Varian Associates

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

Wafer transfer system

Abstract: A system for the automated handling and transfer of wafers individually and repetitively to and between processing stations and cassettes. A track-like conveyor engages a cassette holding a plurality of wafers in vertically facing alignment, to move same horizontally past a loading station of a processing chamber. A vertically moveable blade passes between the conveyor tracks and through the cassette to engage a wafer edgewise from below and move same upwardly to the processing chamber entrance. Vacuum means mounted to the door of the chamber entrance engages and holds the wafer during insertion into the chamber by closure of the door. Clip means are mounted within the periphery of an aperture of a vertical support plate just within the chamber entrance, to engage edgewise the wafer and support it within the plate aperture while in the processing chamber. The wafer is removed after processing by operating the foregoing apparatus in reverse order. The processing chamber may be a vacuum chamber, and minimal-volume load lock means therefor are advantageously provided by the system with the aid of a sealing member within the chamber compressible against the wafer support plate and chamber wall while the chamber door is open, to seal off the entrance area from the remainder of the chamber. The wafer support plate is moveable within the processing chamber to various wafer processing stations once the door is closed and the sealing member withdrawn.

Method of high mass resolution scanning of an ion trap mass spectrometer

Abstract: A method of using a quadrupole ion trap mass spectrometer for high resolution mass spectroscopy is disclosed High resolution of a mass spectrum of a desired species is achieved by first using a slow scanning rate and by first ridding the trap of unwanted ions Accurate mass calibration is achieved by using a reference compound of known mass and using a second supplemental AC dipole voltage to eject the reference ions at nearly the same time as the sample ions of interest are ejected from the trap This eliminates the need to scan the trap between the masses of the sample and reference ions Space charge in the trap is held constant, thereby eliminating a major source of mass axis instability, by using the results of one scan to control the ionization time during the next scan Preferably, during ionization a broadband supplemental dipole voltage is applied to the ion trap to rid it of unwanted ions During a portion of the ionization time the broadband signal is constructed to retain only sample ions in the ion trap, and during the remainder of the ionization time the broadband signal is constructed to retain both sample and reference ions in the ion trap By adjusting the relative lengths of the two portions of the ionization time the total space charge in the ion trap can be held constant notwithstanding variations in sample ion concentration

Planar magnetron sputtering device with combined circumferential and radial movement of magnetic fields

Abstract: A planar magnetron sputtering device has an extended flat circular target source in opposed spaced parallel relationship with a generally flat article to be coated, placed within an evacuated coating chamber. Crossed electric and magnetic fields in the chamber are established in order to set up a plasma adjacent the target. The magnetic field is provided by a magnetic assembly of permanent magnets on the non-vacuum side of the target. The magnetic assembly is smaller in diameter than the target, but is mounted to a means for moving the assembly laterally over the entire area of the target. This means for moving sweeps the magnetic assembly in an eccentric path generally centered on the target center, with the path being non-reentrant and precessing about the target center with time. In this manner, the path sweeps different areas on successive rotations about the center, and a given area of target is exposed to the magnetic field at many successively different orientations. Articles are therefore coated with significantly improved uniformity and step coverage, while utilization of target material is improved.

Compressional wave hyperthermia treating method and apparatus

Abstract: A wide bandwidth compressional wave transducer array obtains information concerning tissue of a subject being treated and supplies hyperthermia compressional wave treating energy to a treated region of the subject. The array transducers are pulsed on and off with an on duty cycle portion of less than one. An array of compressional wave imaging transducers is in the center of the array of compressional wave hyperthermia focused far field transducers used to analyze and treat. The power and duty cycle of the compressional wave hyperthermia focused far field are varied to control the energy incident on certain regions in a treated subject. The ultrasonic frequencies of hyperthermia beams derived from individual transducers are randomly angle modulated so the energy of adjacent far field focused beams overlaps to a greater extent than focused coherent beams.

Radiation therapy unit

Abstract: A radiation therapy unit with a beam of rays propagating from a focal point along a beam axis comprises a radiator head arranged on the beam axis with a double-focus multi-leaf collimator. The multi-leaf collimator exhibits a plurality of adjacently arranged diaphragm plates which in each case have two side faces, two front faces and an inside and an outside face. Each side face of each diaphragm plate forms a part of a surface area of a cone, all such cones having both a common cone axis which extends perpendicularly to the beam axis through the focal point, and a common cone point which coincides with the focal point. Means are provided for guiding the diaphragm plates so that each diaphragm plate performs a pure rotation about the cone axis during its displacement.