Abstract: A C-arm diagnostic equipment is disclosed, which equipment provided counterbalanced variable distance between an image source and an image receptor; an increased range of orbital rotation of the C-arm accomplished by a novel arc-in-the arc structure, which structure is counterbalanced for effective control of the orbital rotation; a suspension means with a counterbalanced means for the C-arm to be used as a ceiling suspended C-arm diagnostic equipment, which suspension means are moveably mounted on ceiling rails laterally displaced from, and not extending over, a patient positioned on an examination table and are linearly displaceable along these rails in a direction generally parallel to the lengthwise axis of the examination table.
Abstract: A .gamma.-ray detector that comprises a dislocation-free single crystal. Typical crystals include silicon and germanium, for example. The crystal is surrounded by an active shield that functions as an anticoincidence counter and a .gamma.-ray detector is disposed adjacent the crystal in order to detect received -65 -rays. The .gamma.-ray detector comprises an imaging proportional counter, scintillation counter, or a .gamma.-ray detecting charge coupled device, for example. The .gamma.-ray detector of the present invention is based on the Bormann effect, which is the anomalous transmission of .gamma.-rays through dislocation free single crystals at the Bragg angle. For extended sources, data processing is provided to separate the directional and wavelength dependence of the intensity variation. The .gamma.-ray detector has angular resolution of at least one arc second and may have an effective aperture of several square meters.
Abstract: A controlled flow of X-ray attenuating gas such as helium is provided to an upper portion of a beam exposure chamber. A vent tube (21) extends from a lower portion of the chamber adjacent a mask to an exterior exit orifice (23) positioned at mask level to prevent ingress of air to the chamber and prevent mask membrane deflecton and change in the mask-to-silicon wafer substrate gap distance. The substrate (20) is positioned below the mask membrane and is surrounded by a mask-to-wafer zone into which is flowed a substrate fabrication process gas which is vented either by a gas flange (25) in spaced gapped relation to the mask holder and mask, or by a vent tube (46) extending from the zone to an orifice end (46a) approximate the level of the mask. There is then no pressure differential on the top and bottom surfaces of the mask membrane affecting the mask-to-wafer gap distance (8) during substrate fabrication operations.
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