Bruker Biospin Ag

Bruker Switzerland Ag

Bruker Ag

Bruker Biospin Gmbh

Other

Robert Schauwecker

Pierre-Alain Bovier

Andreas Amann

Daniel M Eckert

Joerg Hinderer

Patrik Vonlanthen

Kenneth J Guenter

Werner H Tschopp

Wolfgang Frantz

Rolf Spreiter

Matteo Alessandrini

Robert Herzog

Michael Westphal

Klaus Schlenga

Rainer Pietig

Nicolas Freytag

Gerhard Roth

Patrick Wikus

Roger Meister

Frank H Laukien

Daniel Guy Baumann

Markus Mayer

Stephen Alfred March

Franck Borgnolutti

Francesca Venturini

Raffaele Gilardi

Stephan Heiss

Michele Zaffalon

Dmitry Eshchenko

Guenter Kuebler

Andreas Kraus

Martin Woodtli

Thomas Wuethrich

Riccardo Tediosi

Stefan Schneider

Jörg Hinderer

Kenneth J Günter

Kenneth Günter

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 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

A method for charging an HTS shim device in a cryostat having a room temperature bore using a charging device. A shim switch temporarily interrupts the superconducting state in a section of an HTS shim conductor path. The charging device includes a primary circuit with a normal-conducting charging coil and the conductor path forms a secondary circuit. A current change in the secondary circuit results from a change in magnetic flux generated by the charging coil through the secondary circuit. In a first phase the shim switch is opened to interrupt the superconducting state in a section of the conductor path, the charging coil is positioned in the bore, and the current in the primary circuit is changed; in a second phase, the conductor path is superconductingly closed; in a third phase, the current in the primary circuit is changed and/or the charging coil is removed from the bore.

Method for charging an HTS shim device and magnet arrangement

A shim device having an HTS shim conductor track (C) and a shim switch (Sw) The track (C) is curved around an axis (z) and the shim switch is arranged in a first conductor track portion (S), to interrupt its superconducting state. The track (C) extends around at least a first opening (O) and a second opening (O) such that the track (C) has a first circumferential current path (L), a second circumferential current path (L) and a third circumferential current path (L). Two of the three paths (L, L, L) each surround only one of the two openings and one of the three paths (L, L, L) surrounds both openings. The first portion (S) is part of only the first path (L) and the second path (L). This produces a persistent HTS shim for field homogenization, allowing both a complex field distribution and a large degree of design freedom.

Shim device, magnet assembly, and method for charging a shim device

A magnet assembly in a magnetic resonance apparatus includes a cryostat and a superconducting main field magnet coil system arranged therein for generating a magnetic field in the direction of a z-axis in a working volume. The magnet assembly includes a shim device arranged inside the cryostat for adjusting the spatial variation or homogeneity of the magnetic field generated in the working volume by the magnet coil system. The shim device comprises at least one closed superconducting shim conductor path having an HTS layer. The HTS layer forms a surface that is geometrically developable such that unwrapping onto a plane changes the geodesic distance between any two points on the surface formed by the HTS layer by no more than 10%. The inner and/or outer contour of the geometrical development of the HTS layer describes a non-convex curve.

Magnet assembly comprising closed superconducting HTS shims

An NMR rotor comprises a receptacle for inserting a sample container into a homogeneous region of an NMR magnetic field with flux density B, the field vector of which in the homogeneous region extends in the vertical direction along a z-axis. The rotor passes through regions with inhomogeneous magnetic field components and a flux density gradient dB/dz when the sample container is introduced. The rotor includes at least two different materials, one with diamagnetic properties and another with non-diamagnetic properties. The different materials are arranged to be geometrically distributed in the rotor so that the magnetic force on the rotor under the effect of a product t of magnetic flux density B and flux density gradient dB/dz, the magnitude of which exceeds 1400 T/m, either acts in the same direction as the weight force of the rotor or is smaller in magnitude than the weight force of the rotor.

Magnetically compensated NMR rotor

A superconductor magnet apparatus () includes a superconductor bulk magnet (), a cryostat () and a ferromagnetic shielding body (). The bulk magnet has a superconductor bore (), an axis (z) of rotational symmetry, and a maximum outer diameter ODin a plane perpendicular to the z axis. The superconductor bore has a minimum cross-sectional area Sin a plane perpendicular to the z axis. The cryostat has a room temperature bore (), the bulk magnet is arranged within the cryostat and the room temperature bore is arranged within the superconductor bore. The shielding body has a shielding bore (), the bulk magnet is arranged within the shielding bore and the shielding body extends beyond the bulk magnet at each axial end by at least OD/3. For an average cross-sectional area Sof the shielding body, S&#x2265;2.5*S, and the shielding body is arranged within the cryostat.

Superconducting magnet apparatus and method for magnetizing a superconductor bulk magnet by field cooling through a ferromagnetic shield

A superconductive magnet coil assembly includes a layer-wound coil that is cylindrically symmetric, wherein the rectangular coil cross section of the coil has a first rectangular portion ('&#x2033;) within the coil cross section, and at least one second rectangular portion (&#x2032;&#x2033;) and third rectangular portion (&#x2032;&#x2033;) within the first portion which spans the first portion completely in the radial direction and in part in the axial direction, the second portion being completely wound with the first strip-like superconductor, and the third portion being completely wound with the second strip-like superconductor, and the strip-like superconductors being guided into a region outside the coil cross section and being electrically connected there, and wherein the second and the third rectangular portions are disjunct.

Superconductive magnet coil assembly comprising a plurality of layer-wound strip-like superconductors

A layer wound magnet coil includes a central coil region and end coil regions adjoining the central coil region along an axial line of symmetry. The central coil region includes layers of coil windings of an anisotropic material. The end coil regions include layers of coil windings of the anisotropic superconducting material interspersed with layers of non-superconducting material.

Layout for magnet coils wound with anisotropic superconductor, and method for laying out the same

A superconducting magnet assembly includes a cryostat, a vacuum vessel and a refrigeration stage. An NMR probe using the assembly includes comprises cooled probe components, a two-stage cryocooler, and a counter flow heat exchanger. A cooling circuit guides coolant from one outlet of the counter flow heat exchanger back to an inlet of the counter flow heat exchanger via the second cooling stage, a cooled probe component, and a heat exchanger in the cryostat or a heat exchanger in a helium suspension tube. Both the intake temperature of the coolant flowing into the heat exchanger in the cryostat or in the suspension tube and the return flow temperature of the emerging coolant are at least 5 K lower than the operating temperature of the first cooling stage. Excess cooling capacity of the cryocooler reduces the evaporation rate of liquid helium or cools a superconducting magnet in a cryogen-free cryostat.

NMR apparatus comprising a superconducting magnet assembly and cooled probe components

An NMR apparatus includes a superconducting magnet assembly, a cryostat having a vacuum vessel, a refrigeration stage that can be operated at a temperature of &#x3c;100 K, and a magnet coil system that comprises a cold bore into which a room temperature access of the cryostat engages. The NMR apparatus also includes an NMR probe with probe components cooled to an operating temperature of &#x3c;100 K. The probe components are arranged between the cold bore and the room temperature access into the cold bore, radially inside the cold bore but outside the room temperature access. The vacuum vessel includes an opening that can be closed by a lock valve. A lock chamber is directly connected to the opening, such that the cooled probe components can be installed and/or removed through the opening and lock valve without breaking the vacuum in the vacuum vessel of the cryostat.

Introducing an NMR apparatus comprising cooled probe components via a vacuum lock

A method for indicating the level of a liquefied gas in a cryogenic tank having a resistance temperature detector (). The controller applies a heating pulse to the detector and performs a single resistance measurement after the heating pulse. The overheating of the sensor and the time interval for the measurement are found in a separate set of test experiment. As a result, for temperature sensors with negative temperature coefficient, the resistance of the sensor in gas is below some unique characteristic value, which can be used like a threshold criterion to distinguish between the liquid and the gas in a wide temperature range. For sensors with positive temperature coefficient, the resistance of the sensor in gas is larger than some unique characteristic value, which can be used like a threshold criterion to distinguish between the liquid and the gas in a wide temperature range.

Robust dynamical method and device for detecting the level of a liquid using resistance temperature detectors

A method for charging a magnet arrangement having a superconducting tape conductor with a first transition temperature in a cryostat device. The magnet arrangement is temperature-controlled to a first pre-operating temperature between the first transition temperature and the operating temperature, a first pre-operating current is excited, the magnet arrangement is cooled to operating temperature and a first operating current is excited. The magnet arrangement has a second magnet winding composed of a second superconductor material with a second transition temperature above the operating temperature and at least 15 K below the first transition temperature, wherein a second operating current in the second magnet winding is excited at the latest after cooling of the magnet arrangement to the operating temperature, and with the second operating current the second magnet winding generates a second operating magnetic field in the volume of the first magnet winding.

Method for energizing a superconducting magnet arrangement

A method for converting a cryostat configuration () having a first container () with a liquid helium bath () and a second container () which is filled with liquid nitrogen () is characterized in that a cooling medium () which is in a gaseous state at a temperature of 60K and a pressure of 1 bar, is introduced into the second container and is cooled by a refrigerator () by means of a cooling circuit (), the coolant lines of which are guided into the second container, to an operating temperature of &#x2266;60K. With this retrofit for existing cryostat configurations that utilize both liquid helium and also liquid nitrogen for cooling a superconducting coil, use of liquid nitrogen can be completely avoided and the evaporation rate of the liquid helium can also be considerably reduced without having to re-liquefy the cryogens used.

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Zurich, Switzerland

Robert Schauwecker