Bruker Biospin Ag

Bruker Ag

Bruker Switzerland Ag

Bruker Biospin Gmbh

Pierre-Alain Bovier

Robert Schauwecker

Andreas Amann

Daniel M Eckert

Werner H Tschopp

Patrik Vonlanthen

Stephan Heiss

Guenter Kuebler

Michael Westphal

Klaus Schlenga

Nicolas Freytag

Gerhard Roth

Joerg Hinderer

Roger Meister

Wolfgang Frantz

Frank H Laukien

Stephen Alfred March

Beat Grossniklaus

Francesca Venturini

Franck Borgnolutti

Raffaele Gilardi

Rolf Spreiter

Matteo Alessandrini

Thomas Wuethrich

Andreas Kraus

Dmitry Eshchenko

Michele Zaffalon

Stefan Schneider

Jörg Hinderer

Günter Kübler

An NMR apparatus having a magnet coil system for generating a homogeneous magnetic field comprises a superconducting magnet arranged within a vacuum vessel in the cold region of a cryostat, and a shim system containing shim elements arranged outside the vacuum vessel. The superconducting magnet has a first mechanical connection point to the vacuum vessel via a magnet suspension, and the shim system has a second mechanical connection point to the vacuum vessel via a positioning element. On at least one portion of a path along the vacuum vessel from the first connection point to the second connection point and/or on at least one portion of a path along the positioning element from the second connection point to the shim system, a regulating element for regulating thermally caused changes in length is arranged on the relevant path. Magnetic field homogeneity can thus be kept largely stable.

Active reduction of temperature induced shim drift in NMR magnet systems

A cryostat assembly comprises an outer container that houses a coil tank with a superconducting magnet coil system and a first cryogenic fluid, and a storage tank with a second cryogenic fluid. The coil tank is secured to the outer container by a first suspension element and the storage tank is secured to the outer container by a second suspension element. The storage tank is thermally connected to a cover element having a mechanical and thermally-conductive connection to a tube element and to the first suspension element. The cover element connects to the storage tank via a resilient, heat-conducting connection that is in thermal contact with the cover element and the storage tank. This allows thermal coupling between the storage tank and cover element, and independent relative movements between the storage tank and cover element, while suppressing relative movements between the tube element and the superconducting magnet coil system.

Cryostat assembly having a resilient, heat-conducting connection element

A superconductor magnet system () includes a cryostat (), a superconductor bulk magnet (), and a cryogenic cooling system (). The bulk magnet () has at least N axially stacked bulk sub-magnets (-), with N&#x2265;3. Between each two axially neighboring bulk sub-magnets, an intermediate body (-) is arranged. The intermediate bodies (-) are made from a non-metallic thermal insulator material. The cryogenic cooling system () is adapted for independently controlling the temperature of each bulk sub-magnet (-), and has, for each bulk sub-magnet, a temperature sensor (-) for sensing the temperature of the respective bulk sub-magnet and an adjustment unit (-) for adjusting a heating power and/or a cooling power at the respective bulk sub-magnet.

Superconductor magnet system, with individual temperature control of axially stacked bulk sub-magnets

A superconducting magnet assembly with a reinforced coil region () having a layered conductor coil assembly () forming cylindrical conductor layers (, . . . ), each having plural circular conductor turns () centered around and aligned along the axis of cylindrical symmetry (z). The reinforced coil region further includes a layered corset coil assembly () having an inner radius bigger than an outer radius of the layered conductor coil assembly (), and a corset sheet assembly () including a foil element forming a corset sheet (, . . . ). A cross section of the corset sheet with any plane perpendicular to the z-axis forms a segmented circle centered around the z-axis, the radius of which is bigger than that of one of the conductor layers and smaller than that of another of the conductor layers. In addition, the segmented circle covers at least 90% of a full circle but has at most four segments. The assembly provides mechanical reinforcement against radial magnetic forces.

Reinforcement of a superconducting magnet coil

An NMR apparatus includes a superconducting magnet coil system configured to generate a homogeneous magnetic field, and a helium (He) tank having an inner tube mechanically rigidly connected to the He tank and in which the magnet coil system is positioned. The He tank is configured to contain liquid helium to cool the magnet coils. A radiation shield has a radiation shield inner tube encompassing the He tank and spaced from the He inner tube to create a space between the He inner tube and the radiation shield inner tube to reduce an evaporation rate of the liquid helium. The NMR apparatus additionally includes a field shaping device with a magnetic material arranged in the space, in order to shim the homogeneous magnetic field. The field shaping device is fixed in the space so as to be in rigid mechanical contact with the He tank but without contacting the radiation shield.

Easily accessible deep-frozen NMR shim arrangement

An apparatus for DNP-NMR measurement on a sample, with a magnet configuration for producing a magnetic field in a first working volume and in, a second working volume with a magnetic field gradient in the direction of an axis (z) which extends through the second working volume, with a device for measuring MR signals, with a DNP excitation device, and with a positioning mechanism for transferring the sample, is characterized in that, near the second working volume, a compensation configuration made of magnetic material is mounted that, in the operating condition of the magnet configuration, produces a magnetic field gradient in the direction of the axis (z) in the second working volume that is between &#x2212;90% and &#x2212;110% of the magnetic field gradient of the same order of the stray field of the magnet configuration.

Apparatus for carrying out DNP-NMR measurements with a compensation configuration and method for designing the compensation configuration

A magnet arrangement with a magnet coil system (M) with two coil systems (C, D) that are each arranged in a container (B, B) positioned around the z axis and that are axially mechanically separated by a split (G), wherein each coil system (C, D) comprises a first (C, D) and a second coil section system (C, D), wherein the first coil section systems (C, D) are exposed to attractive magnetic forces showing toward the split (G) (K, K) and the second coil section systems (C, D), to repulsive magnetic forces showing away from the split (G) (K, K), and containing in the split (G) at least one mechanical structure that withstands compressive loads (E, E) and that supports a part of the attractive magnetic forces (K, K), is characterized in that, in the split (G) within the dimensions of the containers (B, B), a mechanical structure (H) is provided that mechanically withstands tensile loads in the z direction, supports a part of the repulsive magnetic forces in the axial direction (K, K), is connected to the containers (B, B) and holds them together. With the inventive magnet arrangement, the magnetic forces can be better controlled. At the same time, a low-cost, space and weight saving assembly can be implemented.

Split-coil magnet arrangement with improved mechanical construction

A magnet arrangement (M, M', M&#x2033;, M&#x2032;&#x2033;) for generating a magnetic field in the direction of a z-axis in a working volume (V) disposed on the z-axis about z=0, with a magnet coil system (A, A&#x2032;, A&#x2033;, A&#x2032;&#x2033;) which comprises one or more superconducting magnet partial coil systems (A, A&#x2032;, A&#x2033;, A&#x2032;&#x2033;, A&#x2032;&#x2033;, . . ., An&#x2032;&#x2033;), each forming superconductingly short-circuited current paths in the operating state, and with a further coil system (C, C&#x2032;, C&#x2033;, C&#x2032;&#x2033;) which can be charged or discharged independently of the magnet coil system (A, A&#x2032;, A&#x2033;, A&#x2032;&#x2033;) and comprises a first and a second partial coil system (C, C, C&#x2032; C&#x2032;, C&#x2033;, C, C&#x2032;&#x2033;, C&#x2032;&#x2033;), wherein the first partial coil system (C, C&#x2032;, C&#x2033;, C&#x2032;&#x2033;) and the second partial coil system (C, C&#x2032;, C, C&#x2032;&#x2033;) each comprise at least one coil, wherein all coils of the further coil system (C, C&#x2032;, C&#x2033;, C&#x2032;&#x2033;) are connected in series, wherein g&#x3e;0.1 mT/A, is characterized in that g&#x3e;0.1 mT/A, g&#x3e;0.1 mT/A, wherein A substantially linear field change can thereby be realized in the working volume in dependence on a current change in the further coil system (C, C&#x2032;, C&#x2033;, C&#x2032;&#x2033;).

Superconducting magnet arrangement with hysteresis free field coil

A magnet configuration comprising a superconducting magnet coil system (M) and a current path (P) which comprises parts of the magnet coil system (M), wherein at least two electric connecting points (A, A, A, A) are disposed on the current path (P), which define a section (P, P, P) within the current path (P), wherein the section (P, P, P) does not comprise all parts of the magnet coil system (M) contained in the current path (P), and comprising a resistive element (W, W, W) having an electric resistance value &#x2267;0, and at least two contacts (K, K, K, K), wherein the contacts (K, K, K, K) are disposed between the resistive element (W, W, W) and one connecting point (A, A, A, A), is characterized in that in the superconducting state of the magnet coil system (M), an electric contact (K, K, K, K) between an electric connecting point (A, A, A, A) and a resistive element (W, W, W) can be closed and opened. The inventive magnet configuration provides quench protection and also effective disturbance compensation.

Superconducting magnet configuration with resistive elements

A magnet system with a magnet arrangement (M), a working volume (V) and a pulse tube cooler (P) with magnetic regenerator material (r) is characterized in that a shielding (m) of magnetic material is provided which reduces the stray field of the magnet arrangement at the location of the magnetic regenerator material (r) and is characterized in that&#x2153;|wherein mis the dipole moment of the magnetic material of the shielding (m), &#x394;&#x3c7; is the vibration amplitude of the magnetic material of the shielding (m), mis the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle without magnetic shielding (m), {tilde over (m)}is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle with magnetic shielding (m), and R is the average separation of the magnetic regenerator material (r) from the working volume (V). A magnet system of this type has an optimum stable, temporally constant magnetic field in the working volume (V).

Magnet system with shielded regenerator material

A magnet assembly for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) comprises an actively shielded superconducting magnet coil system (M) and at least one current path (P , . . . , Pn) which is superconductingly closed in the operating state. The actively shielded superconducting magnet coil system (M) has a radially inner partial coil system (C ) and a radially outer partial coil system (C ) disposed coaxially with respect to each other. An external device supplies current to the current paths (P , . . . , Pn) to charge each path to a respective current (IP , . . . , IPn) in the operating state. When optimizing the fringe field behavior outside of the magnet system, the overall magnitude of magnetic dipole moments of the current paths (P , . . . , Pn), charged to their respective operating currents (IP , . . . , IPn), is at least 0.1% of the magnitude of the magnetic dipole moment of the charged partial coil system (C ). When charging the current paths (P , . . . ,Pn) to their respective operating current (IP , . . . , IPn), the resulting change &Dgr; of the coefficient of second order (H ) of the polynomial expansion of the magnetic field (H) of the magnet assembly is given by: &verbar;&Dgr; &verbar;<max (0.25T/m , 0.9&middot;&verbar;H (M)&verbar;), wherein H (M) designates the coefficient of second order of the polynomial expansion of the magnetic field of the actively shielded superconducting magnet coil system (M) in the operating state. This permits compensation for deviations of the fringe field of the magnet assembly from its design values due to deviations of coil parameters from their design values, through an appropriate design of the additional current paths (P , . . . , Pn) and setting their currents to a suitable value.

Actively shielded superconducting magnet assembly with a device for additional fringe field optimization

NMR magnet coil system with separate superconducting short-circuited regions for drift compensation as well as method for operation thereof

A magnet assembly for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) disposed on the z axis about z&equals;0 with an actively shielded superconducting magnet coil system (M) and at least one current path (P , . . . , Pn) which is superconductingly closed in the operating state, wherein the actively shielded superconducting magnet coil system (M) comprises a radially inner partial coil system (C ) and a radially outer partial coil system (C ) disposed coaxially with respect to each other and whose magnetic dipole moments have opposite signs in the operating state and differ by an amount &Dgr; , with &verbar;&Dgr; &verbar;<2.5% of the magnitude of the magnetic dipole moment of the radially inner partial coil system (C ), is characterized in that the current paths (P , . . . ,Pn) are at least temporally superconductingly short-circuited during charging of the actively shielded superconducting magnet coil system (M) and that the current paths (P , . . . , Pn) are designed such that the currents induced therein due to the charging process of the magnet coil system (M) generate an overall magnetic dipole moment of a magnitude of at least 0.1% of the magnitude of the magnetic dipole moment of the charged radially outer partial coil system (C ). Suitable design of the additional current paths compensates for deviations of the fringe field from its design specification, due to deviations of coil parameters from their design values.

Actively shielded superconducting magnet assembly with improved fringe field compensation

In a magnet arrangement (M, D, P , . . . , Pn) having a magnet coil system (M) with at least one current-carrying superconducting magnet coil, with an additional current-carrying coil system (D) which can be fed by an external current source to produce a magnetic field in the working volume which differs substantially from zero, and optionally with additional superconductingly closed current paths (P , . . . , Pn), wherein the magnetic fields in the z direction, generated by the additional current paths (P , . . . , Pn) due to currents induced during operation and the field of the additional current-carrying coil system (D) do not exceed 0.1 Tesla in the working volume, the additional coil system (D) is designed such that its field contribution to the working volume is determined taking into account the diamagnetism of the superconductor in the main coil system. This permits as large as possible an effective field efficiency of the additional coil system (D).

Dimensioning of magnet arrangement comprising an additional current carrying coil system

A magnet arrangement comprising a superconducting magnet coil system (M) for producing a magnetic field in the direction of a z axis in a working volume (AV) disposed on the z axis about z&equals;0, wherein the superconducting magnet coil system (M) comprises a radially inner partial coil system (C ) and a radially outer partial coil system (C ) which is coaxial thereto, and with a field forming device (P) of magnetic material disposed in a preferably cylindrically symmetrical fashion about the z axis, located radially between the radially inner and the radially outer partial coil system (C C ), and being coaxial with respect to the two partial coil systems (C C ), wherein the radially inner partial coil system (C ) produces a homogeneous field in the working volume (AV) and the radially outer partial coil system (C ) produces an inhomogeneous field in the working volume (AV) is characterized in that the radially outer partial coil system (C ) produces, together with the magnetic field forming device (P), a homogeneous field in the working volume (AV), wherein the magnetic material of the field forming device (P) is largely magnetically saturated with its magnetization pointing substantially in a direction along the z axis. In this fashion, a homogenized radially inner partial coil system (C ) can be supplemented with an inhomogeneous radially outer partial coil system (C ), such that, through the use of a magnetic field forming device (P), the overall resulting magnet arrangement once more produces a homogeneous magnetic field in the working volume of the magnet arrangement.

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Zurich, Switzerland

Pierre-Alain Bovier