Abstract: A device for the safe discharge of a superconducting magnet coil (4) which is located inside a cryostat (2) and superconductively short-circuited by a superconducting switch (7) providing at or in the cryostat (2) a transmitter (10) of electromagnetic energy being located at a temperature level considerably above the cryogenic temperature of the superconducting magnet coil (4), which transmitter can be switched on quickly from outside, and by arranging in the region of the superconducting switch (7) at the cryogenic temperature level of the superconducting magnet coil (4) a receiver (20) for the emitted electromagnetic energy, which transmits the received energy directly or indirectly to a heating device (15) of the superconducting switch (7) or which activates an auxiliary energy source (41) in the region of the superconducting switch (7) , which on its turn effects a heating of the superconducting switch (7), so that it becomes normal-conducting and causes a discharge process of the superconducting magnet c

Abstract: A method and an apparatus are disclosed for detecting a first substance within a second substance, preferably for localizing diamonds in kimberlite rocks. The first substance, e.g. the diamonds, have a very long spin-lattice relaxation time (T.sub.1) in the order of hours. For rapidly detecting the first substance, the build-up of magnetization of a predetermined kind of nuclei, e.g. .sup.13 C, being abundant in the first substance only is shortened and the nuclear magnetic resonance of that kind of nuclei is measured thereafter. The shortening is executed within a pre-treatment station, whereas the measurement takes place within an analyzing station. The shortening and the measuring, respectively, are carried out within magnetic fields (B.sub.01, B.sub.02) of different field strengths.

Abstract: In a superconducting magnet coil configuration, in particular for a high resolution analytical nuclear resonance (NMR) spectrometer, with a cryostat having extremely low heat losses (low loss), comprising at least one essentially cylindrical container (1) with a vertical cylinder axis (k), with a vertical cylindrical room temperature bore (3) and with at least one inner tank (4) for a cryogenic liquid in thermal contact with a superconducting magnet coil (2) enclosing the room temperature bore (3), for generating a vertically directed, extremely homogeneous and stable magnetic field of high field strength inside a measuring volume of the room temperature bore (3), the vertical axes (r) of the room temperature bore (3) and of the superconducting magnet coil (2) run parallel to and at a distance from the vertical cylinder axis (k) of at least one of the cylindrical cryostat containers (1). In this way, access to the room temperature bore (3) is considerably simplified.

Abstract: A device for the safe discharge of a superconducting magnet coil (4) which is located inside a cryostat (2) and superconductively short-circuited by a superconducting switch (7) providing at or in the cryostat (2) a transmitter (10) of electromagnetic energy being located at a temperature level considerably above the cryogenic temperature of the superconducting magnet coil (4), which transmitter can be switched on quickly from outside, and by arranging in the region of the superconducting switch (7) at the cryogenic temperature level of the superconducting magnet coil (4) a receiver (20) for the emitted electromagnetic energy, which transmits the received energy directly or indirectly to a heating device (15) of the superconducting switch (7) or which activates an auxiliary energy source (41) in the region of the superconducting switch (7), which on its turn effects a heating of the superconducting switch (7), so that it becomes normal-conducting and causes a discharge process of the superconducting magnet co

Abstract: A gradient coil system for the production of a magnetic transverse gradient field G.sub.x =dB.sub.z /dx in an NMR tomograph has axial and transverse access to the measuring volume. The gradient coil system consists of four partial coils (S.sub.1x, S.sub.2x, S.sub.3x, S.sub.4x) each with two current connections (A.sub.1, A.sub.2), which are arranged mirror symmetrically with respect to the xy-plane (z=0) and mirror symmetrically with respect to the zy-plane (x=0). Each partial coil comprises winding sections on an inner and on an outer cylinder Z.sub.1x, Z.sub.ax) about the z-axis as well as on a radial connecting surface V.sub.+x, V.sub.-x and the radial connecting surfaces V.sub.+x, V.sub.-x of those partial coils (S.sub.1x, S.sub.4x ; S.sub.2x, S.sub.3x,) which face each other opposite the xy-plane are essentially identical. An axial gap for free transverse access to the measuring volume remains between the partial coils.

Abstract: A method and an apparatus are disclosed for detecting an atomic structure of a sample along a surface thereof. The method comprises arranging the sample in a constant magnetic field (B.sub.0) of predetermined field strength and high homogeneity and irradiating a high-frequency magnetic field (B.sub.1) of a predetermined frequency on the sample, wherein the fields (B.sub.0) and (B.sub.1) are oriented perpendicularly to each other. The method further comprises providing a force-sensitive sensor having a paramagnetic tip comprising a paramagnetic material. The sensor is placed in close vicinity to the sample such that the paramagnetic tip is in atomic interaction with the sample surface which means that the distance between the tip and the surface is in the order of between 1 and 10 .ANG.. The predetermined field strength and the predetermined frequency are set such that electron paramagnetic resonance (EPR) is excited within the tip paramagnetic material.

Abstract: In a self-supporting beam-splitter (1), in particular for use in an FTIR-spectrometer for the far-infrared region, with an optical thickness on the order of the interesting wavelength region, the foil beam-splitter (1) consists of an undoped semi-conducter material or carbon which is transparent in the far-infrared, and is preferentially made from thin silicon sheets or diamond foil in the thickness region between 2 .mu.m and 125 .mu.m. In this fashion, an extremely high efficiency for the beam-splitter is achieved, whereby little or no resonant absorption takes place due to the beam-splitter in the interesting wavelength region.

Abstract: A resonator which is arranged on a hollow cylindrical support (1) for the taking of high resolution magnetic nuclear resonance spectra from a sample extending along the cylinder axis within the resonator, and having a shielding (2) which defines the sensitive region of the resonator axially along a certain length which is shorter than the axial extent of the support (1), is characterized in that the resonator is configured as an axially symmetric bird-cage resonator. It only produces static field distortions in its sensitive region which are easily correctable, has an improved fill-factor and reduced ohmic losses, and produces a homogeneous RF field while avoiding topological problems occurring with quadrature detection.

Abstract: A gradient system for a nuclear spin resonance (NMR) tomograph with a main magnet system producing a homogeneous magnetic field directed along a z-axis inside a measuring volume, wherein the main magnet system provides access to the measuring volume along the z-axis and transversely to the z-axis, and wherein the gradient system comprises two first partial gradient systems which are located at opposite sides of a central plane perpendicular to the z-axis, across the measuring volume. At least one of the two partial gradient systems is movable between at least two positions along the z-axis. In this way, with a small constructional size and with a simple manufacturing procedure, a gradient system is obtained with high performance capability with respect to generated gradient strength for given ampere turns, high linearity of the generated gradient fields, minimum inductance and minimum electrical resistance of the conductor segments.

Abstract: A magnet system for a nuclear spin tomograph having at least one field producing magnet coil S.sub.1 with radius r.sub.s1 arranged in a middle plane which produces a homogeneous magnetic field in an investigational volume directed along a z-axis perpendicular to the middle plane, is characterized in that at least one, preferentially at least two, ferromagnetic rings R.sub.i with radius r.sub.Ri are provided in the middle plane concentric to the magnetic coil S.sub.1. A system of this kind can be substantially more compact in construction than conventional systems with equal produced field strength. In addition substantially reduced currents are required through the coil or coils for field production.

Abstract: A gradient coil system for the production of a magnetic transverse gradient field G.sub.x in an NMR tomograph is presented. The main magnetic field B.sub.z is directed along the z-axis, the magnetic transverse gradient field G.sub.x along the x-axis, and the gradient coil system comprises four partial coils (S.sub.1x, S.sub.2x, S.sub.3x, S.sub.4x) each with two current connections (A.sub.1, A.sub.2). The coils are arranged mirror symmetrically with respect to the xy-plane (z=0) and mirror symmetrically with respect to the zy-plane and each partial coil contains only winding sections on an inner and an outer cylinder Z.sub.ix, Z.sub.ax about the z-axis as well as in a radial connecting plane V.sub.+x, V.sub.-x parallel to the xy-plane. The partial coils are configured in such a fashion that the winding sections on the inner and outer cylinder Z.sub.ix, Z.sub.ax are axially further removed from the xy-plane than the corresponding radial connecting planes V.sub.+x, V.sub.-x, and the axial separation d.sub.

Abstract: A method and an apparatus for the automatic quantitative filling of powdered or granulated samples for analytic measurement purposes as well as a shaking and holding device for sample substances utilized therefor with which precisely admeasured amounts of the sample substance can be filled into a measuring vessel. The shaking device permits the sample substance to be filled in a continuous, slow and defined flowing stream. The shaking and holding of the sample vessel transpires preferentially pneumatically.

Abstract: In an NMR tomograph with superconducting main field coil (10) and large transverse access opening a compensation of inhomogeneities of the static magnetic field without hindering the axial and transverse access to the investigational volume (V) can be effected by the following elements:ferromagnetic homogeneity elements (20) which are arranged on the surface of the room temperature bore on both sides of the transverse access opening;at least one or more (a number p.gtoreq.1) superconducting correction coils (C.sub.1 and C.sub.p) which can be separately supplied with current and which are coaxial to the main field coil (10), whereby each correction coil (C.sub.1 through C.sub.p) comprises at least two partial coils (C.sub.1i, C.sub.1a through C.sub.pi, C.sub.pa), whereby all partial coils of all correction coils (C.sub.1 through C.sub.p) are cylindrical coils coaxial to a common axis (z) having a diameter less than the inner diameter (d.sub.

Abstract: The invention relates to a Raman spectrometer connected by a bundle of optical fibers with an external probe to be attached on the surface of the sample with a laser beam for the excitation of Raman radiation within the sample with the laser radiation transported to the sample by one or several central optical fibers and with a collecting element which collects the Raman radiation of the sample and sends it through the optical fiber bundle to a Raman spectrometer to be analyzed. Upon the end of the optical fiber bundle different collecting elements may be attached with the transparent optical elements having the shape of a cylinder, a paraboloid or a truncated sphere. Thus, the spectrometer can be simply adapted to different samples for optimal collection of Raman light.

Abstract: An NMR sample holder comprises:a rotor 2,3 having a central bore 2e with an internal thread for at least a portion 2g of its length, ,a hollow cylindrical sample tube 5 having a closed end and an open end, and having an outer diameter of less than 3 mm, the diameter being such as to enable the sample tube 5 to be accommodated within the central bore 2e in the said rotor,a centring screw 7 having an external thread 7g adapted to engage the said internal thread 2g of the central rotor bore and a central bore 7e adapted to accommodate the sample tube and to centre the sample tube in the central bore of the rotor, anda sealing member 6, 6' which is a sliding fit on the sample tube 5 and adapted to form a seal with an internal surface of the central bore of the rotor and with the sample tube 5.

Abstract: In an AC-powered power supply with a bipolar controller V controlling the instantaneous value of a control quantity measured by a sensor F.sub.1 to a predetermined setting within a deviation of less than 0.1% at 1 Hz via the output DC current I.sub.o, and with an adjustable rectifier EQ followed by a charging inductance L.sub.1 and a filter capacitor C.sub.1, whereby the output of controller V is electrically connected to the output line of the power supply, the output of controller V is AC-decoupled from filter capacitor C.sub.1 by a decoupling inductance L.sub.2, two potentials V.sub.o +V.sub.1 and V.sub.o -V.sub.2 are supplied to controller V, and a sensor F.sub.2 is provided for the output current I.sub.2 of controller V, which feeds an output signal to a control unit CTR which controls rectifier EQ in such a way that the mean value of output current I.sub.2 of controller V is regulated to a minimum value.

Abstract: In an infrared (IR) microscope for a Fourier transform (FT) infrared spectrometer with a Cassegrain mirror-lens with which an incident beam (15) can be focused via a convex mirror (16) and a concave mirror (17) onto a first point-shaped region (19) on the surface of a sample (20) under an angle of incidence .beta.<60.degree.

Abstract: In an NMR tomograph with superconducting main field coil (10) and large transverse access opening a compensation of inhomogeneities of the static magnetic field without hindering the axial and transverse access to the investigational volume (V) can be effected by the following elements:ferromagnetic homogeneity elements (20) which are arranged on the surface of the room temperature bore on both sides of the transverse access opening;at least four superconducting correction coils (C.sub.1 and C.sub.4) which can be separately supplied with current and which are coaxial to the main field coil (10), whereby each correction coil (C.sub.1 through C.sub.4) comprises at least two partial coils (C.sub.1i, C.sub.1a through C.sub.4i, C.sub.4a), whereby all partial coils of all correction coils (C.sub.1 through C.sub.4) are cylindrical coils coaxial to a common axis (z) having a diameter less than the inner diameter (d.sub.a2) of the outer field coil (1a, 1b), whereby in each correction coil one partial coil (C.sub.

Abstract: In a magnetic shielding for a superconducting magnetic coil (2) arranged on the inside of a cryostat (1) and having a vertical axis for the production of a static magnetic field with a homogeneity of <10.sup.-7 in an investigational volume (V) of a nuclear magnetic resonance (NMR) spectrometer, the shielding is a room shielding located at a separation from the cryostat (1), which includes at least two ferromagnetic, horizontally arranged plates (3, 4) of which one is arranged below and other above the cryostat (1), whereby the separation of the upper plate (3) from the center of the investigational volume (V) is approximately 1.5 to 3 times, preferentially approximately twice, as large as the separation (h) of the lower plate (4) from the center of the investigational volume (V), and vertical ferromagnetic side elements (5) are provided for which magnetically connect the upper plate (3) and the lower plate (4) and the upper plate (3) contains 1.

Abstract: A magnet system for nuclear magnetic resonance (NMR) imaging volume has two magnet coils (S1, S2) arranged on both sides of an investigational volume coaxially relative to a z axis running through the center of the investigational volume and assuming positions relative to the center of the investigational volume of z.sub.S1 and z.sub.S2 with average separations r.sub.S1 and r.sub.S2 from the z axis. During operation, currents flow through the coils in the same direction. The system is characterized by ferromagnetic rings (R11 and R21) provided for on each of the two magnet coils (S1, S2) arranged closer to the center of the investigational volume than the corresponding neighboring magnet coil (S1 or S2). The rings (R11, R21) are positioned and dimensioned in such a fashion that the magnetic field in the center of the investigational volume can be rendered homogeneous up to 8th order. The axial separation g.sub.