Bruker Analytische Messtechnik Gmbh

Bruker Medizintechnik Gmbh

Kohler, Schmid Partner

Broker Analytische Messtechnik Gmbh

Rainer Kimmich

Siegfried Hafner

Eberhard Rommel

Dan E Demco

Alexander Knuttel

Peter Nickel

Daniel Pusiol

A new method of spatial localization in solids using the high off-resonance sensitivity of heteronuclear polarization transfer is presented in theory and experiment. Application in imaging and volume-selective spectroscopy are discussed and test experiments to this end are reported.

Slice-selective polarization transfer for localized solid-state NMR

An NMR imaging method for the investigation of, in particular, solid-like substances which are exposed to a sequence of RF pulses in a homogeneous magnetic field, said sequence including an excitation pulse sequence and an additional pulse sequence, whereby, in one case, in at least one time interval between the end of the excitation pulse sequence and the beginning of the additional pulse sequence and/or in the time interval between the end of the additional pulse sequence and the appearance of an echo signal, the homogeneous magnetic field is at least temporarily overlapped with at least one gradient field and, in another case, at least one part of the sequence of RF pulses is overlapped with at least one RF gradient field, is characterized in that the additional pulse sequence includes a magic sandwich.

NMR magic sandwich imaging method

Method for performing magnetic resonance spectroscopy or tomography in a

Method for recording spin resonance spectra and for spin resonance

In an imaging method for spectroscopy of nuclear quadrupole resonances (NQR) with solid samples to which an RF field having a pulse duration t.sub.p with a base amplitude B.sub.10 constant over the sample length for magnetic excitation of NQR with resonance frequencies .omega. and with magnetic moments coupled to the nuclear quadrupole moments is applied and the NQR signal emitting from the sample is time-depentently detected, the RF field is superimposed by a position-dependent field contribution corresponding to a constant gradient B.sub.1.sup.x which yields together with the constant RF field a position-dependent RF field B.sub.1 (x), for each resonance frequency contained in the detected NQR signal the amplitude including its sign is determined, the measurements are carried out at different flip angles.sqroot.3.multidot..gamma..multidot.B.sub.1 (x).multidot.t.sub.p of the excited magnetic moment, the amplitudes including their signs which depend on the flip angle are subjected to a Fourier transformation and finally therefrom the x dependent density distribution of the observed nuclei is reconstructed. The method does without applying of an external B.sub.0 field, so that it can be carried out with a compacter measuring apparatus, in which the sample can also be situated partly outside. Effects of the Zeeman splitting do not have to be taken into consideration.

NQR-imaging

A method is disclosed for a multi-dimensional measurement of magnetic resonance in defined small volume regions of solid-state samples. The samples are arranged in a uniform homogeneous magnetic field and, in a predetermined manner, irradiated with a sequence of high frequency pulses as well as exposed to a sequence of gradient magnetic field pulses. This is done in such a way that the spin magnetization to be measured is maintained for a time interval which is longer then the amount of time needed to switch-off the gradient magnetic field pulses. Initially, in a first time interval, the magnetization of a single slice only of the sample is transferred into a transverse magnetization tilted by 90.degree. with respect to the direction of the constant homogeneous magnetic field. Thereupon, in a second time interval, volume selective gradient magnetic field pulses are irradiated on the sample. In a subsequent third time interval, during the persistance of the volume selective gradient magnetic field pulses, high frequency pulses are irradiated on the sample, for transferring the transverse magnetization in the volume region to be measured into a multipole-state, said state being insensitive to the volume selective magnetic field pulses and persisting until after the point in time when these pulses are switched-off. Finally, in a subsequent fourth time interval, the multipole-state is transferred back again into a transverse magnetization and this magnetization is read-out as a signal.

Method for a multi-dimensional measurement of magnetic resonance in

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Ulm, Germany

Rainer Kimmich