JP7329367B2 - superconducting device - Google Patents

Description

The present invention relates to superconducting devices.

Conventionally, a superconducting device described in Patent Document 1 below is known. In this device, a superconducting element is housed in a cryogenic container cooled to an extremely low temperature. A pair of positive and negative current leads extend from the superconducting element through the wall of the cryocontainer to the outside in order to supply current to the superconducting element from the outside. Condensation occurs at a portion (extraction portion) near the wall of the cryocontainer among the current leads drawn to the outside due to the temperature difference between the extraction portion and the outside of the cryocontainer, and ice adheres to the extraction portion. . If the ice attached to each of the pair of positive and negative lead-out portions grows and the two are brought close to each other, the electric current will be short-circuited. In order to reduce such work load, it is desired to suppress the icing on the drawer portion. In order to solve this problem, Japanese Patent Laid-Open No. 2002-100003 proposes to suppress the icing on the drawn-out portion by arranging a heater around the drawn-out portion.

Patent No. 5649682

However, raising the temperature of the lead-out portion of the current lead by the heater causes an increase in heat penetration into the cryocontainer, which is not preferable. SUMMARY OF THE INVENTION It is an object of the present invention to provide a superconducting device that suppresses icing on the lead-out portion while suppressing an increase in the temperature of the lead-out portion of the current lead.

The superconducting device of the present invention comprises a cryogenic vessel whose interior is cooled by cooling means, a superconducting element housed inside the cryogenic vessel, a superconducting element extending from the superconducting element to the outside of the cryogenic vessel, and a superconducting element extending from the cryogenic vessel to the outside of the cryogenic vessel. Humidity reduction that reduces the humidity around the current lead that supplies current to the superconducting element and the current lead that is drawn to the outside from the container wall that partitions the inside of the cryogenic container, which is the portion near the container wall. and

The humidity lowering section may have a cover surrounding the drawer portion and lower the humidity in the inner space of the cover. Also, the humidity lowering section may have a dehumidifying section that is installed in the internal space of the cover and dehumidifies the internal space. The humidity lowering section may have a low humidity gas supply section that supplies low humidity gas around the drawer portion.

According to the present invention, it is possible to provide a superconducting device that suppresses icing on the lead-out portion while suppressing an increase in the temperature of the lead-out portion of the current lead.

It is a sectional view of a building in which a cyclotron of this embodiment is installed. It is a sectional view of the cyclotron of this embodiment. (a) is a diagram schematically showing a cyclotron according to a modification, and (b) is a diagram schematically showing the vicinity of an input electrode section of a cyclotron according to another modification. (a) is a diagram schematically showing a cyclotron according to still another modification, and (b) is a diagram schematically showing the vicinity of an input electrode section of the cyclotron according to still another modification. FIG. 10 is a diagram schematically showing a cyclotron according to still another modification;

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted.

As shown in FIG. 1, a cyclotron 1 (superconducting device) according to this embodiment is used as an accelerator of a charged particle beam therapy device 101, for example. A charged particle beam therapy system 101 is installed in a building 103 . A cyclotron 1 is installed on the lower floor of the building 103 , and a rotating gantry 105 is installed on the upper floor of the building 103 .

The cyclotron 1 and rotating gantry 105 are connected by a transfer line 107 . A charged particle beam emitted from the cyclotron 1 is transported by a transport line 107 and sent to a rotating gantry 105 . A wall 109 of the building 103 surrounding the cyclotron 1 and the like is a radiation shielding wall having a sufficient thickness for suppressing transmission of radiation, so that the radiation generated by the cyclotron 1 hardly leaks out of the building 103. there is

As shown in FIG. 2, the cyclotron 1 has a circular shape centered on a vertical central axis C in plan view. In FIG. 2, the left side of the central axis C shows a cross section along a vertical plane including the central axis C and the load support 12, and the right side of the central axis C includes the central axis C and the current lead 20. A section along a vertical plane is shown.

The cyclotron 1 is a horizontal circular accelerator that supplies charged particles from an ion source (not shown) into the acceleration space G, accelerates the charged particles in the acceleration space G, and outputs a charged particle beam. Examples of charged particles include protons and heavy particles (heavy ions).

The cyclotron 1 includes a superconducting electromagnet device 5 (superconducting device) in addition to the ion source. The superconducting electromagnet device 5 has poles 3 and 4, a yoke 6, superconducting coils 7 and 8 (superconducting elements), a coil support frame 9, and a vacuum vessel 10 (cryogenic vessel).

The poles 3 and 4 are spaced apart in the direction C of the central axes of the superconducting coils 7 and 8 (the winding central axes of the superconducting coils 7 and 8). The cyclotron 1 is arranged and used so that the central axis C is vertical. The pole 3 is an upper pole arranged above the acceleration space G, and the pole 4 is a lower pole arranged below the acceleration space G. An electrode (di electrode, not shown) is provided between the poles 3 and 4 . An electric field is formed by applying a high frequency to this electrode.

The yoke 6 is a hollow disc-shaped block, in which the poles 3 and 4 and the vacuum vessel 10 are arranged. The yoke 6 prevents the magnetic lines of force generated by the superconducting coils 7 and 8 and the poles 3 and 4 from leaking to the outside.

The upper superconducting coil 7 is wound around the center axis C so as to cover the outer circumference of the pole 3 , and the lower superconducting coil 8 is wound so as to cover the outer circumference of the pole 4 . The superconducting coils 7 and 8 are arranged side by side in the central axis C direction and housed in a coil support frame 9 . The superconducting coils 7 and 8 have a coil body wound with a superconducting wire, and a high-temperature superconducting wire may be used as the superconducting wire. As a high-temperature superconducting wire, an oxide superconductor (for example, Bi2223, Bi2212, Y123), MgB2, or the like may be used. A low-temperature superconducting wire may be used as the superconducting wire. For example, the superconducting coils 7 and 8 are not provided with an inner frame (or an inner winding frame) on the inner peripheral side, and the inner peripheral surfaces of the coils (wire and adhesive for fixing the wire) are adhered by another member.・It is an air-core coil that is not fixed. The coil support frame 9 is fixed to and supported by the yoke 6 via a load support 12 . The load supports 12 are arranged at, for example, four positions in the circumferential direction with the central axis C as the center.

The vacuum vessel 10 includes a coil housing portion 10a extending in an annular shape around the central axis C, a cylindrical support body housing portion 10b extending vertically in communication with the coil housing portion 10a, and a support body housing portion 10b communicating with the coil housing portion 10a. and a cylindrical electrode accommodating portion 10c extending upward. The superconducting coils 7 and 8 mounted on the coil support frame 9 are accommodated in the coil accommodating portion 10a. The load support 12 is accommodated in the support accommodation portion 10b. A current lead 20 for introducing a current to the superconducting coils 7 and 8 from the outside passes through the electrode accommodating portion 10c. The cyclotron 1 has a pair of positive and negative current leads 20, and these pairs of current leads 20 have the same structure.

A refrigerator 13 (cooling means) for cooling the superconducting coils 7 and 8 is connected to the vacuum vessel 10 . The refrigerator 13 is, for example, a GM refrigerator. The refrigerator 13 can cool the inside of the vacuum vessel 10 and cool the superconducting coils 7 and 8 to, for example, 4K. The refrigerator is not limited to a GM refrigerator (Gifford-McMahon cooler), and may be, for example, a Stirling refrigerator or other refrigerators.

A current lead 20 is electrically connected to the superconducting coils 7 and 8, penetrates the container wall that defines the interior of the vacuum container 10, and is led out to the outside. Specifically, each current lead 20 extends from the superconducting coils 7 and 8 to the outside of the vacuum vessel 10 through the electrode housing portion 10 c and through the vessel wall 11 at the upper end of the vacuum vessel 10 . A portion of the current lead 20 drawn out from the container wall 11 to the outside is formed as an input terminal portion 15 (extracted portion) in the immediate vicinity of the container wall 11 . The pair of input terminal portions 15 are connected to the positive and negative electrodes of an external power supply (not shown), which is a current supply source.

Since the surroundings of the input terminal section 15 are at room temperature, dew condensation occurs due to the temperature difference between the input terminal section 15 itself and the room temperature, and ice adheres to the input terminal section 15 . If the ice attached to the pair of positive and negative input terminals 15 grows and the two come close to each other, the current will short circuit. When physically destroying the ice on the input terminal section 15, it is also necessary to do so carefully so as not to damage the input terminal section 15 and the current lead 20. FIG. In order to reduce such work load, it is desirable to suppress the icing on the input terminal portion 15 .

Therefore, the cyclotron 1 is provided with a humidity reduction section 30 that reduces the humidity around the input terminal section 15 . Since the humidity around the input terminal portion 15 is lowered by the humidity lowering portion 30, the dew point of the air around the input terminal portion 15 is lowered, so that dew condensation on the input terminal portion 15 is suppressed. The icing on the terminal portion 15 is suppressed. According to such a humidity lowering unit 30, it is possible to suppress icing without heating the input terminal unit 15 (or by suppressing the heating temperature). Heat penetration into the interior of the vacuum vessel 10 can be suppressed.

Moreover, if it is intended to suppress the icing on the input terminal portion 15 or to thaw the ice on the input terminal portion 15 only by heating the input terminal portion 15, a relatively high output heater is required. become. If a control failure or the like occurs in a high-output heater, the input terminal section 15 and its peripheral parts may be damaged by burning. According to the humidity lowering unit 30, icing can be suppressed without heating the input terminal unit 15 (or by suppressing the heating temperature). problem can also be suppressed.

A specific configuration of such a humidity lowering section 30 will be described below.

The humidity lowering section 30 has a cover 31 surrounding the input terminal section 15 . Further, the humidity lowering section 30 has a dehumidifying section 35 installed in the inner space 33 to dehumidify the inner space 33 in order to lower the humidity in the inner space 33 surrounded by the cover 31 . The cover 31 partitions the internal space 33 from the outside, and may be composed of, for example, a metal frame material and a sheet material (for example, a vinyl sheet) stretched over the frame material. Alternatively, cover 31 may be made of plastic.

The cover 31 is constructed on the outer wall surface of the yoke 6 of the superconducting electromagnet device 5, for example. The dehumidifier 35 may be, for example, a known dehumidifier or a commercially available air conditioner. Also, the dehumidifier 35 may be a dehumidifier (for example, silica gel, etc.) installed in the internal space 33, for example. According to this configuration, the internal space 33 of the cover 31 in which the input terminal portion 15 exists can be made lower in humidity than the outside, and the humidity around the input terminal portion 15 can be reduced.

As shown in FIG. 3( a ), a humidity reducing section 30 may be provided for each of the two input terminal sections 15 . In this case, there are two covers 31 separately surrounding the two input terminals 15, and dehumidifiers 35 are installed in the two internal spaces 33, respectively. Further, if the portion of the cyclotron 1 other than the humidity lowering section 30 is referred to as the "apparatus main body 2", as shown in FIG. The entire device body 2 may be accommodated within 33 .

Also, the configuration of the humidity lowering section 30 for lowering the humidity in the internal space 33 of the cover 31 may be as shown in FIG. 4(a). The humidity lowering portion 30 of FIG. 4A includes a cover 31 provided with an air inlet 37, and a low humidity gas A (a gas containing a small amount of water vapor) is introduced into the inner space 33 of the cover 31 through the air inlet 37. and a blower device 39 (low-humidity gas supply unit) for sending in the gas. As the low-humidity gas A, for example, dry air, dry nitrogen, or the like is applied. A cover 31 surrounds the entire device main body 2 , and the entire device main body 2 is accommodated in an internal space 33 . This configuration also makes it possible to make the internal space 33 of the cover 31 in which the input terminal portion 15 exists lower in humidity than the outside. The blower 39 may be a commercially available air conditioner.

Further, as shown in FIG. 4B, the cover 31 may be further provided with an air outlet 41 so that the low-humidity gas A from the air blower 39 blows through the interior space 33 . According to this configuration, the low-humidity gas A from the blower 39 is efficiently introduced into the internal space 33 .

2 to 4 as described above are different from the wall 109 (see FIG. 1) of the building 103 in which the cyclotron 1 is installed. That is, each cover 31 is provided separately from the wall 109 of the building 103 in which the cyclotron 1 is installed, and exists as part of the cyclotron 1 within the building 103 . Unlike the wall 109, each cover 31 is not expected to have a radiation shielding function, and has almost no radiation shielding function. Furthermore, the dehumidifier 35 and the blower 39 are also provided separately from the air conditioning equipment for air conditioning the interior of the building 103 and exist as a part of the cyclotron 1 within the building 103 .

Also, the configuration of the humidity lowering section 30 for lowering the humidity around the input terminal section 15 may be as shown in FIG. 5, the cover 31 is omitted, and the low-humidity gas A from the air blower 39 is blown toward the input terminal portion 15. As shown in FIG.

Further, the cyclotron 1 shown in FIGS. 2 to 5 may be provided with a heating section (not shown) for heating each input terminal section 15 in addition to the humidity reducing section 30 . In this case, since icing is suppressed by the humidity lowering section 30, heating of the input terminal section 15 by the heating section can be suppressed accordingly, and an increase in temperature of the input terminal section 15 can be suppressed.

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications, and may be modified within the scope of not changing the gist described in each claim. good too. You may use it, combining suitably the structure of each embodiment and a modification.

For example, in the above-described embodiment, the refrigerator 13 is used as an example of cooling means for cooling the inside of the vacuum vessel 10, but this cooling means is not limited to a refrigerator. The inside of the container 10 may be cooled.

DESCRIPTION OF SYMBOLS 1... Cyclotron (superconducting device), 5... Superconducting electromagnet device (superconducting device), 7, 8... Superconducting coil (superconducting element), 10... Vacuum container (low-temperature container), 11... Container wall, 13... Refrigerating machine (cooling means) 15 Input terminal portion (drawer portion) 20 Current lead 30 Humidity lowering portion 31 Cover 33 Internal space 35 Dehumidifying portion 39 Blower (low humidity gas supply section), A: low-humidity gas.

Claims (4)

a cryocontainer whose interior is cooled by a cooling means;
a superconducting element housed inside the cryocontainer;
a current lead extending from the superconducting element to the exterior of the cryocontainer and supplying current from the exterior of the cryocontainer to the superconducting element;
a humidity lowering part for lowering the humidity around a lead-out portion, which is a portion near the container wall, of the current lead drawn to the outside from the container wall that partitions the inside of the low-temperature container ;
The humidity lowering part is
a cover surrounding the pull-out portion;
a dehumidification unit that dehumidifies the internal space of the cover,
The dehumidification unit
A superconducting device that is an air conditioner or a dehumidifier installed in the interior space of the cover . 2. The superconducting device of claim 1, wherein said cover is constructed on said vessel wall. 2. The superconducting device of claim 1, wherein said cover completely surrounds said cryocontainer. 4. The superconducting device according to claim 3, wherein said cover is provided separately from a wall of a building in which said superconducting device is installed.

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