Abstract: The present invention relates to a process of automatic analysis of elements in weak concentration on a support of objects of low occurrence, having a high-contrast surface state, consisting of illuminating the observation zone with a first light source (5) emitting in a first wavelength range, and a second source (4) emitting in the excitation spectrum of the objects (23, 32) of low occurrence, proceeding to focus image acquisition means and after focusing triggering the accumulation of photons emitted by the objects (23, 32) of low occurrence illuminated with a source (4) emitting in the excitation spectrum of said objects (23, 32), characterized in that one proceeds to modify the focusing of the image aquisition means until maximization of the contrast of a zone (30) in said first wavelength range, said zone (30) being dissociatable from the observation zone illuminated from the second light source.

Abstract: A method for providing gain stabilization to a nuclear spectroscopy tool by use of gross features of largely invariant spectra. A particle or gamma ray energy spectrum of an earth formation and wellbore are measured. A ratio of the number of particles or gamma rays measured in a first energy window to the number of particles or gamma rays measured in a second energy window is calculated. The gain of the nuclear spectroscopy tool is adjusted as a function of the calculated ratio. The first energy window is selected to span substantially an entire range of measured energies for the spectrum and the second energy window is selected to span an upper range of the measured energies for the spectrum.

Abstract: Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attentuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power.

Abstract: The present invention, in one form, is a method for enhancing image sharpness in images generated from CT scan data by using enhancement masks. The enhancement masks are generated, in one embodiment, by generating difference image data from the original age data and low pass filtered image data. The original image data CT numbers are assigned to image regions, e.g., bone, air, and soft tissue, and based on such CT number classifications, certain data in the difference image is fully or partially suppressed. Subsequent to suppressing some difference image data, the difference image data set, which is sometimes referred to as an enhancement mask, is then combined With the original image data to increase image sharpness.

Abstract: An energy-resolving x-ray detector for soft x-rays produced by elements having atomic numbers ranging from 9 to 23.

Abstract: Multi-slice selectable resolution NMR data acquisition in which multiple slice regions in an object are defined, and the slice regions are excited to emit NMR signals. The NMR signals are spatially encoded, and at least two selected slice regions are excited to emit NMR signals encoded with different spatial resolutions.

Abstract: A probehead is described for carrying out magnetic resonance imaging measurements on a sample. The sample is located inside a probehead transmission/detection unit in a magnetic field of a predetermined direction. Moreover, the sample may be turned relative to the direction about at least one axis. The transmission/detection unit is a split ring resonator. The split ring resonator may be turned about its resonator axis and may be coupled by coupling means for coupling rf energy to or from, respectively, the split ring resonator. The coupling means are arranged in a stationary position relative to the split ring resonator and are coaxial to the resonator axis.

Abstract: A magnetic resonance imaging machine includes a toroidal vacuum dewer (24) which contains a superconducting magnet (10). A radio frequency coil (32) is mounted within a cylindrical bore (26) of the vacuum dewer. A cylindrical, dielectric former (46) supports an RF shield (34), a z-gradient coil (50), an x-gradient coil (52), and a y-gradient coil (54). The x and y-gradient coils are each composed of four like spiral coil constructions. A metallic layer is cut with cut lines (64) to define a generally spiral coil winding pattern. In a high current density region (68) in which the coil windings are narrower than a preselected width, the cut lines (76) are thinner. In lower current density regions (70), the cut lines (78) are thicker. In lower current density regions, two cut lines are defined between adjacent coil windings such that the coil windings are limited to a maximum width.

Abstract: The magnetic field assembly of a magnetic resonance imaging device includes an annular superconducting magnet (10) which is mounted within a toroidal vacuum vessel (24). A cylindrical member (26) defines a central bore through which the superconducting magnets generate a temporally constant primary magnetic field. A cylindrical, dielectric former (46) is mounted in the bore displaced a small distance from the cylindrical member. A radio frequency coil (32) is mounted within the cylindrical member defining a patient receiving examination region. An RF shield (34) is mounted around the exterior peripheral surface of the former. Primary gradient coils (40) are mounted around and potted to the exterior of the dielectric former around the RF shield. Gradient shield or secondary coils (44) are potted around an exterior of the cylindrical member within the vacuum chamber. As illustrated in FIG.

Abstract: The conductor structures of an antenna in a nuclear magnetic resonance tomography apparatus are covered with lamellae that extend in longitudinal direction of the examination space and have large-area connections at the end sides of the antenna to a shielding that surrounds the examination space. In an alternative embodiment, the lamellae extend the azimuthal direction and are connected to a shielding (3) surrounding the examination space at the respective longitudinal edges of the conductor structure of the antenna via broad-web, planar conductors with a free cross section remaining between the conductors.

Abstract: The invention provides an electron spin resonance device in which a measuring sample is arranged in a cavity resonator in a polarization magnetic field for a receipt of a predetermined microwave power and a subsequent resonance signal detection from said sample. A microwave signal amplifier is arranged on a prestage of a microwave detection circuit for an addition of a part of an output from a microwave oscillator at an input terminal of said amplifier so as to accomplish a balanced cancellation of a microwave reflective power from said cavity resonator.

Abstract: Four QD surface coil assemblies each constituted by an 8-shaped coil and a rectangular coil are one-dimensionally arranged under the spine array of a patient in the direction of the body axis of the patient. Each 8-shaped coil senses an RF magnetic field in an x direction near the spine array of the patient, and each rectangular coil senses an RF magnetic field in a y direction. Outputs from the 8-shaped coils and the rectangular coils are input to 90.degree. hybrid combiner circuits through pre-amplifiers, the phase of any one of the outputs is shifted by 90.degree., and then the outputs are added to each other. Outputs from the 90.degree. hybrid combiner circuits are supplied as raw data, through receiver/data acquisition systems, to a data processing unit (computer). In the data processing unit, raw data are two-dimensionally Fourier-transformed to form image signals p.sub.i (x,y,z) (i=1 to 4). The signals p.sub.1 (x,y,z) are squared, the sum of p.sub.

Abstract: This application describes a nuclear magnetic resonance inspection apparatus. In this apparatus, a nuclear magnetic resonance signal detected by a detection coil is wirelessly transmitted to a signal processing system. In another embodiment, the nuclear magnetic resonance signal is stored in a memory medium provided to the detection coil. This memory medium can be separated from the detection coil. The signal processing system reads out the nuclear magnetic resonance signal from the memory medium separated, and processes the signal.

Abstract: A radio frequency signal detector coil arrangement (17) for a magnetic resonance apparatus comprising a planar coil (25) and an annular magnetic flux rejecting arrangement (25) disposed coaxially with the planar coil, on one side thereof, which reduces the sensitivity of the planar coil to signals from sources remote from the axis of the planar coil. One embodiment of the flux reducing arrangement comprises an annular superconducting member (35) disposed between the planar coil and the body (31). In other embodiments it comprises an arrangement of coils which conform to a tubular surface coaxial with the planar coil, and electrically connected therewith.

Abstract: The MR imaging apparatus comprises an RF shield for interposed between the set of gradient coil and the RF coil. The RF shield is a cylinder which longitudinal axis is substantially coincident to the z-axis in which a static magnetical field is applied. The RF shield comprises two conductive sheet-members which are half-cylinder respectively and integrated into one cylinder. The sheet members have a plurality of generally C-shaped conductive loop portions respectively which are defined by nonconductive lines parallel to RF current flow induced therein by the RF coil and a single radial cut line respectively.

Abstract: A wellbore apparatus adapted to be disposed in a wellbore is electrically connected to a surface apparatus disposed at a surface of the wellbore. When disposed in the wellbore, the wellbore apparatus receives a plurality of input signals from an earth formation traversed by the wellbore which are representative of characteristics of the earth formation. The wellbore apparatus includes a data compression apparatus which receives the input signals and compresses the input signals prior to transmission of the compressed input signals uphole to the surface apparatus. The data compression apparatus compresses the input signals by first subdividing the plurality of input signals into a plurality of groups, where the number of the plurality of groups is much less than the number of the plurality of input signals, and then generating one value for each group.

Abstract: A phantom which simulates the electric load in a magnetic resonance apparatus includes a loop which can be inductively coupled to the RF coil of the MRI apparatus and which has a predetermined electric resistance. The phantom has a simple, rugged and light construction in that the loop includes a member having a shape that corresponds mainly to the shape of the RF coil and which is made of a solid material having a specific electric resistance and a thickness chosen so that the square resistance measured on a surface of the member is between predetermined limits. The member is preferably formed as a layer of an electric resistive material provided on an electrically insulating support having a suitably shaped surface.

Abstract: A pulsed NMR analysis system and process comprising an air curtain (137), sample throughput system (P, LI, V1, V2) and user system controls (104) to establish digitized free induction decay curves (C) , from which components functions are determined using linear or nonlinear regression techniques to correlate the curve components to the target nuclei and to flow rates in plastic including MI and FRR for polyethylene and MF for polypropylene.

Abstract: Apparatus and methods for performing MRI are disclosed wherein the encoding field has a multidimensional, preferably periodic, dependence. Two dimensional image information can be obtained without the necessity for switching the encoding field. Further, velocity information can be obtained. Preferred coil structures for providing preferred encoding fields are described.

Abstract: Acoustic ringing and adverse effects from variations in the NQR detection of explosives and narcotics are minimized or eliminated. A specimen is irradiated with a modified steady state steady state free precession (SSFP) pulse sequence which combines a phase-alternated pulse sequence (PAPS) with a non-phase-alternated pulse sequence (NPAPS). The resulting signals from the PAPS and NPAS may then be coadded to cancel out the FID contributions to the signals. By canceling out the FID contributions to the signals, the effects of probe ringing and other extraneous responses, as well as the effect of temperature variation, are minimized or removed. The present method is especially effective in the detection of explosives and narcotics having .sup.14 N or .sup.35,37 Cl nuclei. A steady state free precession pulse which is especially useful with the method of the present invention is the strong off-resonance comb (SORC).