MAGNET ASSEMBLIES AND METHODS FOR TEMPERATURE CONTROL OF THE MAGNET ASSEMBLIES

A magnet assembly is provided. The magnet assembly comprises a magnet configured to generate a magnetic field and an iron shield configured to shield the magnet. The magnet assembly further comprises one or more positive temperature coefficient heaters disposed on the iron shield and configured to stabilize temperature of the iron shield. An iron shield assembly and a method for temperature control of the magnet assembly are also presented. 1. A magnet assembly having passive temperature control , comprising:a magnet configured to generate a magnetic field;an iron shield configured to shield at least a portion of the magnet; andone or more positive temperature coefficient heaters disposed on the iron shield and configured to stabilize temperature of the iron shield;wherein the magnetic assembly provides the passive temperature control without active controllers or temperature sensors.2. The magnet assembly of claim 1 , wherein each of the one or more positive temperature coefficient heaters have a predetermined protection temperature.3. The magnet assembly of claim 1 , wherein the magnet comprises one of a permanent magnet claim 1 , a resistive magnet claim 1 , and a superconducting magnet.4. The magnet assembly of claim 3 , wherein the magnet comprises a superconducting magnet claim 3 , and wherein the superconducting magnet comprises one or more superconducting coils.5. The magnet assembly of claim 4 , wherein each of the one or more superconducting coils has a solenoidal shape claim 4 , and wherein the iron shield has a cylindrical shape for accommodating the magnet.6. The magnet assembly of claim 1 , wherein the iron shield comprises a body and a pair of end portions disposed on the body claim 1 , and wherein the one or more positive temperature coefficient heaters are disposed on at least one of the body and the end portions.7. The magnet assembly of claim 1 , wherein the one or more positive temperature coefficient heaters are disposed on at least one outside ...

QUENCH PROTECTION CIRCUIT FOR SUPERCONDUCTING MAGNET COILS

A superconducting magnet includes at least one superconducting coil and a quench protection circuit electrically coupled to said at least one coil in parallel. The circuit includes at least one quench heater assembly thermally coupled to the at least one coil, and at least one superconducting current limiter electrically connected in series with the at least one quench heater assembly. The superconducting current limiter has a superconducting state with zero resistance, and a normal state with a normal resistance to decrease an electric current flowing through the quench heater assembly. 1. A superconducting magnet , comprising:at least one superconducting coil; and at least one quench heater assembly thermally coupled to the at least one coil; and', 'at least one superconducting current limiter electrically connected in series with the at least one quench heater assembly, wherein the superconducting current limiter has a superconducting state with zero resistance, and a normal state with a normal resistance to decrease an electric current flowing through the quench heater assembly., 'a quench protection circuit electrically coupled to said at least one coil in parallel, the circuit comprising2. The magnet of claim 1 , wherein the quench protection circuit further comprises at least one voltage blocker electrically connected in series to the quench heater assembly.3. The magnet of claim 1 , wherein the quench protection circuit further comprises a limiter heater thermally coupled to the superconducting current limiter configured to change the superconducting current limiter from the superconducting state to the normal state.4. The magnet of claim 3 , wherein the quench protection circuit further comprises a limiter-heating branch comprising the limiter heater and a voltage blocker electrically connected in series to the limiter heater.5. The magnet of claim 4 , wherein the limiter-heating branch is electrically coupled in parallel to the series connected quench ...

METHODS FOR MAKING LOW RESISTIVITY JOINTS

Method for joining wires using low resistivity joints is provided. More specifically, methods of joining one or more wires having superconductive filaments, such as magnesium diboride filaments, are provided. The wires are joined by a low resistivity joint to form wires of a desired length for applications, such in medical imaging applications. 1. A method of joining wires , the method comprising:introducing a magnesium diboride joint material to an end of a first wire and an end of a second wire at a joint area, wherein at least one of the first and second wires comprises superconductive magnesium diboride filaments; andaffecting the joint area such that the end of the first wire and the end of the second wire are electrically and mechanically coupled through the joint material.2. The method claim 1 , as set forth in claim 1 , wherein each of the first and second wires comprises superconductive magnesium diboride filaments.3. The method claim 1 , as set forth in claim 1 , wherein the first wire comprises magnesium diboride filaments and the second wire comprises filaments that do not comprise magnesium diboride.4. The method claim 3 , as set forth in claim 3 , wherein the filaments of the second wire are superconductive.5. The method claim 1 , as set forth in claim 1 , wherein affecting the joint area comprises at least one of a mechanical process claim 1 , a thermal process claim 1 , a chemical process claim 1 , or combinations thereof.6. The method claim 1 , as set forth in claim 1 , wherein affecting the joint area comprises deforming the joint area to densify the filaments of each of the first and second wires and the magnesium diboride joint material.7. The method claim 1 , as set forth in claim 1 , wherein affecting the joint area comprises heating the joint area to sinter the filaments of each of the first and second wires and the magnesium diboride joint material.8. The method claim 1 , as set forth in claim 1 , wherein affecting the joint area comprises at ...

Supporting structure for a gradient coil assembly of a mri

The invention concerns to a gradient coil assembly (62) for use in a Magnetic Resonance Imaging (MRI) system. The gradient coil assembly (62) comprises primary coils (68), shield coils (72) and a supporting structure (10) being arranged between the primary coils (68) and the shield coils (72), wherein the supporting structure (10) comprises at least a supporting element (12) comprising a first end face (14) and at least a first recess (24) with an opening (26) in the first end face (14), wherein the first recess (24) extends in a longitudinal direction (18) of the supporting element (12) forming a tray for receiving a passive shim bar.

SUPERCONDUCTING COIL SUPPORT DEVICE AND METHOD AND APPARATUS INCLUDING SUPERCONDUCTING COIL SUPPORT DEVICE

An apparatus includes at least a first electrically conductive coil having at least first and second coil sections which are separated and spaced apart from each other, and a support structure disposed to support the first and second coil sections. The support structure, and an associated method of supporting the electrically conductive coil, maintain relative axial positions of the first and second coil sections to be fixed when the first electrically conductive coil is energized and de-energized, and allow each of the first and second coil sections to expand radially when energized. 1. An apparatus , comprising:at least a first electrically conductive coil having at least first and second coil sections which are axially separated and spaced apart from each other; anda support structure disposed to support the first and second coil sections, wherein the support structure is configured to maintain relative axial positions of the first and second coil sections to be fixed when the first electrically conductive coil is energized and de-energized, and to allow each of the first and second coil sections to expand radially when energized;a first support element which has a first portion which is disposed at a first site on the first coil section, and a second portion which is disposed at a first site on the second coil section, wherein the first support element axially, radially, and rotationally fixes the first site on the first coil section with respect to the first site on the second coil section;a second support element which has a first portion which is disposed at a second site on the first coil section, and a second portion which is disposed at a second site on the second coil section, wherein the second support element axially and rotationally fixes the second site on the first coil section with respect to the second site on the second coil section, and allows radial movement of the first and second coil sections;a third support element which has a first portion ...

Thin metal layer vacuum vessels with composite structural support

A composite sealed vessel (12) is provided. The vessel includes a non-metallic, generally cylindrical inner containment piece (30), a non-metallic, generally cylindrical outer containment piece (28) disposed around the inner containment piece (30). A pair of non-metallic flanges (32, 34) are disposed at ends of the inner and outer containment pieces (28, 30) to form a closed structure defining a cavity (24) therein. The vessel also includes a metallic external lining (16, 18) disposed over the closed structure to form a leak-tight pressure boundary.

Open magnet with recessed field shaping coils

A pole piece for use in an open magnet includes a magnetizable body of generally cylindrical shape and made of a ferromagnetic material with a plurality of concentrically-arranged, annular-shaped, radially spaced-apart grooves formed in the inner surface of the pole piece. A plurality of annular-shaped, electrically conductive coils are disposed within the grooves. The pole piece with recessed shielding coils is situated within a cryogenic vessel to maintain the pole pieces at a uniform cryogenic temperature. The result is an open magnet structure which provides a highly uniform, high field, open field of view for MRI with a well-contained stray field.

Superconducting magnet with improved support structure

【課題】マグネットの安定性の改善を達成するような改良型の支持構造をもつ超伝導マグネットを提供すること。 【解決手段】少なくとも１つの超伝導コイルと、該超伝導コイルに結合された少なくとも１つの支持部材と、これら超伝導コイルと支持部材の間にある少なくとも１つのコンプライアント界面と、を含むような超伝導マグネットについて記載している。超伝導コイルは半径方向を規定している。超伝導コイルは、半径方向と実質的に直交した軸方向で超伝導コイルを支持している。コンプライアント界面は、超伝導マグネットが付勢されたときに半径方向に移動するように構成されている。 【選択図】図１

Quench protection circuit including a superconducting current limiter

A superconducting magnet 10 or system or a method for quenching superconducting coils, comprises a quench protection circuit 14 arranged in parallel to at least one superconducting coil 12. The quench protection circuit 14 comprises at least one quench heater 16 and at least one superconducting current limiter 18 and is arranged such that the superconducting current limiter 18 can reduce the current level ih flowing through the quench heater 16. The current limiter 18 is connected in series with the quench heater 16 and is arranged to limit the level of current ih flowing in the heater to a level below the maximum allowable current for the said heater 16. The quench heater 16 is thermally coupled to at least one coil 12. The current limiter 18 may include a heater 22 which heats the current limiter to turn it from a superconducting state to a normal state before the heater current ih reaches the current limit. The limiter heater 22 may be in a branch 24 which is connected in parallel to the coils 12 and the main heating branch 25 with the quench heater 16. The heater branches 24, 25 may include voltage block arrangements 20, 26 involving Zener diodes or MOSFET elements and the branch 24 may include a resistor 28.

Cooling system and method for superconducting magnets

A method for cooling a superconducting magnet enclosed in a cryostat of a magnetic resonance imaging system comprises introducing a gas into a cooling path in the cryostat from an input portion outside the cryostat. A heat exchanger in the cooling path is cooled by a refrigerator outside the cryostat. The gas at the heat exchanger is cooled as a cold gas or is condensed at the heat exchanger into a liquid cryogen. The cold gas or liquid cryogen from the heat exchanger flows through at least a connection tube to a magnet cooling tube, which is in thermal contact with the superconducting magnet. Heat from the superconducting magnet is removed by warming the cold gas into warm gas or by the boiling the liquid cryogen into boiled-off gas. The warm gas or boiled-off gas is transmitted back to the heat exchanger to re-cool the warm gas or re-condense the boiled-off gas for further cooling the superconducting magnet to a superconducting temperature. The input portion is closed to make the cooling path as a closed-loop for maintaining the superconducting magnet below the superconducting temperature.

High efficiency DC/DC current source converter

A DC to DC converter has a transformer with a highly coupled primary and secondary, a first switch connected in series between a current source and the primary, a second switch connected across the current source in parallel with the first switch and the primary, a rectifier connected to rectify the output of the secondary, an energy storage device such as a capacitor connected to receive the output from the rectifier, and a load connected to receive output voltage across the capacitor. The current source which provides the substantially constant current can be a superconducting storage magnet. The first and second switches are controlled to alternately open and close to provide current through the primary of the transformer to recharge the energy storage device. When voltage across the energy storage capacitor reaches a minimum level, the one of the first and second switches which was closed is opened and the other is closed. This cycle is repeated as the voltage across the output capacitor reaches the minimum value to maintain the output voltage substantially at a constant level.

Passive quench protection circuit for superconducting magnets

A superconducting magnet apparatus that in one embodiment includes at least one superconducting coil and a passive quench protection circuit electrically coupled to the coil in parallel. The circuit includes a heater and a current limiter connected in series. The heater is thermally coupled to the coil and the current limiter blocks current through the circuit at a current lower than the current rating of the heater.

Low eddy current cryogen circuit for superconducting magnets

A low eddy current cryogen circuit for superconducting magnets including at least a first cooling coil (102) made of an electrically conducting material and having at least one electrical isolator (104) incorporated in the first cooling coil (102). The electrical isolator (104) is located to inhibit induced eddy current loops due to inductive coupling of the first cooling coil (102) with eddy current inducing field sources.

System and method for quench protection of a superconductor

A system and method for protecting a superconductor from a quench condition. A quench protection system is provided to protect the superconductor from damage due to a quench condition. The quench protection system comprises a voltage detector operable to detect voltage across the superconductor. The system also comprises a frequency filter coupled to the voltage detector. The frequency filter is operable to couple voltage signals to a control circuit that are representative of a rise in superconductor voltage caused by a quench condition and to block voltage signals that are not. The system is operable to detect whether a quench condition exists in the superconductor based on the voltage signal received via the frequency filter and to initiate a protective action in response.

High temperature super-conducting rotor having a vacuum vessel and electromagnetic shield and an assembly method

A rotor is disclosed for a super-conducting synchronous machine comprising: a rotor core; a super-conducting coil extending around at least a portion of the rotor core, said coil having coil side sections on opposite sides of said rotor core; a vacuum housing covering at least one of said coil side sections, and a conductive shield over said vacuum housing and coil side sections.

Apparatus and method for coupling coils in a superconducting magnet

A system and method for connecting superconducting magnet coils made up of coil segments to allow an integrated winding concept. The integrated winding concept can include serially connecting coil segments of coil pairs in an alternating pattern, which causes coil pairs to be electrically symmetric. Symmetric coil pairs can eliminate or significantly reduce the currents in magnet coils induced by gradient or other pulses, produce a homogenous field, and reduce the accumulated voltages in the coils due to gradient pulsing.

Cryogenic cooling system and method with cold storage device

By means of heat transfer tube cooled superconducting magnets with ceramic bobbin

Ein System und Verfahren für ein Magnetresonanz-(MR)-Bildgebungssystem (10) enthalten einen Spulenkörper (72), wenigstens einen Magneten (54), der um den Spulenkörper (72) herum positioniert und zum Erzeugen eines Magnetfeldes konfiguriert ist, wenigstens eine Gradientenspule (50) zum Manipulieren des von dem wenigstens eines Magneten (54) erzeugten Magnetfeldes mittels eines Gradientenfeldes, ein Wärmeübertragungsrohr (78), das thermisch mit dem Spulenkörper (72) verbunden ist und ein Kryokältemittel darin enthält. Das MR-Bildgebungssystem (10) enthält auch eine Kryokühler (80), der mit dem Wärmeübertragungsrohr (78) verbunden ist, um das Wärmeübertragungsrohr (78) und das Kryokältemittel (82) zu kühlen, wobei der Spulenkörper (72) aus einem wärmeleitenden Material besteht, in welchem Wirbelströme erheblich während des Betriebs der wenigstens einen Gradientenspule reduziert sind. A system and method for a magnetic resonance (MR) imaging system (10) includes a bobbin (72), at least one magnet (54) positioned around the bobbin (72) and configured to generate a magnetic field, at least one gradient coil (50) for manipulating the magnetic field generated by the at least one magnet (54) by means of a gradient field, a heat transfer tube (78) thermally connected to the bobbin (72) and containing a cryogenic refrigerant therein. The MRI system (10) also includes a cryocooler (80) connected to the heat transfer tube (78) to cool the heat transfer tube (78) and cryogenic refrigerant (82), the bobbin (72) being made of a thermally conductive material in which eddy currents are significantly reduced during operation of the at least one gradient coil.

A cryogenically cooled current lead assembly for a superconducting magnet and its method of use

A current lead assembly 14 and its cooling method, suitable for a superconducting magnet, comprises at least one current lead 16, 18 with at least one thermal device 30 coupled to a portion 24 of the lead 16, 18, where the said thermal device 30 includes a cryogen fluid flow path 32 extending through it and is arranged to cool the said portion 24 of the current lead. The cooled portion 24 of the current lead is the cold end portion of the lead, which, in use, may be electrically connected to a conductive winding 124, 126 of a superconducting magnet. The thermal device 30 may be made of metal or a metal alloy such as copper, aluminium, silver or brass and it may be an integral portion of a current lead 16, 18. Both positive and negative current leads 16, 18 may be involved with the cooling system. The cooling system may avoid the use of an electrical insulating material between the cooling device 30 and the current leads 16, 18 by either providing separate cooling systems for each of the leads 16, 18 or by providing electrical insulation 48 between portions of the cooling system. Electrical isolation tube portions 48 may be used in the cooling system. The cryogenic fluid may be a liquid/gas and the cooling system may include a cryogenic liquid container 42 and/or a boiled-off gas re-condenser.

Low resistivity joints for joining superconducting wires

A low resistivity joint is made between two wires 116, 118, or 152, 154 having superconductive filaments 126, 156, at least one having magnesium diboride filaments. A joint material 168, also including magnesium diboride is used. The filaments may be exposed before joining, and may be welded together, heated and/or compressed. The wires can be used in medical imaging applications.

Quench protection for persistant superconducting magnets for magnetic resonance imaging

A quench protection circuit for the series connected but spatially separated magnet coils of a superconducting magnet utilizes a parallel circuit of multiple heaters and reverse connected diodes shunting portions of the series connected magnets coils with the heaters physically positioned in thermal contact with other coils in the series circuit to thermally transfer a heat quenching action in any coil to all coils, along with a shunting current through the diodes to shunt peak currents upon coil quenching to avoid undesired spot temperature rise and enable controlled quenching of the entire magnet upon quenching of any coil.

Line-cooled, passively shielded MRI magnet

Ein Magnetresonanz-Abbildungs(MRI)-Gerät (200) zum Abbilden eines Volumens (20) ist mit mindestens einem Hauptmagneten (230) zum Erzeugen eines Magnetfeldes und mindestens einer Gradientenspule (50) zum Manipulieren des durch den mindestens einen Hauptmagneten (230) erzeugten Magnetfeldes zum Abbilden des Volumens (20) versehen. Die durch die mindestens eine Gradientenspule (50) erzeugten Magnetfelder sind im Wesentlichen unabgeschirmt. A magnetic resonance imaging (MRI) device (200) for imaging a volume (20) is provided with at least one main magnet (230) for generating a magnetic field and at least one gradient coil (50) for manipulating the one generated by the at least one main magnet (230) Magnetic field to map the volume (20). The magnetic fields generated by the at least one gradient coil (50) are essentially unshielded.

Rotor and method of making same

Passive quench protection circuit for superconducting magnets

Conduction cooled passively-shielded MRI magnet

A magnetic resonance imaging (MRI) device for imaging a volume is provided with at least one main magnet for generating a magnetic field, and at least one gradient coil for manipulating the magnetic field generated by the at least one main magnet to image the volume. The magnetic fields generated by the at least one gradient coil are substantially unshielded.

System and method for cooling a superconducting rotary machine

A system (10) for cooling a superconducting rotary machine (12) includes a plurality of sealed siphon tubes (24) disposed in balanced locations around a rotor (28) adjacent to a superconducting coil (26). Each of the sealed siphon tubes (24) includes a tubular body and a heat transfer medium (40) disposed in the tubular body that undergoes a phase change during operation of the machine (12) to extract heat from the superconducting coil (26). A siphon heat exchanger (22) is thermally coupled to the siphon tubes (24) for extracting heat from the siphon tubes (24) during operation of the machine (12).

System and method for quench protection of a superconductor

A system and method for protecting a superconductor (12) from a quench condition. A quench protection system (18) is provided to protect the superconductor (12) from damage due to a quench condition. The quench protection system (18) comprises a voltage detector (20) operable to detect voltage across the superconductor (12). The system (18) also comprises a frequency filter (22) coupled to the voltage detector (20). The frequency filter (22) is operable to couple voltage signals to a control circuit (26) that are representative of a rise in superconductor voltage caused by a quench condition and to block voltage signals that are not. The system (18) is operable to detect whether a quench condition exists in the superconductor (12) based on the voltage signal received via the frequency filter (22) and to initiate a protective action in response.

Superconducting magnet assembly and fabricating method

Methods for making low resistivity joints

Method for joining wires using low resistivity joints is provided. More specifically, methods of joining one or more wires having superconductive filaments, such as magnesium diboride filaments, are provided. The wires are joined by a low resistivity joint to form wires of a desired length for applications, such in medical imaging applications.

Conduction Cooled Passively Shielded MRI Magnet

A magnetic resonance imaging (MRI) device (200) for imaging a volume (20) is provided with at least one main magnet (230) for generating a magnetic field, and at least one gradient coil (295) for manipulating the magnetic field generated by the at least one superconducting main magnet (230) to image the volume (20). The magnetic fields generated by the at least one gradient coil (295) are substantially unshielded. A passive shield comprised of several magnetizable rings to suppress eddy current is used.

System and method for quench and over-current protection of superconductor

A system (20) and method for protecting a superconductor (12). The system (20) may comprise a current sensor (22) operable to detect a current flowing through the superconductor (12). The system (20) may comprise a coolant temperature sensor (24) operable to detect the temperature of a cryogenic coolant used to cool the superconductor (12) to a superconductive state. The control circuit (26) is operable to estimate the superconductor temperature based on the current flow and the coolant temperature. The system (20) may also be operable to compare the estimated superconductor temperature to at least one threshold temperature and to initiate a corrective action when the superconductor temperature exceeds the at least one threshold temperature.

System and method for quench protection of a superconductor

A system and method for protecting a superconductor from a quench condition. A quench protection system is provided to protect the superconductor from damage due to a quench condition. The quench protection system comprises a voltage detector operable to detect voltage across the superconductor. The system also comprises a frequency filter coupled to the voltage detector. The frequency filter is operable to couple voltage signals to a control circuit that are representative of a rise in superconductor voltage caused by a quench condition and to block voltage signals that are not. The system is operable to detect whether a quench condition exists in the superconductor based on the voltage signal received via the frequency filter and to initiate a protective action in response.

High temperature superconducting current leads for superconduction magnets

Conduct-cooled, passively shielded MRI magnet.

Cryogenic system and method for superconducting magnets

Unified shimming for magnetic resonance superconducting magnets

Cold mass cryogenic cooling circuit inlet path avoidance of direct conductive thermal engagement with substantially conductive coupler for superconducting magnet

A cold mass for a superconducting magnet system in one example comprises a superconducting magnet, a cryogenic cooling circuit, and a magnet and cooling circuit support. The magnet and cooling circuit support comprises a substantially conductive coupler that serves to couple the superconducting magnet and the cryogenic cooling circuit. The cryogenic cooling circuit comprises an inlet path and a substantially upward outlet path. The inlet path avoids direct conductive thermal engagement with the substantially conductive coupler. The substantially upward outlet path comprises direct conductive thermal engagement with the substantially conductive coupler.

Quench monitoring and control system and method of operating same

A rotating machine comprising a superconductive coil and a temperature sensor operable to provide a signal representative of superconductive coil temperature. The rotating machine may comprise a control system communicatively coupled to the temperature sensor. The control system may be operable to reduce electric current in the superconductive coil when a signal representative of a defined superconducting coil temperature is received from the temperature sensor.

Apparatus for low ac loss thermal shielding and method of making same

A apparatus for low AC loss thermal shielding includes a plurality of thermally conducting fibers positioned along a desired direction of heat conduction. The fibers are electrically insulated from each other. The fibers are bonded together with a matrix, and a thermal link connects the bonded fibers to a cryogenic cold head.

Supporting structure for a gradient coil assembly of a mri

The invention concerns to a gradient coil assembly (62) for use in a Magnetic Resonance Imaging (MRI) system. The gradient coil assembly (62) comprises primary coils (68), shield coils (72) and a supporting structure (10) being arranged between the primary coils (68) and the shield coils (72), wherein the supporting structure (10) comprises at least a supporting element (12) comprising a first end face (14) and at least a first recess (24) with an opening (26) in the first end face (14), wherein the first recess (24) extends in a longitudinal direction (18) of the supporting element (12) forming a tray for receiving a passive shim bar.

マグネットの均一設計方法

(57)【要約】 【課題】 磁気共鳴イメージング用マグネット（１０） を設計する方法を提供する。 【解決手段】 患者を受け入れるマグネットのアキシャ ル・ボア（６）の周りに少なくとも１つの補正コイル （４）を配置させる。この補正コイルは、マグネットが 発生させるより低次の高調波を減少させるために設計過 程において使用する。これにより、マグネットの周りの 選択したボリューム位置における磁場の均一性が改善さ れる。本願発明の好適な一態様では、４組以上の補正コ イルが設けられる。このマグネットは、その長手方向の 軸が水平面または垂直面内に来るように設計することが できる。補正コイルをアキシャル・ボアの周りに配置さ せることもできる。

継手接着層を有する積層複合材料シェル・アセンブリ

(57)【要約】 【課題】 ＭＲＩ装置の磁石用の管懸架装置として使用 することのできる積層複合材料シェル・アセンブリを提 供する。 【解決手段】 本発明の積層複合材料シェル・アセンブ リは、該アセンブリを外部構造物に連結するための継手 接着層（１０２）を有しながら互いに合体された複数の 複合材料シェル（Ｃ’）と、継手接着層を補強するため 継手接着層に隣接しながらシェルに合体されたピンチ・ リング（ＩＰＲ、ＯＰＲ）とを含んでいる。かかる複合 材料シェル及びピンチ・リングは円筒形の形状を有する と共に、所望の堆積順序に従って整列させた繊維を含む 黒鉛−エポキシ樹脂材料製の複合材料層から構成され る。シェル及びピンチ・リングは所望の順序で同心的に 組立てられている。

マグネットアセンブリ及びその製作方法

【課題】磁気共鳴撮像システム内のうず電流を減少させた改良型の超伝導マグネットアセンブリ並びにその製作方法を提供すること。 【解決手段】超伝導マグネットアセンブリを提供する。本超伝導マグネットアセンブリは、静磁場を発生するように構成された超伝導マグネットと、超伝導マグネットを遮蔽するように構成された鉄製シールドと、傾斜磁場を発生するように構成された磁場傾斜コイルアセンブリと、を含む。本超伝導マグネットアセンブリはさらに、傾斜磁場によって鉄製シールド内に誘導されるうず電流を低減するために鉄製シールド上に配置された１つまたは複数の磁気積層要素を含む。同様に方法も提供する。 【選択図】図１

低ａｃ損失熱シールドのための装置及びその製作方法

【課題】熱シールド内のＡＣ磁場によって生成されるクエンチ力及びうず電流を低減するように構成した装置を提供する。 【解決手段】低ＡＣ損失熱シールドのための装置は、所望の熱伝導方向に沿って位置決めされた複数の熱伝導性繊維（７０、８８、１５８、１６８、１８４）を含む。これらの繊維（７０、８８、１５８、１６８、１８４）は互いに電気絶縁されている。これらの繊維（７０、８８、１５８、１６８、１８４）はマトリックス（１１０、１７０）を用いて互いに結合させており、この結合させた繊維（７０、８８、１５８、１６８、１８４）をサーマルリンク（１２６）によって極低温コールドヘッド（１４４）に接続させている。 【選択図】図７

Vorrichtung mit Mitteln zur thermalen Abschirmung gegen Niedrigwechselstromverlust und Herstellungsverfahren dafür

Apparatus comprising means for low ac loss thermal shielding

Schalenanordnung aus Verbundlaminat mit aneinandergefügten Verbindungen

Low eddy current vacuum vessel and method of making same

Werkwijze en inrichting voor het lokaal afschermen van een MR supergeleidende magneetspoel.

Aufhängungseinheit für einen supraleitenden Magnet

Schalenanordnung aus Verbundlaminat mit aneinandergefügten Verbindungen

Koude-massasysteemstructuur en heliumvat van actief afgeschermde open MRI-magneet met een veld van hoog vermogen.

Systemen en werkwijze voor gradientcompensatie bij magnetische-resonantiebeeldvorming.

Laminated composite shell assembly for magnet applications

Schalenanordnung aus Verbundlaminat für Anwendung in Magneten

Einzelfilament-Supraleiter mit geringen Wechselstromverlusten für einen supraleitenden Magneten und Verfahren zu dessen Herstellung

Ein elektrischer Leiter mit geringen Wechselstromverlusten enthält mehrere supraleitende Einzelfilamentstränge (92), die in Längsrichtung übereinander gewickelt sind. Ein Isoliergehäuse (94) umgibt die mehreren supraleitenden Einzelfilamentstränge (92).

Koude-massasysteemstructuur en heliumvat van actief afgeschermde open MRI-magneet met een veld van hoog vermogen.

超伝導マグネットのための冷媒システム及び方法

【課題】完全な閉鎖系で包含する冷媒体積が非常に小さい冷媒システムを提供すること。 【解決手段】超伝導マグネット向けの冷媒システムは閉ループ冷却経路を備える。閉ループ冷却経路は超伝導マグネットに熱的に結合させたマグネット冷却チューブを備える。マグネット冷却チューブは冷媒流通路を備える。閉ループ冷却チューブはさらに、チューブ区画を通じてマグネット冷却チューブに流体結合させた再凝縮器と、マグネット冷却チューブと再凝縮器の間に流体結合させた液体冷媒コンテナと、を備える。接続チューブを通じてマグネット冷却チューブに少なくとも１つの気体タンクを流体結合させている。 【選択図】図１

Schalenanordnung aus Verbundlaminat für Anwendung in Magneten

超伝導マグネット向け冷却システム

【課題】ボイルオフした冷媒を再活用し閉鎖冷媒冷却システム内に蓄積できるシステムを提供する。 【解決手段】冷却システム（１４）はマグネット（１２）と熱的に接触させており、これに対して冷却を提供する。冷却システム（１４）により放出された気体を蓄積するために、蓄積タンク（３２）を冷却システム（１４）と流体接続させている。次いで、必要に応じて蓄積しておいた気体を冷却システム（１４）に戻すように放出することができる。 【選択図】図１

Magnetic resonance imager mobile van magnetic field homogeneity shift compensation

In the installation of a superconducting magnet (10) for magnetic resonance imaging at a preselected position in a mobile van (30), preselected curvilinear magnetic segments (42,44,46) are applied to preselected locations on the exterior of the magnet to counteract magnet inhomogeneities in the imaging bore (12) which would otherwise occur because of magnetic material (34,36) in the van structure.

System and method for automatically ramping down a superconducting persistent magnet

An apparatus includes an electrically conductive coil which produces a magnetic field when an electrical current passes therethrough; a selectively activated persistent current switch connected across the electrically conductive coil; a cryostat having the electrically conductive coil and the persistent current switch disposed therein; an energy dump; at least one sensor which detects an operating parameter of the apparatus and outputs at least one sensor signal in response thereto; and a magnet controller. The magnet controller receives the sensor signal(s) and in response thereto detects whether an operating fault (e.g. a power loss to the compressor of a cryocooler) exists in the apparatus, and when an operating fault is detected, connects the energy dump unit across the electrically conductive coil to transfer energy from the electrically conductive coil to the energy dump unit. The energy dump unit disperses the energy outside of the cryostat.