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: 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: According to the disclosed embodiment of the present invention, a system and method for detecting properties of a material are provided using a detection apparatus including a pair of reflecting surfaces, and directing electromagnetic radiation into the apparatus. The radiation is focused through a slab of material having a negative refractive index to a subwavelength spot. Electromagnetic radiation is detected to determine characteristics of a sample under test.

Abstract: A magnetometer includes a support. The support has two support surfaces that intersect each other along an intersection line. The intersection line is perpendicular to a reference axis of the support. The support surfaces are preferably perpendicular to each other and are each inclined at an angle of 45 degrees to the reference axis. A planar sensor/detector array is mounted on each support surface. Each array includes at least two pairs of magnetic field sensors and associated SQUID detectors arranged such that the magnetic field sensors lie on a line that is parallel to the intersection line of the two support surfaces. The magnetometer can be used adjacent to a surface to measure components and spatial variation of the magnetic field near the surface, with the measured components resolved into the magnetic field vectors parallel to and perpendicular to the surface.

Abstract: A biomagnetometer has a magnetic pickup coil positioned remotely from a detector and inductively coupled to the detector. The detector is preferably made from a low-temperature superconductor, while the pickup coil can be made of a high-temperature superconductor. The detector and pickup coil can therefore be placed into separate containers, with an inductive coupler between the containers. In one approach, the detector is maintained at liquid helium temperature, and the pickup coil and electrical connector are cooled by liquid nitrogen. The resulting biomagnetometer permits the container with the pickup coil to be moved and positioned easily, and to be changed readily between various configurations particularly suited for performing various functions.

Abstract: The operation of a biomagnetometer is verified using a tool containing a dipole source of known strength having a fixed, known position. The tool includes a hollow nonconducting and nonmagnetic sphere filled with an electrically conducting fluid, and at least one well-characterized dipole source within the fluid. The position of the dipole source relative to fixed locations on the surface of the sphere is established by X-ray measurement, and the the fixed surface locations and strength of the dipole source are measured with the biomagnetometer. The position and strength of the dipole source determined in this manner are compared with the known position and strength of the dipole source, to verify the operation of the biomagnetometer.

Abstract: A biomagnetometer has a magnetic pickup coil positioned remotely from the detector. The detector is made from a low-temperature superconductor, while the pickup coil and an electrical connector between the detector and the pickup coil are made of a high-temperature superconductor. Although the detector is maintained in a dewar at a sufficiently low temperature to reduce electronic noise, the pickup coil and the electrical connector need only be maintained at a temperature at which they are superconducting. In one approach, the detector is maintained at liquid helium temperature, and the pickup coil and electrical connector are cooled by liquid nitrogen. The resulting biomagnetometer permits the pickup coil to be moved and positioned easily, and to be changed readily.

Abstract: An information storage device includes a magnetic recording medium, preferably supported upon a rotating disk, an electromagnetic writing device that writes magnetic patterns into the recording medium, and a superconducting quantum interference device (SQUID) that reads the magnetic patterns in the recording medium, the writing device and the SQUID preferably being mounted upon a read/write head. The SQUID as operated in its superconducting state is a highly sensitive and directional detector of the magnetic state of the recording medium, permitting it to be spaced relatively distantly from the recording medium yet read the state of small areas of the medium. Use of high temperature superconductors in the SQUID permits practical construction of the information storage device. The read/write head may support a plurality of write devices, and an array of SQUIDs can be utilized so that little or no relative movement of the read/write head is required to read and write from all tracks of the disk.

Abstract: Apparatus for performing sensitive magnetic measurements using cryogenically cooled instrumentation, wherein the instrumentation is separated from the bubbles present in a cryogenic cooling fluid. In one embodiment, the magnetic measurement instrumentation is placed in a tail piece joined by heat conducting bolts to a dewar containing a cryogenic fluid, and heat from the instrumentation is conducted to the cryogenic fluid heat sink by metallic strips reaching to the bolts. The cryogenic fluid does not contact the instrumentation directly, resulting in a significantly reduced level of noise in the instrumentation. The tail piece may also be evacuated to avoid pressure and temperature variations that may cause noise and affect the magnetic instrumentation.

Abstract: A Malone-type final stage for utilization in a Stirling cycle cryogenic cooler apparatus includes a displacer slidable within a vessel. .sup.4 He, .sup.3 He, or a mixture thereof is made to flow in a pulsating unidirectional manner through a regenerator in the displacer by utilization of check valves in separate fluid channels. Stacked copper screen members extend through the channels and through a second static thermodynamic medium within the displacer to provide efficient lateral heat exchange and enable cooling to temperatures in the range of 3-4 K. Another embodiment utilizes sintered copper particles in the regenerator. Also described is a final stage that has a non-thermally conducting displacer having passages with check valves for directing fluid past a regenerator formed in the surrounding vessel.

Abstract: A heat transfer device is described that can be operated as a heat pump or refrigerator, which utilizes a working fluid that is continuously in a liquid state and which has a high temperature-coefficient of expansion near room temperature, to provide a compact and high efficiency heat transfer device for relatively small temperature differences as are encountered in heating or cooling rooms or the like. The heat transfer device includes a pair of heat exchangers that may be coupled respectively to the outdoor and indoor environments, a regenerator connecting the two heat exchangers, a displacer that can move the liquid working fluid through the heat exchangers via the regenerator, and a means for alternately increasing and decreasing the pressure of the working fluid. The liquid working fluid enables efficient heat transfer in a compact unit, and leads to an explosion-proof smooth and quiet machine characteristic of hydraulics.