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.

A C-band gyro-TWT

Abstract: The operating characteristics of a gyrotron travellng wave tube (gyro-TWT) operating at C-band are reported. Detailed testing showed that at higher beam voltage and current and with a magnetic field profile increasing in magnitude toward the rf output window, the output power could be increased from 50 kW at 16.6% efficiency to 128 kW at 24% efficiency. The maximum efficiency measured was 26% at 120 kW. Experimental data on small and large signal gain, bandwidth, output power and efficiency will be presented. The gyro-TWT employs a magnetron injection gun to provide an electron beam with a prescribed perpendicular to parellel velocity ratio. Inherent in this type of electron gun is a finite spread in the two velocity components. An alternate method for producing an electron beam with very low spread in the velocity components is presented. Design data will be presented.

Assymetric cylinder electron capture detector

Abstract: An asymmetric cylinder electron capture detector comprises an electrode configured to define an ionization volume, a source of ionizing radiation disposed within the ionization volume, a collector electrode, with a gas flowing past the collector electrode into the ionization volume. The electron current to the collector electrode provides an indication of the presence of electronegative constituents in the gas passing into the ionization volume. In order to provide wide dynamic range, the face of the collector electrode is disposed as close as possible to the electrode defining the ionization volume, yet is located so as to minimize field-free background current. The collector electrode and the electrode defining the ionization volume are each of cylindrical configuration, and are coaxially aligned but are spaced apart with respect to each other. The two electrodes are mechanically connected via an intermediately disposed cylindrical insulator cylinder. The collector electrode is received in one end of the insulator cylinder, and the electrode defining the ionization volume is received within the other end of the insulator cylinder. The collector electrode has an elongate portion extending into the interior of the insulator cylinder, but spaced apart from the inner surface of the insulator cylinder. This configuration provides a long insulative path to prevent electrical leakage between the electrodes. A transverse gas exit port is provided in that portion of the collector electrode within the insulator cylinder in order to impart turbulence to the flow of gas through the insulator cylinder into the ionization volume.

Thermionic detector for gas chromatography

Abstract: 1,160,828. Gas analysis. VARIAN ASSOCIATES. June 1, 1967 [June 6, 1966], No.25410/67. Heading G1N. Effluent gas from a chromatographic column is mixed with hydrogen and the mixture is burnt in air at the upper surface of a homogeneous ion source block 29 so that the heat of the resulting flame can ionize material from the surface of the ion source to introduce charged particles into the space between electrodes 32, 34. The ion source block 29 preferably consists of a salt of an alkali, or alkaline earth, metal (examples given) containing 2 to 5% refractory binder, e.g. silica. In the presence of an organic constituent containing phosphorus or a halogen, the rate of ionization of material from the ion source block is increased. The relative sensitivity to phosphorus and halogens depends on the air and hydrogen input flow rates so that by proper adjustment of the flow rates, the detector can be made virtually insensitive to halogens, responding only to phosphorus. A bucking voltage is used to oppose the effect of ions produced in the absence of phosphorus or a halogen. Electrode 32 also serves as an ignition coil.

Gyromagnetic resonance spectrometer having selectable internal and external resonantcontrol groups

Abstract: 1,170, 523. Gyromagnetic spectrometers. VARIAN ASSOCIATES. Feb, 13, 1967 [Feb. 21, 1966], No.6825/67. Heading G1N. In a gyromagnetic side-band resonance spectrometer, in which the applied R.F. or D.C. fields are audio frequency modulated, the resonance condition of the spectrometer is controlled using either an "internal" or "external" reference sample, both being provided. By "internal" is meant a reference sample situated in the same field as the sample under investigation and by "external" a reference sample situated in a different field. The internal reference sample may be intermixed with the sample or may be contained in one chamber of a vial 3, Fig. 2 (not shown), having coaxial chambers or an axial or transverse partition providing the two chambers. It is preferably formed of a substance, e.g. the protons in tetramethylsilane, having a narrow resonance line. The external control sample (13, Fig. 2 not shown), is placed to one side of the internal sample and is surrounded by coaxial coils (14), whose axis is parallel to the D.C. field direction, by which this field may be locally altered. It is preferably composed of the protons in water, having a wide resonance line. In operation, the output of either the internal or external reference sample is fed to an oscilloscope 57, Fig. 3 on which it can be seen whether it is in resonance or not, and to a phase detector 54, the output of which, representative of the dispersion mode resonance signal, is fed to a control 55 by which the D.C. field is regulated to maintain the resonance condition of the spectrometer. Initially the current in the coils (14) is adjusted until the frequencies of resonance of the two reference samples coincide so that, in switching between the two reference samples, the control of the D.C. field is not altered. Thus while the internal reference sample is being removed with the sample under investigation and another sample put in its place, the D.C. field is automatically controlled by the external reference sample, the more exact control provided by the internal reference sample taking effect as soon as the system is switched over without the need to relocate its resonance line.

Gridded convergent flow electron gun for linear beam tubes

Abstract: The electron gun includes a spherically concave cathode emitter with a pair of axially spaced spherically concave focus and control grids closely spaced overlaying the cathode emitter for controlling the beam current. The grids are supported from a common thermally conductive tubular grid support structure via the intermediary of first and second annular members one of which is a thermally conductive insulator. One or more of the grids are serrated about their peripheries to define a plurality of radially directed fingers bonded to the end of a respective annular grid support member. In an alternative embodiment, the end of the annular grid support member, as bonded to the serrated grid, is castellated to accommodate differences in thermal expansion between the grid and the annular grid support member.