Abstract: A refrigeration system includes a refrigeration circuit and a coolant circuit separate from the refrigeration circuit. The refrigerant circuit includes a gas cooler/condenser, a receiver, and an evaporator. The coolant circuit includes a heat exchanger configured to transfer heat from a refrigerant circulating within the refrigeration circuit into a coolant circulating within the coolant circuit, a heat sink configured to remove heat from the coolant circulating within the coolant circuit, and a magnetocaloric conditioning unit configured to transfer heat from the coolant within a first fluid conduit of the coolant circuit into the coolant within a second fluid conduit of the coolant circuit. The first fluid conduit connects an outlet of the heat exchanger to an inlet of the heat sink, whereas the second fluid conduit connects an outlet of the heat sink to an inlet of the heat exchanger.

Abstract: A nuclear medicine imaging device includes a plurality of detector heads (10) mounted to a movable gantry for rotation around an examination region (12). The detector heads (10) include a housing (28) which surrounds a radiation sensitive crystal (26) which converts received radiation events. A positioning mechanism on the gantry maintains a relationship between the detector heads (10) such that the housing for one detector head lies adjacent to and overlaps the housing for another detector head. During an imaging event, the gantry rotates the detector heads (10) about a region of interest (12) while radiation events are sampled. At a predetermined position relative to the area of interest, the overlapping of the detector heads is reversed.

Abstract: The configuration of a multi-head gamma camera requires coordination between tangential and radial motions so that the detectors maintain a desired orientation, either corner to corner or overlapping. Based on the radial and angular positions of the detectors, desired tangential positions are determined. The desired tangential positions are compared with the actual tangential positions, to generate position error signals. Tangential motion is initiated to reduce the position errors. If the required tangential motion exceeds the capability of the tangential drive or cannot be achieved, the radial motion is slowed or stopped.

Abstract: Method and apparatus for imaging of a subject. Radiation intensity data is transformed to a frequency domain, filtered, retransformed and then backprojected to allow an operator to examine a cross sectional image of the subject. Based upon this image, a filter function is adjusted and a second image is presented. Further adjustments can be made in the filter function to fine tune the image. The filter adjustments are all rapidly performed with the aid of a pointing device that can easily and intuitively allow the user to adjust the filter function characteristics.

Abstract: An isotope-ratio-monitoring gas chromatography-mass spectrometry apparatus and method are disclosed which provide for on-line analysis of isotope compositions with high precision. With the apparatus and method, samples are introduced in a hydrogen carrier gas into a gas chromatograph and resolved into discrete compounds. The discrete compounds are thereafter introduced to a selectively permeable membrane separator, empolying palladium, palladium alloy or other suitable material, to separate out the hydrogen carrier. A replacement carrier gas is simultaneously introduced to carry the chromatographic sample to a combustion reactor, water separator and isotope-ratio-monitoring mass spectrometer. The replacement carrier gas is introduced at a lower flowrate than the hydrogen carrier gas, thus permitting lower flowrates to be introduced to the mass spectrometer to improve its precision. Flowrates to the mass spectrometer are thus reduced without any loss or fractionation of the sample.

Abstract: A method and apparatus are described for the quantitative analysis of vaporizable compounds, and in particular of polycyclic aromatic hydrocarbons which may be induced to fluoresce. The sample to be analyzed is injected into a gas chromatography column and is eluted through a narrow orifice into a vacuum chamber. The free expansion of the eluted sample into the vacuum chamber creates a supersonic molecular beam in which the sample molecules are cooled to the extent that the excited vibrational and rotational levels are substantially depopulated. The cooled molecules, when induced to fluoresce by laser excitation, give greatly simplified spectra suitable for analytical purposes. The laser induced fluorimetry provides great selectivity, and the gas chromatograph provides quantitative transfer of the sample to the molecular beam.