Abstract: An improved metal detector characterized by enclosing the detector's circuitry in a foldable enclosure whereby the improved detector may be transported easily and quickly and securely erected for use.

Abstract: A magnetic sensing transducer device that senses low frequency magnetic fields by using flux concentrators that modulate the observed low frequency signal, thereby shifting this observed signal to higher frequencies and minimizing 1/f-type noise. This is accomplished by the oscillatory motion of a microelectromechanical (MEMS)-type magnetic flux concentrator operated with a magnetic sensor, preferably made on a common substrate. Such a combined device can be used in a magnetometer. Such a device is small, low-cost and has low-power-consumption requirements. The magnetic sensor can be a Hall effect or other type of magnetic sensor. At least one MEMS-type fabricated flux concentrator is used with the magnetic sensor. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device.

Abstract: A microelectromechanical systems (MEMS) Device manufactured on a microscopic scale using integrated circuit techniques provides a sensitive magnetic field sensor by detecting motion caused by the Lorentz force produced by a current through a MEMS conductor. The resulting MEMS may be used as a component in a variety of devices including current sensors and proximity sensors.

Abstract: A microelectromechanical systems (MEMS) Device manufactured on a microscopic scale using integrated circuit techniques provides a sensitive magnetic field sensor by detecting motion caused by the Lorentz force produced by a current through a MEMS conductor. The resulting MEMS may be used as a component in a variety of devices including current sensors and proximity sensors.

Abstract: A magnetic sensing device that senses low frequency magnetic fields by using movable flux concentrators that modulate the observed low frequency signal. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device. The modulation shifts this observed signal to higher frequencies and thus minimizes 1/f-type noise. This is preferably accomplished by the oscillatory motion of a microelectromechanical (MEMS)—type magnetic flux concentrator operated with a magnetic sensor, preferably made on a common substrate. Such a combined device can be used in a magnetometer. Such a device is small, low-cost and has low-power-consumption requirements. The magnetic sensor can be a Hall effect or other type of magnetic sensor. At least one modulating flux concentrator is used with the magnetic sensor.

Abstract: The invention includes an apparatus and method for determining the pass through flux of magnetic materials. The apparatus comprises one or more magnetic field sensors arranged in such a way as to collect field strength data in any or all the x, y, z directions. The apparatus also comprises a magnet field source or arrangement of magnet field sources which are placed beneath the material being characterized and includes a mechanism whereby the magnetic material can be mapped by the movement of any one or combination of: magnetic field source or sources, sensors and magnetic material. The invented method comprises the use of various configurations of magnetic sources in order to generate a magnetic field that emulates the open-loop condition found in magnetron sputtering.

Abstract: A resonant micro-compass for detecting the Earth's magnetic field while requiring minimal power is disclosed Generally, the micro-compass comprises a resonant structure that is driven at its resonant frequency, which requires minimal power. The resonant frequency of the resonant structure is then measured and the resonant structure is caused to oscillate. A magnet is located on the resonant structure such that introduction of the Earth's magnetic field to the oscillating resonant structure causes a reaction by the magnet which, in turn, changes the resonant frequency of the resonant structure to shift. This shift of resonant frequency is then measured, thereby allowing the micro-compass to detect the direction of the magnetic field with extreme accuracy.

Abstract: A current sensor includes a deflectable member disposed in a magnetic field. Nulling or compensating members may be mechanically coupled to the deflectable member. Feedback or readout devices coupled to the structure provide signals indicative of deflection of the deflectable member under the influence of applied current and the magnetic field. Nulling current applied to the nulling members tends to oppose deflection of the deflectable member. The nulling current may be modulated to drive the feedback signal to a desired level and is used as a basis for calculating the current to be measured. The current may be measured directly upon calibration of feedback devices coupled to the deflectable member or to the nulling members. Arrays of sensors may be coupled to common busses for applying measured and nulling currents to sensors of the arrays and for detecting feedback signals.

Abstract: There is disclosed a magnetic field characteristics evaluation apparatus for turning off a switching signal, measuring the surface of a magnetic field generating member in a magnetized state by AFM, and storing AFM signal together with a position signal corresponding to a scanning position in a memory to display a surface configuration based on the AFM signal. Subsequently, the switching signal is turned on, the magnetic head is set to a magnetized state, the AFM signal is referred to, the magnetic head surface is measured by MFM, and MFM signal together with the position signal corresponding to the scanning position are stored in the memory to display a surface magnetic field distribution based on the MFM signal. Therefore, it is possible to accurately specify, from the surface, a position in which the magnetic field is generated.

Abstract: A semiconductor magnetic field sensor including a substrate; a semiconductor moveable element suspended above the substrate, the moveable element being configured to have a current passed therethrough and to deflect perpendicularly with respect to an applied magnetic field; and at least one fixed semiconductor element arranged adjacent to the moveable element, the moveable element being deflected to or away from the fixed element in response to an applied magnetic field.

Abstract: A terrestrial change prediction apparatus including an indicator having a fixing member made of a nonmagnetic material and a plurality of magnetic bodies each having an N-pole end and an S-pole end and fixedly secured to the fixing member with the same magnetic polarity ends facing to each other so that a magnetic repulsive force is produced therebetween. The indicator is rotatably supported such that the magnetic bodies normally orient in a substantially constant direction. Before a terrestrial change such as an earthquake occurs, the indicator displaces. By measuring the displacement of the indicator, an occurrence of a terrestrial change can be predected.

Abstract: An electronic compass has a compass housing. An electronic magnetic field sensor is disposed in a fixed position relative to the compass housing. A magnet is rotatably mounted relative to the magnetic field sensor and independently aligned with a terrestrial magnetic field. The magnet has a magnetic field with a magnetic field direction and the electronic magnetic field sensor is located within a range of influence of the magnetic field. The electronic magnetic field sensor has a first magnetoresistor with a first fixed reference axis and an electric resistance of the first magnetoresistor is a function of a first angle of rotation between the fixed first reference axis and the direction of the magnetic field. The electronic magnetic field sensor defines a first differential bridge circuit and the first magnetoresistor is disposed in the first differential bridge circuit which during operation of the compass, supplies an output voltage dependent on the first angle of rotation.

Abstract: Small metallic patches embedded in a mainly non-metallic surface may be detected and mapped by placing a wire coil at the free end of a cantilever, with a fine tip made of a ferro-magnetic material located at its center. An alternating current is passed through the coil so that when it is near a metallic patch eddy currents are induced in the patch. These produce a small magnetic moment in the patch which pulls the tip towards the surface. This movement of the tip is detected by observing a light beam that is reflected off the surface of the cantilever. By plotting the output of a photodetector, sensistive to small changes in the reflected beam's position, as a function of the tip's location over the surface, a map of the metallic patches is produced.

Abstract: A method of and apparatus for torque magnetometry in which a specimen, the magnetic moment of which it is desired to determine, is disposed on a support. A temporally varying, for example sinusoidal, magnetic field is generated in the region of the specimen so that interaction between the magnetic moment of the specimen and the magnetic field causes a torque to be exerted on the specimen. Consequently, the specimen and/or the support are deflected and typically exhibit a vibratory motion. The motion of the specimen and/or support due to the torque is measured. When the magnitude and direction of the magnetic field are known, the magnetic moment of the specimen can be determined from the results of the motion measurement. The frequency of the magnetic field can be adjusted so that the specimen and/or the support resonate. The support is typically a single silicon crystal having two orthogonal modes of vibration which have different resonant frequencies.

Abstract: A microelectromechanical-based magnetostrictive magnetometer that uses, as an active element, a commercial (001) silicon microcantilever coated with an amorphous thin film of the giant magnetostrictive alloy Terfenol-D and a compact optical beam deflection transduction scheme. A set of Helmholtz coils is used to create an ac magnetic excitation field for driving the mechanical resonance of the coated microcantilever. When the coated microcantilever is placed in a dc magnetic field, the dc field will change the amplitude at the mechanical resonance of the coated microcantilever thereby causing a deflection that can be measured. The magnetometer has been demonstrated with a sensitivity near 1 .mu.T.

Abstract: A micromachined magnetometer is built from a rotatable micromachined structure on which is deposited a ferromagnetic material magnetized along an axis parallel to the substrate. A structure rotatable about the Z-axis can be used to detect external magnetic fields along the X-axis or the Y-axis, depending on the orientation of the magnetic moment of the ferromagnetic material. A structure rotatable about the X-axis or the Y-axis can be used to detect external magnetic fields along the Z-axis. By combining two or three of these structures, a dual-axis or three-axis magnetometer is obtained.

Abstract: A torque magnetometer employing integrated piezoresistive levers to measure magnetization of very small anisotropic samples. A sample holding platform is cantilevered from the substrate by parallel legs on which piezoresistors have been applied. A Wheatstone bridge, which includes the piezoresistors, is completely integrated on a magnetometer substrate. Specific output connections are made to the electrical conductors of the bridge in a manner to eliminate Hall effect error signals in an alternative embodiment.

Abstract: A high sensitivity torque and force cantilever magnetometer having a cantilever with isolated capacitance detection and nulling circuits which provides increased sensitivity and accuracy to measurements of a magnetic moment of a sample placed on the cantilever and exposed to a magnetic field. Magnetic detection is by electrical capacitance between a metallized plate and the cantilever. Alternatively, magnetic detection is by electrical resistance of a piezoactive circuit deposited on the surface of the cantilever. The cantilever can be used to measure both isotropic and anisotropic magnetism and is capable of simultaneously measuring the electrical conductivity of the sample using an integrated electrically isolated circuit. The cantilever is constructed of multiple layers of conducting and insulating materials to eliminate leakage current.

Abstract: A magnetic force microscope for measuring a magnetic field near a surface of a magnetic sample includes a cantilever having a ferromagnetic probe at one end thereof and receiving a magnetic force from the surface of the magnetic sample. An oscillation device is fixed to another end of the cantilever for oscillating the cantilever. A voltage application device applies an alternating voltage to the oscillation device. A deflection detecting device detects the oscillation of the cantilever. A magnetic field generating device supplies a magnetic field near the ferromagnetic probe. By this construction, it is possible to correct fluctuations in magnetic field measurements using probes with different magnetic characteristics and magnetic field detecting sensitivity, and to measure an absolute value of the detected magnetic field. Further, since the ferromagnetic probe can be magnetized, it is possible to increase the magnetic sensitivity of the ferromagnetic probe.

Abstract: A method for determining the anisotropy of the magnetic susceptibility of a sample includes determining the resonant frequency of the sample in substantially zero magnetic field, the resonant frequency being for flexure vibration in a selected plane of vibration. A second step is applying a uniform dc magnetic field to the sample, the magnetic field having a component in the selected plane of vibration. A third step is determining the resonant frequency of the sample in the presence of the applied magnetic field, the resonant frequency being for flexure vibration in the selected plane. The fourth step is determining the anisotropy of the magnetic susceptibility of the sample, based on the amplitude of the magnetic field component and on the above-determined resonant frequencies.

Abstract: A coil arrangement having a primary and two balanced secondaries is used to measure ac susceptibility and, using sample movement, also to perform absolute dc moment measurements. Since the same coil arrangement is used for both AC and DC measurements, the measurements can be made successively within a cryogenic chamber without removing the sample. This is a big advantage, because the changed conditions associated with removing and replacing a sample between measurements can cause confusing, uncorrelated results. A high speed voltmeter is used to perform the signal analysis for the moment measurement. The system can be configured to yield high resolution dc moment measurements to 25 ppm and sensitivities to better than 5.times.10.sup.-5 emu.

Abstract: The magnetic sensor of this invention is characterized by a magnet suspen on a torsion bar or wire and by a tunneling tip separated from one end of the magnet, a gap between the tip and the magnet that is small enough to support a tunneling current, an electrical source for imposing a constant biasing voltage across the gap, an electrical force to maintain the magnet and the tip sufficiently close so that a constant tunneling current is maintained therebetween, a feedback circuit to monitor current changes in the gap that result from rotation of the magnet due to changes in the surrounding magnetic field, and at least one recorder to record changes in the magnetic field.

Abstract: On the upper surface of a flexible substrate, four displacement electrodes are arranged. A fixed substrate is arranged thereabove, and fixed electrodes opposite to the displacement electrodes are respectively arranged on the fixed substrate. These displacement electrodes and the fixed electrodes form capacitance elements C1 to C4, respectively. A columnar working body is fixed on the lower surface of the flexible substrate. A bending is produced in the flexible substrate on the basis of an acceleration exerted thereon. As a result, capacitance values of the respective capacitance elements C1 to C4 vary. The capacitance values of the capacitance elements C1 to C4 are converted to respective voltage values V1 to V4. A component in the X-axis direction is obtained as Vx=(V1+V4)-(V2+V3), a component in the Y-axis direction is obtained as Vy=(V1+V2)-(V3+V4), and a component in the Z-axis direction is obtained as Vz=V1+V2+V+V4.

Abstract: A sensing coil arrangement including a pair of sensing coils connected in opposition is used to measure AC susceptibility and, using sample movement and a DC magnetization field source, also to sense signals for absolute DC moment measurements. Since the same sensing coil arrangement is used for both AC and DC measurements, the measurements can be made successively in situ without removing the sample from a sample space (e.g., within a cryogenic chamber). This is a big advantage, because the changed conditions associated with removing and replacing a sample between measurements can cause confusing, uncorrelated results. A high speed voltmeter is used to perform the signal analysis for the moment measurement. The system can be configured to yield high resolution DC moment measurements to 25 ppm and sensitivities to better than 5.times.10.sup.-5 emu.

Abstract: A powder capsule loading system and apparatus for preparing and loading a gelatin capsule with a powder product for testing of the product in a magnetometer. The system includes a gelatin capsule which is readily available, such as those used in the pharmaceutical industry, and a sample tool including a handle section and a cup section which includes an aperture sized to receive part of a capsule portion and holds the capsule portion therein by friction fit. Initially, a top portion of the capsule and a bottom portion of the capsule are each received and held on different sample tools. The capsule portions received within the sample tools are dipped into a sample container of powder product to fill the respective portions with the powder product, followed by assembly of the capsule. The assembled capsule containing a substantially predetermined amount of powder therein is then weighed.

Abstract: A force detector is comprised of resistance elements having a piezo resistance effect such that electric resistance varies due to mechanical deformation, and formed on a single crystal substrate (10), and a strain generative body (20) having a supporting portion (21) and a working portion (23), thus allowing the resistance elements to produce a mechanical deformation on the basis of a displacement with respect to the supporting portion of the working portion. This force detector can detect a force applied to the working portion as changes in resistance values of the resistance elements. The plane on which resistance elements are to be formed on the single crystal substrate is selected so that piezo resistance coefficients in two directions perpendicular to each other exhibit peak. When a weight body (30) is connected to the working portion, it is possible to detect an acceleration acting on the weight body.

Abstract: A magnetic and electric force sensing method uses a force responsive transducer made of a micromachined, solid state magnetic sensor consisting of a central silicon platform surrounded and supported by a thin silicon membrane. The silicon substrate is placed over an aluminum pad recessed into a well on a supporting glass substrate. The magnetic sensor responds to a static method of measuring force whereby the Earth's magnetic field or magnetic field or other origin acts as an attractive or repulsive force towards the magnetic material placed onto the silicon platform. The magnetic force mechanically displaces the silicon platform and diaphragm membrane which is transduced to an electrical signal where a change in capacitance is measured. Geometry of the silicon platform, diaphragm membrane and glass well depth are used to affect the linearity, sensitivity and range of measurements of the magnetic sensor.

Abstract: A detector of ferromagnetic materials having a permanent magnet floating in a contaier and restrained under the influence of a soft ferrite mass spaced below it to rotatable movement about a vertical axis centrally of the container. The magnet has a normal at rest position from which it is rotatable when a ferromagnetic material moves through its magnetic field. The magnet carries a curved mirror onto the concaved face of which a light beam is focused, and which beam in an at rest normal position of the magnet is reflected by the mirror onto a zero point of an observer's readout scale. When the magnet is caused to rotate from its at rest position by a ferromagnetic material moving through its magnetic field, the light beam is caused to move away from the zero point; and when the ferromagnetic material has moved out of the magnetic field, the magnet and light beam return to their normal positions but with some oscillation before doing so.

Abstract: In a magnetometer with an inhomogeneous magnetic field which timewise changes in its intensity periodically and acts upon the specimen to be measured, the latter being attached to the free end of a tongue (8) that can be oscillated and whose oscillations can be determined by piezo elements (12, 13), there occurs a compensation of the magnetic moment of the specimen with the aid of a compensating current loop (33). The current required for arresting the oscillations is a measure of the magnetic moment to be determined. An adaptation to the resonance frequency of the oscillating tongue (8) is effected through a frequency control cirucit (22, 28, 6), making it possible to measure large temperature ranges at great sensitivity and contingent on temperature.

Abstract: An earthquake predicting magnetometer having a compass assembly with a graduated dial and an adjustbly positionable magnet assembly having magnetic poles oriented opposite the direction markings on the compass dial. The device is oriented to the cardinal points using the compass. Then the magnet is adjusted in proximity to the compass assembly until the magnet counterbalances the magnetosphere of the earth. This leaves the compass needle facing east or west. When the magnetosphere of earth weakens prior to a major seismic event, the compass needle will point to the south on a graduated scale on the dial, indicating an imminent quake of large magnitude.

Abstract: 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.

Abstract: A device sensitive to a magnetic field (B) comprising a flap attached to a support by torsion hinges and a conductor. The conductor carries a current I and thus generates under the effect of a magnetic field a force which tends to cause the flap to turn about its hinge axis. The measurement of this rotation or of the compensation required to nullify the effect of the magnetic field (B) constitutes a measure of this magnetic field. Embodiments are disclosed having multi-turn conductors or ferromagnetic coatings instead of conductors on the flaps.

Abstract: An eddy current magnetic field effects measurement apparatus employs, a reference sensor located so that it measures an applied field and any environmental fields but does not measure eddy current effects. Then an estimate(s) of the applied field at the locus of a plurality of measurement sensors is constructed and stored. Next, a conductive object or material to be measured is placed in the applied field in the vicinity of the plurality of measurement sensors away from the reference sensor and measurements are made of the applied field, any environmental fields and any fields due to the effects of eddy currents induced into the conductive object or material. Finally, the aforementioned stored estimate(s) are used to compensate the applied field at the locus of the plurality of measurement sensors so that the eddy current magnetic field effects due to the placement of the conductive object or material can be observed on a keyboard/display or printed via a printer/plotter.

Abstract: A fine balancing three-coil type gradiometer, comprising a support member for the coils which consists of two elements, the first of which bears the central coil and one of the end coils, while the second supports the other coil and is arranged to controllably cause the micrometric axial displacement of the element itself with respect to the other one, in order to vary the distance between the planes of the coils and to achieve the desired balancing.

Abstract: Film related information is applied to a film container in the form of oriented macroscopic magnetic fields having strength sufficient to deflect a mechanical magnetic sensor. In a preferred embodiment of the invention, the metal end cap of a standard 35 mm film can is magnetized to encode film related information. The information is sensed in a simple mechanical camera by a sensing magnet mounted for movement in response to the orientation of the magnetic field directly above the end cap, and a trapping mechanism for trapping the sensing magnet and mechanically amplifying the information contained in the orientation of the sensing magnet. In an electronic camera, the orientation of the magnetic field is sensed by a pair of magneto-electric sensors oriented to sense orthogonal components of the magnetic field.

Abstract: A magnetometer which includes a pair of spaced apart optical fibers at least one of which comprises a cantilevered beam having a dipolar magnet thereon such that fluctuations of the magnetic H field will cause fluctuating mechanical torque on the magnet which will be applied to the cantilevered optical fiber to deflect same and occasion modulation of an optical signal transmitted between the two fibers.

Abstract: A device is disclosed which, in response to forces acting upon it, such as gravity, inertia, magnetic fields and the like, opens or closes electric circuits or otherwise generates signals which may be used to control predetermined functions.

Abstract: An optical null detector design achieves exceptional efficiency of light utilization with a minimum of components providing (1) extremely sharp null recognition, (2) superior long term stability, (3) extremely low power requirement, and (4) minimal size and weight as well as several other desirable properties.The device involves the use of an inherently directional light emitting pattern (DLEP) of optimized geometry, generating nearly all usable light and eliminating several components functionally necessary, though performance limiting in conventional devices. It is particularly suited, though not restricted, to measurement and control applications by means of feedback techniques when high resolution, large dynamic range, and space economy are required simultaneously with sustained effectiveness over long periods of time.

Abstract: A terrestrial magnetic responsive device having a float carrying magnetic north-seeking means and responsive not only to magnetic north, but also to local magnetic force fields, said device having a liquid evaporation and liquid movement control means.