Neuromag Oy

Outokumpu Oy

Elekta Ab (Publ)

Megin Oy

Antti I Ahonen

Juha T Simola

Matti J Kajola

Visa A Vilkman

Jukka E Knuutila

Samu Taulu

Lauri Parkkonen

Georg C Von Alfthan

Pasi Petteri Laine

Jukka Nenonen

Matti S Hamalainen

Pasi P Laine

Rob Blaauwgeers

Sami Antero Lähteenmäki

Juha Tuoriniemi

Sami Antero Lahteenmaki

The invention relates to a method and a magnetoencephalography (MEG) measurement device. In the method there is determined the ending of a scheduled inactivity period of the MEG device. At the ending of the inactivity period a cryocooler of the MEG device is switched off. Helium is allowed to boil in the Dewar vessel of the MEG device when the MEG device is active and used to perform patient measurements. The boiled helium is collected via a compressor to an external storage tank. When a new inactivity period for the MEG device commences, the cryocooler is started anew and helium is let from the external storage tank in-to the Dewar vessel, where it is re-liquefied by the cryocooler. The compressor may be switched off when the cryocooler is switched on.

Apparatus and a method for helium collection and reliquefaction in a magnetoencephalography measurement device

The present invention introduces a method for processing multichannel measurement data achieved especially in MEG and EEG measurements. The method uses a signal space separation (SSS) method and the orthogonality of lead fields in order to calculate linear transformation from physical measurement channels to virtual channels. The geometry related to the measurement arrangement is dissipated and the number of virtual channels is clearly lower than the number of physical sensors. The concept of total information can be applied for such transformed measurement data due to orthogonality. The method offers simplified post-processing of the biomagnetic data, such as for source modelling. The total information can also be interpreted as a robust quantity describing the physiological state of a patient.

Analysis of multi-channel measurement data using orthogonal virtual channels

A method and apparatus is described for making multichannel signal measurements of weak signals in noisy environments, wherein the elimination of background interference signals from the multichannel signal measurement is performed. The method is based on an adaptive compensation technique in which the large interfering background signals are first recorded. By a statistical analysis of this multichannel measurement, independent components of the interference are determined. The apparatus is provided with compensator elements which are coupled to individual sensors for both collection and distribution of information on the interference signals during the measurement. In this way the output of a device can be made immune to the large amplitude interference components present in the device's environment. This reduces the dynamic range requirement for the data transport and storage systems.

Method and apparatus for eliminating background interference signals from multichannel signal measurements

Sensor position indicator coils to be used in magnetoencephalographic experiments and a means of attaching them to the head. The invention comprises a headband (1) and a coil assembly attached to it. The coil assembly consists of a coil set (5) and of at least three fastening strips (6) or of fastening strips having coil sets of individual coils (5') on them. The mechanical properties of the coils are very important. The coil set (5) has three thin- or thick-film coils cast in epoxy resin. The outside surface of the headband (1) and the inside surfaces of the fastening strips (6) have been covered with materials adhering to each other easily. In addition, the underside of the coil set (5) can contain three small knobs, formed during casting, on which the coil set leans when pressed against the head, staying in the tangent plane of the head.

Sensor position indicator coils to be used in magnetoencephalographic

A sensor element of thin film components and fiber glass, and a support structure of fiber glass; when sensor elements are attached to the support structure, a sensor system for magnetoencephalographic measurements is formed. A substrate containing a planar signal coil and a SQUID is attached on a circuit board of fiber glass using a spring cut on the edge of a body plate. On the sensor element, is a small but mechanically stable connector or several such connectors (5); when the sensor element is plugged in receptacles (6) on the support structure (7), the element settles in a well defined orientation. Support structure (7) is made of a fiber glass shell following the shape of the bottom (10) dewar vessel, adapted to the shape of the head. The receptacles (6) are attached to the glass fiber shell by springs (9) made of thin fiber glass plate such that an array covering the whole skull as evenly as possible is formed when the sensor elements are plugged to the receptacles. The spring is cut to enable rotation only around an arbitrary axis in the plane of the spring and a translation only in a direction perpendicular to the plane of the spring. When this support structure is inserted in the dewar, individual sensor elements lean against the dewar bottom (10) by aid of three feet (11), pressed by springs (9), settling perpendicularly to the normal of the dewar bottom passing through the center of the sensor element.

Compact magnetometer probe and an array of them covering the whole human

A superconducting device for measuring weak magnetic fields, especially those generated by the human brain and detected simultaneously over the whole skull. The superconducting magnetometer or gradiometer elements of the device are attached with connectors to a cross-connection/support element which, in turn, is attached to a connecting element containing the electric components necessary for connecting the SQUIDs to the room temperature electronics. The connecting element is attached to a neck plug for the dewar flask. The neck plug is made of a stiff thermal insulation to prevent convection and a ribbon cable containing parallel twisted pairs. The latter element is self-supporting and forms an integral part of the magnetometer support structure. The cables in the neck plug have been made out of wires having a relatively high resistance in order to minimize the heat leak between room temperature and the cryogenic environment of the magnetometers. The excess noise caused by the resistive leads may be compensated by increasing the SQUID gain using positive feedback.

Multi-channel magnetic flux detector comprising a magnetometer modular

A reliable superconducting contact for superconducting thin film components, based on soft superconducting materials, and a method for making the contacts. A wire blank is squeezed to a thin plate and then this plate is cut into slabs used in the bonding. The ends of the slabs are longitudinally cut so that double or multiple parallel joints can be made. The slabs have elastic, bent central portions for absorbing stresses and stiff ends having a U-beam shape joined to the components. The U-beam shape may be formed by the soldering tool used to make the joints. The ribbon-like character, thinness and other features of the bonding slab permit a precise control of the bonding temperature, reduce the strain and bending forces caused by thermal contraction, and prevent the contact from peeling off while cooling the superconducting component to the operational temperature.

Reliable superconducting link for superconducting thin film components

The invention relates to a measuring cell (1) designed for measuring the contents of the components present in slurries which are in a flowing motion, the measuring cell comprising an inlet pipe (2) and an outlet pipe (9) for the slurry and a measuring window (3). According to the invention, the inlet pipe (2) is placed at a given distance from and in an inclined position with respect to the plane contained in the measuring window (3), in order to direct the slurry jet entering from the inlet pipe (2) to a point that is approximately one internal radius of the inlet passage (2) in front of the center of the measuring window (3).

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Helsinki, Finland

Antti I Ahonen