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.

Reagent gas flow control for an ion trap mass spectrometer used in the chemical ionization mode

Abstract: A reagent gas flow control system for use with an ion trap mass spectrometer is shown. The reagent gas flows from a source (5) through a first gas flow restrictor (70) connected to the inputs of second (80) and third (90) gas flow restrictors. The output of the second restrictor (80) is connected to the ion trap (10) where reagent gas is used, and the output of the third restrictor (90) is connected to a vacuum pump (20), which may be the roughing pump used by the ion trap. At least one of the three restrictors is a variable restrictor. The configuration of the present invention allows the use of simple and inexpensive parts to provide exacting flow control.

High-peak-power gallium arsenide oscillators

Abstract: The Gunn effect appears to be the first semiconductor phenomenon capable of generating high peak power at microwave frequencies. This paper describes some preliminary experimental work in which gallium arsenide oscillators were made and operated in the range from 725 to 2000 Mc/s. Two device fabricating techniques and two circuit configurations have been found useful. Individual devices can be made to tune over a 25 percent range with a single capacitor adjustment. Voltage tuning of a few percent is generally observed. The highest peak power observed so far is 205 watts at 1540 Mc/s, obtained from two GaAs wafers operating in parallel. A large number of single devices have worked at power levels between 40 and 100 watts, and efficiencies from 3 to 9 percent. The phenomenon shows considerable promise for moderate power pulsed microwave oscillators. Predictable devices and useful design techniques will be delayed until the reproducibility and temperature variations of the raw material are brought under control.

The relative merits of atomic frequency standards

Abstract: The relative merits of atomic frequency standards based upon resonances in hydrogen, rubidium, or cesium depend upon the particular application and the specific requirement for each of several performance factors combined with physical characteristics. While the properties of an ideal atomic frequency standard may be established, practical instruments depart from the ideal as the result of compromises in the apparatus design and construction. The resonance line sharpness is an important factor which is dependent upon the apparatus; however, others my have a greater influence upon the essential characteristics. These include instrumental offsets due to atomic collisions with neighboring atoms or walls and magnetic fields. The intensity of the resonance signal is also essential in the determination of merit. These factors are discussed in relationship to hydrogen maser rubidium gas cell and cesium beam atomic frequency standards and the merits of each are compared. The possible merits of frequency standards based upon thallium beams are also discussed; however, a lack of extensive operating experience limits the knowledge in this case.

Dual filament ion source

Abstract: An electron bombardment ion source of the Freeman type incorporates an electrode having multiple segments which are electrically connected in parallel to provide increased surface area for constant cross section.