JPH0619313B2 - Sample cooling device using a cryogenic refrigerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sample cooling device using a cryogenic refrigerator.

<Prior Art and Problems> When performing physical property measurement of a sample for research and development under cryogenic temperature using a cryogenic refrigerator, it is necessary to uniformly cool the sample and perform measurement. Particularly, samples having various shapes such as molded solids, massive porous bodies, thin films, powders and fluids are easily cooled to a uniform temperature distribution using a cryogenic refrigerator, and those substances are measured. Development of means is desired.

In order to clarify these problems, a conventional sample cooling method will be described with reference to FIGS. 1 and 2. Cooling methods include heat conduction cooling and helium gas heat exchange cooling.

First, heat conduction cooling will be described (see FIG. 1).

A sample holder 2 to which a sample is directly attached is attached to the tip of the cryogenic refrigerator 1. A measurement lead 3 for measuring physical properties is attached to the sample, taken out of the cryogenic refrigerator 1, and contacted to the measuring instrument.

The inside of the cryogenic refrigerator 1 is evacuated by the evacuation device 4. After that, the cryogenic refrigerator including the cryogenic refrigerator 1 and the compressor unit 5 is activated. At this time, the sample is cooled by heat conduction, and physical properties are measured at cryogenic temperature.

However, the heat conduction cooling method limits the shape of the sample to only molded solids. Moreover, its size is also limited from the viewpoint of achieving a uniform temperature distribution.

Next, heat exchange cooling with helium gas will be described (see FIG. 2).

At the tip of the cryogenic refrigerator 1, the sample is attached to the sample holder 2 in the small container 6. In order to make the small container 6 vacuum-tight, indium wire 7 is usually used to seal the flange surface. The indium wire is cut into a ring shape according to the circumferential length of the flange surface and used as a seal ring. The joints of the indium wire seal rings should be diagonally aligned with each other. The work of converting the small container 6 into a vacuum sealed container requires a high degree of skill. The measurement lead 3 attached to the sample is taken out of the cryogenic refrigerator 1 and contacted with the measuring instrument.

Helium gas is introduced into the small container 6 from the outside of the cryogenic refrigerator 1 using a metal capillary tube 8 and is replaced with air in the small container 6.

The inside of the cryogenic refrigerator 1 is evacuated by the evacuation device 4. Then, the cryogenic refrigerator is activated. At this time, the vacuum-sealed small container 6 is cooled by heat conduction. Helium gas in it is also cooled. As a result, the sample is cooled by heat exchange with helium gas, and physical properties can be measured at cryogenic temperatures.

This helium gas heat exchange cooling method is a method of compensating for the insufficient points of the above-mentioned heat conduction cooling method, but if the processing technique for taking out the measurement leads 3 to the outside of the small container 6 is not advanced, leakage of helium gas There were problems such as being the cause of. Further, since the indium wire used as the sealing material is only wound around the flange surface of the small container 6, this may also cause the helium gas to leak from this portion. Further, since the indium wire is wound around, the sample replacement work is troublesome.

The present invention has been made in order to solve the above problems, using a helium gas heat exchange cooling means without limitation on the type, shape, etc. of the sample, helium gas from a small container forming a vacuum sealed space It is an object of the present invention to provide a sample cooling device using a cryogenic refrigerator that eliminates leakage of water and facilitates the work of making a small container into a vacuum sealed container and facilitates sample replacement work.

<Structure of the Invention> In order to achieve the above-mentioned object, the present inventor has conducted extensive studies, and as a result, it has been used as a component of a vacuum device, but its reliability under cryogenic temperature (-269 ° C) is guaranteed. The present inventors have found that an indium-plated metal seal ring having excellent feedability and a sealability, which is a lead wire introduction terminal, which has not been used yet, can be sufficiently used even at an extremely low temperature, and has completed the present invention.

That is, the sample cooling device using the cryogenic refrigerator of the present invention includes a small container with an open upper surface to be mounted on the cold head of the cryogenic refrigerator, a sample holder arranged in the small container, and a sample holder. A feedthrough for taking out a measurement lead for measuring physical properties attached to the sample held in the outside is provided, and a chamber flange disposed so as to close the upper open portion of the small container, and a small container of the small container. A seamless indium-plated metal seal ring sandwiched between the flange and the flange of the chamber flange, and a metal capillary for introducing helium gas into the space formed by the small container and the chamber flange. It has a tube insertion port, an exhaust port connected to the vacuum exhaust device, and a measurement lead outlet for connecting the measurement leads to the measuring instrument. Rudoheddo a casing which is sealingly disposed around the small containers and the chamber flange,
It is characterized by having.

Hereinafter, the present invention will be described in more detail based on the embodiment shown in FIG.

On the cold head 1a of the cryogenic refrigerator 1, a small container 6 having a flange at the upper edge and having an open top is attached. This small container 6 is for accommodating the sample holder 2 for holding a sample, and has a chamber flange 10 having a flange at the lower edge so as to close the upper surface open portion.
Is attached as a top lid.

Then, the flange of the small container 6 and the chamber flange 1
A seamless indium-plated metal seal ring 11 is sandwiched between the 0 flanges, and the small container 6 and the chamber flange 10 form a closed space.
As a result, the sample holder 2 is housed in this space.

In an appropriate portion of the chamber flange 10 described above, a feedthrough 9 into which the measurement lead 3 can be introduced while maintaining an airtight state is provided in the upper portion in the present embodiment as shown in FIG. The measurement lead 3 is arranged to measure the physical properties of the sample, and one end is attached to the sample housed in the space formed by the small container 6 and the chamber flange 10, and the other end is a casing 12 described later. It is taken out from the measurement lead outlet 12c provided on the outside and connected to the measuring instrument.

The casing 12 includes the small container 6 and the chamber flange 1.
0 is an approximately cylinder having an insertion port 12a for a metal capillary tube 8 for introducing helium gas into a space formed by 0, an exhaust port 12b connected to the vacuum evacuation device 4, and a measurement lead outlet 12c described above. It is configured in the shape of a cold body, the cold head 1a, the small container 6 and the chamber flange 1
It is arranged in a sealed manner around 0.

Next, the operation of this embodiment will be described.

The metal capillary tube 8 replaces the air in the space formed by the small container 6 and the chamber flange 10 with helium gas. Next, drive the vacuum exhaust device 4,
The inside of the casing 12 is evacuated. Then, the cryogenic refrigerator including the cryogenic refrigerator 1 and the compressor unit 5 is activated. As a result, the small container 6 and the chamber flange 10 are cooled by heat conduction, and the helium gas is also cooled. As a result, the sample is cooled by heat exchange with helium gas, so that the physical properties can be measured at cryogenic temperature.

Since the sample is cooled by heat exchange with helium gas, the sample can be cooled to a uniform temperature without being restricted by the shape and size of the sample.

Further, since the feedthrough 9 is used, a processing technique for taking out the measurement lead 3 out of the space formed by the small container 6 and the chamber flange 10 while maintaining the airtight state is easy. Further, since the metal seal ring 11 is used, the small container 6 and the chamber flange 1 are
The space formed by 0 can be completely sealed, and the leakage of helium gas is reduced. As a result of the experiment, the metal seal ring 11 can be reused 50 times or more, which is economical.

<Effects of the Invention> According to the present invention, since the helium gas heat exchange cooling means is used, there is no limitation on the type and shape of the sample. Further, there is almost no leakage of helium gas from the small container forming the vacuum sealed space, and since the feedthrough and the metal seal ring are used, the work of making the small container a vacuum sealed container is easy. Furthermore, since a metal seal ring is used, sample exchange work is easy.

[Brief description of drawings]

1 and 2 are block diagrams of a sample cooling device using a conventional cryogenic refrigerator, and FIG. 3 is a block diagram showing an embodiment of the present invention. 1 ... Cryogenic refrigerator, 1a ... Cold head, 2 ... Sample holder, 3 ... Measurement lead, 4 ... Vacuum exhaust device, 5 ... Compressor unit, 6 ... Small container, 7 ... Indium Wire, 8 ... Metal capillary tube, 9 ... Feedthrough, 10 ... Chamber flange, 11 ... Metal seal ring, 12 ... Casing

Claims (1)

[Claims] 1. A small container with an open upper surface to be mounted on a cold head of a cryogenic refrigerator, a sample holder arranged in the small container, and a physical property measurement attached to a sample held in the sample holder. A feedthrough for taking out the measurement lead of the above is provided, and it is sandwiched between the flange of the small container and the flange of the chamber flange, and the chamber flange arranged so as to close the open portion of the upper surface of the small container. A seamless indium-plated metal seal ring, a metal capillary tube inlet for introducing helium gas into the space formed by the small container and chamber flange, an exhaust connected to a vacuum pump It has a measurement lead outlet for connecting the mouth and the measurement lead to the measuring instrument, and has a cold head, a small container, and a chamber flask. A sample cooling device using a cryogenic refrigerator, comprising: a casing that is hermetically disposed around the container.