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.

Reduction of the effective magnetic susceptibility of superconducting materials in nuclear magnetic resonance (nmr) probes

Abstract: A method and apparatus which utilizes the hysteritic behavior of type II superconductors is provided for reducing the effective magnetic susceptibility of such high temperature superconducting materials being used close to the sample region in nuclear magnetic resonance system probes by providing decaying AC changes in the magnetic field parallel to said superconductive material. The method is particularly applicable to receiver coils reducing the effective magnetic susceptibility of superconducting receiver coils enables the improved sensitivity they inherently provide to be realized without loss of resolution resulting from line broadening caused by susceptibility discontinuities of materials near the sample region of the probe.

Design concepts for a high-impedance narrow-band 42 GHz power TWT using a fundamental/forward ladder-based circuit

Abstract: A low-cost, narrowband, millimeter wave space communications TWT design was studied. Cold test interaction structure scale models were investigated and analyses were undertaken to predict the electrical and thermal response of the hypothetical 200 W TWT at 42 GHz and 21 kV beam voltage. An intentionally narrow instantaneous bandwidth (1%, with the possibility of electronic tuning of the center frequency over several percent) was sought with a highly dispersive, high impedance "forward wave' interaction structure based on a ladder (for economy in fabrication) and nonspace harmonic interaction, for a high gain rate and a short, economically focused tube. The "TunneLadder' interaction structure devised combines ladder properties with accommodation for a pencil beam. Except for the impedance and bandwidth, there is much in common with the millimeter wave helix TWTs which provided the ideal of diamond support rods. The benefits of these are enhanced in the TunneLadder case because of spatial separation of beam interception and RF current heating.

Spatially selective nuclear magnetic resonance pulse sequences

Abstract: Increased spatial sensitivity (Fig. 4) or spatial tolerance (Fig. 1) in selectively manipulated NMR sample analysis excited from a spatially inhomogeneous RF field using pulse sequences which operate to exclude all spins deviating from a selected initial orientation (Figs. 4 and 5) or to inclusively extend the applicable flip angles over a range of initial spin orientation (Fig. 1)

O-ring with integral stem sealing means and butterfly valve using same

Abstract: 1,242,637. Valves. VARIAN ASSOCIATES. 3 Feb., 1969 [19 Feb., 1968], No. 5759/69. Heading F2V. In a butterfly valve 1, proper sealing in all states of the valve between the valve shaft 5, valve member 7 and valve housing bore 3, is achieved by locating a one-piece sealing ring 13 within a peripheral groove 11 formed in valve member 7, the ring having integral radially inwardly directed sleeve portions 16 which are located in appropriate recesses 12 formed in the valve member and serve to embrace the shaft 5, and furthermore, having annular portions 14 which serve to ensure sealing between the shaft and the shaft bores 4 and 4 1 . An adjustable movement-limiting screw 24 is provided on one of the faces of the valve member.

X-Y Work table

Abstract: Apparatus comprising a work table movable along orthogonal axes, and optical means, including orthogonal mirrors movable with the table, for sensing the positions of the table along the axes, featuring an improvement wherein the table comprises a solid block of metal, means are provided to secure a workpiece to move with the block, and two orthogonal external surfaces of the block are polished to provide the mirrors.