Varian Associates, Inc.

Other

James T Arnold

Weston A Anderson

Gordon R Lavering

Charles B Cooper, Iii

Andrew T Zander

Elbert S Lile

Jack J Duffield

A gas flow distribution system accumulates a sample from a sample bearing carrier gas in a micro-accumulator, delivers it using a carrier gas to a gas chromatography column, and supplies a carrier gas to the gas chromatography column to facilitate separation of the sample into sample components and transport the sample components to a mass spectrometer for trace vapor detection and analysis or testing in real time. The system is made of inert components and configured to have low dead volume for improved performance and accuracy of detection. External valves are employed for easy management and balance of the flow in the system to minimize operation time and facilitate continuous accumulation, delivery, and testing of the sample. The delivery of the sample to the gas chromatography column using an electrically heated cold trap as the micro-accumulator can be performed extremely fast. By further combining the sample accumulation phase and the sample testing phase, real time operation of trace vapor detection is achieved. Because the step of delivering the sample to the gas chromatography column is performed quickly, the accumulation of the sample can resume quickly and is nearly continuous for improved efficiency.

Real-time gas-chromatography mass-spectrometry trace vapor detection

An X-ray tube rotating anode is cooled with a liquid metal functioning as a recirculated heat exchange fluid and/or a metal film in a gap between the anode and a stationary structure. The liquid metal is confined to the gap by (a) a labyrinth having a coating that is not wetted by the liquid, (b) a magnetic structure, or (c) a wick. The liquid metal recirculated through the anode is cooled in a heat exchanger located either outside the tube or in the tube so it is surrounded by the anode. The heat exchanger in the tube includes a mass of metal in thermal contact with the recirculating liquid metal and including numerous passages for a cooling fluid, e.g. water. A high thermal conductivity path is provided between an anode region bombarded by electrons and a central region of the tube where heat is extracted. In one embodiment the high thermal conductivity is achieved by stacked pyrolytic structures having crystalline axes arranged so there is high heat conductivity radially of the region and lower thermal heat conductivity normal to the high heat conductivity direction.

X-ray tube having rotary anode cooled with high thermal conductivity

A spark sampling microparticle generator device and method providing means to first ionize a gap and then to switch a stabilized and controllable current into and out of said ionized gap to provide extremely high, selectable current density in a sample material in said gap with very fast rise and fall times to ablate said material to form microparticles. A plurality of identical modular circuits containing high frequency power transistors are selectably switchably connected in parallel simultaneously to the gap to achieve current densities which are higher than achievable with a single transistor, thereby obtaining the benefits of the high frequency response without being limited by the current limitations of the available transistors.

Spark sampling microparticle generator and method

A small sample of material is introduced into a vacuum to be analyzed, by ionization of atoms or molecular fragments of the sample using an electron or photon beam. The ionized species are trapped in a structure that defines electric fields or a combination of electric and magnetic fields in such a way that their motions are confined to the interior of the trap and that their motions within the trap are characterized by unique and discrete frequencies of oscillation dependent on the mass-to-charge ratio of the individual species. In order to provide for the detection of the frequencies of the motions, additional electrical signals are applied to the trapping structure so as to cause the motions to take place with a considerable degree of coherence. Alternatively, the coherence may be caused by creation of the ions during a very short pulse of the electron or photon beam at a position within the trapping structure but displaced from a positon of equilibrium. An electrical response to the individual motions of the ions, taking place at discrete frequencies related to their mass-to-charge ratios, frequency analyzed to determine the mass-to-charge ratios of the ions contribute to that electrical response, thereby indicating the types of ions present and their respective quantities.

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Sunnyvale, CA, United States of America

James T Arnold