Bruker Biospin Gmbh

Bruker Switzerland Ag

Other

Bruker Biospin Ag

Patrick Wikus

Steffen Bonn

Wolfgang Frantz

Joerg Hinderer

Volker Niemann

Marco Strobel

Michael Dumm

Michael Wagenknecht

Robert Schauwecker

Gerhard Roth

Daniel Guy Baumann

Markus Mayer

Martin Woodtli

Heinrich Harsch

Jörg Hinderer

A device for transferring liquid helium into a usage helium tank of a usage cryostat includes a reservoir cryostat with a vacuum-insulated reservoir helium tank configured to store liquid helium available for filling the usage helium tank, a supply line for liquid helium, and a gaseous helium return line. The supply line proceeds from the vacuum-insulated reservoir helium tank and is connected to the usage helium tank. The gaseous helium return line leads into the vacuum-insulated reservoir helium tank and is connected to the usage helium tank. The device further includes a conveying device configured to convey liquid helium from the vacuum-insulated reservoir helium tank through the supply line into the usage helium tank and further configured to convey gaseous helium from the usage helium tank through the return line into the vacuum-insulated reservoir helium tank.

Device for transferring liquid helium, with reduced transfer losses

An NMR measuring arrangement () includes a cryostat (), a superconducting magnet coil system () and an NMR probe (). The cryostat has an evacuated vacuum container () and forms a bore (). A wall () of the bore delimits the vacuum container. The cryostat forms only one evacuated gap () in a space () between the magnet coil system and the wall of the bore. At least a segment of the wall of the bore is thermally coupled to a heat sink of the cryostat. As a result, the NMR measurement arrangement provides more precise NMR measurements (in particular with a higher spectral resolution and/or a higher signal-to-noise ratio) on measurement samples.

NMR measuring assembly with cold bore of the cryostat

A cryostat assembly with an outer container for a storage tank with a first cryogenic fluid and a coil tank for a superconducting magnet coil system. The magnet coil system is cooled by a second cryogenic fluid colder than the first cryogenic fluid, the coil tank being mechanically connected to the outer container and/or to radiation shields surrounding the coil tank via a mounting structure. Liquid helium at an operating temperature of approximately 4.2 K is the first cryogenic, fluid and helium at an operating temperature of &#x3c;3.5 K is the second cryogenic fluid in the coil tank. The mounting structure has mounting elements with thermally conductive contact points thermally coupled to heat sinks having a temperature at or below that of the storage tank, via thermal conductor elements. This ensures long times to quench if malfunctions occur.

Cryostat assembly with superconducting magnet coil system with thermal anchoring of the mounting structure

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 magnet assembly () with a cryostat () has a superconducting magnet coil system (), an active cooling device () for the coil system, and current leads () for charging the coil system. The current leads have at least one normal-conducting region (), wherein multiple cold reservoirs () are thermally coupled to the current leads along the normal-conducting region thereof, in order to absorb heat the normal-conducting region during charging of the magnet coil system. The current leads have a variable cross-sectional area B in the normal-conducting region along the extension direction thereof, wherein at least over a predominant fraction of their overall length in the normal-conducting region, the cross-sectional area B decreases from a cold end () toward a warm end (). This provides a magnet assembly requiring reduced cooling power during charging, with less heat introduced into the magnet coil system in normal operation.

Magnet assembly with cryostat and magnet coil system, with cold reservoirs on the current leads

A cryostat system is kept at a cryogenic operating temperature without providing or supplying cryogenic fluids by a cryocooler. The cryostat system includes a superconducting magnet arrangement and a heat sink apparatus to prolong the time before the superconducting magnet arrangement quenches/returns to the normally conducting state if active cooling fails. The heat sink apparatus includes magnetocaloric material and is thermally connected to the superconducting magnet arrangement and/or to parts of the cryostat system through which ambient heat can flow to the superconducting magnet arrangement. In this way, the cryostat system can be operated in a truly 'cryogen-free' manner while maintaining a sufficiently long time to quench in the event of potential operational malfunctions.

Cryogen-free magnet system comprising a magnetocaloric heat sink

A cryostat arrangement includes a superconducting magnet to be cooled by an active cryocooler. The cryocooler includes a coolant circuit with a compressor, a cold head, and a cold finger in thermal contact with the magnet. A volumetric vessel containing cryogenic fluid is thermally coupled to the magnet. The volumetric vessel is connected to the coolant circuit by a pressure-resistant line. A fluidic component influences the flow rate through the line in a defined manner such that the cryogenic fluid flows between the volumetric vessel and the coolant circuit with a time constant of at least 15 minutes. The cryostat can be operated in a 'cryogen-free' manner and permits a sufficiently long time to quench in the event of operational malfunctions.

Cryogen-free magnet system comprising a heat sink connected to the gas circuit of a cryocooler

A cooling device () has a cryostat () and a cold head () of a cooling system (), and additionally includes a pivot bearing (), with which the cold head () is mounted on the cryostat () so as to be rotatable about a rotation axis (A). A connecting line () for a working gas of the cooling system () is connected to the cold head so that forces caused by the cooling system () act on the cold head () via the connecting line () at a force application point (EP) in a force application direction (ER). The force application direction (ER) is inclined by no more than 40&#xb0; with respect to the normal (N) of a lever plane (HE) which contains the rotation axis (A) and the force application point (EP).

Cooling device, comprising a cryostat and a cold head having improved decoupling to a cooling system

A superconducting magnet coil arrangement has a high-temperature superconductor (HTS) coil section () in the form of a solenoid that is wound with an HTS tape conductor, and also has a field-shaping device comprising at least two field-shaping elements (). At least one respective field-shaping element is arranged adjoining each of the two axial ends of the HTS coil section, the field-shaping elements being configured in such a way that they reduce the field angle of the magnetic field generated by the magnet coil arrangement with respect to the axial direction in the region of the HTS coil section by at least 1.5&#xb0;.

Magnet arrangement with field-shaping element for reducing the radial field component in the region of an HTS section

A cryostat arrangement has an outer jacket, a first tank with a first cryogen, and a second tank with a second liquid cryogen which boils at a higher temperature than the first cryogen. The first tank comprises a neck tube, whose hot upper end is connected to the outer jacket at ambient temperature and whose cold lower end is connected to the first tank at a cryogenic temperature. The arrangement uses a riser pipe protruding into the second tank through which the second liquid cryogen can flow out of the second tank and into a first heat exchanger in thermal contact with the neck tube. An outflow line is provided through which second cryogen evaporating from the first heat exchanger can flow out and into an optional second heat exchanger. It is thus possible to greatly reduce heat input from the neck tube into the first tank.

Cryostat with active neck tube cooling by a second cryogen

A superconducting magnet coil system with high resistance to quench events includes a first coil portion () with a first superconducting material and a second coil portion () with a second superconducting material. The first superconducting material has a higher critical temperature than the second superconducting material. The first and the second coil portions are bridged by a common quench protection element () and together with the quench protection element form a first loop. The magnet coil system also includes a third coil portion () which is part of a second electrical loop with a second quench protection element ()as well as a heating element () which is supplied with a heating voltage in response to a quench of the third coil portion. Among the series connected coil portions () only the second coil portion is in thermal contact with the first heating element ().

Superconducting magnet coil system

A cryostat arrangement (), with a vacuum container () and an object () to be cooled, is provided, wherein the object () to be cooled is arranged inside the vacuum container () comprising a neck tube () leading to the object () to be cooled. A closed cavity () is formed around the cooling arm () of a cold head (), wherein the cavity () in normal operation is filled at least partly with a first cryogenic fluid (), and wherein a first thermal coupling component () is provided for the thermal coupling of the first cryogenic fluid () in the cavity () to the object () to be cooled. The cryostat arrangement () further comprises a pump device (), to which the cavity () is connected, and with which the cavity () is configured to be evacuated upon failure of the cooling function of the cold head (). Various cryostat configurations are provided.

Cryostat arrangement with a vacuum container and an object to be cooled, with evacuable cavity

An arrangement for setting the spatial profile of a magnetic field in a working volume of a main field magnet (), in particular a superconducting main field magnet, of a magnetic resonance installation. The main field magnet is arranged in a cryostat () and the spatial profile is set by a passive shim apparatus () with magnetic field forming elements which are arranged within the cryostat during operation and which have cryogenic temperatures. The magnetic resonance installation contains a room temperature tube (), in which the sample volume is situated during operation. The passive shim apparatus is introduced into or removed from the cold region of the cryostat via a vacuum lock (), without needing to ventilate the cold region of the cryostat. This provides a relatively simple, cost effective, and time-efficient method to carry out a stable field homogenization using a passive shim apparatus.

Magnet and cryostat arrangement, and method for passive shimming

A connecting device in a pulse tube cooler system branches such that a first line branch () has a first flexible line segment () and a second line branch () has a second flexible line segment (), the flexible line segments being arranged in parallel with and offset from one another. The flexible line segments each have a front segment end () and a rear segment end (), the front segment end () of the first flexible line segment () and the rear segment end () of the second flexible line segment () are rigidly connected to one another, the rear segment end () of the first flexible line segment () and the front segment end () of the second flexible line segment () are rigidly connected to one another, and there is no continuous rigid connection between the control valve and the cold head.

Pulse tube cooler system with force-compensated rotary valve line

A cooling device () has a cryostat () and a cold head (), in particular, the cold head () of a pulse tube cooler. The cryostat () has a vacuum container () with a vacuum container wall (), wherein the vacuum container wall () seals off a vacuum inside the vacuum container () from the environment. A flexible sealing section () connects the vacuum container wall () directly or indirectly to the room temperature part () of the cold head (). The flexible sealing section () seals off the inside of the cryocontainer () from the environment. The cooling device further reduces mechanical coupling between the cold head and the cryostat, in particular, in order to enable performance of NMR measurements with fewer disturbances due to external vibrations.

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Nuerensdorf, Switzerland

Patrick Wikus