Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Wafer. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

110) GaAs microwave FET

Abstract: A field effect transistor (FET) structure suitable for use at microwave frequencies is fabricated on a planar surface of a semi-insulating single crystal GaAs substrate which has been cut and polished to present the (110) surface. This orientation is selected because of its non-polar and other unique surface and interface properties. The (110) crystal axis is tilted from the normal of the planar surface in the direction to expose more of the (111) Ga face about 5° to facilitate molecular beam epitaxial (MBE) growth of smooth, defect-free thin films. An elongate gate electrode is formed along the bottom of an anisotropically etched trench having a pair of longitudinal sidewalls, one vertical and the other tilted outwardly. The trench is selectively oriented on the substrate to facilitate such anisotropic etching. Source and drain electrodes are respectively formed proximate the outwardly tilted and vertical trench sidewalls thereby forming a FET with a higher drain-to-gate breakdown voltage combined with lower parasitic resistance between the source and gate electrode. The invention has demonstrated potential for high speed digital circuits as well a microwave power FET applications.

Convergent light illuminated flow cell for liquid chromatography

Abstract: Single and dual beam flow cells for liquid chromatography that provide good detectability and linear response with small sample volumes. A cylindrical window surrounds the sample flow path to permit focusing convergent light rays through the center of the flow path and along optical paths of equal length through the cell. Optical stops limit the light passing through the cell to convergent rays incident to the window surface. A wide acceptance angle for the rays results in high light transmission and averages variations in light output along the light source. A dual beam flow cell utilizes a common exit for the sample and reference liquids. The flow cells are economically constructed for direct coupling to a chromatographic column by using a standard compression fitting union and can be used in a single wavelength or discrete wavelength detector, or in a spectrophotometer.

Achromatic magnetic beam deflection system

Abstract: A collimated beam of non-monoenergetic charged particles, such as electrons, is passed into a magnetic beam deflection system consisting of at least three uniform field, beam bending magnets spaced apart along the central orbital axis of the beam for magnetically bending the beam by a relatively large angle as of 270 DEG The uniform field beam bending magnets are dimensioned, shaped, and spaced apart along the orbital axis such that the collimated beam is imaged at the beam exit plane without incurring either spatial or angular dispersion nor producing a significant increase in the spot size of the beam Such a beam deflection system is particularly advantageous for use in an X-ray therapy machine