Abstract: A certain preselectable region of a sample, for example, a disc or a volume component, is selectively excited in that the transverse magnetization of the desired region is phase-coupled by spin locking, while the spin coherences in the remaining spatial region are destroyed by phase relaxation. The thickness of the desired disc or the dimensions of the desired volume component can be varied by adjusting the amplitude of the spinlock pulse while the magnetic field gradients are kept constant. Comparatively low magnetic field gradients can be used. Even with such low magnetic field gradients, good spatial resolution can be achieved while reducing the energy of the radio-frequency excitation. Because of the relatively low energy irradiation of the material being investigated, the process is especially suitable for in vivo applications.

Abstract: 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.

Abstract: 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.