U.S. Philips Corporation

Olaf H Dossel

Johann E Kruger

Kai-Michael Ludeke

Wilfried Edeler

Walter Heinrich Kullmann

Gert Rabe

Wolfgang Hoppe

Manfred H Fuchs

Rolf U Kobs

Jurgen Kohler

Udo Bringmann

Reiner U Orlowski

Detlef G Schon

Hans-Aloys Wischmann

Klaus W Gerstenberg

Gerhard Kursten

Bernd R David

Robert Oostenveld

Rob Steenbrink

A method of reconstructing the spatial current distribution in a biological object, at least one component of the magnetic field produced by the current sources being measured at a number of points outside the object, after which the current distribution at the volume elements situated within the object is reconstructed from the measuring values. In order to improve the accuracy of reconstruction, in a representation containing the morphological structure of the object the surfaces are specified on which the current sources are presumably present, the reconstruction being limited to the volume elements which are situated on these surfaces.

Method of reconstructing the spatial current distribution in a

The invention relates to a method of reconstructing the spatial current distribution in a biological object, at least one component of the magnetic field produced by the current sources being measured at a number of points outside the object, after which the current distribution at the volume elements situated within the object is reconstructed from the measuring values. In order to improve the accuracy of reconstruction, in a representation containing the morphological structure of the object the surfaces are specified on which the current sources are presumably present, the reconstruction being limited to the volume elements which are situated on these surfaces.

The invention relates to a method of determining the spatial field distribution and/or the spatial position of a useful field source, producing said field distribution, by means of a multichannel field measuring device which comprises a plurality of spatially distributed sensors which produce measured values which contain on the one hand useful measured values stemming from the useful field source and on the other hand noise measured values stemming from at least one noise field source, correction values being formed and superposed on the measured values so that compensated measured values are obtained which are compared with similarly compensated, mathematically derived reference values which are produced by a fictitious reference field source by means of the field sensors, the reference field source being determined for which the pattern of compensated reference values corresponds best to the pattern of compensated measured values.

Method of determining the spatial field distribution

A shielding sleeve (19) for SQUID-magnetometers which serves to shield from electromagnetic interference fields, consists of an electrically conductive shielding material so as to obtain adequate RF shielding in conjunction with a low noise contribution, completely envelops a non-shielding cryostat (10), has a predetermined sheet resistance and consists of at least one layer of the shielding material in order to avoid an increase of the magnetometer overall noise.

Squid magnetivity having a totally enclosing electromagnetic shield with

A miniaturized SQUID module (10), notably for multi-channel magnetometers, for measurement of varying magnetic fields in a field strength range below 10.sup.-10 T, includes superconducting and shielded connections between a SQUID chip (19) and a gradiometer (12). The module can be mounted in the lower part of a cryostat and enables a large number of measurement points per unit of surface area. The SQUID chip (19) is arranged on a fully shielded supporting plate (18) which has a width of only a few millimeters and which is provided with electronic circuitry (23), the SQUID chip (19) being connected in a superconducting manner, at least by soldering, to the wires (11) of the gradiometer (12) via a superconducting, solderable and bondable intermediate support (27).

Miniaturized squid module having an intermediate super conducting

The feedback current for the flux-locked-loop of a DC-SQUID is conductively supplied directly to the input circuit of the SQUID rather than to a separate feedback or modulation coil that is inductively coupled to the SQUID, thereby eliminating the feedback or modulation coil and simplifying construction of an integrated SQUID module.

Squid magnetometer in which feedback current for a squid

A superconducting gradiometer for measuring weak magnetic fields for a measuring device comprising a SQUID (Superconductive Quantum Interference Devices), a gradiometer coil, a coupling coil, a cryosystem and a signal processing device, in which the well-defined gradient of a magnetic field to be measured is detected by means of the gradiometer. A coil of the gradiometer is made of superconducting wire, arranged about a carrier body in axial and circumferential grooves cut in the carrier body, the grooves being coated with a superconducting thin film. The thin film in the circumferential grooves is interrupted by slots. The wire in the respective circumferential grooves comprises loops wound in opposing directions connected by a twisted pair of connecting leads secured in the axial groove.

Gradiometer for detecting weak magnetic fields including grooves

Apparatus for multi-channel measurement of weak magnetic fields having assigned to each channel an assembly, which is arranged on a base carrier (30) and includes a DC-SQUID (6, 27), a gradiometer coil (8, 12, 15, 16, 37), a coupling-in coil (9, 19, 38), superconductive connecting leads (10, 17, 18, 41), and a modulation coil (7, 26). The gradiometer coil, the coupling-in coil and the SQUID are made from thin-film structures. An evaluation element (11) serves to evaluate the signals generated in each channel by the SQUIDS. A separate plate (29) is provided for each channel, on which the SQUID and the modulation coil are deposited. The assembly of gradiometer coil, connecting leads and coupling-in coil provided for each channel is deposited on a separate gradiometer carrier (12, 32). A plate is arranged on a gradiometer carrier, and the individual gradiometer carriers are attached to the base carrier.

Apparatus for multi-channel measurement of weak magnetic fields with

Thin film strain gauge system consisting of an elastically deformable flexible metallic substrate on which an electrically insulating layer of a plasma-polymerized material, in particular of Si:N:O:C:H-containing compounds and thereon a structured resistance layer as well as an electrically readily conducting layer having a structure for the electrical contacting are provided.

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Tangstedt, Germany

Olaf H Dossel