A low-temperature sample holder with pitch and rotation function based on a GM refrigerator

Abstract

This invention provides a low-temperature sample holder with pitch and rotation function based on a GM refrigerator, including a refrigerator and a sample holder head. Its key feature is that it further includes an adapter, a rotating mechanism, a flexible shaft, an upper transmission rod, a lower transmission rod, a gear set, a worm gear assembly, and a sample stage. The sample stage is used to place and move the sample. The adapter has an external interface. The rotating mechanism connects to the flexible shaft. The flexible shaft passes through the adapter via the external interface. The flexible shaft connects to the upper transmission rod. The upper transmission rod connects to the lower transmission rod. The lower transmission rod connects to the gear set. The gear set connects to the worm gear assembly. The worm gear assembly connects to the sample stage. The advantages of this invention are: the design is compact, the sample stage can achieve pitch and rotation under extremely low temperatures, and the pitch angle movement is smooth over a wide temperature range, avoiding rotational jamming caused by thermal expansion and contraction.

Description

Technical Field

[0001] This invention relates to the fields of ultra-high vacuum and ultra-low temperature, and particularly to a low-temperature sample holder with pitch and rotation function based on a GM refrigerator. Background Technology

[0002] Angle-resolved photoelectron spectroscopy (ARPES) utilizes the photoelectric effect to study the electronic structure of solids. The cryogenic sample holder, serving as the measurement platform for the sample, is a crucial component of the ARPES system, providing an ultra-low temperature, multi-degree-of-freedom, and non-magnetic measurement environment. Cryogenic sample holders based on GM refrigerators offer inherent advantages: they do not require liquid helium, resulting in low operating costs; they enable fully motorized multi-degree-of-freedom motion for convenient operation; and they can rapidly change temperature and operate stably for extended periods, making them an ideal choice for ARPES researchers.

[0003] However, the main design challenges of low-temperature sample holders based on GM refrigerators are as follows: 1. Achieving a design that allows the sample stage to reach the liquid helium temperature range (temperature less than 4K); 2. Ensuring that the sample stage can be driven by an external vacuum motor for pitch rotation while meeting the requirements of ultra-high vacuum and non-magnetic conditions; 4. Ensuring that the sample position remains unchanged with temperature within a very large temperature range.

[0004] Therefore, the market urgently needs a low-temperature sample holder with pitch and rotation based on a GM refrigerator that can be compatible with ultra-high vacuum environments and provide a temperature range from low temperature to liquid helium, with smooth pitch and rotation over a very wide temperature range. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention discloses a pitch-rotation cryogenic sample holder based on a GM refrigerator. The technical solution of this invention is implemented as follows:

[0006] A pitch-rotating low-temperature sample holder based on a GM refrigerator includes a refrigerator and a sample holder head. The refrigerator includes a primary cold head and a secondary cold head, with the secondary cold head connected to the primary cold head. The holder further includes an adapter, a rotating mechanism, a flexible shaft, an upper transmission rod, a lower transmission rod, a gear set, a worm gear assembly, and a sample stage. The sample stage is used to hold samples. The adapter has an external interface. The rotating mechanism connects to the flexible shaft. The flexible shaft passes through the adapter via the external interface. The flexible shaft connects to the upper transmission rod. The upper transmission rod connects to the lower transmission rod. The lower transmission rod connects to the gear set. The gear set connects to the worm gear assembly. The worm gear assembly connects to the sample stage.

[0007] Preferably, it also includes a thermally conductive extension rod; one end of the thermally conductive extension rod is disposed on the secondary cold head, and the other end is connected to the sample stage.

[0008] Preferably, the thermally conductive extension rod is connected to the sample stage by a braid; the material of the braid is selected from one or more of copper, gold or silver.

[0009] Preferably, the upper transmission rod and the lower transmission rod are connected by a coupling.

[0010] Preferably, it further includes a sleeve; the sleeve connects to the primary cold head; the sleeve encloses the secondary cold head.

[0011] Preferably, it further includes a clamp support; the clamp support is disposed on the upper transmission rod; the clamp support is sleeved on the sleeve.

[0012] Preferably, it further includes a support plate; the support plate is fixed to the lower transmission shaft via a bearing seat; the sample stage includes a triangular support, a shield, a shield door, a shield baffle, and a sample holder; the shield door is provided with a measurement hole; the shield door is installed on the shield, and the shield baffle is installed on the shield; the shield baffle is installed on the shield; the sample holder and the triangular support are disposed inside the shield; the sample holder is connected to the triangular support.

[0013] Preferably, a gold column is provided on the sample stage.

[0014] Preferably, the sample stage is provided with an accessory interface.

[0015] The technical solution of this invention can solve the technical problem in the prior art that it is impossible to achieve multi-degree-of-freedom rotation on a GM refrigerator under the premise of extremely low temperature of the sample holder, with each degree of freedom moving independently and without interference, and with smooth pitch angle movement over a very large temperature range; the technical solution of this invention can achieve the technical effect of multi-degree-of-freedom rotation on a GM refrigerator under the premise of extremely low temperature of the sample holder, with each degree of freedom moving independently and without interference, and with smooth pitch angle movement over a very large temperature range. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an overall structural diagram of a pitch-rotation low-temperature sample holder based on a GM refrigerator;

[0018] Figure 2This is a schematic diagram of the transmission structure of a pitch-rotation low-temperature sample holder based on a GM refrigerator;

[0019] Figure 3 This is a schematic diagram of a sample stage structure for a pitch-rotation cryogenic sample holder based on a GM refrigerator;

[0020] Figure 4 This is a schematic diagram of the sample holder head of a pitch-rotating low-temperature sample holder based on a GM refrigerator.

[0021] In the above figures, the figure numbers indicate the following:

[0022] 1-Refrigeration unit; 2-Adapter; 3-Sample stage; 4-Rotating machine; 5-Flexible shaft; 6-Upper transmission rod; 7-Lower transmission rod; 8-Gear set; 9-Worm gear set; 10-Coupling; 11-Clamp support; 12-Sample holder; 13-Shielding cover; 14-Shielding cover door; 15-Shielding baffle; 16-Gold pillar. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] For ease of description, Z represents the opposite direction of gravity, X and Y are the X and Y directions of a spatial rectangular coordinate system established with the Z-axis as the standard, and R1 is the angle between the cold head and the horizontal plane.

[0025] In one specific embodiment, such as Figures 1 to 4 As shown, a pitch-rotation low-temperature sample holder based on a GM refrigerator (1) includes a refrigerator (1) and a sample holder head. The refrigerator includes a primary cold head and a secondary cold head, with the secondary cold head connected to the primary cold head. The holder is characterized by further including an adapter (2), a rotating mechanism (4), a flexible shaft (5), an upper transmission rod (6), a lower transmission rod (7), a gear set (8), a worm gear assembly (9), and a sample stage (3). The sample stage (3) is used to place samples. The adapter (2) has an external interface. The rotating mechanism (4) is connected to the flexible shaft (5). The flexible shaft (5) passes through the adapter (2) via the external interface. The flexible shaft (5) is connected to the upper transmission rod (6). The upper transmission rod (6) is connected to the lower transmission rod (7). The lower transmission rod (7) is connected to the gear set (8). The gear set (8) is connected to the worm gear assembly (9). The worm gear assembly (9) is connected to the sample stage (3).

[0026] In this specific embodiment, using a spatial rectangular coordinate system, the adapter (2) is used on the one hand to isolate the vacuum environment from the conventional environment, and on the other hand to provide a motion transmission interface for external signals and machines; the rotary machine (4) is used to provide motion power; the flexible shaft (5) is used to connect the rotary machine (4) and the upper transmission rod (6) and change the direction of motion, changing the direction of motion to the direction suitable for the upper transmission rod (6), thereby avoiding the problems of transmission shaft angle deviation and misalignment between the conventional environment and the vacuum environment. Stainless steel is generally used as the material; the external motion is generated by the rotary machine (4), and the motion is transmitted from the conventional environment into the vacuum environment by the flexible shaft (5), which then drives the upper transmission rod (6) to move. The upper transmission rod (6) drives the lower transmission rod (7) to move, and then the rotation amplitude is converted into the range suitable for the motion of the sample stage (3) through the gear set (8). Finally, the gear set ( 8) The worm gear assembly (9) drives the sample stage (3) to move in the pitch angle. The X, Y, Z and R1 directions are achieved by the placement of the external moving platform or sample holder. The transmission rod is generally made of molybdenum or titanium, which has good toughness and small deformation during thermal expansion and contraction. The gear set (8) is a spur gear set (8). The drive gear has a certain amount of mobility in the axial direction, which allows the pitch angle transmission module to be unaffected by thermal expansion and contraction in the variable temperature environment of 4K-350K, and also does not affect the movement in the X, Y, Z and R1 directions, thus making them independent of each other. Through the interaction between the above modules, it is realized that the GM refrigerator (1) can achieve multi-degree-of-freedom rotation under the premise of extremely low temperature of the sample holder (12), and the movement between each degree of freedom is independent and uninterrupted, and the pitch angle movement is smooth in a very large temperature range.

[0027] In a preferred embodiment, a thermally conductive extension rod is also included; one end of the thermally conductive extension rod is disposed on the secondary cold head, and the other end is connected to the sample stage (3).

[0028] In this preferred embodiment, the thermal extension rod is used to adapt to different experimental needs and is suitable for experimental needs under different conditions. Depending on the different experimental needs, only the corresponding thermal extension rod needs to be replaced, and there is no need to modify the cold head.

[0029] In a preferred embodiment, the thermally conductive extension rod is connected to the sample stage (3) by a braid; the material of the braid is selected from one or more of copper, gold or silver.

[0030] In this preferred embodiment, the braid is made of multiple metal wires twisted together in the shape of a hair braid. Since the heat-conducting extension rod cannot directly contact the sample stage (3) in space, the braid is used to connect the heat-conducting extension rod and the sample stage (3). One end of the braid is connected to one end of the heat-conducting extension rod, and the other end is connected to the sample stage (3), thereby dissipating heat. The material of the braid must have good thermal conductivity and good flexibility, so it is copper, gold, silver or other materials with the above properties.

[0031] In a preferred embodiment, such as Figure 2 As shown, the upper transmission rod (6) and the lower transmission rod (7) are connected by a coupling (10).

[0032] In this preferred embodiment, a coupling (10) is used to avoid the problem of misalignment between the upper transmission rod (6) and the lower transmission rod (7) during the movement process, thereby ensuring smooth rotation.

[0033] In a preferred embodiment, the system further includes a sleeve; the sleeve connects to the primary cold head; the sleeve encloses the secondary cold head; and a clamp support (11) is also included; the clamp support (11) is disposed on the upper transmission rod (6); the clamp support (11) is sleeved on the sleeve.

[0034] In this preferred embodiment, the sleeve is installed on the first-stage cold head through the mounting hole provided on the first-stage cold head. On the one hand, it provides support for the sample stage (3), and on the other hand, it acts as a cold screen to conduct the cold energy of the first-stage cold head to all the cold screens. The clamp support (11) has two functions: on the one hand, it provides sufficient strength support for the transmission rod to facilitate concentric adjustment, and on the other hand, it avoids the transmission rod from being separated from the sleeve, thereby reducing the heat conduction between the sleeve and the component that plays the role of transmission.

[0035] In a preferred embodiment, a support plate is further included; the support plate is fixed to the lower drive shaft by a bearing seat.

[0036] In this preferred embodiment, the support plate is used to fix the sample stage (3) and other devices, thereby enabling efficient management and saving space.

[0037] In a preferred embodiment, the sample stage (3) includes a triangular support, a shield (13), a shield door (14), a shield baffle (15), and a sample holder (12); the shield door (14) is provided with a measurement hole; the shield door (14) is installed on the shield (13), and the shield baffle (15) is installed on the shield (13); the shield baffle (15) is installed on the shield (13); the sample holder (12) and the triangular support are disposed inside the shield (13); the sample holder (12) is connected to the triangular support.

[0038] In this preferred embodiment, the shield (13), shield door (14), and shield baffle (15) are used to isolate thermal radiation. Generally, gold-plated oxygen-free copper sheets are used, but other materials that can provide good thermal insulation can also be used. The measuring hole on the shield door (14) is directly opposite the sample position of the sample holder (12). When in use, the sample is placed on the sample holder (12), the shield door (14) is opened, the sample holder (12) is placed on the tripod support, and then the shield door (14) is closed. At this time, the sample is directly opposite the measuring hole. In the formal experiment, the range of the sample exposed to thermal radiation can be minimized as much as possible.

[0039] In a preferred embodiment, such as Figure 4 As shown, a gold column (16) is provided on the sample stage (3).

[0040] In this preferred embodiment, the gold column (16) is made of pure gold. The gold column (16) is used to calibrate the Fermi level and is used as a reference sample to measure the actual sample, which is more convenient to use.

[0041] In a preferred embodiment, the sample stage (3) is provided with an accessory interface.

[0042] In this preferred embodiment, an accessory interface is provided on the sample stage (3), which can be used to expand the equipment and install modules such as sample parking platform, high temperature heating platform, and sample cleaving platform.

[0043] In a preferred embodiment, such as Figure 3 As shown, the shielding baffle (15) is inclined to the shielding cover (13) and the shielding cover door (14).

[0044] In this preferred embodiment, the shielding baffle (15) is inclined to the shielding cover (13) and the shielding cover door (14). During the movement of the sample holder (12), the inclined setting can ensure that the sample holder (12) is always within the range protected by the shielding baffle (15), thereby isolating heat radiation.

[0045] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-temperature sample holder with pitch and rotation function based on a GM refrigerator, comprising a refrigerator and a sample holder head, wherein the refrigerator includes a primary cold head and a secondary cold head, the secondary cold head being connected to the primary cold head, characterized in that: It also includes adapters, rotary machines, flexible shafts, upper transmission rods, lower transmission rods, gear sets, worm gear sets, sample stages, sleeves, clamp supports, heat-conducting extension rods, and support plates; The sample stage is used to place samples. The sample stage includes a triangular support, a shielding cover, a shielding cover door, a shielding baffle, and a sample holder. The shielding cover door is provided with a measuring hole, which is directly opposite the sample position on the sample holder. The shielding cover door is installed on the shielding cover, and the shielding baffle is installed on the shielding cover. The sample holder and the triangular support are disposed inside the shielding cover. The sample holder is connected to the triangular support. The adapter is provided with an external interface; the rotating mechanism is connected to the flexible shaft; the flexible shaft is made of stainless steel; the flexible shaft passes through the adapter via the external interface; the flexible shaft is connected to the upper transmission rod; the upper transmission rod is connected to the lower transmission rod; the lower transmission rod is connected to the gear set; The gear set is connected to the worm gear assembly; the worm gear assembly is connected to the sample stage; The upper and lower transmission rods are made of molybdenum or titanium. The gear set is a spur gear set. The drive gear of the gear set has a margin of movement in the axial direction, so that the low-temperature sample holder can maintain the pitch rotation function in a variable temperature environment of 4K-350K, and keep the movements in the X, Y, Z and R1 directions independent of each other. Here, Z is the opposite direction of gravity, X and Y are the X and Y directions of a spatial rectangular coordinate system established with the Z axis as the standard, and R1 is the angle between the first-stage cold head or the second-stage cold head and the horizontal plane. The clamp support is used to support the upper transmission rod; the clamp support is sleeved on the sleeve; The sleeve connects to the primary cold head; the sleeve encloses the secondary cold head; One end of the thermally conductive extension rod is disposed on the secondary cold head, and the other end is connected to the sample stage; The support plate is fixed to the lower drive shaft by a bearing seat.

2. A low-temperature sample holder with pitch and rotation function based on a GM refrigerator according to claim 1, characterized in that: The thermally conductive extension rod is connected to the sample stage via a flexible braid; the material of the flexible braid is selected from one or more of copper, gold, or silver.

3. A low-temperature sample holder with pitch and rotation function based on a GM refrigerator according to claim 1, characterized in that: The upper and lower transmission rods are connected by a coupling.

4. A low-temperature sample holder with pitch and rotation function based on a GM refrigerator according to claim 1, characterized in that: A gold pillar is set on the sample stage.

5. A low-temperature sample holder with pitch and rotation function based on a GM refrigerator according to claim 1, characterized in that: The sample stage is equipped with an accessory interface.

6. A low-temperature sample holder with pitch and rotation function based on a GM refrigerator according to claim 1, characterized in that: The shielding baffle is inclined to the shielding cover and the shielding cover door.

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