JPH05161625A - Superconducting device - Google Patents
Superconducting deviceInfo
- Publication number
- JPH05161625A JPH05161625A JP3329217A JP32921791A JPH05161625A JP H05161625 A JPH05161625 A JP H05161625A JP 3329217 A JP3329217 A JP 3329217A JP 32921791 A JP32921791 A JP 32921791A JP H05161625 A JPH05161625 A JP H05161625A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic shield
- magnetic
- temp
- temperature
- shield
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Measuring Magnetic Variables (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ＭＲＩ装置（医療用磁
気共鳴イメージング装置）等において、使用される超電
導装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting device used in an MRI apparatus (medical magnetic resonance imaging apparatus) or the like.
【０００２】[0002]
【従来の技術】ＭＩＲ装置では、強くかつ均一な磁場を
必要とするところから超電導装置が使用されることが多
い。2. Description of the Related Art Superconducting devices are often used in MIR devices because they require a strong and uniform magnetic field.
【０００３】このような超電導装置においては、周辺へ
の漏洩磁場のレベルが５ガウス（電子機器等に影響を及
ぼさないレベル）以上である空間範囲を出来るだけ小さ
くするために、超電導磁石の周囲に磁気シールドが配置
される。図２はその一例を示すもので、超電導装置は円
筒状の超電導磁石１と、この超電導磁石を取り巻く磁気
シールド２とからなる。In such a superconducting device, in order to minimize the spatial range in which the level of the leakage magnetic field to the surroundings is 5 gauss (the level that does not affect electronic equipment) or more, the surroundings of the superconducting magnet are used. A magnetic shield is placed. FIG. 2 shows an example thereof, and the superconducting device comprises a cylindrical superconducting magnet 1 and a magnetic shield 2 surrounding the superconducting magnet.
【０００４】磁気シールド２は、円筒状の磁性体２ａと
この構造体の両端に配した円環状の磁性端板２ｂ，２ｃ
から構成されており、その材質には、通常一般構造材
（ＪＩＳ ＳＳ４１）を用いている。The magnetic shield 2 includes a cylindrical magnetic body 2a and annular magnetic end plates 2b and 2c arranged at both ends of this structure.
The general structure material (JIS SS41) is used for the material.
【０００５】[0005]
【発明が解決しようとする課題】このような構造の超電
導装置においては、磁気シールド２により漏洩磁場を低
減するとともに、中心磁場の10％程度を分担して発生し
ている。In the superconducting device having such a structure, the magnetic shield 2 reduces the leakage magnetic field and shares about 10% of the central magnetic field.
【０００６】このため、磁気シールド材の磁気特性の温
度依存性により、また、シールド材の熱膨張による形状
変化により、外気温度が変化すると、中心磁場も変動す
るという問題があった。本発明は、上記問題を解決する
ためになされたもので、中心磁場の変動の少ない超電導
装置を提供することを目的とするものである。Therefore, there has been a problem that the central magnetic field also changes when the outside air temperature changes due to the temperature dependence of the magnetic characteristics of the magnetic shield material and the shape change due to the thermal expansion of the shield material. The present invention has been made to solve the above problems, and an object of the present invention is to provide a superconducting device in which the fluctuation of the central magnetic field is small.
【０００７】[0007]
【課題を解決するための手段】本発明の超電導装置は、
超電導磁石と、この超電導磁石からの漏洩磁場を低減す
る磁気シールドを備え、前記磁気シールドの周りに断熱
材を配置し、更に、磁気シールドには磁気シールド温度
を上昇させるためのヒータと磁気シールド温度を測る温
度センサーを設け、この温度センサーの信号を受けてヒ
ータを動作状態にする温度コントローラを備えた構成と
する。The superconducting device of the present invention comprises:
A superconducting magnet and a magnetic shield for reducing a leakage magnetic field from the superconducting magnet are provided, a heat insulating material is arranged around the magnetic shield, and the magnetic shield has a heater for increasing the magnetic shield temperature and a magnetic shield temperature. A temperature sensor for measuring the temperature is provided, and a temperature controller that receives a signal from the temperature sensor and activates the heater is provided.
【０００８】[0008]
【作用】上述のような構成の本発明の装置においては、
磁気シールドの周りに断熱材を配したため、外気温度が
変動しても、磁気シールド温度は一定に保たれる。更
に、温度コントローラにより磁気シールドに設けられた
ヒータを制御し磁気シールド温度を一定に保つ。これら
のことから、磁気特性の温度依存性による中心磁場の変
動及び、シールド材の熱膨張による形状変化による中心
磁場の変動を低減できる。In the apparatus of the present invention having the above-mentioned structure,
Since the heat insulating material is arranged around the magnetic shield, the magnetic shield temperature is kept constant even if the outside air temperature fluctuates. Further, the temperature controller controls the heater provided on the magnetic shield to keep the magnetic shield temperature constant. From these, it is possible to reduce the fluctuation of the central magnetic field due to the temperature dependence of the magnetic characteristics and the fluctuation of the central magnetic field due to the shape change due to the thermal expansion of the shield material.
【０００９】[0009]
【実施例】次に図面を参照しながら、本発明の実施例を
説明する。図１は本発明にかかる超電導装置の実施例を
示す図である。Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a superconducting device according to the present invention.
【００１０】この図において、超電導磁石１は超電導コ
イル３を液体ヘリウム等の極低温冷媒と共に極低温冷媒
容器（図示せず）内に収容し、これらと更に真空断熱空
間を形成する真空容器４内に収めて構成されている。In this figure, a superconducting magnet 1 accommodates a superconducting coil 3 together with a cryogenic refrigerant such as liquid helium in a cryogenic refrigerant container (not shown), and a vacuum container 4 which forms a vacuum heat insulation space with them. It is housed in.
【００１１】超電導磁石１の外側には、磁気シールド２
が配置されている。この磁気シールドは円筒状の磁性体
２ａとこの構造体の両端に配した円環状の磁性端板２
ｂ，２ｃから構成されており、円筒状の磁性体２ａ、円
環状の磁性端板２ｂ，２ｃの外側には断熱材５が配置さ
れ、更に、磁気シールド２には磁気シールド温度を上昇
させるためのヒータ６とシールド温度を測る温度センサ
ー７を設けている。磁気シールド２に設けられたヒータ
６はコントローラ８から電流を流して動作させる。A magnetic shield 2 is provided outside the superconducting magnet 1.
Are arranged. This magnetic shield comprises a cylindrical magnetic body 2a and an annular magnetic end plate 2 arranged at both ends of this structure.
b, 2c, and a heat insulating material 5 is arranged outside the cylindrical magnetic body 2a and the annular magnetic end plates 2b, 2c. Further, the magnetic shield 2 is for increasing the magnetic shield temperature. The heater 6 and the temperature sensor 7 for measuring the shield temperature are provided. The heater 6 provided on the magnetic shield 2 is operated by supplying a current from the controller 8.
【００１２】このような構成の本実施例の超電導装置に
おいては、磁気シールド２は断熱材５により外気から遮
蔽されているため、外気温度が変化しても磁気シールド
２の温度は一定に保たれる。更に、磁気シールド温度が
Ｔ１以下になると温度センサー７からの信号がコントロ
ーラ８に入り、ヒータ６を動作させ、磁気シールド温度
を上昇させる。次に、磁気シールド温度が一定温度Ｔ２
（ただしＴ１＜Ｔ２）を超えるとコントローラは自動的
にＯＦＦになる。このようにして磁気シールド温度を一
定に保つ。これらのことから、熱膨張による磁気シール
ドの形状変化及び、磁気シールド材の磁気特性の温度依
存性による中心磁場の変動が低減される。In the superconducting device of this embodiment having such a structure, since the magnetic shield 2 is shielded from the outside air by the heat insulating material 5, the temperature of the magnetic shield 2 is kept constant even if the outside air temperature changes. Be done. Further, when the magnetic shield temperature becomes T1 or lower, a signal from the temperature sensor 7 enters the controller 8 to operate the heater 6 to raise the magnetic shield temperature. Next, the magnetic shield temperature is a constant temperature T2.
When (T1 <T2) is exceeded, the controller automatically turns off. In this way, the magnetic shield temperature is kept constant. From these facts, the shape change of the magnetic shield due to the thermal expansion and the fluctuation of the central magnetic field due to the temperature dependence of the magnetic characteristics of the magnetic shield material are reduced.
【００１３】なお、上記実施例では磁気シールドの構成
体全ての外側に断熱材を配した装置について説明した
が、本発明はこれに限定されるものではなく、断熱材を
円筒状磁性体の外側のみ配した場合でも十分効果が得ら
れる。更に、断熱材の配置のみを単独で実施する、ある
いは、温度センサーとコントローラとヒータの装備のみ
を単独で実施してもよい。In the above embodiment, the heat insulating material is arranged on the outer side of all the magnetic shield components, but the present invention is not limited to this, and the heat insulating material is placed on the outer side of the cylindrical magnetic body. Even if only it is placed, the effect is sufficient. Furthermore, only the disposition of the heat insulating material may be carried out alone, or only the equipment of the temperature sensor, the controller and the heater may be carried out alone.
【００１４】[0014]
【発明の効果】以上説明したように本発明に係る超電導
装置においては、外気温度が変動しても、磁気シールド
材の温度依存性による中心磁場の変動及びシールド材の
熱膨張による形状変化による中心磁場の変動を低減でき
る。As described above, in the superconducting device according to the present invention, even if the outside air temperature fluctuates, the central magnetic field fluctuates due to the temperature dependence of the magnetic shield material and the center due to the shape change due to the thermal expansion of the shield material. The fluctuation of the magnetic field can be reduced.
【図１】本発明の超電導装置の実施例を示す縦断概略
図、FIG. 1 is a schematic vertical sectional view showing an embodiment of a superconducting device of the present invention,
【図２】従来の超電導装置の縦断断面図である。FIG. 2 is a vertical sectional view of a conventional superconducting device.
１…超電導磁石 ２…磁気シールド ３…超電導コイル ４…真空容器 ５…断熱材 ６…ヒータ ７…温度センサー ８…コントローラ 1 ... Superconducting magnet 2 ... Magnetic shield 3 ... Superconducting coil 4 ... Vacuum container 5 ... Heat insulating material 6 ... Heater 7 ... Temperature sensor 8 ... Controller
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 7621−2Ｊ Ｇ０１Ｒ 33/22 Ｍ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Office reference number FI technical display location 7621-2J G01R 33/22 M
Claims (2)
洩磁場を低減する磁気シールドを備え、前記磁気シール
ドの周りに、断熱材を配したことを特徴とする超電導装
置。1. A superconducting device comprising: a superconducting magnet; and a magnetic shield for reducing a leakage magnetic field from the superconducting magnet, wherein a heat insulating material is arranged around the magnetic shield.
洩磁場を低減する磁気シールドを備え、前記磁気シール
ドに、磁気シールド温度を上昇させるためのヒータと磁
気シールド温度を測る温度センサーを設け、この温度セ
ンサーの信号を受けてヒータを動作状態にする温度コン
トローラを備えたことを特徴とする超電導装置。2. A superconducting magnet and a magnetic shield for reducing a leakage magnetic field from the superconducting magnet, wherein the magnetic shield is provided with a heater for increasing the magnetic shield temperature and a temperature sensor for measuring the magnetic shield temperature. A superconducting device comprising a temperature controller that receives a signal from a temperature sensor and activates a heater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3329217A JPH05161625A (en) | 1991-12-13 | 1991-12-13 | Superconducting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3329217A JPH05161625A (en) | 1991-12-13 | 1991-12-13 | Superconducting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05161625A true JPH05161625A (en) | 1993-06-29 |
Family
ID=18218964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3329217A Pending JPH05161625A (en) | 1991-12-13 | 1991-12-13 | Superconducting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05161625A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009119261A (en) * | 2007-11-09 | 2009-06-04 | General Electric Co <Ge> | System, method and apparatus for controlling drift of a main magnetic field in mri system |
| JP2012039092A (en) * | 2010-06-30 | 2012-02-23 | General Electric Co <Ge> | Magnet assembly and method for temperature control of the magnet assembly |
| JP2014233635A (en) * | 2013-06-03 | 2014-12-15 | シーメンス アクチエンゲゼルシヤフトＳｉｅｍｅｎｓ Ａｋｔｉｅｎｇｅｓｅｌｌｓｃｈａｆｔ | Method for operating mobile magnetic resonance tomography |
-
1991
- 1991-12-13 JP JP3329217A patent/JPH05161625A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009119261A (en) * | 2007-11-09 | 2009-06-04 | General Electric Co <Ge> | System, method and apparatus for controlling drift of a main magnetic field in mri system |
| JP2012039092A (en) * | 2010-06-30 | 2012-02-23 | General Electric Co <Ge> | Magnet assembly and method for temperature control of the magnet assembly |
| JP2014233635A (en) * | 2013-06-03 | 2014-12-15 | シーメンス アクチエンゲゼルシヤフトＳｉｅｍｅｎｓ Ａｋｔｉｅｎｇｅｓｅｌｌｓｃｈａｆｔ | Method for operating mobile magnetic resonance tomography |
| CN104215923A (en) * | 2013-06-03 | 2014-12-17 | 西门子公司 | Mobile Magnetic Resonance Tomography |
| US9709647B2 (en) | 2013-06-03 | 2017-07-18 | Siemens Aktiengesellschaft | Mobile magnetic resonance tomography |
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