Abstract: In order to simplify the process of plotting a pulse sequence controlling the course of an MR experiment, for example an NMR tomographic investigation, by which the excitation of an RF pulse bringing about transverse magnetization, the switching on and off of field gradients acting in different directions, superposed on a constant magnetic field, as well as the acquisition times, it is proposed to generate this pulse sequence by modification of standard pulse sequences and/or by composition from standard pulses. These pulses are offered on a picture screen (22) as simple symbols (42-49), icons, or brief designations for standard pulse sequences (36-41). By clicking-on of the offering fields, for example by means of a mouse (51), these elements can be copied on time axes (58) allocated to them and attached at the suitable release time point onto these axes. The pulse sequence thus determined is stored on-line.

Abstract: In order to compensate external interfering fields inside a superconducting magnet coil, these interfering fields are measured outside of the magnet coil by means of a small induction coil in order to obtain a regulation signal, and, by means of a regulation algorithm, the current through a compensation coil is controlled. The induction coils are effectively decoupled from fluctuations of the stray field of the magnet coil and from vibrations.

Abstract: In a magnet system with two coil systems of different mean diameter arranged coaxially with respect to the longitudinal axis of the system defined by the direction of the field in the homogeneity region, which are rotationally symmetrical and are arranged symmetrically about the transverse median plane of the system perpendicular to the longitudinal axis and can carry exciting currents which result in overlapping magnetic fields that compensate, at least approximately, for the dipole fields of the two coil systems, an operating mode selector switch device (22) configured as a superconducting network is provided, by means of which the magnet system (10) can also be switched, as an alternative to the operating mode which provides considerable dipole-field compensation in the outer space of the magnet system (10), to that operating mode in which the magnetic fields generated by the two coil systems (11 and 12) at the center thereof are aligned in the same direction. In a special configuration, the ratio B.sub.

Abstract: An NMR spectrometer is utilized in order to determine the magnetic susceptibility of a sample, in which, by means of the sample, a change in the homogeneous magnetic field in the region of a probe substance is effected and the change in the spectrum of the probe substance which is thereby caused is observed. A method known in the art is based on the modulation of the resonance frequency which occurs when the probe substance is caused to rotate about an axis perpendicular to the direction of the magnetic field. The application of this method encounters difficulties with spectrometers whose probe volume is penetrated axially by the magnetic field. In accordance with the invention, by means of the sample (14), a change is produced in the magnetic field along the probe axis in a sample substance (12) preferentially positioned along the direction of the magnetic field.

Abstract: An X-ray computer tomography system with a stationary ring anode and a plurality of stationary electron sources for the construction of fast scan images from the inside of an object is improved in such a way that there is free access from both sides of the scan region, that the gantry unit can be tilted, and that the image quality which can be achieved is comparable to that of conventional tomography systems with mechanical motion of the anode. A plurality of electron sources are configured in proximity to the ring anode on a stationary ring, with each source being capable of sweeping its respective electron beam over a portion of the anode ring.

Abstract: An X-ray computer tomography system with a ring anode and substantially without mechanically moving parts for the production of fast image slices from the inside of an object is improved in such a way that a detector ring is comprised of two adjacent parallel partial detector rings of substantially equal size, whereby the detector ring is arranged within and coplanar to the anode ring. The two partial rings of the detector ring are displaced in a direction largely pependicular to the scan slice so that a ring-shaped detector ring gap is formed between them through which the fan beam coming from the focal spot on the anode passes.

Abstract: The present invention relates to a method and a device for compensating undesirable side bands in nuclear magnetic resonance spectrometers. The frequency (.omega..sub.m) and the phase of rotation of the sample (10) are detected by means of a light sensor (12) and supplied to a compensation generator (18). The latter generates modulation signals (44 and 43) for modulating the amplitude and the phase of the detected nuclear magnetic signal of the sample, using an amplitude modulator (13) and a phase modulator (14), the modulation frequency being equal to an integral multiple, including the simple value, of the frequency of rotation (.omega..sub.m) of the sample. The additional frequency components heterodyne with the side bands provoked by the rotation of the sample (10) in the static magnetic field (B.sub.O), whereby the said side bands are eliminated.

Abstract: A method for operating submerged submarines and a submarine are disclosed which are used to camouflage submerged submarines which, while submerged and travelling, draw a trail of heated cooling water behind themselves. In order to reduce the risk of detection of such submerged submarines by means of heat-sensitive detectors, either the density of the heated cooling water is increased through the introduction of additives, or, the heated cooling water is brought, by mechanical means, to a depth far below the submarine for preventing heated-up cooling water to rise up to the sea surface.

Abstract: A method and an apparatus are disclosed serving to reduce acoustic emission from submerged submarines in which vibrations from moving mechanical elements within an inner region are transmitted to an outer hull via a vibration transmission path. For decoupling the outer hull as completely as possible from the moving mechanical elements, for example periodically moving nuclear reactor control rods, the vibrations are actively damped. Means are provided for ascertaining the motion of the mechanical elements relative to the outer hull and for superimposing upon said motion of counter-motion of opposite direction.