Bruker Biospin Ag

Arthur Schwilch

Daniel Marek

Martin Luke

Nicolas Freytag

Walter Roeck

Michael Schenkel

Christoph Martin Gosteli

Christoph Gosteli

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 ICR cell () operates with a duplexer (), which is an integral part of a transmission and receiving device () of an FT-ICR mass spectrometry device. The device transmits a transmitter () voltage to at least one electrode () of the ICR cell during an ion excitation phase and protects a preamplifier () from overvoltage. An ion received signal passes through a reception path () to the preamplifier during an ion detection phase. The duplexer has at least one active serial switch () with two switchable states, each with different series impedances, which is inserted in the reception path (). As a result, a duplexer for an ICR cell of an FT-ICR mass spectrometry device is provided in which at least one electrode can be used for both ion excitation and for subsequent ion detection.

ICR cell operating with a duplexer

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

A device has a first control loop () with which a frequency RF of an RF generator is synchronized with a resonance frequency Fof an NMR line. A phase shifter () is provided to rotate the radio frequency phase of the NMR receiver system in the first control loop. The phase shifter is controlled by a second control loop () whose input signal comes from a signal extraction stage.

Device for highly precise synchronization of the NMR transmission frequency to the resonance frequency of an NMR line while taking into consideration a non-constant RF phase

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 method of operating a high-resolution NMR spectrometer comprising a DDS generator containing an NCO for generating an LO frequency, wherein the frequency of the NCO is defined by inputting a numerical value Z, is characterized in that this numerical value Z may assume only values which satisfy the equation Z&equals;n&middot;N/m, wherein Z, n, N, and m are integer and positive numbers, N is a power of 2 with a positive integer exponent, wherein said exponent represents the maximum number of bits during the calculation process, m is approximately 2&middot;f /&Dgr;B, n approximately m&middot;f /f and m additionally a common integer divisor of n&middot;N and f is the clock frequency of the NCO , &Dgr;B is the desired bandwidth with high spectral purity and f is the output frequency of the NCO . This method allows the use of a DDS generator even in the case where very high spectral purity is required, wherein in particular quantization noise is largely eliminated over the frequency range relevant for NMR measurements.

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Uster, Switzerland

Arthur Schwilch