Closed-cycle extremely-low-temperature six-axis sample holder

Abstract

The invention relates to a closed-cycle extremely-low-temperature six-axis sample holder, which relates to the technical field of ultrahigh vacuum experimental equipment and low-temperature angle-resolved photoelectron spectroscopy equipment, and comprises an ultrahigh vacuum cavity module, a cold head and helium compressor module, a three-stage cold disc and heat shielding cover module, a six-axis sample support frame module and a helium closed-cycle pipeline module, the six-axis sample supporting frame module is arranged in the ultrahigh vacuum cavity module, the cold head and helium compressor module is connected with the three-stage cold disc and heat shielding cover module, and the three-stage cold disc and heat shielding cover module and the helium closed circulation pipeline module are both connected with the six-axis sample supporting frame module. Under the combined action, the sample position of the six-axis sample supporting frame module reaches extremely low temperature, and six-degree-of-freedom motion control is realized. According to the invention, six-degree-of-freedom motion control of a sample can be realized, stable 1.52 K extremely low temperature of the sample can be realized, and high refrigeration power is achieved. Moreover, since the sample holder adopts a helium closed-cycle refrigeration technology, no helium is consumed during an experiment.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-high vacuum experimental equipment and low-temperature angle-resolved photoelectron spectroscopy equipment, and in particular to a design scheme of a low-temperature sample holder. Background Art

[0002] Angle-resolved photoemission spectroscopy (ARPES) is an experimental method capable of revealing the most fundamental physical properties of matter, playing an irreplaceable role in the field of condensed matter physics. For example, the experimental progress in the study of superconductivity mechanisms, two-dimensional materials, the observation of electronic states in topological insulators and topological semimetals, the exploration of topological superconductivity, the theoretical verification of the quantum anomalous Hall effect, the exploration of Majorana fermions, and the study of electron-phonon coupling, all of these novel physical phenomena, all rely on the application of ARPES.

[0003] The current mainstream ARPES system uses a liquid helium open-circulation sample holder, and the minimum temperature of this type of sample holder can only reach about 6-7K. Moreover, since the cooling source comes from liquid helium, a large amount of liquid helium will be lost while conducting experiments. Some ARPES system sample holders are also equipped with helium compressors and cold heads, and their lowest temperature can only be maintained at about 4.6K. Some foreign ARPES are equipped with coke soup refrigeration technology, but their lowest temperature can only reach 2.9K, and their sample space freedom is limited. However, a considerable part of the physical phenomena mentioned above can only appear in lower ultra-low temperature environments, and under such extreme conditions there may be more unknown novel physical properties waiting to be discovered. Summary of the Invention

[0004] The purpose of this invention is to provide a novel closed-cycle, ultra-low-temperature six-axis sample holder to meet the extremely low-temperature requirements of ARPES experiments. This system combines a conventional ARPES six-axis sample holder with Jiaotang refrigeration technology, enabling six-degree-of-freedom motion control of the sample while maintaining a stable, ultra-low temperature of 1.52K at the sample site and boasting high cooling power. Furthermore, because the sample holder utilizes helium closed-cycle refrigeration technology, no helium is consumed during experiments.

[0005] In order to achieve the above-mentioned objectives, the technical solution of the present invention provides a closed-loop ultra-low-temperature six-axis sample holder, comprising an ultra-high vacuum chamber module, a cold head and helium compressor module, a three-stage cold plate and heat shielding cover module, a six-axis sample support frame module and a helium closed-loop pipeline module. The six-axis sample support frame module is arranged in the ultra-high vacuum chamber module, the cold head and helium compressor module are connected to the three-stage cold plate and heat shielding cover module, the three-stage cold plate and heat shielding cover module, and the helium closed-loop pipeline module are all connected to the six-axis sample support frame module, and together they make the sample of the six-axis sample support frame module reach an ultra-low temperature and realize six-degree-of-freedom motion control.

[0006] Preferably, the cold head and helium compressor module includes a cold head and a helium compressor connected by a high-pressure helium hose, and the cold head includes a first-level cold head and a second-level cold head. The first-level cold head can reach a low temperature of 40K, and the second-level cold head can achieve a low temperature of 3 to 4K, providing cooling capacity for the system, so that the sample can be reduced from room temperature 300K to a low temperature of 10K.

[0007] Preferably, the three-stage cold plate and heat shield module includes a 50K plate, a 4K plate, a 1K plate and a heat shield. The three-stage cold plate is made of high-purity oxygen-free copper. The 50K plate is thermally connected to the first-stage cold head, and the 4K plate is thermally connected to the second-stage cold head. The 50K plate and the cavity, as well as the three cold plates are relatively fixed to each other. The heat shield is made of gold-plated beryllium copper foil and is thermally connected to the 50K plate to reduce the influence of external heat radiation on the sample temperature.

[0008] Preferably, the heat shield cover at the sample stage has two switch doors, the main door adopts a concave design, and a cross hole is opened in the middle.

[0009] Preferably, the six-axis sample support frame module includes the sample table, oxygen-free copper support rods, stainless steel support rods and a six-axis displacement stage. The six-axis displacement stage is composed of a translational motion component and a rotational motion component. The translational motion component is located on the top large flange of the main cavity, and the rotational motion component is located above the translational motion component. The stainless steel support rod and the differential rotation flange of the rotational motion component are fixedly connected in an ultra-high vacuum. The stainless steel support rod and the oxygen-free copper support rod are fixedly connected, and the sample table and the oxygen-free copper support rod are fixedly connected. The stainless steel support rod is thermally connected to the cold plates of each level at the position where it passes through the three-level cold plate by a support rod copper braid to achieve heat conduction without affecting the freedom of movement of the support rod.

[0010] Preferably, the helium closed-loop pipeline module includes a gas storage tank, a needle valve, a 1KPot, a dry pump, and a helium circulation pipeline. The helium flows out of the gas storage tank, flows through the first-stage cold head, the second-stage cold head, the needle valve, the 1KPot, and the sample stage in sequence, and finally undergoes adiabatic expansion under the action of the dry pump and returns to the gas storage tank.

[0011] Preferably, a spiral capillary is provided in the helium flow line and spirally wound around the oxygen-free copper support rod so as not to affect the free movement of the oxygen-free copper support rod and the sample stage.

[0012] Preferably, the differential rotating flange realizes polar angle rotation driven by a motor, and the sample stage rotates in the same direction and angle accordingly. The translation motion assembly can drive the entire rotation motion assembly to perform translational motion in the x, y, and z directions, thereby driving the sample stage to move in the same direction and distance. Two motors are also fixed on the differential rotating flange, which are used to drive the two pitch angle transmission rods and in-plane angle transmission rods in the vacuum to rotate outside the vacuum. The rotational motion of the transmission rod is transmitted to the sample stage through the mechanical connection between the coupling and the transmission rod, and cooperates with the worm gear and bevel gear at the sample stage to realize the rotation of the pitch angle and in-plane angle of the sample holder.

[0013] Preferably, the heat shield is provided with a main door, a side door and corresponding door buckles, and a door handle is provided on the door. The two doors are connected to the heat shield by a copper braid of the shield. When transferring samples, the sample holder is introduced from the side door by a mechanical gripper. The main door is used to observe and perform cleavage operations on the sample. When conducting experimental tests, the main door is closed, and light energy is incident on the sample from the left or right groove of the aperture. The generated photoelectrons fly out from the center of the aperture and enter the analyzer opposite, realizing the collection and testing of photoelectrons. A liquid nitrogen cold screen is installed at the head of the hemispherical analyzer, and the temperature of the liquid nitrogen can be reduced to 77K by passing liquid nitrogen through the liquid nitrogen pipeline, thereby realizing all-round heat shielding at the sample.

[0014] Preferably, the cold finger and the sample holder are connected by a sample holder copper braid, which realizes heat conduction while ensuring free rotation of the pitch angle and in-plane angle of the sample holder.

[0015] Compared with traditional cryogenic sample holder technology, the closed-loop cryogenic sample holder of the present invention has the following significant benefits:

[0016] The sample holder of this invention achieves high-precision motion control of the sample in six degrees of freedom, meeting the requirements of high-precision experiments such as ARPES, which place strict demands on sample position and angle. Furthermore, through the coordinated operation of multiple modules, the sample holder can maintain a stable temperature of around 1K at the sample site, providing a reliable platform for ultra-low-temperature experiments.

[0017] The sample holder of this invention is not only suitable for novel closed-loop, ultra-low-temperature ARPES experiments but can also, through minor modifications and conceptual integration, be applied to other low-temperature experimental platforms, such as conventional open-loop ARPES systems. The unique design of the heat shield ensures a low-temperature environment for the sample while facilitating sample transfer, cleavage, and testing operations. This balances experimental convenience and efficiency, further expanding its application scenarios and improving experimental efficiency.

[0018] The closed-loop cryogenic sample holder utilizes helium closed-cycle refrigeration technology, eliminating the high consumption of liquid helium required by traditional sample holders for cryogenic experiments. Helium is recycled within the system, eliminating the need for continuous replenishment of liquid helium, significantly reducing experimental costs and conserving helium resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional stereogram of the present invention;

[0020] Figure 2 It is a schematic diagram of the principle of the present invention;

[0021] Figure 3 Schematic diagram of spiral capillary;

[0022] Figure 4 A top view of the present invention;

[0023] Figure 5 This is a three-dimensional image of the six-axis translation stage;

[0024] Figure 6 This is a three-dimensional image of the sample stage;

[0025] Figure 7 This is the oblique rear view of the sample stage;

[0026] Figure 8 This is a three-dimensional image of the heat shield at the sample stage;

[0027] Figure 9 Schematic diagram of the sample transfer process;

[0028] Figure 10 Schematic diagram of the relative positions of the hemispherical analyzer head and the sample stage;

[0029] Figure 11 A cross-sectional view of the hemispherical analyzer head and sample stage.

[0030] Figure numerals: 21, cold head; 22, helium compressor; 23, high-pressure helium hose; 24, first-stage cold head; 25, second-stage cold head; 31, 50K disk; 32, 4K disk; 33, 1K disk; 34, heat shield; 35, shield copper braid; 36, main door; 37, side door; 38, door handle; 39, door buckle; 41, sample stage; 42, oxygen-free copper support rod; 43, stainless steel support rod; 44, six-axis translation stage; 45, support rod copper braid; 46, translation motion assembly; 47, rotation motion assembly Parts; 48. Differential rotation flange; 49. Pitch angle transmission rod; 410. In-plane angle transmission rod; 411. Coupling; 412. Pitch angle bevel gear; 413. Worm gear; 414. In-plane angle bevel gear; 415. Sample holder; 416. Cold finger; 417. Sample holder copper braid; 51. Gas storage tank; 52. Needle valve; 53. 1KPot; 54. Dry pump; 55. Spiral capillary; 61. Sample holder; 62. Sample; 63. Hemispherical analyzer head; 64. Liquid nitrogen cold shield; 65. Liquid nitrogen pipeline. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] The closed-loop cryogenic sample holder comprises an ultra-high vacuum chamber module, a cold head and helium compressor module, a three-stage cold plate and heat shield module, a six-axis sample support module, and a helium closed-loop piping module. These five modules enable the sample 62 to reach a cryogenic temperature of approximately 1K and maintain it stably for ARPES experiments.

[0033] The ultrahigh vacuum chamber module is constructed from non-magnetic stainless steel, ensuring that the entire six-axis sample support module is housed in an ultrahigh vacuum insulation environment of 10-11 Torr, providing the primary safeguard for maintaining the extremely low temperatures of sample stage 41. Furthermore, the high mechanical strength of the stainless steel chamber provides fundamental mechanical support for other modules.

[0034] The cold head and helium compressor module are the source of the system's cooling capacity. The cold head 21 and helium compressor 22 are connected by a high-pressure helium hose 23. The cold head 21 comprises a primary cold head 24 and a secondary cold head 25. The primary cold head 24 can reach temperatures of approximately 40K, while the secondary cold head 25 can achieve temperatures of 3-4K. These provide a continuous supply of cooling capacity for the system, allowing the sample stage 41 to cool from room temperature (300K) to a low temperature of 10K.

[0035] The three-stage cold plate and thermal shield module includes a 50K plate 31, a 4K plate 32, a 1K plate 33, and a thermal shield 34. To achieve higher thermal conductivity, the three cold plates are made of high-purity oxygen-free copper. The 50K plate 31 is thermally connected to the first cold head 24, and the 4K plate 32 is thermally connected to the second cold head 25. Stainless steel columns secure the 50K plate 31 to the chamber and to each other, ensuring mechanical strength and thermal insulation between them. Furthermore, due to the extremely low emissivity of gold at low temperatures, to minimize the impact of external thermal radiation on the temperature of sample 62, a thermal shield 34 is made of gold-plated beryllium copper foil. Thermal shield 34 is thermally connected to the 50K plate 31 to reduce the impact of external thermal radiation on the temperature of sample 62. The thermal shield 34 at the sample stage 41 has two doors. The main door 36 is concave with a small cross-shaped hole in the center.

[0036] The six-axis sample support frame module consists of a sample table 41, an oxygen-free copper support rod 42, a stainless steel support rod 43, and a six-axis translation stage 44. The six-axis translation stage 44 is located as a whole on the ultra-high vacuum chamber, and includes a translational motion component 46 and a rotational motion component 47. The six axes include translational motion in the three directions of x, y, and z, and rotation at three spatial angles: polar angle, in-plane angle, and pitch angle. The translational motion component 46 is located on the large flange at the top of the main chamber, and the rotational motion component 47 is located above the translational motion component 46. The differential rotation flange 48 between the stainless steel support rod 43 and the rotational motion component 47 is mechanically fixed in the ultra-high vacuum, the stainless steel support rod 43 and the oxygen-free copper support rod 42 are mechanically fixed, and the sample table 41 and the oxygen-free copper support rod 42 are mechanically fixed. The stainless steel support rod 43 is thermally connected to each level of the cold plate at the position where it passes through the three-level cold plate by the support rod copper braid 45. The flexible design of the copper braid can not only prevent external heat from reaching the sample 62 through the support rod, but also ensure the free movement of the support rod in the four degrees of freedom of x, y, z, and polar.

[0037] The helium closed-loop pipeline module primarily consists of a gas storage tank 51, a needle valve 52, a 1KPot 53, a dry pump 54, and helium circulation piping. During operation, room-temperature helium flows from the outlet of the gas storage tank 51, enters the refrigerator through a bellows, and flows through the primary and secondary cold heads 24 and 25, where it is gradually cooled. It liquefies to form liquid helium at the secondary cold head 25, enters a capillary, and flows through the needle valve 52. The capillary then nests into the bellows for the return helium flow, then enters the 1KPot 53. It then exits the nested piping and flows along the capillary to the sample stage 41. Once at the sample stage 41, it flows upward along the capillary until it enters the 1KPot 53. Continuous air extraction by the downstream dry pump 54 causes the liquid helium to undergo adiabatic expansion there, transforming from liquid to gas. This further lowers the temperature of the liquid helium, achieving refrigeration of the coke soup. The temperature of the 1KPot 53 is generally maintained at around 1.3K. The temperature of the helium that has turned into gas is still very low. It exchanges heat with the newly liquefied helium in the nested pipeline: while further cooling the flowing liquid helium, its own temperature rises. The gasified helium is pumped away by the dry pump 54 through the bellows and enters the gas storage tank 51. In order not to affect the free movement of the oxygen-free copper support rod 42 and the sample stage 41, Figure 2 The dotted circle is specially designed. Figure 3 This is a top-down view of the helium flow path. A spiral capillary tube 55 is wound around the oxygen-free copper support rod 42, allowing the rod 42 and the sample stage 41 to freely translate and rotate at the polar angle. The arrow in the figure indicates the direction of helium flow.

[0038] Driven by a motor, the differential rotating flange 48 realizes polar angle rotation. Due to a series of mechanical fixing relationships, the sample stage 41 will rotate in the same direction and angle as the differential rotating flange 48. The translation motion assembly 46 can drive the entire rotation motion assembly 47 to perform translational motion in the three directions of x, y, and z, thereby driving the sample stage 41 to move in the same direction and distance. In addition, two motors are fixed on the differential rotating flange 48, which can drive two transmission rods (pitch angle transmission rod 49 and in-plane angle transmission rod 410) in the vacuum to rotate outside the vacuum. The rotational motion of these two transmission rods is transmitted to the position of the sample stage 41 through the mechanical connection of multiple couplings 411 and multiple transmission rods, and cooperates with the worm gear and bevel gear at the sample stage 41. The pitch angle transmission rod 49 cooperates with the pitch angle bevel gear 412 to realize the pitch angle rotation of the sample holder 415. The in-plane angle transmission rod 410 first cooperates with the worm gear 413 , and then the worm gear 413 cooperates with the in-plane angle bevel gear 414 to realize the in-plane angle rotation of the sample holder 415 . Figure 6 The cold finger 416 is connected to the sample holder 415 by a sample holder copper braid 417, which not only achieves heat conduction but also ensures the free rotation of the pitch angle and in-plane angle of the sample holder 415. Figure 7 shown.

[0039] In order to achieve extremely low temperature at the sample stage 41 while realizing sample transfer, cleavage, laser injection, photoelectron collection and testing required for ARPES experiments, the heat shield 34 is specially designed. Figure 8 The following is a detailed diagram. The heat shield 34 has two switch doors (main door 36 and side door 37) and door buckles 39. There is a door handle 38 on the door to facilitate opening and closing operations in ultra-high vacuum. The two doors are connected to the heat shield 34 by the shield copper braid 35 to ensure temperature conduction on the door. When transferring samples, both doors need to be opened, and the sample holder 61 is introduced from the side door 37 by a mechanical gripper. The main door 36 is used for observation to ensure a smooth sample transfer process. After the sample transfer is completed, the sample 62 is cleaved through the main door 36. The main door 36 adopts a concave design with a cross hole in the middle. During experimental testing, it is closed, and light energy is incident on the sample 62 from the left or right slot of the hole. The generated photoelectrons fly out from the center of the hole and enter the analyzer opposite to realize the collection and testing of photoelectrons. The hemispherical analyzer head 63 is equipped with a liquid nitrogen cold shield 64, which can reduce the temperature of the sample 62 to about 77K by passing liquid nitrogen through the liquid nitrogen pipeline 65, so as to achieve almost all-round heat shielding at the sample 62. Figure 10 、 Figure 11 shown.

[0040] This closed-loop cryogenic sample holder achieves six-degree-of-freedom motion control at the sample 62 and an extremely low temperature of 1.52K without consuming large amounts of liquid helium. Utilizing closed-loop helium refrigeration technology, there is no helium loss during experiments, conserving helium resources while reducing the cost of the experimental platform. Furthermore, this refrigeration system provides a novel solution for the cryogenic ARPES sample stage 41. The lowest temperature achievable depends on a variety of factors, and lower temperatures can be achieved by replacing components or refrigerants. For example, replacing a pump with a more powerful pump can reduce the vapor pressure downstream of 1KPot53. Based on the temperature-saturation vapor pressure curve of helium-4, when the vapor pressure of helium-4 is sufficiently low, the temperature can drop below 1K. By replacing the refrigerant with helium-3 or a mixture of helium-3 and helium-4, temperatures can even be reduced to millikelvin levels. Furthermore, compared to conventional ARPES sample holders, this sample holder features significant improvements in the worm gear 413, bevel gears, and other transmission designs at the sample stage 41, as well as the door and heat shield 34, making it equally applicable to conventional open-loop ARPES systems.

[0041] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A closed-cycle ultra-low temperature six-axis sample holder, characterized in that: The invention comprises an ultra-high vacuum chamber module, a cold head and a helium compressor module, a three-stage cold plate and a heat shielding cover module, a six-axis sample support frame module and a helium closed-circuit pipeline module. The six-axis sample support frame module is arranged in the ultra-high vacuum chamber module. The cold head and the helium compressor module are connected to the three-stage cold plate and the heat shielding cover module. The three-stage cold plate and the heat shielding cover module and the helium closed-circuit pipeline module are all connected to the six-axis sample support frame module. The six-axis sample support frame module and the sample (62) of the six-axis sample support frame module are made to reach an extremely low temperature and realize six-degree-of-freedom motion control.

2. The closed-cycle ultra-low temperature six-axis sample holder according to claim 1, characterized in that: The cold head and helium compressor module includes a cold head (21) and a helium compressor (22) connected by a high-pressure helium hose (23). The cold head (21) includes a first-level cold head (24) and a second-level cold head (25). The first-level cold head (24) can reach a low temperature of 40K, and the second-level cold head (25) can achieve a low temperature of 3 to 4K, providing cooling capacity for the system, so that the sample (62) can be reduced from room temperature 300K to a low temperature of 10K.

3. The closed-cycle ultra-low temperature six-axis sample holder according to claim 2, characterized in that: The three-stage cold plate and heat shield module includes a 50K plate (31), a 4K plate (32), a 1K plate (33) and a heat shield (34). The three-stage cold plate is made of high-purity oxygen-free copper. The 50K plate (31) is thermally connected to the first-stage cold head (24), and the 4K plate (32) is thermally connected to the second-stage cold head (25). The 50K plate (31) and the cavity and the three cold plates are relatively fixed to each other. The heat shield (34) is made of gold-plated beryllium copper foil and is thermally connected to the 50K plate (31) to reduce the influence of external heat radiation on the temperature of the sample (62).

4. The closed-cycle ultra-low temperature six-axis sample holder according to claim 3, characterized in that: The heat shield cover (34) at the sample stage (41) has two switch doors, and the main door (36) adopts a concave design with a cross hole in the middle.

5. A closed-cycle ultra-low temperature six-axis sample holder according to claim 3 or 4, characterized in that: The six-axis sample support frame module includes the sample stage (41), the oxygen-free copper support rod (42), the stainless steel support rod (43) and the six-axis displacement stage (44), the six-axis displacement stage (44) is composed of a translation motion component (46) and a rotation motion component (47), the translation motion component (46) is located on the top large flange of the main cavity, the rotation motion component (47) is located above the translation motion component (46), the stainless steel support rod (43) and the differential rotation flange (48) of the rotation motion component (47) are fixedly connected in ultra-high vacuum, the stainless steel support rod (43) and the oxygen-free copper support rod (42) are fixedly connected, the sample stage (41) and the oxygen-free copper support rod (42) are fixedly connected, and the stainless steel support rod (43) is thermally connected to the cold plates of each level by the support rod copper braid (45) at the position where it passes through the three-level cold plate, so as to achieve heat conduction without affecting the freedom of movement of the support rod.

6. The closed-cycle ultra-low temperature six-axis sample holder according to claim 5, characterized in that: The helium closed-circuit pipeline module includes a gas storage tank (51), a needle valve (52), a 1KPot (53), a dry pump (54) and a helium circulation pipeline. The helium flows out of the gas storage tank (51), flows through the refrigerator, the first-stage cold head (24), the second-stage cold head (25), the needle valve (52), the 1KPot (53), and the sample stage (41) in sequence, and finally undergoes adiabatic expansion under the action of the dry pump (54) and returns to the gas storage tank (51).

7. The closed-cycle ultra-low temperature six-axis sample holder according to claim 6, characterized in that: A spiral capillary (55) is provided in the helium flow line and spirally wound around the oxygen-free copper support rod (42) so as not to affect the free movement of the oxygen-free copper support rod (42) and the sample stage (41).

8. A closed-cycle ultra-low temperature six-axis sample holder according to claims 6 and 7, characterized in that: The differential rotation flange (48) realizes polar angle rotation under the drive of the motor, and the sample stage (41) rotates in the same direction and angle accordingly. The translation motion component (46) can drive the entire rotation motion component (47) to perform translation motion in the three directions of x, y, and z, thereby driving the sample stage (41) to perform motion in the same direction and distance. Two motors are also fixed on the differential rotation flange (48) for driving two pitch angle transmission rods (49) and in-plane angle transmission rods (410) in the vacuum to rotate outside the vacuum. The rotational motion of the transmission rod is transmitted to the sample stage (41) through the mechanical connection between the coupling (411) and the transmission rod, and cooperates with the worm gear and bevel gear at the sample stage (41) to realize the rotation of the pitch angle and in-plane angle of the sample holder (415).

9. The closed-cycle ultra-low temperature six-axis sample holder according to claim 1, characterized in that: The heat shield (34) is provided with a main door (36), a side door (37) and a corresponding door buckle (39), and a door handle (38) is provided on the door. The two doors are connected to the heat shield (34) by a shield copper braid (35). When transferring samples, the sample holder (61) is introduced from the side door (37) by a mechanical gripper. The main door (36) is used to observe and perform cleavage operations on the sample (62). When performing experimental tests, the main door (36) is closed, and light energy is incident on the sample (62) from the left or right groove of the aperture. The generated photoelectrons fly out from the center of the aperture and enter the analyzer on the opposite side, realizing the collection and testing of photoelectrons. A liquid nitrogen cold screen (64) is installed on the head (63) of the hemispherical analyzer. Liquid nitrogen can be passed through the liquid nitrogen pipeline (65) to reduce its temperature to 77K, thereby realizing all-round heat shielding at the sample (62).

10. The closed-cycle ultra-low temperature six-axis sample holder according to claim 1, characterized in that: The cold finger (416) and the sample holder (415) are connected by a sample holder copper braid (417), which realizes heat conduction while ensuring the free rotation of the pitch angle and in-plane angle of the sample holder (415).

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