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.

Apparatus and method for multiple ring sputtering from a single target

Abstract: A source for sputtering from concentric rings (15) on the surface of a single target is shown. The source comprises a rotatable closed-loop magnet (21) having a plurality of curved sections of different average radius interconnected by an equal number of radial sections. In the preferred embodiment the curved sections each have a shape which results in a predetermined erosion profile in the associated concentric ring (15) of the sputter target (17). The relative rate of sputtering from each of the rings (15) may be controlled by adjusting the relative lengths of the curved portions of the closed-loop magnet (21).

Method for suppression of acoustic ringing in NMR measurements

Abstract: Compensation rather than direct suppression removes the effects of acoustic ringing as encountered in pulsed nuclear magnetic resonance experiments. Single and double spin-echo excitation, combined with several alternative schemes for phase cycling both transmitter and receiver, is one type of compensatory technique. Another technique consists of acquiring free induction decay signals in pairs, with the second preceded by an inversion pulse a short time prior to the normal excitation pulse, and with the second acquisition acquired subtractively, assuring phase coherence of the signals and phase opposition and hence cancellation of the acoustic ringing. Phase cycling of the inversion pulse may also be employed in the latter technique to suppress acoustic ringing stimulated by the inversion pulse.

Method of space charge control for improved ion isolation in an ion trap mass spectrometer by dynamically adaptive sampling

Abstract: A method of using a quadrupole ion trap mass spectrometer for high resolution mass spectroscopy is disclosed. In the preferred embodiment, the space charge in the ion trap is controlled to high accuracy. This is done by using a prescan of the trap before each analytical scan, where the ionization parameters used in the prescan are not fixed, but rather are based on the previous analytical scan. The method is especially useful in connection with performance of high resolution MS/MS experiments of the type described in the inventor's prior U.S. Pat. No. 5,198,665.