Siemens Aktiengesellschaft

Siemens Aktiengellschaft

Eckhardt Hoenig

Helmut Reichenberger

Siegfried Schneider

Volker Lehmann

Burkhard Lischke

Hanns-Jorg Weisse

Ulf Buerker

A sensor arrangement having a substrate of doped silicon with channels in a principal face, a selective means for detecting a material, the selective means covering the principal face without filling the channels, and a measuring instrument for registering a physical quantity dependent on the influence of a material is provided. A catalytic layer is particularly used as selective means and a temperature sensor is particularly used as measuring instrument. Alternatively, the sensor arrangement is fashioned as a capacitor having a porous cooperating electrode. The channels are preferably produced by electrochemical etching.

Sensor arrangement

An apparatus for measuring weak, location-dependent and time-dependent magnetic fields emitted from a source situated in an examination subject includes a sensor arrangement having at least ten gradiometers of the first order, each gradiometer being inductively coupled to a DC-SQUID. The sensor arrangement and the examination subject are disposed in a room which shields the examination subject and the sensor arrangement from magnetic fields. The room has a shielding factor of at least 10 for magnetic alternating fields having a frequency of 0.5 Hz, the shielding factor increasing with increasing frequency. A method for operating the apparatus is also disclosed.

Apparatus for measuring weak, location-dependent and time-dependent

Apparatus and method for measuring weak, location-dependent and

A magnetometer device for measuring the magnetic fields caused by field sources includes a Dewar vessel that has an interior with access through a neck. The interior contains several superconducting gradiometers as well as corresponding SQUIDs. The Dewar vessel is arranged underneath or laterally to the field source. An insertion vessel for a liquid refrigerant which is thermally coupled to the SQUIDs and is located in the interior. The gaseous refrigerant taken from the insertion vessel is supplied to the gradiometers through hose lines. The refrigerant escaping into the interior is discharged to the outside via the neck. A throttling device is inserted into the neck to prevent warmer gaseous refrigerant from entering the interior.

Magnetometer device with a Dewar vessel for measuring weak magnetic

With the method a layer-like composition of an oxide-ceramic superconducting material with a high transition temperature and great current carrying capacity on the basis of a materials system containing metallic components and oxygen can be prepared. The method is to be improved in the direction that layers with great current-carrying capacity can be formed also on non-monocrystalline substrates. It is provided for this purpose that a multi-layer layer of the superconductive material is applied on a fine-crystalline substrate by first making successive layers of individual films with a respective film thickness under 10 nm, and then this multilayer structure is converted into the desired superconducting phase by means of supplying oxygen and at a temperature below 400.degree. C. For developing each individual film, the metallic components of the system are applied to the substrate that may be available, by means of a physical deposition process and while oxygen is being supplied, at a temperature below 400.degree. C., and by means of short thermal pulses a column structure is generated which comprises columns tightly packed with c-axes at least approximately perpendicular to the respective underlayer.

Method for producing a layer-like composition of oxide-ceramic

An apparatus for measuring magnetic fields which change only at an extremely low frequency contains a SQUID magnetometer which comprises a superconducting flux transformer for inductively coupling the measuring signal into a d-c SQUID sensor. With this apparatus, also quasi-static magnetic fields with frequencies far below 1 Hz should be detectable. A device for modulating the measuring signal to be coupled into the SQUID sensor is associated at least with the flux transformer, the modulation frequency of which is in a frequency range characteristic for low-noise operation of the SQUID. The modulation frequencies are generally above 1 Hz and optionally even above 1 kHz.

Measuring device having a squid magnetometer with a modulator for

An apparatus for measuring magnetic fields that change at extremely low frequency contains a SQUID magnetometer having a super-conducting flux transformer for inductively coupling the measuring signal into a direct current SQUID sensor. Quasi-static magnetic fields that have frequencies far below 1 Hz are detected. The flux transformer has two inductively coupled windings. At least one winding is arranged on a first carrier element (chip) that enclose a common coupling hole. A second carrier element (counter chip) is attached to the first carrier element. A super-conducting oscillating diaphragm is positioned opposite the coupling hole. The mutual inductance of the windings is modulated with this super-conducting vibrating diaphragm through appropriate changes of the effective size of the coupling hole with a frequency that lies in a characteristic frequency range for low-level noise operation of the SQUID.

Squid magnetometer including a flux-gate chopper using a mechanically

For electro-optical image conversion as well as for optical image processing by spatial filtering, a two-dimensional optical filter is provided which comprises a microstructured grid, the openings of which are designed as a matrix of windows, the windows being provided with electrostatically movable thin-film closures. The window openings are controlled by electrostatic charges which are provided by an electron beam. This matrix of light valves can preferably be used as a electro-optical converter as well as a Fourier filter in an optical computer.

Arrangement for optical image processing

A multichannel device for measuring weak, varying magnetic fields contains in each channel a gradiometer formed by superconducting loops on a planar carrier element; a superconducting direct current quantum interferometer (DC-SQUID) rigidly joined to the carrier element mechanically; and superconducting rigidly connecting links between the gradiometer and the interferometer, including a coupling-in coil. The active area of the gradiometer system is to be kept as small as possible and should approach the contour of a patient to be examined at the same time. Towards this end, several planar carrier elements fastened to one common carrier structure are provided, there being disposed on each carrier element the superconducting components such as the gradiometer, interferometer formed directly on the carrier element, and connecting links associated with at least one channel.

Multichannel device with superconductor gradiometers for measuring weak

Apparatus comprising a gradiometer array having a plurality of gradiometers, with which at least one SQUID array having a multiplicity of DC-SQUIDs is associated therewith forms, with the respective coupling coils, modulation coils and superconducting shielding rings serving for the magnetic decoupling, a thin-film structure. Furthermore, metallic coupling by ground planes is provided for at least part of the common leads. By the metallic coupling and magnetic decoupling of the parallel measuring channels, a simple embodiment with few contacts is obtained which makes possible parallel signal processing without crosstalk.

Apparatus for measuring weak magnetic fields having a DC-SQUID array and

An improved device for the multi-channel measurement of weak variable magnetic fields with fields strengths below 10.sup.-10 T, having in each channel a superconducting quantum interference device (SQUID), a gradiometer consisting of superconducting coils and superconducting elements between the quantum interference device and the gradiometer, and a coupling transformer and connecting leads. In addition, the device includes electronic equipment for the evaluation, processing and presentation of the information obtained at the quantum interference elements. In order to use this measurement device to obtain spatial field distributions, particularly those of biomagnetic fields, during reasonable measuring times, with a substantial coherence among the field data, the invention provides for a rigid substrate on which direct-current quantum interference devices with associated planar-designed gradiometer coils and the superconducting connecting elements are arranged, and in which case the coils and the connecting elements are thin-film structures on at least one level.

Device for the multi-channel measurement of weak variable magnetic

Between a SQUID array having contact pads and a gradiometer array there is a multiplicity of superconducting connections. The superconducting connections contain a contact comb which comprises flat, substantially U-shaped, at least partially superconducting spring contacts which are electrically insulated from each other and combined with their flat sides parallel to each other and perpendicularly to the surface of the contact pads to form a packet. One leg of the spring contacts is provided with a projection which is intended as a pressure contact for one of the contact pads of the SQUID array and a further leg is associated with a pressure plate, the force of which is directed parallel to the flat side of the spring contact and perpendicularly to the surface of the contact pads. An adjusting block permits a simple adjustment of the projections on the contact pads of the SQUID array via a projection of a middle leg of the spring contact.

Apparatus for measuring weak magnetic fields having superconducting

The gradiometers are arranged with their associated SQUIDs in a double-wall Dewar vessel which is equipped with a narrow neck. A gradiometer array is provided with a multiplicity of individually mountable gradiometers, the detector coils of which are arranged side-by-side. The radiometers are connected via a superconducting plug connection to a SQUID array of DC-SQUIDs which is designed with a measuring head and a multiple connector as a plug-in module. The multiple connector can be inserted with the SQUID array through the neck of the Dewar vessel and can be plugged into a mating plug-in device which is associated with the gradiometer array and is fastened by a mounting device to the bottom of the Dewar vessel. In this embodiment of the apparatus, for instance, a plane gradiometer array for magnetocardiography can be exchanged for a curved gradiometer array for magnetoencephalography.

Apparatus for measuring weak magnetic fields having several gradiometers

For manufacturing a gradiometer having a three-dimensional structure for a single or multi-channel device for measuring magnetic fields with field intensities to below 10.sup.-10 T, the superconducting gradiometer coils of predetermined dimensions lying in different planes are connected to each other via superconducting connecting lines and are coupled to at least one superconducting quantum interference element (SQUID). The connecting lines are designed in a simple manner. First, the gradiometer coils are applied in spaced position, with the connecting lines running between the coils, to an at least largely planar flexible substrate body. Then, the substrate body is bent such that the three-dimensional gradiometer structure is obtained. For the substrate body, a thin polyimide foil, in particular, can be used.

Method for manufacturing a three-dimensional gradiometer for a device

A superconducting gradiometer coil system is provided for an apparatus for the multi-channel measurement of weak non-stationary magnetic fields in a field intensity range under 10.sup.-10 T. The apparatus includes, in each channel, at least one detection coil and at least one compensation coil comprising a gradiometer coil pair, a superconducting quantum interference device (SQUID) and corresponding superconducting connecting members coupling the coils and the SQUIDs, and electronic apparatus for evaluating, processing and displaying the information generated by the quantum interference devices. The gradiometer coil system permits a relatively simple one-time adjustment and has an active area as small as possible. At least the gradiometer detection and compensation coils and their mutual connecting elements are deposited as planar thin-film structures on a common rigid support body. The compensation coils are combined to form a reference coil arrangement about which the individual detection coils are disposed. In particular, the compensation coils of the reference coil arrangement can be formed at least partially of individual loops which surround each other and lie in one plane.

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Erlangen, Germany

Eckhardt Hoenig