear and worm. The outer end of the worm extends out of the swing stage 54 housing and is equipped with a knob. Rotating the knob drives the worm to rotate, which in turn drives the meshing worm gear to swing at an angle. The output end of the worm gear drives the sample vacuum component 6 mounted above to deflect synchronously, thereby achieving a small-angle attitude deflection of the sample. In another embodiment, the swing stage 54 is a micrometer-driven swing stage. The feed of the micrometer head drives the swing angle output end of the swing stage to deflect, resulting in higher precision adjustment.

[0048] The Z-axis translation stage 53 is a vertically adjustable stage capable of outputting continuous vertical displacement of the sample to compensate for the height difference between the sample plane and the emission plane of the ultrafast X-ray source device 2. A transition plate is fixedly mounted on the upper end of the Z-axis translation stage 53, which is fixedly connected to the sample vacuum component 6. Changing the transition plate to a different thickness can also achieve height compensation between the sample and the ultrafast X-ray source device 2. The XY-axis translation stage 52 is used to adjust the X and Y plane positions of the sample, while the Z-axis translation stage 53 enables height adjustment of the sample. The XY-axis translation stage 52 and the Z-axis translation stage 53 work together to calibrate any region of the sample to be aligned with the rotation center of the rotary stage 51, thereby selecting different diffraction regions of the sample. The swing stage 54 can fine-tune the sample's pitch attitude, correct placement tilt errors, and ensure that the X-ray incident plane is parallel to the sample surface, avoiding diffraction pattern distortion caused by attitude deviations.

[0049] In this embodiment, the cryogenic component 7 is fixed to the top outer wall of the sample vacuum component 6. The cryogenic component 7 has a cryogenic head that penetrates downward through the top wall of the sample vacuum component 6 and extends into the sealed cavity of the sample vacuum component 6. A sample stage 64 is fixed to the cryogenic head, which is used to hold the sample to be tested. In addition to the cryogenic head, the cryogenic component 7 also includes a Dewar flare, a Dewar plug, a heater, and a temperature sensor. The Dewar flare is connected to the cryogenic head and is filled with cryogenic liquid as a cold source, which outputs cold energy through the cryogenic head. The Dewar plug is mounted on the Dewar flare and is used to adjust the output of the cold source. The heater is arranged on the outer wall of the cryogenic head and can output controllable heat to adjust the temperature of the cryogenic head when energized. The temperature sensor is in close contact with the cryogenic head to collect the real-time temperature of the cryogenic head. The data is transmitted to an external control program, which dynamically adjusts the heater power according to the preset temperature. The temperature of the cryogenic head can be maintained in a stable state by relying on the thermal balance of the cryogenic component and the heater. The cryogenic head is rigidly attached to the sample stage 64, allowing for rapid heat conduction. The sample stage 64 can maintain a stable low temperature simultaneously, reducing the interference of temperature fluctuations on the sample's microstructure and diffraction data.

[0050] In this embodiment, the sample stage 64 is made of pure copper. Pure copper provides uniform and stable thermal conductivity, enabling rapid heat transfer from the cryogenic head and reducing the temperature difference between them. The sample stage 64 is assembled to the cryogenic head using a dual-fixation structure: firstly, multiple sets of screws are evenly tightened along the edges to press the sample stage 64 firmly against the cryogenic head; secondly, a low-temperature thermally conductive medium is applied to the contact surface between the sample stage 64 and the cryogenic head to fill tiny assembly gaps, reduce interfacial thermal resistance, and improve heat transfer efficiency. The sample to be tested is bonded to the surface of the sample stage 64 using the low-temperature thermally conductive medium. The medium fills the gap between the sample and the sample stage 64, eliminating insulation gaps and ensuring that the sample temperature is consistent with the sample stage 64 temperature, thus avoiding localized temperature gradients in the sample.

[0051] like Figure 4 , Figure 5 As shown, in this embodiment, each opening 63 is fitted with an annular rubber ring 65. The outer side of the annular rubber ring 65 is an optical transducer 8 or an X-ray transducer 9. A gasket 62 is fitted to the outer side of both the optical transducer 8 and the X-ray transducer 9. Each gasket 62 has a cover plate 61 with a through hole on its outer side. The cover plate 61, through the gasket 62 and the corresponding optical transducer 8 and X-ray transducer 9, presses the annular rubber ring 65, causing it to elastically deform and completely fill the gap between the optical transducer 8 and the X-ray transducer 9 and the side wall of the sample vacuum component 6. This achieves the fixation of the optical transducer 8 and the X-ray transducer 9 on the sample vacuum component 6 and the vacuum sealing of the sealed cavity, isolating it from the external atmosphere and maintaining a high vacuum environment within the sealed cavity. In this embodiment, the cover plate 61 is made of aluminum alloy. In this embodiment, the gasket 62 has a buffering function, preventing the cover plate 61 from damaging the corresponding optical transducer 8 and X-ray transducer 9.

[0052] In this embodiment, the optical transmissive sheet 8 is made of quartz plate, which has high transmittance to the pump laser band and reduces light energy attenuation. In another embodiment, the optical transmissive sheet 8 is made of sapphire, optical glass, or a coated transmissive sheet.

[0053] In this embodiment, the X-ray transmitting sheet 9 is made of PET film. The PET film is fixed to the corresponding opening 63 using vacuum sealant to seal the cavity. X-rays pass through the PET film and irradiate the sample. Furthermore, the PET film is transmissible to visible light, allowing operators to visually observe the sample's orientation within the cavity, facilitating pre-experiment calibration. In another embodiment, the X-ray transmitting sheet 9 uses thin sheets of transmissive metals such as beryllium or aluminum.

[0054] The workflow of this invention is as follows:

[0055] Before the experiment, the operator selected an adapter plate of appropriate thickness based on the reference height of the on-site ultrafast X-ray source device 2 to achieve height matching. The XY-axis translation stage 52, Z-axis translation stage 53, and swing stage 54 were adjusted sequentially to calibrate the sample's planar position and pitch attitude, ensuring the sample center coincided with the rotation center of the rotary stage 51. After calibration, the vacuum pump was activated to remove air from the sample vacuum component 6. Once the required vacuum level was reached, cryogenic liquid was added to the Dewar flask, the Dewar plug was closed, and the control program was activated. The control program dynamically adjusted the heater power based on feedback from the temperature sensor until the cryogenic head, sample stage 64, and sample to be tested stabilized at the preset low temperature. After the temperature reached the target, the sample position and attitude were recalibrated.

[0056] In the testing phase, the ultrafast X-ray source device 2 is first activated. Ultrafast X-ray source device 2 outputs femtosecond X-ray pulses, which pass through the X-ray transmission plate 9 to irradiate the sample. The X-rays diffract with the sample lattice, and the diffracted beam exits the sealed cavity through the other X-ray transmission plate 9. The rotating stage 51 and X-ray detector 3 are rotated so that the X-ray detector 3 receives the diffraction pattern. Next, pump unit 1 is activated, outputting a high-intensity pump laser. The pump laser passes through the optical transmission plate 8 and irradiates the region on the sample where X-ray diffraction occurs, transferring energy to the sample within femtoseconds, perturbing the internal electronic, lattice, and magnetic structures of the sample, and inducing ultrafast dynamic behaviors such as structural phase transitions, carrier relaxation, and lattice vibrations. After activating pump unit 1, the timing of the pump laser reaching the sample should be precisely adjusted until the X-ray detector 3 receives the ultrafast dynamic diffraction pattern induced by the pump light. The operator pre-operates the X-ray detector 3 to slide along track 31 to adjust the acquisition distance. After adjustment, the set screw 33 is tightened to lock the X-ray detector 3, completing the acquisition of the two-dimensional diffraction pattern under the current delay condition. By continuously changing the time delay between the pump laser and the X-ray pulse through pump unit 1, multiple sets of diffraction images corresponding to different delays are acquired. After stitching together all the images, the complete process of the evolution of the sample's microstructure over time can be reconstructed, completing the ultrafast X-ray diffraction characterization under low-temperature vacuum conditions.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A low-temperature ultrafast X-ray diffraction system, characterized in that, The device includes a connecting assembly (4), a five-axis motion mechanism (5), a sample vacuum component (6), and a low-temperature component (7) arranged sequentially from bottom to top. The connecting assembly (4) is surrounded by an ultrafast X-ray source device (2), a pump unit (1), and an X-ray detector (3). The X-ray detector (3) is rotatably mounted on the connecting assembly (4), and the rotation axis of the X-ray detector (3) is consistent with the rotation center of the five-axis motion mechanism (5). The sample vacuum component (6) is used to place and position the sample, the low temperature component (7) is used to control the temperature during sample testing, the sample vacuum component (6) is provided with an optical transmissive plate (8) and an X-ray transmissive plate (9), the ultrafast X-ray source device (2) and the pump unit (1) respectively irradiate the sample through the X-ray transmissive plate (9) and the optical transmissive plate (8), and the X-ray detector (3) is used to collect the two-dimensional X-ray diffraction pattern after sample diffraction; The sample vacuum component (6) is mounted on the five-axis motion mechanism (5), which is used to adjust the position and orientation of the sample.

2. The low-temperature ultrafast X-ray diffraction system according to claim 1, characterized in that, The pump unit (1) can control the time when the pump light reaches the sample by controlling the optical path of the pump light.

3. The low-temperature ultrafast X-ray diffraction system according to claim 1, characterized in that, The connecting assembly (4) includes a base, a bearing and a clamping member (41). The five-axis motion mechanism (5) is assembled on the base. The inner ring of the bearing is interference-fitted with the base. The outer ring of the bearing is fixedly connected to the X-ray detector (3) through the clamping member (41), so that the X-ray detector (3) rotates synchronously with the bearing around the rotation center of the five-axis motion mechanism (5).

4. The low-temperature ultrafast X-ray diffraction system according to claim 3, characterized in that, The bearing includes an end cap located above the inner ring and outer ring of the bearing.

5. The low-temperature ultrafast X-ray diffraction system according to claim 2, characterized in that, The X-ray detector (3) is slidably mounted on the track (31), the track (31) is fixedly connected to the outer ring of the bearing, and the X-ray detector (3) is provided with a set screw (33) that can be pressed and locked on the track (31).

6. The low-temperature ultrafast X-ray diffraction system according to claim 3, characterized in that, The five-axis motion mechanism (5) includes a rotary table (51), an XY two-axis translation stage (52), a Z-axis translation stage (53), and a swing table (54). The rotary table (51) is fixed on the base of the connecting assembly (4), and the rotation center of the X-ray detector (3) is consistent with the rotation center of the rotary table (51).

7. The low-temperature ultrafast X-ray diffraction system according to claim 4, characterized in that, The low-temperature component (7) includes a low-temperature head that extends into the sample vacuum component (6). A sample stage (64) is fixed on the low-temperature head, and the sample stage (64) is used to place the sample.

8. The low-temperature ultrafast X-ray diffraction system according to claim 5, characterized in that, The sample stage (64) is made of pure copper. The sample stage (64) is fixed to the low-temperature head by screws and a low-temperature heat-conducting medium. The sample is bonded to the surface of the sample stage (64) by the low-temperature heat-conducting medium.

9. The low-temperature ultrafast X-ray diffraction system according to claim 5, characterized in that, The sample vacuum component (6) has two sets of opposing openings (63). One set of openings (63) is used to assemble the optical transmissive sheet (8), and the other set of openings (63) is used to assemble the X-ray transmissive sheet (9). The outer sides of the optical transmissive sheet (8) and the X-ray transmissive sheet (9) are provided with cover plates (61). The cover plates (61) press the annular rubber ring (65) through the optical transmissive sheet (8) and the X-ray transmissive sheet (9) to fix the optical transmissive sheet (8) and the X-ray transmissive sheet (9) on the sample vacuum component (6) and to vacuum seal the sample vacuum component (6).

10. The low-temperature ultrafast X-ray diffraction system according to claim 4, characterized in that, The rotary table (51) is a turntable driven by a motor, and the XY two-axis translation stage (52) is composed of two sets of single-axis translation stage bodies that realize X-axis and Y-axis displacement respectively, which are connected and stacked in the longitudinal and transverse directions.

Images