JPH01109708A - Superconducting magnet device - Google Patents
Superconducting magnet deviceInfo
- Publication number
- JPH01109708A JPH01109708A JP62266300A JP26630087A JPH01109708A JP H01109708 A JPH01109708 A JP H01109708A JP 62266300 A JP62266300 A JP 62266300A JP 26630087 A JP26630087 A JP 26630087A JP H01109708 A JPH01109708 A JP H01109708A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- gradient magnetic
- heat shield
- field coil
- superconducting magnet
- 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
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 5
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 238000000137 annealing Methods 0.000 claims description 2
- 230000006698 induction Effects 0.000 abstract description 5
- 230000003247 decreasing effect Effects 0.000 abstract 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 239000007788 liquid Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 6
- 239000001307 helium Substances 0.000 description 5
- 229910052734 helium Inorganic materials 0.000 description 5
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 238000004804 winding Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000016507 interphase Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000002595 magnetic resonance imaging Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Landscapes
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は例えば磁気共鳴イメージング用などに好まし
く用いることのできる超電導マグネット装置に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a superconducting magnet device that can be preferably used, for example, for magnetic resonance imaging.
第４図は従来の超電導マグネット装置の要部を示す俯敞
図であり１図において、（りは靜磁界発生用の超電導マ
グネツ） 、 （２）はこの超電導マグネット（りの開
口部に取付けられたパルス磁場発生用の傾斜磁場コイル
、軸Ｏは超電導マグネット（１）の中心線である。又矢
印ｘ、ｙ、ｚは座標系を示す。Figure 4 is an overhead view showing the main parts of a conventional superconducting magnet device. The axis O is the center line of the superconducting magnet (1), and the arrows x, y, and z indicate the coordinate system.
第５図は第４図に示した超電導マグネット装置の縦（ｙ
ｚ面）断面図を示す。第５図において（１ａ）は均一な
静磁場を発生する超電導コイル、（１ｂ）は超電導を維
持するに必要な寒剤である液体ヘリウムを貯液する液体
ヘリウム槽、 （Ｉｃ）は液体窒素槽、（１ｄ）はこの
液体窒素槽に接合された鏡板状の熱シールド板、 （１
ｅ）はこの熱シールド板（１ｄ）に接合された円筒状の
熱シールド部材を示す。これら熱シールド部材（１ｄ）
Ｉ（１ｅ）は液体窒素槽（ＩＣ）と〆に液体ヘリウム槽
（１ｂ）を囲みこの液体ヘリウム槽（１ｂ）への熱侵入
を低減する。Figure 5 shows the vertical (y) superconducting magnet device shown in Figure 4.
z-plane) sectional view is shown. In Figure 5, (1a) is a superconducting coil that generates a uniform static magnetic field, (1b) is a liquid helium tank that stores liquid helium, a cryogen necessary to maintain superconductivity, (Ic) is a liquid nitrogen tank, (1d) is a mirror-like heat shield plate joined to this liquid nitrogen tank, (1
e) shows a cylindrical heat shield member joined to this heat shield plate (1d). These heat shield members (1d)
I (1e) surrounds a liquid helium tank (1b) between the liquid nitrogen tank (IC) and reduces heat intrusion into the liquid helium tank (1b).
（２ａ）は傾斜磁場コイル巻枠、 （２ｂ）は円筒形の
傾斜磁場コイル、（２Ｃ）は鞍形の傾斜磁場コイルを示
す。上記円筒形の熱シールド部材（１ｅ）は例えば銅な
どの単一の金属板で構成されている。(2a) shows a gradient magnetic field coil winding frame, (2b) shows a cylindrical gradient magnetic field coil, and (2C) shows a saddle-shaped gradient magnetic field coil. The cylindrical heat shield member (1e) is made of a single metal plate, such as copper.
第６図は上記円筒状の熱シールド部材（１ｅ）と。FIG. 6 shows the cylindrical heat shield member (1e).
傾斜磁場コイル巻枠（２ａ）、又傾斜磁場コイルの１例
として２方向に１次の傾斜ａ場を発生させる円筒形傾斜
磁場コイル（２ｂ）の相間関係を示したものである。こ
の場合円筒形傾斜磁場コイル（２ｂ）はＺ方向に１次の
傾斜磁場を発生するためにβ＝ Ｉ −Ｉｓ ／２に取
付けられている。熱シールド部材（１ｅ）は液体窒素槽
（１ｃ）に鏡板状の熱シールド板（１ｄ）を介して接合
されており、液体窒素温度となっている。一方傾斜磁場
コイル（２ｂ） Ｋ、は図示しない電源装置によりパル
ス状の電流が通電され、マグネット中心付近で空間直線
性の高いパルス状の傾斜磁界を発生させる。この時上記
の如く円筒形の熱シールド部材（１ｅ）は傾斜磁場コイ
ル（２ｂ）との相互誘導作用による誘導電流が傾斜磁場
コイル（２ｂ）との最短距離部位を中心として円筒形の
熱シールド部材（１ｅ）の表面に流れる。This figure shows the interphase relationship between a gradient magnetic field coil winding frame (2a) and a cylindrical gradient magnetic field coil (2b) that generates a first-order gradient a field in two directions as an example of a gradient magnetic field coil. In this case, the cylindrical gradient coil (2b) is mounted at β=I-Is/2 in order to generate a first-order gradient magnetic field in the Z direction. The heat shield member (1e) is joined to the liquid nitrogen tank (1c) via a mirror-like heat shield plate (1d), and is at the liquid nitrogen temperature. On the other hand, the gradient magnetic field coil (2b) K is supplied with a pulsed current by a power supply device (not shown), and generates a pulsed gradient magnetic field with high spatial linearity near the center of the magnet. At this time, as described above, the cylindrical heat shield member (1e) is such that the induced current due to mutual induction with the gradient magnetic field coil (2b) is centered on the shortest distance part from the gradient magnetic field coil (2b). It flows on the surface of (1e).
第７図はこの誘導電流の分布を傾斜磁場コイルとの相対
位置で示したものである。第７図において１点０はマグ
ネット中心であり、傾斜磁場コイル巻枠（２ａ）の軸０
方向の中心部である。−点鎖線りは点０な通り、軸０に
直交する直線、ｚ、は直線りと円筒形傾斜磁場コイル（
２ｂ）の中心部との距離、ｒ、は円筒形傾斜磁場コイル
（２ｂ）の半径、ｒ、は熱シールド部材（１ｅ）の半径
である。FIG. 7 shows the distribution of this induced current in terms of its relative position to the gradient magnetic field coil. In FIG. 7, point 0 is the center of the magnet, and the axis 0 of the gradient coil winding frame (2a)
The center of the direction. - The dotted chain line represents the point 0, a straight line orthogonal to the axis 0, and z represents the straight line and the cylindrical gradient magnetic field coil (
2b), the distance from the center, r, is the radius of the cylindrical gradient magnetic field coil (2b), and r is the radius of the heat shield member (1e).
円筒形傾斜磁場コイル（２ｂ）のマグネット中心０から
の軸方向距離２．と、径方向距離ｒ、との比をβとする
と、第６図に示すものは、の位置となっているが、熱シ
ールド部材（１ｅ）の誘導電流は。Axial distance from the magnet center 0 of the cylindrical gradient coil (2b)2. If the ratio between r and radial distance r is β, the position shown in FIG. 6 is , but the induced current in the heat shield member (1e) is .
／ ： ”１／ｒ、 ＜ ｖ／ ３／２の位置を中心に
流れることとなる。/: ``1/r, < v/ 3/2 The flow will be centered at the position.
従来の超電導マグネット装置は以上のように構成され動
作するので、傾斜磁場コイルが所定の位置β＝Ｉ名１で
直線性の良い１次の傾斜磁場な出力しても、熱シールド
部材に流れる誘導電流が傾斜磁場コイルとは逆の磁界を
出力するため、傾斜磁場コイルの磁界が低下するだけで
は無く誘導電流はβ＝Ｉｙ【の位置に流れないため磁場
の直線性を損うとい５問題点があった。Conventional superconducting magnet devices are configured and operate as described above, so even if the gradient magnetic field coil outputs a first-order gradient magnetic field with good linearity at a predetermined position β = I, the induction flowing into the heat shield member Since the current outputs a magnetic field opposite to that of the gradient magnetic field coil, not only does the magnetic field of the gradient magnetic field coil decrease, but the induced current does not flow to the position β = Iy, which impairs the linearity of the magnetic field. there were.
この発明は上記のような問題点を解消するためになされ
たもので傾斜磁場コイルが直線性の良い１へ出力となる
超電導マグネット装置を得ることを目的とする。This invention was made to solve the above-mentioned problems, and an object thereof is to obtain a superconducting magnet device in which a gradient magnetic field coil outputs a linear output with good linearity.
この発明に係る超電導マグネット装置は、熱シールド部
材の一部を低抵抗体で構成したものである。In the superconducting magnet device according to the present invention, a part of the heat shield member is made of a low resistance material.
この発明における熱シールド部材はその一部を低抵抗体
で構成したことにより、この低抵抗部分に傾斜磁場コイ
ルの誘導電流を選択的に流し、傾斜磁場の直線性を損う
ことの無い様にする。The heat shield member in this invention has a part made of a low-resistance material, so that the induced current of the gradient magnetic field coil can be selectively passed through this low-resistance part, so as not to impair the linearity of the gradient magnetic field. do.
以下、この発明の一実施例を図について説明する。第１
図は１円筒形の熱シールド部材（１ｅ）と。An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a cylindrical heat shield member (1e).
傾斜磁場コイル巻枠（２ａ）、傾斜磁場コイルの１例と
してＺ方向に１次の傾斜磁場を発生させる円筒形傾斜磁
場コイル（２ｂ）の相間関係を示したものである。又図
中（４ａ）は円筒熱シールド板内に設けた低抵抗体部分
を示す。This figure shows the interphase relationship between a gradient magnetic field coil winding frame (2a) and a cylindrical gradient magnetic field coil (2b) that generates a primary gradient magnetic field in the Z direction as an example of a gradient magnetic field coil. Further, (4a) in the figure shows a low resistance element portion provided within the cylindrical heat shield plate.
第２図は第１図の中心線に沿った縦断面図に傾斜磁場コ
イル（２ｂ）による円筒熱形のシールド部材（１ｅ）へ
の誘導電流の分布グラフを併記したものである。図にお
いて円筒形熱シールド部材（１ｅ）に設けた低抵抗体（
４ａ）が傾斜磁場コイル（２ｂ）よりも磁界中心九対し
て外側にあるため、誘導電流も傾斜磁場コイル（２ｂ）
よりも外側に分布すること〜なる。FIG. 2 is a vertical cross-sectional view taken along the center line of FIG. 1 with a graph of the distribution of the induced current flowing into the cylindrical thermal shield member (1e) caused by the gradient magnetic field coil (2b). In the figure, a low resistance element (
4a) is located outside the gradient magnetic field coil (2b) with respect to the center of the magnetic field, so the induced current also flows to the gradient magnetic field coil (2b).
It is to be distributed on the outside.
以上の如く誘導電流が傾斜磁場コイル（２ｂ）より外側
に流れるため誘導電流が作る磁場中心付近での磁界が小
さ（なる。これに伴い磁場中心付近では誘導電流が作る
磁場に含まれる１次出力に対する誤差成分の絶対値も小
さくなる。この結果傾斜ａ場コイル（２ｂ）が作る直線
性の良い１次傾斜磁場を損うことが低減できる。As described above, since the induced current flows outside of the gradient magnetic field coil (2b), the magnetic field near the center of the magnetic field created by the induced current becomes small.As a result, near the center of the magnetic field, the primary output included in the magnetic field created by the induced current The absolute value of the error component for the gradient a-field coil (2b) also becomes smaller.As a result, damage to the primary gradient magnetic field with good linearity produced by the gradient a-field coil (2b) can be reduced.
又、円筒形の熱シールド部材（１ｅ）内の低抵抗体（４
ａ）部分を誘導電流が１円筒傾斜磁場コイル（２ｂ）と
同じβの位置
ｒ、 ｒ２
となる様に低抵抗体を設ける。この場合誘導電流による
磁界成分は、直線性の良い１次成分とすることができ、
傾斜磁場コイル（２ｂ）が作る直線性の良い１次傾斜磁
場を損うことが無くなる。Moreover, the low resistance element (4) inside the cylindrical heat shield member (1e)
A low resistance body is provided in the a) part so that the induced current is at the same β positions r and r2 as the one cylindrical gradient magnetic field coil (2b). In this case, the magnetic field component due to the induced current can be a linear component with good linearity,
The primary gradient magnetic field with good linearity produced by the gradient magnetic field coil (2b) is not impaired.
尚、円筒形の熱シールド部材（１ｅ）が銅板で構成され
ている場合、低抵抗部分は銅板を焼なますことにより作
ることが可能である。Note that when the cylindrical heat shield member (1e) is made of a copper plate, the low resistance portion can be made by annealing the copper plate.
上記の実施例では円筒形傾斜磁場コイルについて述べた
がこれに限定されるものではな（１例えば第６図に示す
如（鞍形傾斜磁場コイルについても適用することができ
る。なお、図中、（４ｂ）は低抵抗体である。In the above embodiments, a cylindrical gradient magnetic field coil was described, but the invention is not limited to this (1) For example, as shown in FIG. 6 (the saddle-shaped gradient coil can also be applied. (4b) is a low resistance material.
また、上記実施例では超電導コイルとして液体ヘリウム
で冷却するものについて説明したが、将にこれて限定さ
れず種々の超電導材を用い得ろことは当然である。Further, in the above embodiments, a superconducting coil cooled with liquid helium has been described, but the present invention is not limited to this, and it goes without saying that various superconducting materials may be used.
以上のようにこの発明によれば、熱シールド部材の一部
を低抵抗体で構成したことにより傾斜磁場コイルによる
誘導電流を低抵抗体部分に選択的に流すことができ、直
線性の良い１次の傾斜磁場を得ることができるという効
果がある。As described above, according to the present invention, by configuring a part of the heat shield member with a low-resistance material, the induced current by the gradient magnetic field coil can be selectively passed through the low-resistance material part. This has the effect that the following gradient magnetic field can be obtained.
第１図はこの発明の一実施例による超電導マグネット装
置の要部としての円筒形傾斜磁場コイルと熱シールド部
材を示す俯敞図、第２図は第１図の中心軸に沿った縦断
面の構成と誘導電流の特性とを併記して示す説明図、第
６図はこの発明の他の実施例としての鞍形傾斜磁場コイ
ルに適用した場合の要部を示す俯諏図、第４図は従来装
置の外観を示す斜視図、第５図は第４図の中心軸に沿っ
た要部断面図、第６図は第５図の要部を示す斜視図、第
７図は第６図の中心軸に沿った縦断面の構成と、誘導電
流の特性とを併記して示す説明図である。
図において、（２ｂ）は（円筒形）傾斜磁場コイル、
（２ｃ）は鞍形傾斜磁場コイル、 （１ｅ）は熱シール
ド部材、（ｄａ）、（４ｂ）は低抵抗体である。
なお、各図中、同一符号は同−又は相当部分を示す。
代理人 曽 我 道 照 ・′第４図
范５区
手続補正書
１．事件の表示 特願昭６２−２６６３００号２、発
明の名称
超電導マグネット装置
３、補正をする者
事件との関係 特許出願人
住 所 東京都千代田区丸の内二丁目２番３号
名 称 （６０１）三菱電機株式会社代表者志岐守哉
４、代理人
住 所 東京都千代田区丸の内二丁目４番１号
丸の内ビルディング４階
（１）図 面FIG. 1 is an overhead view showing a cylindrical gradient magnetic field coil and a heat shield member as essential parts of a superconducting magnet device according to an embodiment of the present invention, and FIG. 2 is a vertical cross-section along the central axis of FIG. An explanatory diagram showing the configuration and the characteristics of the induced current, FIG. 6 is an overhead view showing the main parts when applied to a saddle-shaped gradient magnetic field coil as another embodiment of the present invention, and FIG. FIG. 5 is a sectional view of the main part along the central axis of FIG. 4, FIG. 6 is a perspective view of the main part of FIG. 5, and FIG. 7 is a cross-sectional view of the main part of FIG. FIG. 2 is an explanatory diagram showing the configuration of a longitudinal section along the central axis and the characteristics of induced current. In the figure, (2b) is a (cylindrical) gradient magnetic field coil;
(2c) is a saddle-shaped gradient magnetic field coil, (1e) is a heat shield member, and (da) and (4b) are low resistance bodies. In each figure, the same reference numerals indicate the same or corresponding parts. Agent: Dao Teru Zeng ・'Figure 4 Fan 5th District Procedural Amendment Form 1. Indication of the case: Japanese Patent Application No. 62-266300 2, name of the invention: superconducting magnet device 3, person making the amendment Relationship with the case: Address of the patent applicant: 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Denki Co., Ltd. Representative: Moriya Shiki 4, Agent address: 4th floor (1), Marunouchi Building, 2-4-1 Marunouchi, Chiyoda-ku, Tokyo.
Claims (3)
ット、この超電導マグネットの開口部に設けられたパル
ス磁場発生用の傾斜磁場コイルを備えた超電導マグネッ
ト装置において、上記熱シールド部材の一部を低抵抗体
で構成したことを特徴とする超電導マグネット装置。(1) In a superconducting magnet device equipped with a superconducting magnet for generating a magnetic field having a heat shield member, and a gradient magnetic field coil for generating a pulsed magnetic field provided in the opening of this superconducting magnet, a part of the heat shield member has a low resistance. A superconducting magnet device characterized by being composed of a body.
焼なますことにより低抵抗体を構成したことを特徴とす
る特許請求の範囲第１項記載の超電導マグネット装置。(2) The superconducting magnet device according to claim 1, wherein the heat shield member is a copper plate, and a low resistance element is constructed by annealing a part of the copper plate.
はマグネット中心からの軸方向距離と径方向距離の比）
となる位置に設けたことを特徴とする特許請求の範囲第
１項記載の超電導マグネット装置。(3) The low resistance body has the same β as the gradient magnetic field coil (however, β
is the ratio of the axial distance to the radial distance from the center of the magnet)
2. The superconducting magnet device according to claim 1, wherein the superconducting magnet device is provided at a position where .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62266300A JPH01109708A (en) | 1987-10-23 | 1987-10-23 | Superconducting magnet device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62266300A JPH01109708A (en) | 1987-10-23 | 1987-10-23 | Superconducting magnet device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01109708A true JPH01109708A (en) | 1989-04-26 |
Family
ID=17429023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62266300A Pending JPH01109708A (en) | 1987-10-23 | 1987-10-23 | Superconducting magnet device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01109708A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011200348A (en) * | 2010-03-25 | 2011-10-13 | Hitachi Ltd | Superconductive magnet device and magnetic resonance imaging apparatus |
| WO2013150951A1 (en) * | 2012-04-06 | 2013-10-10 | 株式会社 日立メディコ | Superconductor electromagnet and magnetic resonance imaging device |
-
1987
- 1987-10-23 JP JP62266300A patent/JPH01109708A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011200348A (en) * | 2010-03-25 | 2011-10-13 | Hitachi Ltd | Superconductive magnet device and magnetic resonance imaging apparatus |
| WO2013150951A1 (en) * | 2012-04-06 | 2013-10-10 | 株式会社 日立メディコ | Superconductor electromagnet and magnetic resonance imaging device |
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