Bruker Biospin Ag

Spectrospin Ag

Bruker Ag

Bruker Analytische Messtechnik Gmbh

Bruker Biospin Mri Gmbh

Daniel Marek

Oskar Schett

Nicolas Freytag

Daniel Guy Baumann

Arthur Schwilch

Marco Sacher

Roberto Seydoux

Philippe Stauffenegger

Ralf Haueisen

Michael Warden

Marc A Schnell

Cengiz Cetrefli

Martin Luke

Tobias Leutenegger

Arne Kasten

Frank H Laukien

Beat Mraz

René Triebe

Beat Grossniklaus

Anton Kuster

Alia Hassan

Hansjörg Tschirky

Hansjoerg Tschirky

Klemens Kessler

Jean-Claude Riboulet

Francedillaois Metz

Urban Frey

Marcellus Burgers

Patrick Favre

Rene Triebe

Stephan Graf

Peter Scheuzger

Ren&eacute; Triebe

Tschopp Werner

Christoph Notzli

Marc Enrique Paredes

Ernst Ungricht

Markus Haberli

Marc Schnell

A method for the transmission/reception of RF signals for NMR measurements uses a heat exchanger () for cooling heat sources (), the heat exchanger having a contact element () for thermal connection between a cryogenic fluid and the heat source, is characterized in that the heat exchanger comprises a container having an interior volume Vinto which a first cryogenic fluid Fthat has a liquid component Fand a gaseous component Fflows through an inflow conduit () and from which a second cryogenic fluid Fthat has liquid component Fand a gaseous component Fflows out through an outflow conduit (). The inflow conduit has a flow cross-section Qand a circumference Ufrom which an associated parameter V=4&#xb7;Q/Uresults, wherein V&#x3e;10&#xb7;V, and the outflow conduit has a flow diameter Qwherein Q&#x2265;Q. The contact element is in close thermal contact with both the liquid volume component Vof the cryogenic fluid and with the heat source. A device for setting the inflow quantity of the first cryogenic fluid Finto the container is provided that ensures a state F/F&#x3e;F/Fduring operation. In this way, vibrations due to the cooling process can be largely reduced and the consumption of cryogenic fluid minimized.

Method for cryogenic cooling of an NMR detection system with the assistance of a container filled with a cryogenic fluid

An electronic interface () between a pure NMR receiver resonator (RO) and a preamplifier is characterized in that one or more control diodes (D, D) are provided by means of which the current designed to flow through the switching diodes can be fed into these switching diodes, and the control diodes are connected to the switching diodes directly or via one or more additional series impedances. In this fashion, the impedance of the resonator is transformed to the required preamplifier or line impedance during the receiving process with little loss. In particular, during the receiving process, matching can be adjusted during the transmitting process, the current in the inductance of the resonator generated by the Bfield of the transmitting resonator is minimized and all components are protected against damage.

Electronic interface for NMR receiver resonators

An electrical circuit with one or more semiconductor components () is characterized in that at least one semiconductor junction of at least one of the semiconductor components of the electrical circuit is disposed such that the average direction of motion of the charge carriers in the semiconductor junction is essentially parallel to the lines of force of the magnetic field B, wherein the corresponding semiconductor component is disposed directly on a substrate (), which is made of a material with good thermal conduction properties. In this way, undistorted characteristics of the semiconductor component used can be ensured despite the very strong magnetic field and the low operating temperatures.

Electrical circuit in the magnetic field of an MR apparatus

An NMR (nuclear magnetic resonance) apparatus has a magnet system disposed in a cryostat (), the cryostat having at least one nitrogen tank () for receiving liquid nitrogen () and a room temperature bore () for receiving an NMR probehead (), wherein part(s) of the probehead or the overall probehead can be cooled to cryogenic temperatures by supplying liquid nitrogen () via a supply line (). The nitrogen tank () of the cryostat () is connected to the NMR probehead () by means of a supply line () in such a fashion that liquid nitrogen () is removed from the nitrogen tank () and guided to the NMR probehead (). The overall apparatus is therefore more compact, the operating comfort of the apparatus is increased, and the costs for acquisition, operation and maintenance are considerably reduced compared to previous comparable devices.

Cryogenic probehead cooler in a nuclear magnetic resonance apparatus

A magnetic resonance (MR) detection configuration comprising at least one RF resonant circuit with an inductance, a preamplifier module and an RF receiver, wherein a reactive transformation circuit is connected between a high-impedance point of the inductance and a low-impedance connecting point of the RF resonant circuit, which acts as an impedance transformer and wherein the low-impedance connecting point is connected to the preamplifier module via an RF line having a characteristic impedance, is characterized in that at least one passive damping impedance is provided in the preamplifier module downstream of the RF line, wherein the passive damping impedance can be connected to the resonant circuit by a switching means during a damping and/or transmitting process, and wherein the respective amount of the complex reflection factor of passive damping impedance relative to the characteristic impedance of the RF line exceeds a value of 0.5. This presents an MR detection configuration with an extensive damping concept, wherein all three processes (transmitting, damping and receiving processes) are optimized.

Passively damped magnetic resonance (MR) detection configuration

A magnetic resonance (MR) probe head comprises a detecting device with at least one antenna system which is cryogenically cooled by a cooling device, and a cooled preamplifier in a preamplifier housing which is spatially separated from the detecting device, and a thermally insulating connecting means via which the detecting device and the preamplifier housing are connected, wherein the connecting means comprises at least one cooling line for supplying and/or returning a cooling fluid, and with at least one RF line for transmitting the electric signals. The connecting means is implemented as a mechanically flexible connecting line with mechanically flexible RF lines and cooling lines disposed therein. The MR probe head is easy to handle and can be highly sensitive, wherein the detecting device can be quickly installed, removed and put into operation.

Cooled NMR probe head with flexible cooled connecting conduit

A magnetic resonance (MR) probe head comprises a detecting device () with at least one antenna system which is cryogenically cooled by a cooling device, a cooled preamplifier () in a preamplifier housing () which is spatially separated from the detecting device (), and a thermally insulating connecting means via which the detecting device () and the preamplifier housing () are connected, wherein the connecting means () comprises at least one cooling line () for supplying and/or returning a cooling fluid, and at least one RF line () for transmitting electric signals. The connecting means (), including its RF and cooling lines (), can be separated from the preamplifier housing () by a coupling. The MR probe head is an open system which can be used in a universal fashion through use of different measuring inserts. The system can be expanded for further measuring configurations at little cost and can be easily handled in a time-saving fashion with an optional arrangement having a flexible connecting line.

Cooled NMR probe head which can be coupled

A nuclear magnetic resonance probe head comprising at least two orthogonal coil/resonator configurations Aand Ahaving different resonance frequencies, wherein at feast one of the coil/resonator configurations Ahas two saddle-shaped coils Sand S, wherein each coil has a window about which N windings are disposed which are connected in series, wherein N&#x2267;. Each coil Sand Sis formed mirror-symmetrically relative to a central plane of the respective coil, which is perpendicular to the window of the respective coil, wherein the central planes of the coils Sand Sare identical to minimize the electromagnetic coupling between the two coil/resonator configurations Aand Aat the resonance frequency of A. The NMR probe head reduces coupling between the two coil/resonator configurations.

Electrically symmetric NMR coils with a plurality of windings connected in series

A tubular capacitor with variable capacitance, including a cylindrical tube () of dielectric material, a metallic outer electrode () which surrounds the cylindrical tube (), and an inner electrode which can axially move in the inner bore () of the cylindrical tube () and which abuts the inner bore (), wherein the inner electrode includes a metallic rod ('), located in the inner bore () of the cylindrical tube (), using a rod () of dielectric material. The inventive tubular capacitor has an increased dielectric strength and improves the resolution of NMR spectrometers.

Tubular capacitor with variable capacitance and dielectrically elongated inner electrode for NMR applications

An NMR probe head for investigating a temperature-sensitive test object in a volume under investigation with at least one RF receiver coil which is cooled to cryogenic temperatures during operation, and is surrounded by a housing, wherein at least one heatable separating wall is provided between the RF receiver coil and the test object, is characterized in that the separating wall is produced from a material having excellent heat conducting properties, wherein the separating wall is coupled in a heat conducting fashion to at least one heating element at a separation from the volume under investigation via at least one contact location. The inventive NMR probe head permits disposition of the RF receiver coil in close proximity to the test object to be measured without inadvertently cooling it.

NMR probe head with heated housing

An NMR spectrometer comprising an NMR magnet system () disposed in a helium tank of a cryostat and an NMR probe head () disposed in a room temperature bore of the cryostat, which contains a cooled RF resonator () for receiving NMR signals from a sample to be investigated, and a cooled pre-amplifier (), wherein the NMR probe head () is cooled by a common multi-stage compressor-operated refrigerator (), wherein the refrigerator () comprises a cold head and several heat exchangers () at different temperature levels, wherein the refrigerator () is disposed at a spatial separation from the cryostat in a separate, evacuated and thermally insulated housing () and wherein at least one cooling circuit with cooling lines, which are thermally insulated by a transfer line () is disposed between the housing () containing the heat exchangers () and the NMR probe head (), is characterized in that additional cooling lines to an LNtank () or radiation shield () disposed in the cryostat and surrounding the helium tank are provided, and the refrigerator () also cools the LNtank () or the radiation shield (). The inventive NMR spectrometer comprises a simple and inexpensive device for matching the holding time of LNto that of LHe through cooling the LNtank using the refrigerator provided for cooling the NMR probe head and without great expense.

NMR spectrometer with refrigerator cooling

A cryohead () for nuclear magnetic resonance (NMR) measurements, comprising at least one detection channel for receiving NMR signals and at least one transmitting and decoupling channel, wherein different radio frequency (RF) coils or resonators () are provided for the different channels, wherein the cryohead () comprises a heat exchanger which can be cooled by a passing fluid, in particular helium, and wherein the RF coils or resonators () of at least one detection channel and also of at least one transmitting or decoupling channel can be cooled to cryogenic temperatures, is characterized in that at least two heat exchangers () are provided., wherein at least one first heat exchanger () cools the RF coil or the resonator () of the at least one detection channel, and at least one further heat exchanger () cools the RF coil or the resonator () of the at least one transmitting or decoupling channel, and wherein the at least one first heat exchanger () is separated from the at least one further heat exchanger (). The inventive cryohead minimizes the absolute temperature of the detection coil during operation and eliminates temperature fluctuations in the detection coil.

Cryo head with a plurality of heat exchangers for cooling the RF coils or resonators

A radio-frequency (RF) resonator system, in particular, for an NMR (nuclear magnetic resonance) probe head, with at least one RF resonator which comprises at least three non-interrupted conducting elements () which form at least one window () in the RF resonator, wherein only part of the conducting elements delimits the at least one window, wherein the conducting elements are coupled through electromagnetic fields, wherein each conducting element has a limiting current density, is characterized in that the eigen-resonances of the individual conducting elements and/or the electromagnetic coupling between the conducting elements is/are selected such that upon excitation of the RF resonator system, the maxima of the quotient values along the individual conducting elements are substantially equal for all conducting elements, wherein these quotient values are defined as a quotient between an average current density which occurs in a cross-section of the conducting elements and the respective local limiting current density, or in that peak-shaped current excesses () which may occur mainly in the edge region of packets of conducting elements (), in particular, at the edge of windows () along individual conducting elements () or along conductor groups of several conducting elements () are substantially eliminated. The RF resonator system thereby allows large RF magnetic field strengths.

Radio frequency resonator system with optimized current distribution in the conducting elements

A nuclear magnetic resonance (NMR) spectrometer with a magnet arrangement ( ) for generating a homogeneous static magnetic field B in the direction of a z axis and a radio frequency (RF) resonator ( ) for receiving NMR signals from a measuring volume which has one or more superconducting components, is characterized in that a stabilization device is provided which keeps the magnetic field components B , transverse to the homogeneous magnetic field B , which acts on the superconducting components of the RF resonator ( ), constant. The stabilization device can act actively or passively. It is thereby possible to completely suppress generation of disturbing transverse magnetization for RF resonator coils with superconducting components. Moreover, a demagnetised coil always remains demagnetised during the entire subsequent operation.

Stabilization of transverse magnetization in superconducting NMR resonators

An NMR resonator with RF resonator for receiving RF signals at a resonance frequency from a measuring sample in a volume under investigation of an NMR apparatus with a means for producing a homogeneous magnetic field B in the direction of a z axis, wherein normally conducting conductor structures of the RF resonator which act inductively and partially also capacitively are disposed between z&equals;&minus;&verbar;z &verbar; and z&equals;&plus;&verbar;z &verbar; on a surface which is translation-invariant (&equals;z-invariant) in the z direction at a radial (x, y) separation from the measuring sample, is characterized in that a compensation arrangement is additionally provided on the z-invariant surface, which extends to values of at least z<&minus;&verbar;z &verbar;&minus;0.5&verbar;r&verbar; and z>&plus;&verbar;z &verbar;&plus;0.5&verbar;r&verbar;, wherein &verbar;r&verbar; is the minimum separation between the measuring sample and the compensation arrangement, wherein the compensation arrangement comprises additional normally conducting conductor structures which are largely RF-decoupled from the RF resonator, with the conductor structures of the compensation arrangement and of the RF resonator being composed of individual surface sections (&ldquo;Z-structures&rdquo;) which comprise normally conducting structures and which are disposed in the z-invariant surface to each extend in the z direction along the entire length of the conductor structures of the compensation arrangement and of the RF resonator, their structures being disposed such that, under decomposition of the surface of the Z structures into a plurality of equally sized surface elements, an equal mass of normally conducting material is contained in all surface elements which differ only with respect to their z position. This produces a new type of normally conducting NMR resonators whose additional conductor structures are decoupled from the actual RF resonator and which compensate for the disturbing influence caused by the susceptibility of the conductor.

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Moeriken, Switzerland

Daniel Marek