Abstract: A method and device for purifying a process gas mixture, such as a cryogen gas, in which impurity components of the mixture are removed by de-sublimation via cryo-condensation. The gas mixture is cooled to a temperature well below the condensation temperature of the impurities, by direct exchange of the gas mixture with a cooling source disposed in a first region of the device. The de-sublimated or frozen impurities collect about the cooling region surfaces, and ultimately transferred to a portion of the device defining an impurities storage region. The output-purified gas is transferred from the impurities storage region, is optionally passed through a first micrometer sized filter, through a counter-flow heat exchanger, and ultimately up to an output port at room temperature. A method of purging the collected impurities and regenerating the device is also disclosed.

Abstract: A cryocooler-based gas scrubber, or cryocooler-based gas purifier, utilizes the cooling power of a cryocooler to cool and condense cryogen gas forming coalesced impurities which are then filtered through a filter matrix, such as for example a fiberglass filter matrix. The scrubber may further comprise a counter-flow heat exchanger for warming the purified gas prior to dispensing at an outlet for storage or consumption.

Abstract: A modular architecture for helium compressors is described. In the modular architecture, oil is cooled independently from gas. In one aspect, the oil is cooled subsequent to the gas with a series of water-cooled heat exchangers. In another aspect, the oil is cooled using a water-cooled heat exchanger coupled to a radiator, and the gas is independently cooled using a refrigerant-cooled heat exchanger coupled to a condensing unit.

Abstract: A method and device for purifying a process gas mixture, such as a cryogen gas, in which impurity components of the mixture are removed by de-sublimation via cryo-condensation. The gas mixture is cooled to a temperature well below the condensation temperature of the impurities, by direct exchange of the gas mixture with a cooling source disposed in a first region of the device. The de-sublimated or frozen impurities collect about the cooling region surfaces, and ultimately transferred to a portion of the device defining an impurities storage region. The output-purified gas is transferred from the impurities storage region, is optionally passed through a first micrometer sized filter, through a counter-flow heat exchanger, and ultimately up to an output port at room temperature. A method of purging the collected impurities and regenerating the device is also disclosed.

Abstract: An ultrasensitive ratiometric capacitance dilatometer and related methods are described. The dilatometer provides a capacitance measurement based on a ratiometric capacitance, or the capacitance ratio measured between two or more parallel plate capacitors of the dilatometer. In this regard, an absolute capacity bridge is not required, and even more advantageously, the effects of adsorbed gas are greatly reduced compared to conventional dilatometers. The ratiometric capacitance dilatometer provides a symmetrical configuration, which reduces the effects of temperature gradients. Moreover, certain embodiments provide a “v-groove design”, wherein a first parallel plate capacitor forms an angle with a second parallel plate capacitor of the dilatometer along a key centerline of the dilatometer cell, which improves manufacturability due to simpler grinding, metalizing and assembly.

Abstract: An ultrasensitive ratiometric capacitance dilatometer and related methods are described. The dilatometer provides a capacitance measurement based on a ratiometric capacitance, or the capacitance ratio measured between two or more parallel plate capacitors of the dilatometer. In this regard, an absolute capacity bridge is not required, and even more advantageously, the effects of adsorbed gas are greatly reduced compared to conventional dilatometers. The ratiometric capacitance dilatometer provides a symmetrical configuration, which reduces the effects of temperature gradients. Moreover, certain embodiments provide a “v-groove design”, wherein a first parallel plate capacitor forms an angle with a second parallel plate capacitor of the dilatometer along a key centerline of the dilatometer cell, which improves manufacturability due to simpler grinding, metalizing and assembly.

Abstract: A cryocooler-based gas scrubber, or cryocooler-based gas purifier, utilizes the cooling power of a cryocooler to cool and condense cryogen gas forming coalesced impurities which are then filtered through a filter matrix, such as for example a fiberglass filter matrix. The scrubber may further comprise a counter-flow heat exchanger for warming the purified gas prior to dispensing at an outlet for storage or consumption.

Abstract: A modular architecture for helium compressors is described.

Abstract: A multi-well helium Dewar is provided for recirculating coolant about a cryostat probe; the Dewar includes a first well containing a first coolant reservoir, and a second well containing a second coolant reservoir. A fluid connection extends between the first and second coolant reservoirs. A low impedance conduit further connects a top end of the second well to the first well. In this regard, the Dewar at least partially contains a cryocooler within the first well and a cryostat probe within the second well. Vibrational noise is reduced by the incorporation of soft mounting components for connecting various features. A thermal shield of the Dewar can be thermally connected to isolated components for additional cooling power and increased efficiency during initialization. A second fluid connection may include a valve attached to a counter-flow heat exchanger for efficiently re-condensing excess gas within the Dewar.

Abstract: A valve assembly is provided for dynamically controlling the inlet and exhaust of refrigeration gas between a cryocooler coldhead and a remote compressor. The valve assembly is optimized to minimize friction, power consumption, and wear while providing complete flexibility as to the timing, duration, and amplitude of its inlet and exhaust actions. The valve assembly comprises two separate open-close sections for the inlet and exhaust functions. These are mounted along a single rod, the position of which is controlled by a linear motor. The two sections are configured so that only one is open at each the rod's travel and neither is open at the midpoint of travel. A microprocessor and appropriate drive circuits precisely control the position of the rod as a function of time, and of displacer position when used with a Gifford-McMahon (G-M) cooler.

Abstract: An apparatus is provided for quantitatively measuring samples whose amount or other characteristic quality is to be determined. The samples are arranged in a predefined pattern and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one substantially flat sensor such as sensing coils fabricated in a gradiometer configuration.

Abstract: An apparatus is provided for quantitatively measuring combinations of magnetic particles combined with analytes whose amount or other characteristic quality is to be determined. The magnetic particles are complexed with the analytes to be determined and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: An apparatus is provided for quantitatively determining amounts and identities of substances whithin patterns of magnetic particles, such as within lateral flow membranes, microfludic systems, and the like. Magnetic particles are complexed with substances to be determined and are excited in an oscillating magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: An apparatus is provided for quantitatively measuring groups of magnetic particles. The particles are complexed with substances to be determined and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: An apparatus is provided for quantitatively measuring combinations of magnetic particles combined with analytes whose amount or other characteristic quality is to be determined. The magnetic particles are complexed with the analytes to be determined and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: An apparatus is provided for quantitatively measuring groups of magnetic particles. The particles are complexed with substances to be determined and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: An apparatus is provided for quantitatively measuring groups of magnetic particles. The particles are complexed with substances to be determined and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: Apparatus for quantitatively measuring groups of magnetic particles. The particles are complexed with substances to be determined and are excited in a magnetic field. The magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: Apparatus for quantitatively measuring groups of magnetic particle. The particles are complexed with substances to be determined and are excited in a magnetic field. The magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

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.