Bruker Switzerland AG

An additional element for focusing a time-varying magnetic flux (B1), for installation in a sample receptacle of an NMR probe head includes one or more cover elements that are each electrically conductive along a respective outer surface. The cover elements form one or more closed conductor loops, each enclosing a conductor loop area, that collectively form the cover zone, which has an area A cover . The cover zone at least partially encloses a passage window having an area A window with A cover ≥2 *A window . The additional element includes at least one capacitively acting structure, so that the additional element forms an electrical resonant circuit comprising the one or more cover elements, with a natural resonance of a resonance frequency RF, where 5 MHz≤RF≤3000 MHz. The additional element can be used to improve the signal-to-noise ratio with low-volume test samples when measuring in an existing NMR probe head.

An NMR apparatus ( 10 ) with an NMR magnet system for generating an NMR magnetic field, which comprises an NMR coil ( 11 ) for modifying the magnetic field, and with a stable and low-noise current source that supplies the NMR coil with electrical current, comprising a linear current controller ( 12 ) that is electrically connected to a first end of the NMR coil, is characterized in that the current source comprises a digital voltage source ( 13 ) using switching technology, which is connected to a second end of the NMR coil, such that the NMR coil, as an electrical consumer, is connected between the linear current controller and the digital voltage source, that the current controller is connected to the digital voltage source via a control line ( 14 ) for controlling the electrical voltage, and that the linear current controller regulates the digital voltage source such that the voltage on the side of the linear part of the arrangement lies in a preselected operating range, so that the lowest possible electrical power is consumed in the linear part of the arrangement. This allows the NMR coil to be supplied with power in an adjustable, stable and low-noise manner with high electrical efficiency, while the homogeneity of the NMR magnetic field is kept stable and constant even under changing external conditions.

A device for transferring liquid helium into an application cryostat comprises a storage dewar, a transfer line with a first transfer line end in the storage dewar and a second transfer line end for insertion into the application cryostat. An apparatus is provided for generating a pressure difference between the storage dewar and the application cryostat. A condensation heat exchanger, cooled by a cryocooler, condenses helium gas to liquid helium for insertion into the application cryostat. A control apparatus, using a measure of gas pressure in the application cryostat provides a control output to the apparatus for generating a pressure difference such that a volume of liquid helium transferred through the transfer line per unit of time is approximately equal to the change in volume of the helium which condenses from helium gas to liquid helium per unit of time at the condensation heat exchanger.

The invention relates to a radio-frequency bandpass filter for an MR apparatus, in particular for a transmission and/or receiving arrangement of the MR apparatus, comprising a resonator arrangement with a signal input, a signal output and at least one resonator, wherein each resonator has a capacitor which is connected in parallel to an inductor, characterized in that the inductor comprises an electrically conductive coil body having a cavity which is closed in a substantially RF-tight manner. As a result, an RF bandpass filter of high quality, high electric load-bearing capacity and simultaneously a low impedance level is achieved which can be produced simply and at low cost.

The disclosure relates, in particular, to the operation of radio frequency (RF) ion guides which receive, intermediately store, separate according to a physical-chemical property, spatially translate and finally output gas-phase ions. RF ion guides according to the disclosure may be part of, or be coupled with, a mass analyzer. The disclosure serves to improve the space charge capacity of an RF ion guide, and to minimize fragmentation losses of ions contained in such RF ion guide over a wide range of masses and/or mobilities. The disclosure further serves to optimize the operational characteristics of an RF ion guide over a wide range of physical-chemical property values at minimal loss of ions due to fragmentation by RF ion heating.

A method for producing a superconductive joint from a number of electrical conductors each having at least one filament comprising a superconductor precursor material or a mixture of superconductor material and superconductor precursor material, encapsulated in a metallic structure, includes joining end sections of the conductors by generating two complementary cut surfaces on the end sections to expose cross sections of the filaments, forming an interface area of the cut surfaces by aligning the two end sections in a connection zone such that the cut surfaces face each other and the exposed filament cross sections abut each other, and pressing the aligned complementary cut surfaces together. The metallic structure of the conductors is then hermetically sealed against gases, vapors, or liquids at room temperature. This is followed by a synthesis step in which superconductor precursor material is converted into superconductor material by annealing.

A method for charging a superconductor bulk magnet includes: step a) charging the magnet charger system so as to generate a first magnetic field in the sample volume, the superconductor bulk magnet having a temperature T>T c ( 300 ); step b) cooling the superconductor bulk magnet to a temperature T<T c ( 400 ); step c) discharging the magnet charger system, which inductively charges the superconductor bulk magnet, such that the superconductor bulk magnet traps a second magnetic field in the sample volume ( 500 ). In step a), the field adjustment unit is set such that the first magnetic field generated by the magnet charger system in the sample volume includes a homogeneous magnetic field component and at least one non-homogeneous magnetic field component ( 300 ). The non-homogeneous field component is chosen so that the second magnetic field of step c) has a higher homogeneity than the first magnetic field of step a) in the sample volume.

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.

The present invention relates to a compound which comprises or consists of (a) a reactive moiety, said reactive moiety being capable of reacting with a functional group of a peptide to form a covalent bond; and covalently joined thereto (b) a moiety which fragments in the mass spectrometer (i) at an energy below the energy required for fragmenting peptides and/or a higher conversion rate than peptides; and (ii) at said energy according to (i) and when coupled to a peptide via said reactive group, at a single site within said compound coupled to a peptide, to yield a first moiety and a second moiety, said second moiety being coupled to said peptide.

An NMR spectrometer having an NMR magnet system which is mounted on a device for isolating the vibrations of the NMR magnet system from the environment includes a sample storage means for providing and temporarily storing NMR measurement samples to be measured, and a transport device for transporting one NMR measurement sample at a time from the sample storage means to a measurement volume within the NMR magnet system. The transport device comprises a continuous, pneumatically bidirectionally operable, gastight transport tube that is mechanically flexibly constructed from a plurality of interconnected sub-elements in the form of separate rigid tube sections that can move relative to one another and are dimensionally stable relative to a flow cross-section of the transport tube. This allows a passive mechanical decoupling from the NMR magnet system, without the need to actively monitor the position of the NMR magnet system relative to the sample storage means.