Bruker Biospin Gmbh

Bruker Analytische Messtechnik Gmbh

Bruker Analytik Gmbh

Other

Bruker Medizintechnik Gmbh

Bruker Ag

Brucker Analytik Gmbh

Michael Westphal

Gunther R Laukien

Hartmut Schmidt

Arne Kasten

Gerald Neuberth

Bertold Knuttel

Wolfgang H Muller

Robert Schauwecker

Gerhard Roth

Pierre-Alain Bovier

Marco Strobel

Daniel M Eckert

Victor Ringeisen

Arne Kastep

Genther Laukien

A superconducting magnet configuration () for generating a homogeneous magnetic field Bin an examination volume (), has an interior radial superconducting main field coil () which is disposed rotationally symmetrically about an axis (z-axis) and an oppositely driven coaxial radially exterior superconducting shielding coil () is characterized in that the magnet configuration () consists of the main field coil (), the shielding coil (), a ferromagnetic field formation device () and a ferromagnetic shielding body (AK), wherein the ferromagnetic field formation device () is located at the radially inside of the main field coil () and the ferromagnetic shielding device (AK) surrounds the main field coil () and the shielding coil () in a radial and axial direction, the main field coil () consisting of an unstructured solenoid coil or of several radially nested unstructured solenoid coils () which are driven in the same direction, the axial extent Lof the shielding coil () being smaller than the axial extent Lof the main field coil (), wherein the axial magnetic field profile () generated by the main field coil () and the shielding coil () during operation has a minimum of the field strength along the axis (z-axis) in the center () and a maximum of the field strength on each side of the center (), and wherein the axial magnetic field profile () generated by the ferromagnetic field formation device () and the ferromagnetic shielding body (AK) during operation has a maximum of the field strength along the axis (z-axis) in the center () and a minimum of the field strength on each side of the center (). The magnet configuration in accordance with the invention has a very simple structure.

Compact superconducting magnet configuration with active shielding having a shielding coil contributing to field formation

An actively shielded superconducting magnet configuration (M; M; M) for generating a homogeneous magnetic field Bin a volume under investigation () has a radially inner superconducting main field coil () which is disposed rotationally symmetrically about an axis (z axis) and a coaxial radially outer superconducting shielding coil () which is operated in an opposite direction. The magnet configuration consists of the main field coil, the shielding coil and a ferromagnetic field-shaping device (), wherein the ferromagnetic field-shaping device is disposed radially inside the main field coil. The main field coil consists of an unstructured solenoid coil or of several radially nested unstructured solenoid coils () which are operated in the same direction. An extension Lof the shielding coil in the axial direction is smaller than the extension Lof the main field coil in the axial direction. applies for the axial magnetic field profile B(z) generated by the main field coil and the shielding coil during operation along the z-axis in the center at z=0 and applies for the axial magnetic field profile B(z) generated by the ferromagnetic field-shaping device () during operation along the z-axis in the center at z=0, wherein the z-axis is oriented in a positive direction of the B-field. An actively shielded superconducting magnet configuration of considerably simplified structure is thereby provided with a homogeneous and particularly high magnetic field Bin the volume under investigation.

Compact superconducting magnet configuration with active shielding, wherein the shielding coil damps the field maximum of the main coil as well as associated magnetic resonance tomograph, NMR spectrometer and ion cyclotron resonance mass spectrometer

A superconducting magnet configuration () for generating a homogeneous magnetic field Bin an examination volume (), has an interior radial superconducting main field coil () which is disposed rotationally symmetrically about an axis (z-axis) and an oppositely driven coaxial radially exterior superconducting shielding coil () is characterized in that the magnet configuration () consists of the main field coil (), the shielding coil (), and a ferromagnetic field formation device (), wherein the ferromagnetic field formation device () is located at the radially inside of the main field coil (), the main field coil () consisting of an unstructured solenoid coil or of several radially nested unstructured solenoid coils () which are driven in the same direction, the axial extent Lof the shielding coil () being smaller than the axial extent Lof the main field coil (), wherein the axial magnetic field profile () generated by the main field coil () and the shielding coil () during operation has a minimum of the field strength along the axis (z-axis) in the center () and a maximum of the field strength on each side of the center (), and wherein the axial magnetic field profile () generated by the ferromagnetic field formation device () during operation has a maximum of the field strength along the axis (z-axis) in the center () and a minimum of the field strength on each side of the center (). The magnet configuration in accordance with the invention has a very simple structure.

A superconducting magnet configuration with a magnet coil () of inductance L which is disposed in a cryostat () at a cryogenic temperature, for generating a temporally stable magnetic field, in a working volume, which is suitable for NMR measurements, and with current feed lines to an external current source () via which a current of a current strength Ican be supplied, wherein, at a cryogenic temperature, the magnet coil () can be exclusively short-circuited via a switch (), is characterized in that the switch () is normally conducting and comprises a mechanically operable bridge () with an ohmic resistance Rwhich can be predetermined. The inventive magnet configuration ensures straightforward stable permanent operation via a mains supply even at high currents (&#x3e;1000 A) and also effective discharge of the energy released during a quench.

Superconducting magnet configuration with switch

The invention concerns a magnet configuration comprising a superconducting magnet coil () within which a gradient system is to be switched. All low temperature oscillation systems (R) with a temperature T&#x3c;10K within the magnet coil () are produced from a material having good electrical conducting properties, and at least one warm oscillation system (R2) with a temperature T&#x3e;10K within the magnet coil () has worse electrical conducting properties and has a considerably different mechanical resonance frequency (separation approximately 500 Hz or more) than at least one of the low temperature oscillation systems (R). This reduces the undesired heating power supplied to the low temperature oscillation systems due to mechanical oscillations and induced eddy currents.

Superconducting magnet configuration with reduced heat input in the low temperature regions

A co-axial magnet configuration for the production of a magnetic field and investigational volume which is suitable for measurement of magnetic resonance has at least one superconducting solenoid coil or solenoid coils which are radially nested within each other, wherein the windings of the solenoid coil(s) in a radial region about the axis of the magnetic configuration are disposed between rand r, wherein rris characterized in that the windings are surrounded by at least one rotationally symmetric magnet body made from ferromagnetic material which extends over a radial region between rand rwherein rrwherein rr&#x3c;1.3 rand r&#x3e;1.3 r, wherein the rotationally symmetric magnet body or bodies are structured, dimensioned and positioned in such a fashion that the magnetic field is homogenized in the investigational volume and the magnetic fringe field outside the magnet configuration is essentially suppressed to permit the production of strong magnetic fields of high homogeneity without requiring notches in the coil configuration.

Hybrid magnet configuration

A magnet system of a magnetic resonance apparatus for generating a magnetic field which is homogeneous and temporally highly stable within a volume under investigation and which extends along a z-axis, with a superconducting magnet coil () which is disposed in a cryostat () and with a periodically operated refrigerator () having a magnetic regenerator material which is disposed in a regenerator housing () within the cryostat () in the stray field of the magnet coil (), and which is provided with a device () for shielding or compensating a magnetic disturbing field in the volume under investigation generated by the periodic operation of the refrigerator () due to regenerator magnetization changes is characterized in that the regenerator housing () is surrounded by a compensation coil arrangement () which can be superconductingly short-circuited and which is made from a plurality of conductor loops () which are separately short-circuited during measurement to keep a plurality of magnetic fluxes through these conductor loops () constant in the superconductingly short-circuited state. A magnet system of this type facilitates effective compensation of the disturbing fields caused by a magnetic regenerator material at the location of the volume under investigation.

Magnet system with shielded regenerator housing

A flat multi-layer arrangement () of superconducting wires () with normally conducting substrate () and at least one fiber () which is electrically conductingly connected to the substrate () and is superconducting under predetermined operating conditions is characterized in that the superconducting wires () in a respective layer () are substantially disposed such that they do not cross. A resistive electric contact is provided between the superconducting wires () of different layers () and the superconducting wires () of at least two neighboring layers () do cross, wherein no closed superconducting loops are present in the arrangement (). This arrangement permits shielding of the working volume of a magnet coil arrangement against low-frequency stray fields in an efficient and reliable manner.

Low resistance shield

The system describes a means and a method for stabilizing the magnetic field generated in the measuring volume of a high-resolution magnetic resonance spectrometer having an actively shielded magnet coil () which is located in a cryostat () and which is superconductingly short-circuited. The system comprises a compensation coil () which is decoupled from the magnet coil (), and is disposed on the shielding coil () of the magnet coil ().

Superconducting magnet system with drift compensation

An actively shielded superconducting magnet coil system () for generating a magnetic field in a working volume (), which is rotationally symmetric about a z-axis, comprising a radially inner main field winding () and a radially outer shielding winding (), and an electrically highly conductive shielding cylinder (radially inner shielding cylinder) () which is disposed radially inside the main field winding () or between main field winding () and the shielding winding () is characterized in that at least one further electrically highly conductive shielding cylinder () is disposed radially outside the shielding winding (). The inventive magnet coil system prevents generation of a fringe field flash in the outer region of the magnet coil system in case of a quench.

Additional fringe field shield for a superconducting magnet coil system

In a magnetic resonance (MR) apparatus comprising a main field magnet system with a tubular opening for receiving the object to be investigated and at least one tubular mechanically oscillatory component, disposed in this opening, in particular a gradient coil system, and at least one cylindrical element of electrically conducting material surrounded by the main field magnet system, which is rigidly mechanically connected to at least one of the mechanically oscillatory components or forms an integral mechanical component thereof, the sum of the products p of the electric conductivities &sgr;, the cylinder radii R and the wall thicknesses d of the cylindrical element per mechanically oscillatory component is between 1 Am/V and 10,000 Am/V, preferably between 10 Am/V and 1000 Am/V, and particularly preferred between 20 Am/V and 500 Am/V. This produces good noise damping in an inward direction.

Magnetic resonance apparatus with damping of inner mechanical vibrations

A main field magnet arrangement for a one-sided magnet resonance device produces a homogeneous magnetic field B in a working volume ( ). The working volume ( ) and the main field magnet ( ) are disposed on different sides of a plane E and the main field magnet ( ) has a geometric shape which permits disposal of a radio frequency (RF) receiver coil system and optionally a gradient coil system on the same side of the plane E as the main field magnet ( ). Field-generating elements of permanent-magnetic material form a radially outer part ( ) and a radially inner part ( ) relative to an axis A extending through the center of the working volume ( ), wherein the surface, facing the working volume ( ), of the radially inner part ( ) is axially further spaced apart from the center of the working volume ( ) than the surface of the radially outer part ( ) facing the working volume ( ), such that a depression ( ) is formed in the radially inner part ( ) in the axial direction. At least the radially inner part ( ) of the field-generating elements is made from permanent-magnetic material, the axes of the prismatic rods forming a grid of lines having a grid constant a. The surfaces of the prismatic rods, facing the working volume ( ), of the radially inner part ( ) of the field-generating elements have different axial separations from the center of the working volume ( ) which deviate from a rotationally-symmetrical distribution about the axis A, with the grid of lines extending in two main directions over at least four grid constants. Such an arrangement is particularly suited for use in a magnetic resonance tomography system for examining e.g. skin.

Asymmetric arrangement of permanent-magnetic elements for a magnetic resonance apparatus

The magnetic field in the working volume of an apparatus for measuring the magnetic resonance, in particular nuclear magnetic resonance, is homogenized in that shim plates are disposed at predetermined positions about the working volume and, in sum, do not generate a field in the center of the working volume. The summed effect of the shims is preferably inductively decoupled from the coil generating the magnetic field.

Device for homogenizing a magnetic field

A magnet coil arrangement comprising an actively shielded superconducting primary circuit ( ) comprising first and second magnet windings ( and ), and being wound e.g. in winding chambers ( and ) in a supporting body ( ) for generating a strong magnetic field in a working volume with a small magnetic stray field and a short circuited secondary circuit ( ) which is inductively coupled with the primary circuit ( ) and contains third and fourth magnet windings ( and ) is characterized in that the magnet windings ( and ) of the secondary circuit ( ) form an actively shielded magnet coil. This permits a simple and robust coil protection for actively shielded superconducting magnets during a quench wherein the superconducting magnet windings are reliably relieved and the magnetic stray field of the entire arrangement remains small.

Actively shielded superconducting magnet with protection means

The invention concerns a gradient system of a magnetic resonance apparatus comprising an additional, rigidly mechanically coupled highly conductive shielding cylinder which dampens excitation of mechanical vibrations of the apparatus during gradient switching.

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Offenbach, Germany

Michael Westphal