JPS6145177B2 - - Google Patents

Abstract

An apparatus for transferring refrigeration to an object to be cooled without mechanical contact of the refrigerator and object so that vibrational loads are not transferred to the object. The apparatus is characterized in that a fluid transfer medium is caused to circulate in a confined path adjacent the refrigeration source and the object to effect cooling of the object. An apparatus such as disclosed is ideally suited for cooling samples for Mossbauer Spectroscopy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device, and more specifically to an object to be cooled (hereinafter referred to as an object to be cooled).
A power source that generates low temperature (hereinafter referred to as a cooling source)
This relates to a cooling transmission device that transmits only the low temperature of the cooling source without transmitting the vibrations of the cooling source.

A cooling transfer device that transmits only the low temperature without transmitting the vibrations of the cooling source to the object to be cooled is especially necessary for cooling a specimen (hereinafter referred to as the object to be cooled) to be analyzed by emission spectroscopy or absorption spectroscopy. Mössbauer spectroscopy is known as one area of spectroscopy.

In the late 1950s, Rudolf Mössbauer discovered that atomic nuclei embedded in solids emit and absorb low-energy gamma rays that possess a complete transition energy over their characteristic width, and that the recoil energy is due to lattice vibrations. I discovered that it was not transmitted. This discovery is known as the Mössbauer effect.

In an atomic nucleus placed at a low Debye temperature,
The gamma ray emitter and absorber need to be cooled to temperatures on the order of 10 degrees Kelvin. To maintain this temperature, it is necessary to use liquid helium or liquid nitrogen. However, in researching Coulomb excitation or nuclear reactions, each task takes several days, and the labor costs required to maintain liquid helium at a constant level are enormous. It had become a thing.

Recently, the use of closed-circulation helium coolers to cool specimens for Mössbauer research has been proposed. This is called ``The Use of a Helium Cooler for Mössbauer Research.''
It was published in a paper titled ``Refrigerator for Mossbauer Studies'', written by Y. Double. Chiyo (YWChow), E. S. ES Greenbaun, R. Etsuchi. RHHowes, F. Etsuchi. Etsuchisu (FHHHsu), P. Etsuchi. Swadlow (P.
H. Swerdlow) and C. S. C (CS
Wu) and The North Holland Publishing Company (The North Holland Publishing Company).
Nuclear Instruments and Methods, published by Publishing Company.
66 (1968), pp. 177-180.

In this paper, the authors present the use of a closed circulation helium cooler mechanically coupled to the specimen holder, and the use of a bellows configuration to reduce the transmission of vibrations generated by the cooling source to the specimen holder. is listed.

However, in the aforementioned article and most other prior art devices in commercial use, there is a mechanical connection between the specimen holder and the cooling source, on which the object to be cooled is mounted; In this connection part,
Typically, flexible knitted copper strings are used to reduce the transmission of vibrations from the cooling source to the object being cooled.

In order to make this mechanical connection a high thermal conductor, it is necessary to have a sufficiently large cross section, but it also clearly transmits vibrations well, which is a factor in efficiency. There has always been a compromise between having a large cross section for good heat transfer and having a small cross section to reduce transmitted vibrations.

The present invention has been made in order to solve the above-mentioned problems and to transmit only cooling to the object to be cooled without transmitting the mechanical vibration of the cooling source from the cooling source to the object to be cooled. A certain amount of fluid transfer medium is injected into the closed circulation path, and the object to be cooled is brought into contact with this fluid transfer medium, so that the object to be cooled can be effectively cooled. In this device, the specimen holder for mounting the object to be cooled can be suspended and supported independently of the cooling source, thereby preventing mechanical contact between the cooling source and the object being cooled. It is possible to have none at all.

Accordingly, a primary object of the present invention is to provide an improved cooling system for transferring cooling from a cooling source to an object to be cooled.

Another object of the present invention is to provide a cooling device that transmits cooling from a cooling source to an object to be cooled without providing mechanical contact between the cooling source and the object to be cooled.

Another object of the present invention is to provide a cooling device that cools objects to be cooled using a closed circulation helium cooler.

Another object of the present invention is to provide a cooling device for use in Mössbauer spectroscopy, which is configured so that vibrations are not transmitted from a cooling source to an object to be cooled.

As an example of the present invention, the present invention will be described as applied to Mössbauer spectroscopy.

The specimen holder part of the Mössbauer spectroscopy technique is shown in Figures 1 and 2. 10 is a closed circulation type helium cooling source. The cooling source 10 is of a two-stage type and includes a first cooling section 12 and a second cooling section 14. The cooling source 10 can maintain a temperature of 10° at the extension stud 16, which is the lower end of the second cooling section 14 (the cooling end of the cooling source), and the extension stud 16 is made of high-quality material such as copper. Made of conductive material.

The cooling source 10 is disclosed in U.S. Pat.
3620029, which patent specification is incorporated herein by reference.

The cooling source 10 is mounted by a support ring 18, which is mounted on a hard primary surface such as a laboratory floor.
is fixed to a sturdy support body through a support member 20. 22 is a specimen holder, and the specimen holder 22 is supported by a support 24. The support 2
4 is fixed to the optical bench of the second solid support via a support member 26. A first cooling unit 12 and a second cooling unit 14 connected to the cooling source 10 are inserted into the specimen holder 22, and are connected to the cooling source 10.
0 and specimen holder 22 is a flexible vibration isolation sleeve 28, such as a very thin corrugated rubber sleeve. That is, the sleeve 28 forms a sealed path between the cooling source 10 and the specimen holder 22.

The specimen holder 22 has an outer vacuum shielding plate 30
It is composed of components forming an internal system, which will be described later. The outer vacuum shielding plate 30 includes the vacuum shielding plate 3
A suitable air outlet 32 is provided to evacuate the space formed by the air. Reference numeral 34 denotes an inner vacuum jacket sleeve made of stainless steel, which is provided so as to be surrounded by the outer vacuum shielding plate 30 and to surround the first cooling section 12 . The vacuum jacket sleeve 34
A support adapter 36 for blocking radiant heat is provided at the lower end of the
is attached, and a radiant heat shield 38 is screwed below the support adapter 36. The radiant heat shield 38 is formed from a copper cylinder or an aluminized plastic commonly used in cryogenic equipment. An extension 40 is mounted within the radiant heat shield 38 in a watertight manner relative to the vacuum jacket sleeve 34 and surrounds the second cooling section 14. A cooled object adapter 42 is attached to the lower end of the extension part 40, and a cooled object 44 is attached to the cooled object adapter 42. A series of vertical passages 43, which will be described later, are formed within the cooled object adapter 42.

46 is a first stage heat exchanger, and the cooling source 10
It is fixed around the first cooling section 12 attached to the.
Further, a second stage heat exchanger 48 of the same structure is fixed around the extension stud 16 provided at the lower end of the second cooling section 14. Of the heat exchangers 46 and 48, a cross section of heat exchanger 48 is shown in FIG. heat exchanger 46,
48 is constructed by holding a plurality of thin copper plate cylinders with different diameters by vertical spacing pieces 49 to provide a plurality of vertical flow paths.

Reference numeral 52 denotes an inlet for supplying the fluid transfer medium to the cooling source 1.
The first cooling section 12 and the second cooling section 14 on the zero side and the vacuum jacket sleeve 34 on the specimen holder 22 side
The space formed between the extended portion 40 and the extended portion 40 is filled. The inlet 52 is provided with a pressure relief valve to maintain the fluid transfer medium at atmospheric pressure. The cooling source 10 is provided with an inlet pipe 54 and an outlet pipe 56, which circulate compressed helium from a compressor (not shown) to the cooling source 10 through a flexible conduit. let

The illustrated apparatus incorporates a vibration isolation sleeve 28 mounted in a watertight manner between the cooling source 10 and the specimen holder 22. The fluid transfer medium, preferably helium, is introduced from the inlet 52 into the space formed between the first cooling section 12 and the second cooling section 14, the vacuum jacket sleeve 34, the extension section 40, and the object adapter 42. is injected into. The fluid transmission medium is connected to a fluid transmission medium maintained at atmospheric pressure. Therefore, when the cooling source 10 acts, the cooling effect is transmitted to the first cooling section 12 and the second cooling section 14, and the cooling effect is injected into the space formed around the first cooling section 12 and the second cooling section 14. A convection phenomenon is caused in the fluid transmission medium, causing it to circulate in the vertical direction. In addition, this convection phenomenon is more effectively carried out by the first stage heat exchanger 46 and the second stage heat exchanger 48, and the vertical The passage 43 lengthens the circulation path of the fluid transfer medium and improves the cooling heat exchange between the second cooling section 14 of the cooling source and the object 44 to be cooled.

As mentioned above, since there is no mechanical connection between the heat exchangers 46, 48 and the object to be cooled 44,
There is no direct vibration transmission between the cooling source 10 and the specimen holder 22. That is, the heat exchanger 4
6, 48 and the object to be cooled 44, only a fluid transmission medium is filled, and the only contact between the cooling source 10 and the specimen holder 22 is the vibration isolation sleeve 28 other than the fluid transmission medium. It is. Therefore, vibrations of the cooling source 10 or other forces generated by its operation are not transmitted to the specimen holder 22 to which the object to be cooled 44 is attached, and only cooling is transmitted. Additionally, the vibration isolation sleeve 28
As long as the fluid transfer medium is operated at atmospheric pressure, there is no pressure difference, and therefore only a very thin flexible material is required.

The apparatus illustrated in FIG. 1 is designed to provide maximum cooling transfer with a minimum of fluid transfer medium by convection. The driving force for circulation is the density difference between the warm and cold gases and the relationship between the cooling front edge of the cooling source and the second stage heat exchanger 4.
Depending on the length of the closed circuit determined by the length of 8. Although this circulation is somewhat enhanced by the vertical passage 43 of the object adapter 42,
The figure shows another means of increasing circulation.

As shown in FIG. 3, a substantially cylindrical chimney 100 is provided between the second stage heat exchanger 48 and the cooled object adapter 42, and the chimney 100 has a long length that passes through the heat exchanger group and reaches the cooled object 44. form a passage. Through this passage, the fluid transmission medium flows downward while being cooled around the chimney 100, and the object to be cooled 4
4, the object to be cooled 44 is allowed to pass through the vertical passage 43 and return upward after being cooled. The chimney 100
is preferably made of a non-conducting material such as Bakelite or other plastic material. This chimney 1
Since the 00 does not mechanically connect the cooling source to the object 44 to be cooled, it does not transmit vibration loads to the object 44 to be cooled, thus making this device ideal for studying the Mössbauer effect. Make it.

By using different fluid transfer media in conjunction with the first cooling section 12 and the specimen holder 22 as shown, it is possible to achieve various temperature levels and temperature controls. For example, high temperature level e.g. 20
In this case, a more effective cooling effect can be achieved by using hydrogen as a fluid transfer medium and condensing it into a liquid and also vaporizing it. Also, by mixing different fluid transfer media different temperature ranges can be obtained to suitably change the condensation mode.

An alternative embodiment is shown in FIG. 4, in which the overall length of the cooling system is reduced. Simply put, this is a combination of two circulating fluid transmission systems.

In the embodiment of FIG. 4, the design of FIG. 1 is changed and the first cooling section 12' and the second cooling section 1 are
Cooling source 10' is shown having 4'.

In the embodiment of FIG. 4, the cooling source 10' is located within a fluid housing 70, which is isolated from the cooling source 10' by a thin vibration isolating sleeve 28' as in FIG. There is.
The first cooling section 12' is provided with two heat exchangers 58 and 60 vertically spaced apart from each other, and a chimney 62 is provided within the space. This chimney 62 is fixed to the upper heat exchanger 58 and is not brought into contact with the lower heat exchanger 60. The second cooling section 14' is a heat exchanger 6
4, 66 and a chimney 68 formed similarly to chimney 62. Heat exchanger 6 of second cooling section 14'
4 and 66 are provided within a sleeve 72 that fits within the fluid housing 70 as shown.

A cap 74 is provided at the lower end of the sleeve 72 and is cooled at the cooling end of the second cooling section 14' of the cooling source 10'. Similar to the embodiment of FIG. 1, the fluid transfer medium, namely helium, is introduced through suitable inlets 52 to form the first cooling section 12' and the second cooling section 1.
4' between the fluid housing 70 and the sleeve 72. The heat exchanger and chimney combination cooperates with the cooling effect of the cooling source to provide convective circulation of the fluid transfer medium at each stage, providing cooling without mechanically coupling the cooling source to the cap 74.

FIG. 5 shows yet another embodiment of the invention. This embodiment is for cooling a superconducting magnet, and this magnet structure includes first shielding plates 82, 20, called outer vacuum shell plates 80, 75 and 75〓 shielding plates (plates that shield 75〓). A second shielding plate 84 called a shielding plate, a brewer bottle 86 containing liquid helium, a magnetic cavity 88, a magnet 90, a tube 92, and an electricity supply body 94
is included. The cooling source is similar to the embodiment shown in FIG.
There are a first cooling section 12' and a second cooling section 14', and the heat exchanger is as shown. The first cooling part 12' serves to maintain the first shielding plate 82 at a temperature of approximately 75°, and the second cooling part 14' serves to maintain the second shielding plate 84 at a temperature of approximately 20°. leakage into the liquid helium in the brewer bottle 86 is minimized. With the above configuration, a cooling source is used to take gaseous helium in the space above the liquid level and condense it into liquid to maintain the level of liquid helium in the brewer bottle 86. It becomes possible to maintain the shape at low temperatures. Such low temperature maintenance is known to those skilled in the art and can be readily adopted by those skilled in the art.

As mentioned above, the heat exchanger is preferably formed by brazing a copper plate at intervals, but the heat exchanger may be formed by winding the copper plate in several layers or by using a plurality of tubes to connect the fluid at each stage of the cooling source. Of course, various types of heat exchangers may be used, provided that the transfer medium forms a long closed circulation path.

It is also within the scope of the present invention to use a first stage cooling source to achieve a constant low temperature at the cold end of the cooling source in a similar construction and in a similar manner.

It is also within the scope of the invention to use fluid transfer media such as nitrogen, argon, air, hydrogen, halocarbons, inert gases, methane, and mixtures thereof.

It is also within the scope of the present invention to provide a small mechanical fan or the like at the top of each stage of the cooling source to enhance circulation of the fluid transfer medium.

Preferred embodiments of the present invention are listed below.

(1) The device as claimed in the claims, characterized in that the cooling source and the cooling object support device are arranged within a vacuum jacket sleeve, and the fluid transmission medium is maintained at atmospheric pressure.

(2) The device as claimed in the claims, wherein the device for sealing and circulating a fluid transfer medium has a first heat exchanger in contact with the cooling source, and the heat exchanger circulates the fluid transfer medium by convection. 3. The device as described above, further comprising a plurality of elongated, generally parallel flow paths for providing a flow path.

(3) An apparatus as defined in the preceding paragraph, having a second heat exchanger positioned coaxially with the first heat exchanger in contact with the cooling source, thereby controlling the length of the circulation path of the fluid transfer medium. The device as described above, characterized in that it is elongated.

(4) The device according to the preceding item, characterized in that a chimney is interposed between the first heat exchanger and the second heat exchanger in order to further strengthen the circulation of the fluid transfer medium by convection.

(5) The device according to the claims, characterized in that the fluid transmission medium is helium.

(6) A vertically elongated cooling section having a cooling end disposed near the superconducting magnet, a device for sealing and circulating a fluid transfer medium in contact with the cooling end of the cooling section, and the device for cooling the cooling section. an end-mounted heat exchanger for circulating a fluid transfer medium in an elongated closed circulation channel, a superconducting magnetic support, and a superconducting magnetic support; is placed in contact with the circulating fluid transmission medium, and its support is mounted so that the force generated by the movement of the cooling part is not directly transmitted to the superconducting magnet. Cooling transmission device that does not transmit.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal side view of the device according to the invention;
2 is an enlarged sectional view taken along line 2-2 in FIG. 1, FIG. 3 is an enlarged partial view of FIG. 1 illustrating another embodiment of the present invention, and FIG. FIG. 5 is a partially longitudinal side view showing an embodiment suitable for cooling a superconducting magnet. Explanation of symbols, 10... Closed circulation helium cooling source, 12... First cooling section, 14... Second cooling section, 16... Extension stud, 18... Support ring, 20... Support member, 22... ...specimen holder,
24...Support, 26...Support member, 28...Flexible vibration isolating sleeve, 30...Outer vacuum shielding plate, 32...Air outlet, 34...Vacuum jacket sleeve, 36...Radiant heat shield support adapter for, 38... radiant heat shield, 40... extension part, 4
2... Cooled object adapter, 43... Vertical passage,
44...Object to be cooled, 46...First stage heat exchanger, 4
8... Second stage heat exchanger, 49... Spacing piece, 5
2...Inlet, 54...Intake pipe, 56...Outlet pipe, 58...Heat exchanger, 60...Heat exchanger, 62
... Chimney, 64, 66 ... Heat exchanger, 68 ... Chimney, 70 ... Fluid housing, 72 ... Sleeve, 74 ... Cap, 80 ... Outer vacuum shell plate,
82...First shielding plate, 84...Second shielding plate, 86
...Jewel bottle, 88...Magnetic cavity, 90...Magnet, 92...Tube, 9
4... Electricity supply body, 100... Chimney, 10'...
Cooling source, 12'...first cooling section, 14'...second cooling section, 28'...vibration isolation sleeve.

Claims (1)

[Claims] 1 A device that transmits cooling from a cooling source to an object to be cooled via a cooling stage, in which the cooling source is fixed to a support of an immovable structure via a support member, and a fluid transmission system is installed around the cooling stage. Forms a circulation flow path for the medium,
A circulation means for the fluid transfer medium is provided in the circulation flow path, and the circulation means is a heat exchanger having a plurality of long substantially parallel flow paths for causing ring convection of the fluid transfer medium. , the heat exchanger is secured to the cooling stage and the cooled object is secured to the specimen holder via a cooled object adapter and its extension and vacuum jacket sleeve in contact with a circulating fluid transfer medium; The specimen holder is attached via a support member to an optical table that moves back and forth and left and right on a stand different from the support member of the cooling source attached to the support of the immovable structure, and the specimen holder is attached to the support member of the cooling source. are connected in a water-tight manner through a flexible vibration isolating sleeve to prevent the fluid transmission medium from leaking; A cooling transmission device that does not transmit vibrations and is configured to circulate within a flow path.