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.

Means for avoiding locking in ring lasers

Abstract: Means are disclosed for frequency modulating opposing modes in a ring laser assembly whereby locking is minimized or eliminated. The use of three types of modulators comprising an acoustic generator, a light shutter and an electro-optic crystal are described. In each case, the modulators are driven in accordance with a time-varying signal provided by a signal generator.

Fluorescent composition, a process for synthesizing the fluorescent composition

Abstract: A fluorescent composition useful in thin-layer chromatography comprises an inert porous particle having a fluorescent material fixedly attached by covalent chemical bonding to the surface thereof. A process for synthesizing this fluorescent composition is disclosed. A method for detecting the radioactivity of a radioactive species using a cell packed with such a fluorescent composition is also disclosed.

Counterflow leak detector with high and low sensitivity operating modes

Abstract: A counterflow helium mass spectrometer leak detector in which a helium sample passes in a reverse direction through a diffusion pump (26) to a mass spectrometer (36) for measurement. The diffusion pump (26) includes a conventional foreline (24) and a second foreline (32) provided with an ejector stage (79). A test sample (8) is coupled from a test port (10) through a bypass valve (22) to the conventional foreline (24) in a high sensitivity mode and is coupled to the second foreline (32) in a low sensitivity mode. In the low sensitivity mode, the bypass valve (22) is closed. An apertured control plate (84) in the diffusion pump (26) controls the relative reverse rates of diffusion from each foreline (24, 32) to the diffusion pump inlet (38) by controlling the rates of vapor flow to annular pumping stages (75, 77) and to the ejector stage (79). The ejector stage (79) includes a nozzle (80) for directing a stream of vapor into the second foreline (32) so as to inhibit flow of helium into the diffusion pump (26) and establish a lower reverse diffusion rate at the second foreline (32). The disclosed configuration permits measurement of a large range of leak rates.

Leak detection cyclic pumping control

Abstract: MASS SPECTROMETER LEAK DETECTOR (OR VACUUM APPARATUS) GENERALLY CONTROLLED IN ITS PUMPING CYCLES BY SOLENOID OPERATED ROUGHING AND ISOLATION VALVES AND UTILIZING ROUGHING LINE SUCTION FOR EFFECTIVE OPERATION OF THE ROUGHING VALVE IN OPENING AND SEALING. THE ROUGHING VALVE IS ALSO USED FOR TEST PORT AIR RELEASE IN CONJUNCTION WITH SEALING OF THE ROUGHING VALVE PER SE. AUTOMATIC, PRESSURERESPONSIVE, CONTROL OF THE SYSTEM IS PROVIDED TO ALLOW COMPLETE CONTROL OF PUMP-DOWN, TEST AIR RELEASE AND STAND-BY PHASES OF A SINGLE CYCLE USING A SINGLE ELECTRICAL SWITCH.