WO2013125471A1 - Source de refroidissement pour système de refroidissement à circulation, et microscope ionique utilisant cette source - Google Patents

Source de refroidissement pour système de refroidissement à circulation, et microscope ionique utilisant cette source Download PDF

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Publication number
WO2013125471A1
WO2013125471A1 PCT/JP2013/053789 JP2013053789W WO2013125471A1 WO 2013125471 A1 WO2013125471 A1 WO 2013125471A1 JP 2013053789 W JP2013053789 W JP 2013053789W WO 2013125471 A1 WO2013125471 A1 WO 2013125471A1
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WIPO (PCT)
Prior art keywords
heat exchanger
vacuum
stage heat
cooling system
cryogenic refrigerator
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PCT/JP2013/053789
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English (en)
Japanese (ja)
Inventor
田中　弘之
佐保　典英
松田　和也
川浪　義実
Original Assignee
株式会社 日立ハイテクノロジーズ
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Publication of WO2013125471A1 publication Critical patent/WO2013125471A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/20—Means for supporting or positioning the objects or the material; Means for adjusting diaphragms or lenses associated with the support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/002—Cooling arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/20—Positioning, supporting, modifying or maintaining the physical state of objects being observed or treated
    • H01J2237/2001—Maintaining constant desired temperature

Definitions

  • the present invention relates to a circulating cooling system using a refrigerant cooled to a cryogenic temperature by a cryogenic refrigerator and an ion microscope using the same in order to cool an object to be cooled to a cryogenic temperature.
  • GM Gifford McMahon
  • pulse tube refrigerators As commercially available refrigerators. Since these generate large vibrations from the cryogenic refrigerator itself, it is difficult to apply them to cooling ultra-low vibration devices such as ion microscopes.
  • the cryogenic refrigerator that has the lowest vibration in the market today is a Stirling refrigerator.
  • the compressor In this Stirling refrigerator, the compressor is placed opposite to reduce vibration due to the compressor operation, and a mechanism that applies a reaction force in the opposite phase to the reciprocating motion of the displacer (piston) is provided. The vibration of the head is reduced.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. 2011-14245 (Patent Document 1) is a technique related to a circulating cooling system of an ion microscope.
  • a refrigerator that cools the gas field ion source is installed independently of the ion microscope main body, and the gas field ion source is installed between the gas field ion source and the refrigerator.
  • Cryogenic refrigerators used for circulating cooling need regular maintenance.
  • a GM refrigerator has been used.
  • internal wear parts could be replaced without removing the housing of the GM refrigerator, which is a part of the vacuum vessel.
  • the cryogenic refrigerator is temporarily stopped, the worn parts are replaced, or the cryogenic refrigerator itself is replaced. Since the equipment cannot be used while the cryogenic refrigerator is stopped, a reduction in maintenance time is required.
  • it is necessary to break the vacuum, and the countercurrent heat exchanger having a large heat capacity disposed in the vacuum vessel must be heated to room temperature. Therefore, there is a problem that it takes time to raise and re-cool the countercurrent heat exchanger, and the maintenance time is prolonged.
  • a vacuum vessel includes a first vacuum tank including the stage heat exchanger, and a second counter including the counterflow heat exchanger.
  • the vacuum chamber is separated by a vacuum partition.
  • Sectional drawing which shows the structure of the circulating cooling system in the Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure of the circulation cooling system in the Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure before removing the cryogenic refrigerator in the Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure at the time of cryogenic refrigerator removal in the Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure of the circulation cooling system in another Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure of the circulation cooling system at the time of removing the cryogenic refrigerator in another Example of this invention.
  • Sectional drawing which shows the structure which shows the circulating cooling system in the 3rd Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure of the circulation cooling system in the 3rd Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure of the cooling system before removing the refrigerator in the 3rd Example of this invention.
  • Detailed sectional drawing which shows the refrigerator attachment / detachment part structure of the cooling system at the time of cryogenic refrigerator removal in the 3rd Example of this invention.
  • Sectional drawing which shows the structure of the circulating cooling system in the 4th Example of this invention.
  • Sectional drawing which shows the structure of the system at the time of refrigerator removal in the 4th Example of this invention.
  • Sectional drawing which shows the detail of the structure of a heat insulation vacuum wall.
  • Sectional drawing which shows the detail of the structure of a stage heat exchanger. Sectional drawing of an ion microscope and a cooling system.
  • a technology for cooling a refrigerant typified by helium gas to a cryogenic temperature and transporting the refrigerant to cool the device is applied to various systems.
  • it is effective in conditions where it is difficult to directly connect a refrigerator, for example, in a strong magnetic field environment or in a system where vibration of the refrigerator is a problem.
  • the present invention can be applied to a nuclear magnetic resonance (NMR) apparatus, an MRI (Magnetic Resonance Imaging), and the like.
  • NMR nuclear magnetic resonance
  • MRI Magnetic Resonance Imaging
  • FIG. 1 is a cross-sectional view showing a configuration of a circulating cooling system in an embodiment of the present invention.
  • the cooling unit 55 includes a cryogenic refrigerator 1, a stage heat exchanger 4 that is in thermal contact with the cryogenic refrigerator 1, a first countercurrent heat exchanger 6, and a second countercurrent heat exchanger 7.
  • the pipes 5 are connected to the heat exchangers.
  • Each heat exchanger is stored inside the vacuum vessel 2, and heat conduction from the surrounding room temperature is suppressed by vacuum insulation, and heat intrusion to the low temperature part due to convection is suppressed.
  • the cooling unit 55 includes a part in which the stage heat exchanger 4 and the cryogenic refrigerator 1 are stored, and a part in which the two counter-current heat exchangers 6 and 7 are stored. 23. Further, a part or all of the vacuum partition is constituted by a heat insulating vacuum wall 24.
  • the transfer tube 50 passes through a pipe (not shown) inside, and has a structure in which the refrigerant flows through the pipe.
  • a vacuum is formed between the piping of the transfer tube and the outer wall of the transfer tube, and heat intrusion from the outer wall at room temperature to the cryogenic piping is suppressed by vacuum insulation.
  • the object to be cooled 60 cools the object to be cooled 54 to a cryogenic temperature using the refrigerant sent from the cooling unit 55 through the transfer tube 50.
  • a heater (not shown) may be used for heating.
  • the piping 51 separates the vacuum tank of the body to be cooled 60 from the vacuum tank of the transfer tube 50 and the cooling unit 55.
  • the transfer tube 50 is generally made of a plastic laminated heat insulating material. When an ultra-high vacuum is used, gas emission from this plastic becomes a problem. Because.
  • the room-temperature refrigerant gas sent from the compressor 100 is cooled to a low temperature by passing through the countercurrent heat exchanger 6.
  • the stage heat exchanger 4 that is thermally connected to the cold head 3 of the cryogenic refrigerator 1
  • the refrigerant cooled to a low temperature by the stage heat exchanger 4 thermally connected to the cold head 3 of the cryogenic refrigerator 1 is transported to the cooled object 60 through the transfer tube 50, so that the inside of the cooled object 60
  • the object 54 can be cooled to a very low temperature.
  • FIG. 2 is a detailed cross-sectional view showing the configuration of the refrigerator attaching / detaching portion of the circulating cooling system in the present embodiment.
  • the arrow in FIG. 2 represents the refrigerant
  • the cryogenic refrigerator 1 has one end fixed to the vacuum vessel 2 and serves as a partition that evacuates the cold head 3 of the cryogenic refrigerator 1.
  • the cold head 3 is fixed to the stage heat exchanger 4 with screws. At this time, in order to reduce the contact thermal resistance between the stage heat exchanger 4 and the cold head 3 between the cold head 3 and the stage heat exchanger 4, vacuum grease (not shown) or indium (not shown), or Both are installed.
  • the low-vibration type Stirling refrigerator is applied to a system in which vibration is a problem in a commercially available Stirling refrigerator, compared with a pulse tube refrigerator or a GM type refrigerator, which is currently on the market.
  • the Stirling refrigerator has a displacer driven by a piston in the cold head, and the vibration level is large with a simple structure. However, it has succeeded in reducing the vibration level by adding vibration that cancels vibration.
  • the cryogenic refrigerator 1 is fixed to the lower side of the vacuum vessel 2.
  • a compressor (not shown) and a valve switching device (not shown) are mounted on the room temperature portion of the cryogenic refrigerator 1 and serve as a vibration source. By installing the cryogenic refrigerator 1 downward, it becomes easy to fix the vibration source to the floor.
  • the vacuum vessel 2 is divided by a partition wall 23 into a vacuum chamber 21 containing the components of the circulating cooling system other than the stage heat exchanger 4 and a vacuum chamber 22 storing the stage heat exchanger 4.
  • the piping 5 for transporting the refrigerant passes through the vacuum chamber 21 and the vacuum chamber 22, and in order to reduce the heat load from the partition wall 23 of the vacuum vessel at room temperature to the piping 5, the heat insulating vacuum wall 24 is provided with the partition wall of the vacuum vessel. 23.
  • FIG. 13 is a cross-sectional view showing details of the structure of the heat insulating vacuum wall 24.
  • the heat insulating vacuum wall 24 is a combination of cylinders having different diameters, and is made of stainless steel or glass fiber reinforced plastic.
  • the heat insulating vacuum wall 24 is generally made of stainless steel as a material in a system that performs baking and evacuation, and is made of a polymer material such as glass fiber reinforced plastic when baking is not performed. In addition to baking reasons, it may be made of fiber reinforced plastic for weight reduction.
  • the room temperature portion of the heat insulating vacuum wall 24 is integrated with the partition wall 23, but may be fixed with an O-ring and a screw.
  • the adiabatic vacuum wall is divided into three stages of room temperature, intermediate temperature, and minimum cooling temperature.
  • the adiabatic vacuum wall 24 includes a normal temperature cylinder 241 from a room temperature portion to an intermediate temperature, a low temperature cylinder 242 from an intermediate temperature to a minimum cooling temperature, an intermediate temperature cooling surface 243, and a minimum cooling temperature cooling surface 244.
  • the intermediate temperature cooling surface 243 is cooled to an intermediate temperature by the refrigerant pipe 51 cooled to the intermediate temperature.
  • the minimum cooling temperature cooling surface 244 is cooled to the minimum cooling temperature by the refrigerant pipe 52 cooled to the minimum temperature.
  • the portion where the pipe through which the refrigerant flows is fixed from the vacuum container can have a heat insulating vacuum wall structure. Heat intrusion due to heat conduction to the pipe cooled to a low temperature can be suppressed.
  • the heat insulating vacuum wall 24 is not limited to the structure shown in FIG.
  • the heat insulating vacuum wall 24 may use a bellows structure in the cylindrical portion.
  • FIG. 14 is a cross-sectional view showing details of the structure of the stage heat exchanger 4.
  • the stage heat exchanger 4 has a structure in which a copper tube 42 is wound around a copper cylinder 41.
  • This circulation cooling system is an indirect cooling structure in which an object to be cooled is cooled by the refrigerant cooled by the cold head 3 of the cryogenic refrigerator 1, and the area of the cold head 3 of the cryogenic refrigerator 1 is small. Since sufficient heat exchange cannot be performed between the two, a stage heat exchanger 4 made of copper is manufactured to expand the heat exchange area.
  • the stage heat exchanger 4 may have a structure in which a through hole is provided at the center.
  • the length of the copper tube 42 wound around the stage heat exchanger 4 only needs to be longer than the length calculated from the heat exchange amount of refrigerant in the stage heat exchanger 4 and the temperature efficiency.
  • the stage heat exchanger 4 has a through hole 43 for coupling to the cryogenic refrigerator 1 and is coupled to the cryogenic refrigerator 1 by screws (not shown). Further, the stage heat exchanger 4 has a through hole or screw hole 44 for attaching the support 200 to the vacuum vessel 2. When the cryogenic refrigerator 1 is removed, this through hole or screw is provided. The support 200 is fixed to the vacuum vessel 2 using the holes 44.
  • a stage heat exchanger that performs heat exchange between the refrigerant and the cryogenic refrigerator is supported by a cryogenic refrigerator and a pipe through which the refrigerant flows. It is necessary to suppress the amount of heat penetration from the piping into the cryogenic refrigerator. This pipe is thin and does not have a function of supporting the stage heat exchanger. Therefore, when the cryogenic refrigerator is removed at the time of maintenance, there is a problem that stress due to the weight of the stage heat exchanger is applied to the pipe and damage such as bending of the pipe occurs.
  • FIG. 2 is a cross-sectional view showing the configuration of the circulating cooling system in the present embodiment.
  • the cold head 3 and the stage heat exchanger 4 of the cryogenic refrigerator 1 are heated by a heater (not shown).
  • the temperature is raised to room temperature.
  • a valve (not shown) capable of opening and closing the vacuum chamber 22 attached to the vacuum vessel 2 is opened to make the inside of the vacuum chamber 22 equivalent to the atmospheric pressure.
  • the lid 11 attached to the vacuum vessel 2 is removed with the valve (not shown) open, so that the cold head 3 and the stage heat exchanger 4 of the cryogenic refrigerator 1 can be seen. To do.
  • FIG. 3 is a cross-sectional view showing the configuration before removing the cryogenic refrigerator in this embodiment.
  • the arrow in FIG. 3 represents the refrigerant
  • the support 200 is inserted between the stage heat exchanger 4 and the vacuum vessel 2 before removing the fixing screw (not shown) that connects the stage heat exchanger 4 and the cold head 3.
  • the stage heat exchanger 4 has a structure supported from the cryogenic refrigerator 1 and the vacuum vessel 2.
  • the support 200 may be made of a metal such as stainless steel in order to increase the rigidity.
  • FIG. 4 is a cross-sectional view showing the configuration when removing the cryogenic refrigerator in this embodiment.
  • the arrow in FIG. 4 represents the refrigerant
  • the stage heat exchanger 4 is supported only from the vacuum vessel 2 by the support 200.
  • the stage heat exchanger 4 is supported by the vacuum vessel 2 and therefore does not move, and the stage heat exchanger
  • the pipe 5 is not bent by its own weight. This can prevent damage to the piping due to the weight of the stage heat exchanger when the refrigerator is removed.
  • stage heat exchanger 4 when the stage heat exchanger 4 is supported by the cryogenic refrigerator 1 by setting the mounting direction of the cryogenic refrigerator 1 in the vertical direction with respect to the stage heat exchanger 4, the stage heat exchanger 4 is interposed via the stage heat exchanger 4. Therefore, it is possible to prevent the pipe 5 from being bent or damaged by preventing the bending direction force from being applied to the connected pipe 5.
  • the stage heat exchanger 4 has a structure supported only from the cryogenic refrigerator 1, has no portion in direct contact with the vacuum vessel 2 at room temperature, and the thermal load received by the stage heat exchanger 4 and the cold head 3 from the vacuum vessel 2. Can be minimized.
  • the stage heat exchanger 4 is attached to the cold head 3 with a fixing screw (not shown), the support 200 is removed, and the state shown in FIG. 2 is obtained.
  • the lid 11 After attaching the cryogenic refrigerator 1, the lid 11 is attached to the vacuum vessel 2 and the state shown in FIG. 1 is set, and then the vacuum chamber 22 is evacuated by a vacuum pump (not shown). After confirming that the vacuum degree of the vacuum chamber 22 is in a vacuum insulation state by a display value of a vacuum gauge (not shown), the cryogenic refrigerator 1 is started to start circulation cooling.
  • the stage heat exchanger When replacing the stage heat exchanger, the stage heat exchanger is supported from the vacuum vessel using a support, and during normal operation, the stage heat exchanger is supported only from the cryogenic refrigerator, so Operation without heat load on the refrigerator is possible.
  • the high vacuum degree of the vacuum chamber 21 is maintained without returning the components built in the vacuum chamber 21 to the atmospheric pressure. Moreover, it is not necessary to bake high vacuum parts including the vacuum chamber 21, and the operation of the refrigerator can be resumed even if the vacuum level of the vacuum chamber 22 is worse than that of the vacuum chamber 21. Shorter.
  • FIG. 5 is a cross-sectional view showing the configuration of the circulating cooling system in the second embodiment.
  • FIG. 6 is a cross-sectional view showing the configuration of the circulating cooling system when the cryogenic refrigerator in Example 2 is removed.
  • the arrows in FIG. 5 and FIG. 6 represent the flow direction of the refrigerant pipe and the refrigerant.
  • the stage heat exchanger 4 is supported from the vacuum vessel 2 by the support 200 from the cryogenic refrigerator side of the vacuum vessel 2 constituting the vacuum chamber 22 before the cryogenic refrigerator 1 is removed. Is done.
  • the support 200 is attached from the same direction as the vacuum vessel surface to which the cryogenic refrigerator 1 is attached. By installing the support 200 below the stage heat exchanger 4, the support 200 disappears above the stage heat exchanger 4, and the stage heat exchanger 4 is removed from the cold head 3 of the cryogenic refrigerator 1. The workability is improved because a space for putting work tools and hands is secured during work.
  • the state shown in FIG. 6 is obtained. That is, the cryogenic refrigerator 1 is removed from the vacuum vessel 2 and the stage heat exchanger 4 is supported by the support 200 from the cryogenic refrigerator side of the vacuum vessel 2.
  • downward refers to a configuration in which the stage heat exchanger 4 is positioned below the cryogenic refrigerator 1 and the cryogenic refrigerator 1 is connected to the lower stage heat exchanger 4.
  • FIG. 7 is a cross-sectional view showing the configuration of the circulating cooling system in the third embodiment.
  • FIG. 8 is a cross-sectional view showing the configuration of the circulating cooling system in the third embodiment.
  • FIG. 9 is a cross-sectional view illustrating the configuration of the cooling system before removing the refrigerator in the third embodiment.
  • FIG. 10 is sectional drawing which shows the structure of the cooling system at the time of cryogenic refrigerator removal in Example 3. As shown in FIG.
  • the cryogenic refrigerator 1 is fixed to the upper side of the vacuum vessel 2.
  • the stage heat exchanger 4 is supported by the support 200 from the vacuum vessel 2.
  • the support 200 is inserted from the surface of the vacuum container 2 on the side facing the cryogenic refrigerator 1.
  • the stage heat exchanger 4 is supported by the cryogenic refrigerator 1 and the support 200.
  • the state shown in FIG. 10 is obtained. That is, the cryogenic refrigerator 1 is removed from the vacuum vessel 2 and the stage heat exchanger 4 is supported by the support 200 from the lower surface of the vacuum vessel 2.
  • FIG. 11 is a cross-sectional view illustrating a configuration of the circulating cooling system in the fourth embodiment.
  • FIG. 12 is sectional drawing which shows the structure of the system at the time of the refrigerator removal in Example 4.
  • 11 and 12 indicate the refrigerant piping and the flow direction of the refrigerant.
  • the stage heat exchanger 4 has the cryogenic refrigerator 1 fixed to the vacuum vessel 2 by the support 200 from the cryogenic refrigerator side of the vacuum vessel 2 before the cryogenic refrigerator 1 is removed. Supported from the surface side. Thereby, since there is no support body 200 in the side which removes the connection screw with which the stage heat exchanger 4 and the cryogenic refrigerator 1 are not shown in figure, workability
  • the state shown in FIG. 12 is obtained. That is, the cryogenic refrigerator 1 is removed from the vacuum vessel 2, and the stage heat exchanger 4 is supported by the support 200 from the surface side where the cryogenic refrigerator 1 is attached.
  • the structure of the sample surface can be observed.
  • SEM scanning electron microscope
  • SIM scanning ion microscope
  • SIM images using hydrogen or helium ions are more polar samples than SEM images. Sensitive to surface information. Further, from the viewpoint of a microscope, ions are heavier than electrons, and therefore, the diffraction effect can be ignored in the beam focusing, and an image having a very deep depth of focus can be obtained.
  • an electron or ion beam is irradiated on a sample and electrons or ions transmitted through the sample are detected, information reflecting the structure inside the sample can be obtained. These are called transmission electron microscopes or transmission ion microscopes. In particular, if a sample is irradiated with a light ion species such as hydrogen or helium, the rate of transmission through the sample increases, which is suitable for observation.
  • the gas electrolysis ion source is a suitable ion source for the above-described scanning ion microscope and transmission ion microscope because a fine beam is expected because the ion energy width is narrow and the ion generation source size is small.
  • emitter tip cooling means include mechanical vibration generators such as a mechanical refrigerator, and the emitter tip easily vibrates.
  • mechanical vibration generators such as a mechanical refrigerator
  • the emitter tip easily vibrates.
  • the ion beam is shaken and the resolution of sample observation is deteriorated.
  • FIG. 15 is a cross-sectional view of an ion microscope and a cooling system in Example 5.
  • the ion gun 70 which is the basis of the ion microscope includes an emitter tip 71 and a helium gas filling chamber 72, an electrode 73, a heat exchanger 74 for cooling the emitter tip 71 and the helium gas filling chamber 72, an emitter tip 71 and a helium gas filling chamber.
  • a heat shield 75 that surrounds the heat shield 75, a heat exchanger 76 that cools the heat shield 75, and the like are included.
  • a vacuum exhaust system (turbo molecular pump, NEG, etc.) and an optical system (not shown) are also included.
  • the cryogenic refrigerator 10 is a compressor-integrated Stirling refrigerator.
  • the mounting direction may be vertically upward or downward.
  • the cryogenic refrigerator 10 is attached to the vacuum vessel 2 vertically upward.
  • the helium gas pressurized by the compressor 100 installed in the room temperature portion is sent to the cooling unit 55 and cooled when passing through the counterflow heat exchanger 6.
  • the cooled helium gas is cooled by the cryogenic refrigerator 1 in the vacuum chamber 22 separated by the vacuum partition.
  • the helium gas that has passed through the vacuum partition and passed through the countercurrent heat exchanger 7 on the vacuum chamber 21 side is further cooled.
  • This helium gas is cooled by another cryogenic refrigerator 1 (not shown) in a vacuum chamber 22 separated by a vacuum partition.
  • the helium gas cooled to the lowest temperature passes through the vacuum partition, passes through the transfer tube 50, is sent to the ion gun 70, passes through the vacuum partition 77 of the ion gun 70, and the emitter tip 71 and the inside of the ion gun 70. It is sent to a heat exchanger 74 that cools the helium gas filling chamber 72.
  • the helium gas whose temperature has risen by cooling the emitter tip 71 and the helium gas filling chamber 72 inside the ion gun 70 passes through the transfer tube 50 and again passes through the countercurrent heat exchanger 7 installed in the vacuum chamber 21. The temperature rises further.
  • the helium gas that has passed through the counterflow heat exchanger 7 is again sent to the ion gun 70 side through the transfer tube 50.
  • the helium gas is sent to a heat exchanger 76 that cools the shield 75 of the ion gun 70.
  • the helium gas that has passed through the heat exchanger that cools the shield 75 and has risen in temperature passes through the transfer tube again to the vacuum chamber 21, passes through the countercurrent heat exchanger 6, and rises in temperature to room temperature. Room temperature helium gas returns to the compressor.
  • a vacuum partition wall 77 is also provided on the ion gun 70 side, so that the vacuum tank of the ion gun 70 and the vacuum tank of the transfer tube 50 can be separated.
  • the operation of the cryogenic refrigerator 1 and the compressor 100 is stopped at the time of baking, and the helium gas is not circulated so that the amount of heat applied by the ion gun 70 does not propagate to the transfer tube 50 and the cooling unit 55. Yes.
  • the vacuum partition walls at two locations (between the ion gun 70 and the transfer tube 50 and inside the cooling unit 55), a high degree of vacuum is maintained during baking and replacement of the cryogenic refrigerator 1. Deterioration of the space can be prevented.
  • the vacuum partition wall 77 between the ion gun 70 and the transfer tube 50, the volume of the high vacuum portion can be reduced, and the exhaust characteristics of an exhaust system (not shown) can be improved. As a result, diffusion due to impurity contamination during beam emission can be prevented, and the beam convergence is improved.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Containers, Films, And Cooling For Superconductive Devices (AREA)

Abstract

L'invention concerne une source de refroidissement destinée à un système de refroidissement à circulation dans lequel la source de refroidissement est conçue, d'une part pour éviter d'endommager la tuyauterie pendant les opérations de branchement et de débranchement du dispositif de réfrigération, et d'autre part pour ramener à un minimum une charge thermique s'appliquant à un échangeur de chaleur du plateau du microscope. À cet effet, l'invention propose une structure permettant d'obtenir par cloisonnement, d'une part un réservoir à dépression devant contenir une tête froide et un échangeur de chaleur de plateau d'une machine de refroidissement cryogénique, et d'autre part un réservoir à dépression devant contenir d'autres parties. Cette structure permet ainsi également de ne pressuriser que les parties de la tête froide et de l'échangeur de chaleur du plateau de la machine de refroidissement cryogénique en passant du vide à la pression atmosphérique. L'invention propose également une structure dans laquelle l'échangeur de chaleur du plateau est supporté par un récipient sous vide adapté à un élément support pendant le débranchement du dispositif de réfrigération.
PCT/JP2013/053789 2012-02-21 2013-02-18 Source de refroidissement pour système de refroidissement à circulation, et microscope ionique utilisant cette source WO2013125471A1 (fr)

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JP2012034625A JP2015111010A (ja) 2012-02-21 2012-02-21 循環冷却システムの冷却源およびこれを用いたイオン顕微鏡
JP2012-034625 2012-02-21

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105151535A (zh) * 2015-07-29 2015-12-16 程路 一种具有制冷功能的冷链物流箱
CN106440481A (zh) * 2016-11-30 2017-02-22 无锡溥汇机械科技有限公司 一种超声喷雾制冷装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6371881B1 (ja) * 2017-03-15 2018-08-08 大陽日酸株式会社 ガス冷却システム

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008075893A (ja) * 2006-09-19 2008-04-03 Hitachi Ltd 極低温冷却システム
JP2011014245A (ja) * 2009-06-30 2011-01-20 Hitachi High-Technologies Corp イオン顕微鏡

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008075893A (ja) * 2006-09-19 2008-04-03 Hitachi Ltd 極低温冷却システム
JP2011014245A (ja) * 2009-06-30 2011-01-20 Hitachi High-Technologies Corp イオン顕微鏡

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105151535A (zh) * 2015-07-29 2015-12-16 程路 一种具有制冷功能的冷链物流箱
CN106440481A (zh) * 2016-11-30 2017-02-22 无锡溥汇机械科技有限公司 一种超声喷雾制冷装置

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