Extremely low temperature vacuum sample rod for 3He refrigerator

Abstract

The invention provides an extremely-low-temperature vacuum sample rod for a 3He refrigerator. The extremely-low-temperature vacuum sample rod comprises a sliding main pipe unit; the vacuum cavity unit comprises an outer pipe, a vacuum cavity formed in the outer pipe, a first vacuum suction opening used for vacuumizing the vacuum cavity, and a vacuum connecting flange arranged at one end of the vacuum cavity unit and used for being fixed to a valve connector of the 3He refrigerator. And the lower supporting rod and sample seat assembly comprises a lower supporting rod which is arranged in the vacuum cavity along the longitudinal axis direction of the vacuum cavity unit, and a sample seat which is arranged at one end, close to the vacuum connecting flange, of the lower supporting rod. The other end of the sliding main pipe unit extends into the vacuum cavity unit and communicates with the vacuum cavity in the mode that the sliding main pipe unit is connected with the vacuum cavity unit in an airtight mode, the other end of the lower supporting rod is fixed to the other end of the sliding main pipe unit, and the sliding main pipe unit is configured to be capable of moving in the vacuum cavity unit in a piston mode. The lower supporting rod and the sample seat are driven to move along the axial direction of the vacuum cavity unit.

Description

Technical Field

[0001] The present invention generally relates to the technical field of ultra-low temperature physics research equipment, and in particular to a method for 3 Ultra-low temperature vacuum sample holder of the He refrigerator. Background Art

[0002] With the deepening of condensed matter physics research, more and more quantum effects have been discovered by researchers, such as the quantum Hall effect. In addition, the discovery of two-dimensional graphene materials has also made the research of new two-dimensional materials a hot topic. The emergence of two-dimensional superconductivity, two-dimensional magnetism, and slip ferroelectricity have opened up new physical research topics. For these novel quantum research fields, ultra-low temperature precision electrical transport is the best research method for related topics and is an indispensable experimental technology in the field of cutting-edge condensed matter research. However, the development of ultra-low temperature scientific research equipment in China is still relatively slow, and there is an urgent need to develop ultra-low temperature vacuum sample rods, especially ultra-low temperature vacuum precision electrical transport measurement sample rods, to make up for the shortage of equipment in related fields. Summary of the invention

[0003] In view of the above problems, the present invention proposes a method for overcoming the above problems or at least partially solving the above problems. 3 The cryogenic vacuum sample holder of the He refrigerator.

[0004] One object of the present invention is to provide a 3 The He refrigerator's ultra-low temperature vacuum sample holder ensures the vacuum inside the sample holder. 3 And the normal operation of the refrigerator.

[0005] A further object of the present invention is to eliminate the influence of minute air leakage generated through the sliding portion when the sliding main body unit slides.

[0006] Another further object of the present invention is to improve the effectiveness of the sample rod in performing precise electrical transport measurements.

[0007] In particular, the present invention provides a method for 3 Ultra-low temperature vacuum sample holder for He refrigerator, including:

[0008] a sliding main unit, one end of which is sealed by a closure element;

[0009] A vacuum chamber unit, comprising:

[0010] External pipe;

[0011] a vacuum cavity formed in the outer tube;

[0012] A first vacuum extraction port, used to evacuate the vacuum chamber; and

[0013] The vacuum connection flange is provided at one end of the vacuum chamber unit and is used to 3 He refrigerator valve interface fixed; and

[0014] The lower support rod and sample holder assembly is arranged in the vacuum chamber and includes:

[0015] A lower support rod is arranged in the vacuum chamber along the longitudinal axis direction of the vacuum chamber unit; and

[0016] The sample holder is arranged at one end of the lower support rod close to the vacuum connection flange, and the lower support rod, the sample holder and the vacuum chamber unit form an inner and outer nested structure;

[0017] The other end of the sliding main unit extends into the vacuum chamber unit and communicates with the vacuum chamber body in a manner that the sliding main unit is airtightly connected to the vacuum chamber unit, the other end of the lower support rod is fixed to the other end of the sliding main unit, and the sliding main unit is configured to be able to move like a piston inside the vacuum chamber unit to drive the lower support rod and the sample holder to move along the longitudinal axis of the vacuum chamber unit.

[0018] Optionally, the vacuum chamber unit further comprises:

[0019] A vacuum isolation chamber is formed at the other end of the vacuum chamber unit;

[0020] The outer wall of the sliding main unit passes through the vacuum isolation chamber and forms a tight fit with the vacuum isolation chamber, so that the sliding main unit can move airtightly along the longitudinal axis of the vacuum chamber unit;

[0021] The vacuum isolation chamber is provided with a second vacuum extraction port for evacuating the vacuum isolation chamber.

[0022] Optionally, the vacuum isolation chamber comprises:

[0023] a top ring cover disposed at the end of the other end of the vacuum chamber unit; and

[0024] A bottom annular seal is spaced apart from the top annular cover along the longitudinal direction of the outer tube and fixed to the outer tube by welding, wherein the top annular cover, the bottom annular seal and the outer tube enclose a vacuum isolation chamber;

[0025] The vacuum isolation chamber also includes:

[0026] a support block filling the space between the top ring cover, the bottom annular seal, the outer tube and the outer wall of the sliding main tube unit, the top ring cover being fixed to the support block by a first fastener; and

[0027] Two O-type sealing rings are arranged on the inner side surface of the outer wall of the support block facing the sliding main unit in a manner of being spaced apart from each other along the longitudinal direction of the outer tube. The outer wall of the sliding main unit is covered by the O-type sealing ring to form a tight fit.

[0028] Optionally, the sliding main unit includes a connecting pipe with a hole fixed at the other end thereof, so that the interior of the sliding main unit is connected to the vacuum chamber through the hole;

[0029] The other end of the lower support rod is provided with a connecting flange;

[0030] The connecting pipe with holes is connected to the connecting flange through a second fastener.

[0031] Optionally, the ultra-low temperature vacuum sample holder further comprises:

[0032] An upper support rod is arranged inside the sliding main body unit along the longitudinal axis direction of the sliding main body unit to form an inner-outer nested structure with the sliding main body unit; and

[0033] One or more radiation-proof support metal sheets are arranged along the longitudinal direction of the upper support rod and are used to position the upper support rod in the sliding main unit.

[0034] Optionally, the cryogenic vacuum sample holder further comprises a head wiring unit as the closing element, which comprises:

[0035] A lead interface for leading out a measurement lead from the sample holder and passing through the inside of the vacuum chamber unit and the sliding main unit to connect to an external measurement device; and

[0036] A seal is used to seal the lead interface.

[0037] Optionally, the head wiring unit further includes:

[0038] A head body, on which the lead interface is arranged; and

[0039] a top cover plate connected to the head body by a third fastener;

[0040] A fixing ring is provided at one end of the sliding main unit;

[0041] The head body is airtightly fixed to the fixing ring by a fourth fastener so that the head wiring unit seals the sliding main body unit as a closing element, and the interior of the head wiring unit is evacuated through the interior of the sliding main body unit via the vacuum chamber unit;

[0042] A support rod fixing groove is also provided in the head body, which is configured to allow one end of the upper support rod to be inserted therein to fix the upper support rod.

[0043] Optionally, the lower support rod and sample holder assembly further comprises:

[0044] One or more radiation-proof metal sheets are arranged in the vacuum chamber unit along the longitudinal direction of the lower support rod;

[0045] The heat sink metal flange is arranged in the vacuum chamber and penetrates the lower support rod, and is configured to utilize 3 The specific cooling part of the He refrigerator provides cooling for the measuring lead; and

[0046] One or more wiring grooves are arranged near the heat sink metal flange or other positions in the vacuum chamber, and are used to guide or transfer the measurement leads, wherein the measurement leads are coupled to the heat sink metal flange via or without the wiring grooves.

[0047] Optionally, the lower support rod and sample holder assembly further comprises:

[0048] One or more heat-insulating filling blocks are disposed in the vacuum chamber and on the lower support rod passing through between the heat sink metal flange and the sample holder; and

[0049] The filter is arranged in the vacuum chamber and located between the heat sink metal flange and the sample holder, and is connected to the measuring lead wire, and is used for filtering the signal transmitted by the measuring lead wire.

[0050] Optionally, the outer tube of the vacuum chamber unit and the sliding main tube unit are made of thin-walled metal tubes;

[0051] The measuring leads include leads with various functions, and each lead with a certain function is wrapped by a metal braided mesh.

[0052] The present invention provides 3 The ultra-low temperature vacuum sample holder of the He refrigerator is a long rod-shaped entity formed by a sliding main unit and a vacuum chamber unit. The lower support rod and the sample holder are arranged inside the vacuum chamber unit in an inner-outer nested manner. When in use, the vacuum chamber unit is fixed to the 3 The upper valve interface of the He refrigerator, the sliding main unit moves up and down like a piston inside the vacuum chamber unit to drive the lower support rod and the sample holder to move up and down, so as to realize the sample holder 3 The He refrigerator is transferred from the room temperature end to the low temperature end. The vacuum chamber is evacuated through the first vacuum port to ensure the vacuum inside the vacuum chamber and the sliding main unit connected to the gas, avoiding 3 Other gases enter the He refrigerator, thus ensuring good 3 And the normal operation of the refrigerator.

[0053] Furthermore, the vacuum chamber unit of the ultra-low temperature vacuum sample rod provided by the present invention is provided with a vacuum isolation chamber at one end close to the sliding main unit, and a second vacuum extraction port is provided on the vacuum isolation chamber. The outer wall of the sliding main unit passes through the vacuum isolation chamber and forms a tight fit with the two O-rings of the vacuum isolation chamber. Through this configuration, it is ensured that when there is refrigerant gas inside the vacuum chamber unit, when the sliding main unit slides, the trace leakage generated through the sliding part can be extracted in the vacuum isolation chamber.

[0054] Furthermore, in the ultra-low temperature vacuum sample holder provided by the present invention, the 3 The refrigeration adsorption pump of the He refrigerator structure and the 1K cell refrigeration part provide specific positions corresponding to the refrigeration power parts, and set corresponding heat sink metal flanges. Thermal contact is used to cool the measurement leads led down from room temperature, reduce system heat leakage and reduce thermal noise.

[0055] In addition, the outer tube of the vacuum chamber unit and the sliding main unit are both made of thin-walled metal tubes, so that the measuring leads are well shielded from external electromagnetic noise from the beginning to the end inside the metal pipes of the sliding main unit and the vacuum chamber unit. In addition, electromagnetic shielding isolation can be achieved between measuring leads with different functions (for example, different functional leads of large signal power circuits and precision small signal measurement circuits) through metal braided mesh sleeves. Thus, the conditions for the ultra-low temperature vacuum sample rod to perform precise electrical transport measurements are guaranteed, thereby improving the effect of the sample rod in performing precise electrical transport measurements.

[0056] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below.

[0057] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0059] Figure 1 is a schematic diagram of the overall structure of a cryogenic vacuum sample holder according to an embodiment of the present invention;

[0060] Figure 2A schematic three-dimensional model perspective view of a cryogenic vacuum sample holder according to an embodiment of the present invention;

[0061] Figure 3 for Figure 1 An enlarged schematic diagram of the head wiring unit of the extremely low temperature vacuum sample holder is shown;

[0062] Figure 4 for Figure 1 A partially enlarged schematic diagram of an upper support rod and a sliding main unit of an ultra-low temperature vacuum sample holder is shown;

[0063] Figure 5 for Figure 1 An enlarged schematic diagram of a portion of the sliding main unit of the extremely low temperature vacuum sample holder, the vacuum chamber unit, the lower support rod and the sample holder assembly is shown;

[0064] Figure 6 Schematic diagram of the structure of a vacuum isolation chamber of a cryogenic vacuum sample holder according to an embodiment of the present invention. DETAILED DESCRIPTION

[0065] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0066] In order to solve the above technical problems, the embodiment of the present invention provides a 3 The cryogenic vacuum sample holder of the He refrigerator.

[0067] The extremely low temperature in this article may refer to a temperature below 4.2K, such as 1.2K or even 0.3K.

[0068] Figure 1 is a schematic diagram of the overall structure of a cryogenic vacuum sample holder 100 according to an embodiment of the present invention. Figure 2 FIG. 1 is a schematic three-dimensional perspective view of a cryogenic vacuum sample holder 100 according to an embodiment of the present invention.

[0069] Figure 3 for Figure 1 The enlarged schematic diagram of the head wiring unit 140 of the cryogenic vacuum sample holder 100 is shown in FIG. Figure 4 for Figure 1 The upper support rod 112 and the sliding main unit 110 of the ultra-low temperature vacuum sample holder 100 are partially enlarged schematic diagrams. Figure 5 for Figure 1FIG. 1 is an enlarged schematic diagram of a portion of the sliding main unit 110 of the cryogenic vacuum sample holder 100 , a vacuum chamber unit 120 , a lower support rod and a sample holder assembly 130 , Figure 6 FIG. 1 is a schematic structural diagram of a vacuum isolation chamber 125 of a cryogenic vacuum sample holder 100 according to an embodiment of the present invention.

[0070] See also Figure 1 and Figure 2 As shown, in one embodiment, the cryogenic vacuum sample holder 100 of the present invention generally includes a sliding main tube unit 110, a vacuum chamber unit 120, and a lower support rod and sample holder assembly 130. One end of the sliding main tube unit 110 (also referred to as the top end of the sliding main tube unit 110) is sealed by a sealing element. The various parts of the cryogenic vacuum sample holder 100 are described in detail below in conjunction with the accompanying drawings.

[0071] See also Figure 1 and Figure 5 As shown, in some embodiments, the vacuum chamber unit 120 includes: an outer tube 121; a vacuum chamber 122 formed in the outer tube 121; a first vacuum port 123 for evacuating the vacuum chamber 122; and a vacuum connection flange 124, which is disposed at one end of the vacuum chamber unit 120 (also referred to as the bottom end of the vacuum chamber unit 120) and is used to connect with the outer tube 121; a vacuum chamber 122 formed in the outer tube 121; a first vacuum port 123 for evacuating the vacuum chamber 122; and a vacuum connection flange 124, which is disposed at one end of the vacuum chamber unit 120 (also referred to as the bottom end of the vacuum chamber unit 120) and is used to 3 The valve interface of the He refrigerator is fixed. The lower support rod and sample holder assembly 130 is arranged in the vacuum chamber 122 of the vacuum chamber unit 120, and includes: a lower support rod 131, which is arranged in the vacuum chamber 122 along the longitudinal axis direction of the vacuum chamber unit 120; and a sample holder 132, which is arranged at one end of the lower support rod 131 close to the vacuum connection flange 124 (also referred to as the bottom end of the lower support rod 131). The lower support rod 131 and the sample holder 132 form an inner and outer nested structure with the vacuum chamber unit 120.

[0072] The other end of the sliding main tube unit 110 (also referred to as the bottom end of the sliding main tube unit 110) extends into the vacuum chamber unit 120 from the other end of the vacuum chamber unit 120 (also referred to as the top end of the vacuum chamber unit 120) in a manner that the sliding main tube unit 110 is airtightly connected to the vacuum chamber unit 120 and communicates with the vacuum chamber body 122, the other end of the lower support rod 131 (also referred to as the top end of the lower support rod 131) is fixed to the other end of the sliding main tube unit 110, and the sliding main tube unit 110 is configured to be piston-movable inside the vacuum chamber unit 120 to drive the lower support rod 131 and the sample holder 132 to move along the longitudinal axis direction of the vacuum chamber unit 120. Since the other end of the sliding main tube unit 110 is in gas communication with the vacuum chamber body 122 of the vacuum chamber unit 120, the interior of the sliding main tube unit 110 can be evacuated via the vacuum chamber unit 120.

[0073] The embodiment of the present invention provides 3 The extremely low temperature vacuum sample holder 100 of the He refrigerator is formed into a long rod-shaped entity by a sliding main unit 110 and a vacuum chamber unit 120. The lower support rod 131 and the sample holder 132 are arranged inside the vacuum chamber unit 120 in an inner-outer nested manner. When in use, the vacuum chamber unit 120 is fixed to the vacuum chamber unit 120 by a vacuum connection flange 124. 3 The upper valve interface of the He refrigerator, the sliding main unit 110 moves up and down in the piston-like manner inside the vacuum chamber unit 120 to drive the lower support rod 131 and the sample holder 132 to move up and down, thereby realizing the sample holder 132 3 The He refrigerator is transferred from the room temperature end to the low temperature end. The vacuum chamber 122 is evacuated through the first vacuum port 123 to ensure the vacuum inside the vacuum chamber 122 and the sliding main unit 110 connected to the gas therewith, so as to avoid 3 Other gases enter the He refrigerator, thus ensuring good 3 And the normal operation of the refrigerator.

[0074] In some embodiments, the lower support rod 131 may be composed of a plurality of, for example, 2 to 3, thin-walled metal tubes (e.g., stainless steel tubes). These metal tubes may be evenly arranged around the central axis of the outer tube 121 of the vacuum chamber unit 120, for example, for 2 metal tubes, they may be arranged in a centrally symmetrical manner; for 3 metal tubes, they may be arranged in an equilateral triangle.

[0075] Continue to see Figure 1 and Figure 5 In some embodiments, the vacuum chamber unit 120 may further include a vacuum isolation chamber 125 formed at the other end of the vacuum chamber unit 120. The outer wall of the sliding main tube unit 110 passes through the vacuum isolation chamber 125 and forms a tight fit with the vacuum isolation chamber 125, so that the sliding main tube unit 110 can move airtightly along the longitudinal axis direction of the vacuum chamber unit 120. The vacuum isolation chamber 125 is also provided with a second vacuum extraction port 127 for evacuating the vacuum isolation chamber 125.

[0076] See also Figure 6 As shown, in some embodiments, the vacuum isolation chamber 125 includes: a top ring cover 1251, which is arranged at the end of the other end of the vacuum chamber unit 120; and a bottom annular seal 1252, which is arranged with the top ring cover 1251 in the longitudinal direction of the outer tube 121 and fixed to the outer tube 121 by welding. The top ring cover 1251, the bottom annular seal 1252 and the outer tube 121 enclose the vacuum isolation chamber 125.

[0077] The vacuum isolation chamber 125 may further include: a support block 1253, which is filled in the space between the top ring cover 1251, the bottom annular seal 1252, the outer tube 121 and the outer wall of the sliding main tube unit 110 (i.e., the internal vacuum chamber 1255). In this way, the center of the support block 1253 leaves an axial cylindrical area for the sliding main tube unit 110 to slide. The top ring cover 1251 is fixed to the support block 1253 by a first fastener (e.g., a screw). The sliding main tube unit 110 slides through the center hole of the top ring cover 1251, the axial cylindrical area of ​​the support block 1253 and the center hole of the bottom annular seal 1252. The material of the support block 1253 may be, for example, polytetrafluoroethylene.

[0078] The vacuum isolation chamber 125 may further include: two O-rings 1254, which are arranged on the inner surface of the outer wall of the support block 1253 facing the sliding main tube unit 110 in a manner of being arranged at intervals along the longitudinal direction of the outer tube 121, and the outer wall of the sliding main tube unit 110 is covered by the O-rings 1254 to form a tight fit. In this way, the gap between the support block 1253 and the sliding main tube unit 110 can be evacuated into a vacuum state through the second vacuum extraction port 127, and sealed by the two O-rings 1254, so as to ensure that the air leakage generated during the sliding process can be evacuated in time.

[0079] In some embodiments, the support block 1253 may include a plurality of sub-support blocks 1253 closely arranged along the axial direction of the outer tube 121, each O-ring 1254 may be embedded in a gap between two sub-support blocks 1253, and the O-ring 1254 may partially protrude from the inner surface of the outer wall of the support block 1253 facing the sliding main tube unit 110. In other alternative embodiments, two corresponding grooves may be formed on the inner surface of the outer wall of the support block 1253 facing the sliding main tube unit 110, and two O-rings 1254 may be respectively installed in the two grooves, and the O-ring 1254 may partially protrude from the inner surface of the outer wall of the support block 1253 facing the sliding main tube unit 110.

[0080] The vacuum chamber unit 120 of the cryogenic vacuum sample holder 100 provided in the embodiment of the present invention is provided with a vacuum isolation chamber 125 at one end close to the sliding main unit 110, and a second vacuum extraction port 127 is provided on the vacuum isolation chamber 125. The outer wall of the sliding main unit 110 passes through the vacuum isolation chamber 125 and forms a tight fit with the two O-rings 1254 of the vacuum isolation chamber 125. Through this configuration, it is ensured that when there is refrigerant gas inside the vacuum chamber unit 120, when the sliding main unit 110 slides, the trace gas leakage generated through the sliding part can be extracted in the vacuum isolation chamber 125, so as to prevent external gas from entering the vacuum chamber body 122 of the vacuum chamber unit 120 and interfering with the refrigeration.

[0081] Continue to see Figure 5 In some embodiments, the sliding main tube unit 110 includes a perforated connecting tube 111 fixed (e.g., by welding) at the other end (i.e., the bottom end) thereof, so that the interior of the sliding main tube unit 110 is connected to the vacuum chamber 122 of the vacuum chamber unit 120 through the holes of the perforated connecting tube 111. The holes may be distributed on the peripheral wall or the bottom wall of the perforated connecting tube 111.

[0082] The other end (i.e., the top end) of the lower support rod 131 may be provided with a connection flange 133. The perforated connection pipe 111 and the connection flange 133 may be connected by a second fastener (such as a screw), thereby achieving a fixed connection between the lower support rod 131 and the sliding main unit 110.

[0083] See also Figure 1 and Figure 4 As shown, in some embodiments, the cryogenic vacuum sample holder 100 may further include an upper support rod 112. The upper support rod 112 is disposed in the sliding main body unit 110 along the longitudinal axis direction of the sliding main body unit 110 to form an inner-outer nested structure with the sliding main body unit 110. The upper support rod 112 may be composed of a plurality of, for example, three, thin-walled metal tubes (for example, stainless steel tubes). These metal tubes may be evenly arranged around the central axis of the sliding main body unit 110, for example, the three metal tubes may be arranged in an equilateral triangle.

[0084] Optionally, the cryogenic vacuum sample holder 100 may further include one or more radiation-proof support metal sheets 113, which are arranged along the longitudinal direction of the upper support rod 112 and are used to position the upper support rod 112 in the sliding main unit 110. The metal sheet may be, for example, a steel sheet.

[0085] See also Figure 1 and Figure 3 In some embodiments, the cryogenic vacuum sample rod 100 may further include a head wiring unit 140. The head wiring unit 140 includes: a lead interface 141, which is used to lead out the measurement leads (such as low-temperature measurement lines) from the sample holder 132 and passing through the vacuum chamber unit 120 and the sliding main unit 110 to connect to an external measurement device; and a seal (not shown in the figure) for sealing the lead interface 141. The lead interface 141 can be formulated according to the specifications of the vacuum sealing joint actually used. The seal can be an O-ring, which matches the threaded cap to seal the lead interface 141.

[0086] Continue to see Figure 3In some embodiments, the head wiring unit 140 may further include: a head body 142, on which the lead interface 141 is disposed; and a top cover plate 143, which is connected to the head body 142 via a third fastener (e.g., a screw). The connection between the top cover plate 143 and the head body 142 may also be sealed via a sealing element (e.g., an O-ring, not shown in the figure).

[0087] Further, the one end (i.e., the top end) of the sliding main body unit 110 is provided (e.g., by welding) with a fixing ring 114. The head body 142 is airtightly fixed to the fixing ring 114 of the sliding main body unit 110 by a fourth fastener (e.g., a top screw), so that the head wiring unit 140 seals the sliding main body unit 110 as a closing element, and the interior of the head wiring unit 140 can be evacuated through the interior of the sliding main body unit 110 via the vacuum chamber unit 120. Specifically, the airtight fixation between the head body 142 and the sliding main body unit 110 is sealed by a seal 115, which can be an O-ring, and is provided in a groove reserved on the head body 142 and / or the fixing ring 114.

[0088] In some embodiments, a support rod fixing groove 144 is also provided in the head body 142 of the sliding main unit 110 , which is configured to allow one end of the upper support rod 112 to be inserted therein to fix the upper support rod 112 , thereby achieving convenient and accurate positioning of the upper support rod 112 .

[0089] See also Figure 1 and Figure 5 As shown, in some embodiments, the lower support rod and sample holder assembly 130 may further include one or more radiation-proof metal sheets 134, which are arranged in the vacuum chamber unit 120 along the longitudinal direction of the lower support rod 131. The metal sheet may be, for example, a steel sheet.

[0090] In some embodiments, the lower support rod and sample holder assembly 130 may further include a heat sink metal flange 135 disposed in the vacuum chamber 122 and passing through the lower support rod 131, and configured to utilize 3 The cooling capacity provided by the specific cooling part of the He refrigerator cools the measuring lead. Specifically, 3 The specific refrigeration part of the He refrigerator may be a refrigeration adsorption pump, a 1K cell refrigeration part, etc. The heat sink metal flange 135 may be made of a metal with good thermal conductivity, such as copper.

[0091] In this embodiment, by connecting the vacuum chamber unit 120 with the 3The refrigeration adsorption pump of the He refrigerator structure and the 1K cell refrigeration part provide specific positions corresponding to the refrigeration power parts, and set the corresponding heat sink metal flange 135. The thermal contact is used to cool the measurement leads from room temperature, reduce system heat leakage and thermal noise, and provide conditions for precise low-temperature measurement.

[0092] In some embodiments, the lower support rod and sample holder assembly 130 may further include one or more wiring grooves 136 disposed near the heat sink metal flange 135 or at other locations within the vacuum chamber 122 for guiding or transferring measurement leads, wherein the measurement leads are coupled to the heat sink metal flange 135 via or without the wiring grooves 136 .

[0093] Specifically, according to the specific situation of the measurement lead connection, a wiring groove 136 is configured near the heat sink metal flange 135, and the measurement lead is coupled to the heat sink metal flange 135 through the wiring groove 136, or the wiring groove 136 is not used for connection, and the lead is directly coupled to the copper flange, and the radiation-proof metal sheet 134 is used to fix the lower support rod 131 at the remaining positions.

[0094] Continue to see Figure 1 and Figure 5 In some embodiments, the lower support rod and sample holder assembly 130 may further include: one or more heat insulating filling blocks 137, which are arranged in the vacuum chamber 122 and penetrate the lower support rod 131 between the heat sink metal flange 135 and the sample holder 132. The heat insulating filling block 137 may be made of a polymer material. By arranging the heat insulating filling block 137 between the heat sink metal flange 135 and the low temperature sample holder 132, the 3 Heat leakage ensures the cooling effect.

[0095] In some embodiments, the lower support rod and sample holder assembly 130 may further include: a filter 138 disposed in the vacuum chamber 122 and between the heat sink metal flange 135 and the sample holder 132 , and connected to the measurement lead for filtering the signal transmitted by the measurement lead.

[0096] The measurement lead wire can be formed by connecting multiple sections of low-temperature twisted pair wires from the lead wire interface 141 at the head of the sample rod 100 to the low-temperature sample holder 132 at the bottom. By performing heat sinking in key refrigeration parts (such as refrigeration adsorption pumps and 1K cell refrigeration parts), a low-temperature section filter 138 can be additionally added to provide good precision low-temperature measurement effects.

[0097] In some embodiments, the outer tube 121 of the vacuum chamber unit 120 and the sliding main tube unit 110 are made of thin-walled metal tubes (e.g., stainless steel tubes). Since the measuring lead is inside the metal tubes of the sliding main tube unit 110 and the vacuum chamber unit 120 from beginning to end, good external electromagnetic noise shielding can be obtained.

[0098] Optionally, in some embodiments, the measurement leads include multiple leads with different functions, and each lead with a function is wrapped by a metal braided mesh (not shown in the figure). Electromagnetic shielding isolation is achieved between the measurement leads with different functions (for example, different functional leads of a large signal power circuit and a precision small signal measurement circuit) through the metal braided mesh.

[0099] Through the above configuration, the conditions for the ultra-low temperature vacuum sample holder 100 to perform precise electrical transport measurements can be guaranteed, thereby improving the effect of the sample holder 100 performing precise electrical transport measurements.

[0100] Combine the following Figure 1 The illustrated embodiment specifically illustrates the structure and working method of the cryogenic vacuum sample holder 100 of the present invention.

[0101] The sample rod 100 includes multiple units and an inner and outer nested structure. The vacuum chamber unit 120 will be fixed to the refrigerator through the vacuum connecting flange 124 and remain stationary. The head wiring unit 140, the upper and lower support rods 131 and the sliding main pipe unit 110 are integrated through a variety of fixing methods, including: the head wiring unit 140 is fixed to the sliding main pipe unit 110 through the main pipe fixing ring 114 by means of a top screw; the upper support rod 112 is fixed to the head wiring unit 140 by means of a screw through the support rod fixing groove 144 inside the head body 142; the sliding main pipe unit 110 is fixed to the lower support rod 131 by means of a perforated connecting tube 111 and a connecting flange 133 by means of a top screw. The long rod-type entity formed in this way allows the sliding main pipe unit 110 to move like a piston inside the vacuum chamber unit 120, thereby realizing the low-temperature sample holder 132 in 3 The vacuum chamber unit 120 is fixed to the room temperature end of the He refrigerator by the vacuum connection flange 124. 3 The valve interface on the upper part of the He refrigerator can be used to perform vacuum pumping operation through the first vacuum pumping port 123 and the second vacuum pumping port 127 to ensure the vacuum inside the vacuum chamber 122 and the sliding main unit 110 that can be ventilated therewith, thereby avoiding 3 The double O-ring vacuum isolation chamber 125 ensures that when there is refrigerant gas inside the vacuum chamber unit 120 and the sliding main unit 110 slides, the trace gas leakage generated through the sliding part can be drawn away in the isolation chamber.

[0102] During operation, the chip to be tested is first inserted into the matching low-temperature sample holder 132, and then the internal low-temperature measurement lead wire is introduced into the head wiring unit 140 and led out from the corresponding lead interface 141, and then connected to the measurement equipment through the external measurement line. Then, the sliding main unit 110 is clamped on the upper part of the double O-ring vacuum isolation chamber 125 to prevent it from sliding relative to the vacuum chamber unit 120, and then the sample rod 100 is fixed to the vacuum connection flange 124. 3 The upper interface of the He refrigerator is opened, and the refrigerator interface valve is kept closed. The cavity of the vacuum chamber unit 120 and the vacuum isolation chamber 125 are evacuated through the first vacuum interface and the second vacuum interface. When the vacuum value reaches the requirements of the refrigerator system, the vacuum chamber 122 is stopped from being evacuated and the vacuum isolation chamber 125 is kept evacuated. The refrigerator interface valve is opened, and the fixing of the sliding main unit 110 is released, so that the sliding main unit 110 slowly slides deep into the refrigerator until the low-temperature sample holder 132 reaches the low-temperature end. At this time, the head wiring unit 140 just reaches the top of the vacuum chamber unit 120, preventing the sliding main unit 110 from sliding further down, and at the same time, the vacuum isolation chamber 125 is stopped from being evacuated, and then the low-temperature measurement experiment can be carried out. Finally, after the measurement is completed, the vacuum isolation chamber 125 is evacuated again, and the sliding main unit 110 slowly slides up to the room temperature end, and the refrigerator interface valve is closed. After the sample rod 100 is completely warmed up, the connection between the sample rod 100 and the refrigerator can be disconnected to retrieve the sample.

[0103] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0104] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A method for 3 Ultra-low temperature vacuum sample holder for He refrigerator, including: a sliding main unit, one end of which is sealed by a closure element; A vacuum chamber unit, comprising: External pipe; a vacuum chamber formed in the outer tube; A first vacuum port, used to evacuate the vacuum chamber; and A vacuum connection flange is provided at one end of the vacuum chamber unit and is used for connecting with the 3 He refrigerator valve interface fixed; and The lower support rod and sample holder assembly is arranged in the vacuum chamber and comprises: a lower support rod, arranged in the vacuum chamber along the longitudinal axis direction of the vacuum chamber unit; and A sample holder is arranged at one end of the lower support rod close to the vacuum connection flange, and the lower support rod, the sample holder and the vacuum chamber unit form an inner-outer nested structure; The other end of the sliding main unit extends into the vacuum chamber unit and communicates with the vacuum chamber body in a manner that the sliding main unit is airtightly connected to the vacuum chamber unit, and the other end of the lower support rod is fixed to the other end of the sliding main unit, and the sliding main unit is configured to be piston-like movable inside the vacuum chamber unit to drive the lower support rod and the sample holder to move along the longitudinal axis direction of the vacuum chamber unit.

2. The cryogenic vacuum sample holder according to claim 1, wherein: The vacuum chamber unit further comprises: a vacuum isolation chamber formed at the other end of the vacuum chamber unit; The outer wall of the sliding main unit passes through the vacuum isolation chamber and forms a tight fit with the vacuum isolation chamber, so that the sliding main unit can move airtightly along the longitudinal axis of the vacuum chamber unit; The vacuum isolation chamber is provided with a second vacuum outlet for evacuating the vacuum isolation chamber.

3. The cryogenic vacuum sample holder according to claim 2, wherein: The vacuum isolation chamber comprises: a top ring cover disposed at the distal end of the other end of the vacuum chamber unit; and A bottom annular seal is arranged with a spacing from the top annular cover along the longitudinal direction of the outer tube and fixed to the outer tube by welding, wherein the top annular cover, the bottom annular seal and the outer tube enclose the vacuum isolation chamber; The vacuum isolation chamber also includes: a support block filling a space between the top ring cover, the bottom annular seal, the outer tube, and an outer wall of the sliding main tube unit, the top ring cover being fixed to the support block by a first fastener; and Two O-rings are arranged on the inner surface of the outer wall of the support block facing the sliding main unit in a manner of being spaced apart from each other in the longitudinal direction of the outer tube. The outer wall of the sliding main unit is covered by the O-rings to form a tight fit.

4. The cryogenic vacuum sample holder according to claim 1, wherein: The sliding main pipe unit includes a connecting pipe with a hole fixed at the other end thereof, so that the interior of the sliding main pipe unit is connected with the vacuum chamber through the hole; The other end of the lower support rod is provided with a connecting flange; The perforated connecting pipe is connected to the connecting flange via a second fastener.

5. The cryogenic vacuum sample holder according to claim 1, further comprising: An upper support rod is arranged inside the sliding main body unit along the longitudinal axis direction of the sliding main body unit to form an inner-outer nested structure with the sliding main body unit; as well as One or more radiation-proof support metal sheets are arranged along the longitudinal direction of the upper support rod and are used to position the upper support rod in the sliding main unit.

6. The cryogenic vacuum sample holder according to claim 5, further comprising a head wiring unit as the closing element, comprising: A lead interface, used to lead out a measurement lead from the sample holder and through the inside of the vacuum chamber unit and the sliding main unit, so as to access an external measurement device; as well as A sealing member is used to seal the lead interface.

7. The cryogenic vacuum sample holder according to claim 6, wherein: The head wiring unit also includes: a head body, the lead interface being arranged on the head body; and a top cover plate connected to the head body by a third fastener; The one end of the sliding main unit is provided with a fixing ring; The head body is airtightly fixed to the fixing ring by a fourth fastener, so that the head wiring unit seals the sliding main pipe unit as the closing element, and the interior of the head wiring unit is evacuated through the interior of the sliding main pipe unit via the vacuum chamber unit; The head body is also provided with a support rod fixing groove, which is configured to allow one end of the upper support rod to be inserted therein to fix the upper support rod.

8. The cryogenic vacuum sample holder according to claim 6, wherein: The lower support rod and sample holder assembly further comprises: One or more radiation-proof metal sheets are arranged in the vacuum chamber unit along the longitudinal direction of the lower support rod; The heat sink metal flange is arranged in the vacuum chamber and penetrates the lower support rod, and is configured to utilize the 3 The specific refrigeration part of the He refrigerator provides cooling for the measuring lead; and One or more wiring grooves are arranged near the heat sink metal flange or at other positions in the vacuum chamber, and are used to guide or transfer the measurement leads, wherein the measurement leads are coupled to the heat sink metal flange via or without the wiring grooves.

9. The cryogenic vacuum sample holder according to claim 8, wherein: The lower support rod and sample holder assembly further comprises: One or more heat-insulating filling blocks are disposed in the vacuum chamber and penetrate the lower support rod between the heat sink metal flange and the sample holder; and The filter is arranged in the vacuum chamber and located between the heat sink metal flange and the sample holder, and is connected to the measuring lead, and is used for filtering the signal transmitted by the measuring lead.

10. The cryogenic vacuum sample holder according to claim 6, wherein: The outer tube of the vacuum chamber unit and the sliding main tube unit are made of thin-walled metal tubes; The measuring leads include leads with multiple different functions, and each lead with a different function is wrapped by a metal braided mesh sleeve.

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