Abstract: The device for sensing a magnetic field comprises a closed superconducting pick-up loop (1) having a path width (d) etched out of a single layer superconducting thin film and provided with a constriction (15) having a width (w) of narrow dimension smaller than the path width (d). The closed superconducting pick-up loop (1) constitutes a flux-to-field transformer (FFDT). At least one magnetoresistive element (2) is placed on top of or below the superconducting thin film, is isolated from the superconducting thin film by a thin insulating layer and is located so that an active part of the magnetoresistive element (2) is at the location of the constriction (15) and has a width equal to or less than the width of the constriction (15). The active part of the magnetoresistive element (2) is oriented so that the bias current in this active part is directed essentially along the constriction (15), orthogonally to the width of narrow dimension.

Abstract: The object of the invention is to provide a biomagnetism measuring device using a high-performance cylindrical shielding apparatus provided with a flange-type plate having an opening formed on a circumferential face, an auxiliary cylinder in which one or plural cylindrical members are connected so that the central axis of the opening of the flange-type plate and each central axis of the cylindrical members are coincident, cylindrical shields having first, second and third angular ranges with the y-axis, a revolving door having a cutout in a portion parallel to the y-axis and acquired by integrating the cylindrical shields, shield bases for supporting the cylindrical shield to which the flange-type plate is connected in a circular-arc part at both ends, revolving parts for revolving the revolving door in a circumferential direction of the y-axis along a circumferential part of the cylindrical shield and opening or closing an opening in the circumferential direction, a cryostat arranged inside the opening of th

Abstract: A readout scheme for measuring the output from a SQUID-based sensor-array using an improved subranging architecture that includes multiple resolution channels (such as a coarse resolution channel and a fine resolution channel). The scheme employs a flux sensing circuit with a sensing coil connected in series to multiple input coils, each input coil being coupled to a corresponding SQUID detection circuit having a high-resolution SQUID device with independent linearizing feedback. A two-resolution configuration (course and fine) is illustrated with a primary SQUID detection circuit for generating a fine readout, and a secondary SQUID detection circuit for generating a course readout, both having feedback current coupled to the respective SQUID devices via feedback/modulation coils. The primary and secondary SQUID detection circuits function and derive independent feedback.

Abstract: A scanning SQUID microscope is set forth to provide improved output imaging. The SQUID microscope includes a vertically adjustable housing adapted to securely retain a SQUID loop or sensor. A scanning stage of the SQUID microscope is adapted to support a sample while moving the sample along a predetermined path to selectively position predetermined portions of the sample in close proximity to the SQUID loop or sensor to permit the loop or sensor to detect predetermined magnetic field information provided by the predetermined portions of the sample. A position control processor coupled to the scanning stage is operative to receive and process the predetermined magnetic field information to provide corresponding position noise information. Criteria are also presented for determining the expected level of position noise under given experimental conditions.

Abstract: An apparatus for measuring spin polarization via Point Contact Andreev Reflection (PCAR) at a magnet-superconductor junction, with variable magnetic fields and temperature control. A cryostat probe investigates superconducting energy gap and Andreev reflection in superconductor-half metal junctions, in a wide range of magnetic fields and temperature from 2K-300K. The cryostat probe is integrated with a commercial physical properties measurement system. The measurement probe includes a rotary-translation stage with coarse and fine screws that enable a user to make point contacts in a cryogenic, evacuated environment where the point contact junction can be controlled at room temperature by turning a knob. Copper wires are connected as electrical leads from an aluminum housing, descend down to a copper housing, for measurement, when contact is made by tip with a half-metal sample, such as CrO2.

Abstract: A scanning microscope for high resolution current imaging by direct magnetic field sensing of a sample maintained in an ambient environment. The scanning microscope uses a magnetic sensor such as a SQUID and a fiber probe magnetically coupled between the SQUID sensor and the sample under study. The fiber probe has a sharply defined tip for high resolution probing and for reaching minute cavities on the surface of the sample. The coupling between the tip of the fiber probe and the sample is controlled by a distance control mechanism, in the range of 1-100 nm. The material of the fiber probe with high permeability and low magnetic noise is chosen to optimize flux transmission to the magnetic sensor. Magnetic coupling to the sensor is maximized by keeping the distance between the end of the fiber probe and the sensor to approximately 0-100 ?m. The fiber probe is integrated into the fiber holder for easy replacement of the fiber probe.

Abstract: A non-destructive method of narrowing down the location of a failure in a sample includes a first step of acquiring first and second images of magnetic-field distributions obtained by scanning a laser beam irradiating first and second samples, respectively, and if there is a difference between the first and second images of the magnetic-field distributions, a second step of acquiring first and second current images from magnetic-field distributions acquired by scanning the first and second samples by a magnetic-field detector in a state in which a prescribed location on the first and second samples is being irradiated by the laser beam. The difference between the first and second current images is found and, based upon the difference image found, it becomes possible to identify a disparity in current paths relating to the prescribed location on the first and second samples.

Abstract: In a SQUID magnetometer, high resolution, a high slew rate, and a high dynamic range are achieved without using expensive circuit components having a large number of processing bits and enabling a high speed processing operation. A digital FLL circuit using a double counter system is provided. This circuit utilizes two or more counters, for example, a change range counter in a digital FLL for carrying out a processing operation at a high speed and a reproducing counter in a control/measuring computer. In addition, in the present invention, hysteresis characteristics having a 1?0 positive margin is used. That is, a change of a state of a magnetic flux is counted by means of a counter. At the time of this change, control is made so as to track a different channel between cases in which a magnetic flux increases and decreases, thereby stabilizing the control.

Abstract: The invention relates to a magnetic flow sensor (1, 21, 51) comprising a) a loop-shaped magnetic field conductor comprising a point (2, 22, 32, 52) which expands to form a bar or a film (3, 23, 52), a loop-shaped part (3a, 23a, 53a) and at least one part (4, 24, 54?, 54?) which guides back the magnetic field lines of the probe, b) SQUID (7, 27, 57), c) and a diaphragm (5, 25, 35, 55) comprising a hole (6, 26, 36, 56), whereby the part (4, 24, 54?, 54?) which guides the magnetic field lines of the probe back to the loop-shaped magnetic field conductor is connected to the diaphragm (5, 25, 35, 55).

Abstract: According to certain embodiments of the present invention, there is provided a mounting arrangement for a magnetoencephalography (MEG) system headrest assembly forming a portion of a SQUID dewar and having a fixed headrest and an array of sensors, wherein a sensor array plate positions the sensors relative to the headset. A plurality of first rods interconnecting the array plate and the movable mounting member. A plurality of second rods are fixed at one of their ends relative to the dewar and are connected at their opposite ends to the movable mounting member.

Abstract: A magnetic field measurement apparatus which reduces an interference magnetic field entering into a pick-up coil is provided. The magnetic field measurement apparatus includes a superconducting quantum interference device (SQUID) magnetometer having a pick-up coil for picking up a magnetic field generated from an examination object, a SQUID control unit for controlling the SQUID magnetometer, a magnetometer for picking up the interference magnetic field, a magnetometer control unit for controlling the magnetometer, a modulation circuit, a current converter, a current amount adjusting device, a coil which is positioned outside the pick-up coil and through which the current thus adjusted by the current amount adjusting device flows, a demodulation circuit, a low-pass filter (LPF) for extracting a low frequency element of the output voltage from the demodulation circuit, and a subtraction circuit for subtracting the output of the LPF from the output of the SQUID control unit.

Abstract: A superconducting magnetic field generating apparatus includes a superconducting body for generating a magnetic field below a critical temperature of the superconducting body, a thermal insulation vessel having a space for accommodating the superconducting body, and a ferromagnetic body for adjusting a magnetic field distribution generated from the superconducting body wherein at least a part of the ferromagnetic body is disposed around the superconducting body and a magnetic circuit is formed so as to form the magnetic field distribution in a common side of the superconducting body and the part of the ferromagnetic body.

Abstract: A beam current measuring device (BMD) capable of measuring beam current while radiating the beam on a target, such as a semiconductor wafer. The BMD at least includes: (a) a detecting part operable to detect or collect a magnetic field corresponding to the beam current; and (b) a measuring part including (i) a SQUID sensitive to magnetic flux, and (ii) a feedback coil operable to carry feedback current wherein the feedback current is operable to cancel out a change in the magnetic flux penetrating through the SQUID. Wherein the operating point of the SQUID is set according to a finite beam current value, other than zero, which penetrates through the detecting part. A BMD of the present invention can be incorporated and used in an ion-implantation apparatus, an electron beam exposure apparatus, an accelerator, and the like.

Abstract: According to certain embodiments of the present invention, there is provided a magnetoencephalography and method employing a portable cart having a SQUID dewar mounted in an inverted manner thereon, and having a headrest assembly mounted on the cart for supporting the head of a patient and forming a portion of the dewar. The headrest assembly includes an array of magnetic sensors of the SQUID dewar for responding to electrical activity of the brain of the head.

Abstract: An apparatus and a method for testing semiconductor devices, such as individual integrated circuits in semiconductor chips, by directing a current in each circuit through a respective selected predetermined path to establish, in each circuit, a respective focused magnetic field and converting each such magnetic field into a respective voltage which, when fed to respective amplifier gated with a respective selected frequency, will modulate each such respective voltage. Each such respective voltage is then used to create a respective pulsating magnetic field that when detected by a respective remote magnetic sensor will provide a series of respective signals representative of the current in the respective circuit from which the pulsating magnetic field was derived.

Abstract: A scanning SQUID microscope capable of high frequency magnetic field measurements uses a hysteretic SQUID detector and a pulsed sampling technique which permits to extend the bandwidth of the SQUID microscope to above GHz region. The system can be readily incorporated into a 4.2k scanning SQUID microscope for imaging chips at room temperature. By biasing the hysteretic SQUID with pulses of a predetermined amplitude, and adjusting a modulation flux applied to the hysteretic SQUID at a plurality of time delays between the activation of the sample under study and the bias pulse, the hysteretic SQUID can be switched on, and the modulation flux value corresponding to such a switching event as a function of time is considered as representation of the magnetic field emanating from the sample under study.

Abstract: To obtain a superconducting driver circuit which can obtain an output voltage of several millvolts or above, can use a DC power source as a driving power source, can form no capacitance between it and a ground plane, and has a small occupation area, the superconducting driver circuit is constructed by superconducting flux quantum interference devices (SQUIDs) each constructing a closed loop having as components two superconducting junctions and an inductor. The SQUIDs share the inductors and are connected in series in three or more stages.

Abstract: A system (10) for measuring magnetic fields, wherein the system (10) comprises an unmodulated or direct-feedback flux locked loop (12) connected by first and second unbalanced RF coaxial transmission lines (16a, 16b) to a superconducting quantum interference device (14). The FLL (12) operates for the most part in a room-temperature or non-cryogenic environment, while the SQUID (14) operates in a cryogenic environment, with the first and second lines (16a, 16b) extending between these two operating environments.

Abstract: A SQUID (Superconducting QUantum Interference Device) sensor using an auxiliary sensor, includes a SQUID sensing unit having a SQUID and a first feedback coil for creating a magnetic field at a periphery of the SQUID; an auxiliary sensor having a lower magnetic sensitivity and a higher operation range than the SQUID sensing unit; and a sensor reading unit for operating the SQUID sensing unit and the auxiliary sensor to read out a signal of the SQUID and at the same time, supplying the SQUID sensing unit with an offset magnetic field through the first feedback coil.

Abstract: A method and apparatus for interrogating a sample that exhibits molecular rotation are disclosed. In practicing the method, the sample is placed in a container having both magnetic and electromagnetic shielding, and Gaussian noise is injected into the sample. An electromagnetic time-domain signal composed of sample source radiation superimposed on the injected Guassian noise is detected, and this signal is cross-correlated with a second time-domain signal produced by the same or similar sample, to produce a cross-correlated signal with frequency domain components. The latter is plotted in the frequency domain by a fast Fourier transform to produce a frequency domain spectrum in a frequency range within DC to 50 KHz. From this spectrum, one or more low-frequency signal components that are characteristic of the sample being interrogated are identified.

Abstract: Circuit flaws in microelectronic circuitry present regions of high resistance in which a current distribution deviates from that of a defect-free circuit. The altered current distribution emits a correspondingly altered magnetic field in accordance with Ampere's Law. When compared with the magnetic field of a defect-free circuit, the anomaly in the magnetic field of the defective device is detected and the location of the circuit flaw may be determined therefrom. As the anomaly in the magnetic field is very small in magnitude, a sensitive magnetic microscope is utilized to obtain images of the magnetic fields of a defect-free reference device and a device-under-test. The distance between the magnetic sensor and the devices being scanned is precisely controlled to minimize influences of scanning distance on the difference in measured magnetic field strength. Comparative image analysis reveals the location of the circuit flaw.

Abstract: A method and apparatus performs high resolution imaging. The disclosed apparatus includes a low temperature SQUID sensor mounted in close proximity to a dewar thin window. A radiation shield has an extension surrounding the detection coil.

Abstract: A method and apparatus for interrogating a sample that exhibits molecular rotation includes placing the sample in a container having both magnetic and electromagnetic shielding, where Gaussian noise is injected into the sample. An electromagnetic time-domain signal composed of sample source radiation superimposed on the injected Guassian noise is detected, and this signal is used to generate a spectral plot that displays, at a selected power setting of the Gaussian noise source, low-frequency spectral components characteristic of the sample in a selected frequency range between DC and 50 kHz. In one embodiment, the spectral plot that is generated is a histogram of stochastic resonance events over the selected frequency range. From this spectrum, one or more low-frequency signal components that are characteristic of the sample being interrogated are identified.

Abstract: Magnetic field sensor probes are disclosed which comprise primary or drive windings having a plurality of current carrying segments. The relative magnitude and direction of current in each segment are adjusted so that the resulting interrogating magnetic field follows a desired spatial distribution. By changing the current in each segment, more than one spatial distribution for the magnetic field can be imposed within the same sensor footprint. Example envelopes for the current distributions approximate a sinusoid in Cartesian coordinates or a first-order Bessel function in polar coordinates. One or more sensing elements are used to determine the response of a test material to the magnetic field. These sense elements can be configured into linear or circumferential arrays.

Abstract: A scanning SQUID microscope for acquiring spatially resolved images of physical properties of an object includes a SQUID sensor arranged in perpendicular to the plane of the object under investigation for detecting tangential component of the magnetic field generated by the object. During scanning of the SQUID sensor over the object under investigation, the position signal from a position interpreting unit, as well as relevant output signals from the SQUID sensor are processed by a processing unit which derives from the data, spatially resolved images of the physical properties of the object. The specific orientation of the SQUID sensor with respect to the plane of the object permits an enlarged area of the SQUID chip on which the modulation and feedback line can be fabricated in the same technological process with the SQUID sensor. Additionally, larger contact pads afforded provide for lower contact resistance and ease in forming contact with bias and read-out wires.

Abstract: A method for processing biomagnetic fields generated by biocurrents resulting from activities of human brain or myocardia and its mapping apparatus are provided, which features biomagnetic measurement and its analysis, magnetic field mapping and its imaging and their waveform generation by a simple operation. Biomagnetic fields emitted from the patient are measured at a plurality of measurement positions, and a contour map of magnetic field obtained as a result of processing of these measured biomagnetic fields is imaged in the magnetic contour map display apparatus, which display apparatus comprises: the process function display area indicating process function items including measurement; and the analysis data display area which displays the waveform together with a designated measurement time, the waveform being generated during measurement at least based on the measured biomagnetic fields and during the designated measurement period of time.

Abstract: A biomagnetic measurement apparatus having functions to detect the release of a magnetic field lock in a SQUID fluxmeter operation circuit due to the influence of a much greater noise level than that of a biomagnetic signal, to notify an operator of the release of the magnetic field lock, and to automatically or manually revert to a state for allowing magnetic measurement. The release of the magnetic field lock occurs when an integrator of the fluxmeter operation circuit is saturated. Thus, a high pass filter is provided at a subsequent stage of the integrator, and a function is provided to judge that the integrator is in a saturated state when the noise level of the output after passing through the high pass filter is lower than a pre-set threshold.

Abstract: The invention relates to a device for setting an operating point of a magnetic field sensor having a periodic characteristic, in particular for a device for detecting a magnetic field and/or flux, having a SQUID as magnetic field sensor and a control unit which is connected downstream of the SQUID, has a control time constant (t) and has a feedback loop which acts on the SQUID and is designed such that it is active about a number of operating points of the SQUID, where flux quantum pump means are provided which are assigned to the SQUID, have a signal generation unit for generating a control and/or regulation signal for the SQUID and are designed such that, in order to pump at least one flux quantum into and out of the SQUID, a signal form of the control and/or regulation signal, generated by the signal generation unit, is different and, referred to a rising and a falling edge of a signal form, is unsymmetrical, where in each case only one of the edges of a signal form is short referred to the control time co

Abstract: A magnetic field measurement system for canceling an external field is provided, in which plurality of sensing magnetometers (3) for measuring a magnetic field signal in a direction perpendicular to the center axis of a cylindrical magnetic shield (1) are arranged in two dimensions on a plane parallel to the center axis and a reference magnetometer (4) for measuring the external field parallel to the center axis as a reference signal is disposed on a plane perpendicular to the plane parallel to the center axis. The reference signal multiplied by a specified factor is subtracted from a difference between signals from the adjacent sensing magnetometers (3). The magnetic field measurement system allows measurement of an extremely weak magnetic field by efficiently canceling the external field.

Abstract: The present invention provides a magnetic field measurement apparatus which reduces an interference magnetic field entering into a pick-up coil. The magnetic field measurement apparatus includes, a SQUID magnetometer having a pick-up coil for picking up a magnetic field generated from an examination object, a SQUID control unit for controlling the SQUID magnetometer, a magnetometer for picking up the interference magnetic field, a magnetometer control unit for controlling the magnetometer, a modulation circuit, a current converter, a current amount adjusting means, a coil which is positioned outside the pick-up coil and through which the current thus adjusted by the current amount adjusting means flows, a demodulation circuit, a low-pass filter (LPF) for extracting a low frequency element of the output voltage from the demodulation circuit, and a subtraction circuit for subtracting the output of the LPF from the output of the SQUID control unit.

Abstract: According to certain embodiments of the present invention, there is provided a mounting arrangement for a magnetoencephalography (MEG) system headrest assembly forming a portion of a SQUID dewar and having a fixed headrest and an array of sensors, wherein a sensor array plate positions the sensors relative to the headset. A plurality of first rods interconnecting the array plate and the movable mounting member. A plurality of second rods are fixed at one of their ends relative to the dewar and are connected at their opposite ends to the movable mounting member.

Abstract: An instrument for measuring sub-pico Tesla magnetic fields using a superconducting quantum interference device (SQUID) inductively coupled to an unshielded gradiometer includes a filter for filtering magnetically—and electrically coupled radio frequency interference (RFI) away from the SQUID. This RFI is principally coupled to the SQUID via the unshielded gradiometer. In addition, a shielding enclosure is used to electromagnetically shield the filter circuit from the SQUID, and a method is employed to increase the impedance between the input coil and the SQUID without diminishing the overall sensitivity of the instrument.

Abstract: A magnetic field measurement system for canceling an external field is provided, in which plurality of sensing magnetometers (3) for measuring a magnetic field signal in a direction perpendicular to the center axis of a cylindrical magnetic shield (1) are arranged in two dimensions on a plane parallel to the center axis and a reference magnetometer (4) for measuring the external field parallel to the center axis as a reference signal is disposed on a plane perpendicular to the plane parallel to the center axis. The reference signal multiplied by a specified factor is subtracted from a difference between signals from the adjacent sensing magnetometers (3). The magnetic field measurement system allows measurement of an extremely weak magnetic field by efficiently canceling the external field.

Abstract: An apparatus can detect a magnetic field with a high sensitivity using an ordinary-temperature pickup coil even when the pickup coil is arranged outside a cryostat. Specifically, the apparatus for measuring a magnetic field includes a pickup coil for detecting an external magnetic field, a SQUID electrically or magnetically connected to the pickup coil, a cryostat for holding the SQUID at low temperatures, and a driving device for driving the SQUID. The pickup coil is made of a normal-conducting material and is placed at an ordinary temperature outside the cryostat. By arranging outside the cryostat, the pickup coil can be brought close to a subject and can thereby detect a weak magnetic field in the subject with a high sensitivity.

Abstract: The invention relates to a device for setting an operating point of a magnetic field sensor having a periodic characteristic, in particular for a device for detecting a magnetic field and/or flux, having a SQUID as magnetic field sensor and a control unit which is connected downstream of the SQUID, has a control time constant (t) and has a feedback loop which acts on the SQUID and is designed such that it is active about a number of operating points of the SQUID, where flux quantum pump means are provided which are assigned to the SQUID, have a signal generation unit for generating a control and/or regulation signal for the SQUID and are designed such that, in order to pump at least one flux quantum into and out of the SQUID, a signal form of the control and/or regulation signal, generated by the signal generation unit, is different and, referred to a rising and a falling edge of a signal form, is unsymmetrical, where in each case only one of the edges of a signal form is short referred to the control time co

Abstract: The present invention provides a biomagnetic measurement technique which can obtain a potential waveform corresponding to a ventricular muscle cell action potential in a non-invasive manner. The biomagnetic measurement apparatus including an operating circuit for magnetometer, and means collecting output data of the operating circuit for magnetometer, has means calculating a current vector at time t, means calculating absolute value Ixy of the current vector, means calculating potential waveform V (t) in time corresponding to depolarization of a heart from the absolute value of the current vector, and means calculating potential waveform V (t) in a refractory period of the heart to a period corresponding to repolarization from the absolute value of the current vector.

Abstract: A method and apparatus for interrogating a sample that exhibits molecular rotation are disclosed. In practicing the method, the sample is placed in a container having both magnetic and electromagnetic shielding, and Gaussian noise is injected into the sample. An electromagnetic time-domain signal composed of sample source radiation superimposed on the injected Guassian noise is detected, and this signal is used to generate a spectral plot that displays, at a selected power setting of the Gaussian noise source, low-frequency spectral components characteristic of the sample in a selected frequency range between DC and 50 kHz. In one embodiment, the spectral plot that is generated is a histogram of stochastic resonance events over the selected frequency range. From this spectrum, one or more low-frequency signal components that are characteristic of the sample being interrogated are identified.

Abstract: A self-adjusting assembly and method are disclosed. In the disclosed embodiments, a support assembly for supporting a device comprises a pair of support members for supporting the device. One of the members is adapted to help support the device from a ground, and another of the members is adapted to provide lateral support for the device and to permit free longitudinal movement of the device as it expands or contracts due to temperature variations.

Abstract: A method and apparatus are disclosed for high resolution imaging. The disclosed apparatus includes a low temperature SQUID sensor mounted in close proximity to a dewar thin window. A radiation shield has an extension surrounding the detection coil.

Abstract: An apparatus for measuring electromagnetic characteristics includes a sample rod with a sample fixed to a lower part thereof, a helium 3 refrigerator, in which the sample rod is inserted, having a main pipe that forms around the sample rod a space that is cooled by helium 3, a device for supplying helium 3 to the helium 3 refrigerator, an inner tube portion, into which the main pipe is inserted, that supports at an upper part thereof the refrigerator, an outer tube that cools an outer periphery of the inner tube with helium, a liquid helium container that supplies liquid helium to the outer tube, and a device for measuring the electromagnetic characteristics of the sample.

Abstract: A bounding box or volume of interest is flooded with a modulated AC electromagnetic signal from a source. Different types of modulated signals may be used, including single-tone AM and FM. One or more sensors disposed on an object or body within the volume are then used to detect the signal, and a digital and/or analog spectral and phase analysis is performed on the received signal in hardware or software. The processing distinguishes between the direct source to sensor response and the response due to eddy currents. By removing the response due to the distorters, the effects of the electromagnetic distortion can be removed through a more conventional “free-space” solution. The invention finds applicability in a wide variety of environments, including head tracking systems and helmet-mounted displays for fighter aircraft; head trackers for armored vehicles; medical-guided surgery and biopsy; remote sensing, among other potential uses.

Abstract: There is provided a magnetic shield which can shield external magnetic fields in the direction of an axis of a tubular magnetic shield and in the direction vertical to the axis.

Abstract: A biomagnetic field measuring apparatus includes a plurality of SQUID magneto-meters for measuring a biomagnetic field generated from a living body, living-body signal measuring devices and for measuring and collecting living-body signals generated periodically, an operation processing device for operation processing the biomagnetic field signal and the living-body signal measured simultaneously as pairs in a plurality of directions, and a display unit for displaying a result of the operation processing. Change in time of excitation can be grasped in detail by using a small number of maps without presumption of a magnetic field source and display of many iso-magnetic field maps.

Abstract: Method of manufacture a wide bore, high field superconducting magnet. The superconducting magnet has a plurality of superconducting coils impregnated with epoxy and nested within each other. An innermost one of the nested coils has a bore therethrough that defines a bore width of the magnet. The bore width is greater than approximately 100 millimeters. The nested coils are electrically connected in series and cooled to an operating temperature less than approximately 4 degrees K. The magnet also has external reinforcements on the coils that are applied prior to impregnating the coils with epoxy. An active protection circuit protects the coils in response to a quench in the magnet. The protection circuit includes heater elements positioned in thermal contact with the coils prior to impregnating the coils with epoxy. The magnet further has lead supports for supporting the lead wires with epoxy that extend from the coils.

Abstract: A biomagnetic field measuring apparatus has a plurality of fluxmeters disposed externally of a living body and each including a superconducting quantum interference device (SQUID) for detecting a biomagnetic field generated from the living body, the plurality of fluxmeters being operative to detect a temporal change of a component of the biomagnetic field in a first direction which is vertical to the surface of the living body, an operation processor for performing computation for determining a temporal change of a value proportional to a root of square sum of differential value of the first-direction magnetic field component in second and third directions which cross the first direction and computation for integrating the temporal change of the value over a predetermined interval to determine an integral value, and a display for displaying the determined integral value. Distribution of magnetic fields generated from the heart is determined with a small number of fluxmeters.

Abstract: An apparatus and method for the repeatable detection and recording of low-threshold molecular electromagnetic signals. The sample material and detection apparatus are contained with a magnetically shielded faraday cage to shield them from extraneous electromagnetic signals. The detection apparatus includes a detection coil and Super Conducting Quantum Interference Device (“SQUID”). White noise is injected external to the SQUID and the signals emitted by the sample material enhanced by stochastic resonance.

Abstract: A biomagnetic field map display apparatus for measuring a biomagnetic field generated by a biotest sample at positions arranged in rows and columns and displaying a magnetic field map obtained by processing the measured biomagnetic field. An analysis data display area waveform-displays the measured biomagnetic field at channels in a row or a column of channels which are arranged in rows and columns so as to respectively correspond to the positions. A particular channel is designated as a reference channel for an averaging process out of the plurality of channels or different channels therefrom at which different biosignals from those of the biomagnetic field are acquired from the biotest sample. Means for averaging-processing the measured biomagnetic field using the designated particular channel as the reference channel displays in the analysis data display area a map on the averaging-processed biomagnetic field.

Abstract: A scanning SQUID microscope for acquiring spatially resolved images of physical properties of an object includes a SQUID sensor arranged in perpendicular to the plane of the object under investigation for detecting tangential component of the magnetic field generated by the object. During scanning of the SQUID sensor over the object under investigation, the position signal from a position interpreting unit, as well as relevant output signals from the SQUID sensor are processed by a processing unit which derives from the data, spatially resolved images of the physical properties of the object. The specific orientation of the SQUID sensor with respect to the plane of the object permits an enlarged area of the SQUID chip on which the modulation and feedback line can be fabricated in the same technological process with the SQUID sensor. Additionally, larger contact pads afforded provide for lower contact resistance and ease in forming contact with bias and read-out wires.

Abstract: An improved method, termed “statistical synthetic aperture magnetometry” (SSAM) of transforming magnetoencephalographic (MEG) measurements into corresponding three-dimensional images of the electrophysiological activity within the brain. The computed images are static, representing the time-integrated brain activity over a selected period. By selecting the time periods and frequency bands of interest, the SSAM method selectively images brain activity relating to different types of brain pathology or to cognitive events. Unlike prior art methods, the SSAM method compensates for the growth of ionic signal source strength estimates with depth into the head, resulting, in part, from the declining sensitivity of the MEG sensors. This is achieved by computing and displaying functions of the ratio of source strength to its noise for each element comprising the image.

Abstract: A device is proposed for high-resolution measurement, in particular for high-resolution absolute measurement of magnetic fields, having a network (1) of transitions (3) between superconductors (5, 6) which exhibit Josephson effects, called junctions below, the network comprising closed meshes (7, 8, 9, 10, 11, 12, 13), denoted by cells below, which in each case have junctions (3), which junctions are connected in a superconducting fashion, and at least three of these cells being connected in a superconducting and/or nonsuperconducting fashion. The object of the invention consists in further developing this device in such a way that it is possible to make absolute measurements of magnetic fields in a highly sensitive fashion.