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.

Dual channel signal processor using weighted integration of log-ratios and ion beam position sensor utilizing the signal processor

Abstract: A signal processor receives random input signals from a pair of sensors such as beam sensing electrodes, antennas, microphones or optical position sensors. An estimation equation implemented by the signal processor uses weighted integration of log ratios where the weighting is adaptive and depends upon the values of signal samples being processed. The signal processor uses digital signal processing to provide an estimate of the desired parameter. Nonlinear functions such as hyperbolic tangent and logarithm are contained in programmable read only memories in order to obtain high speed operation. When the signal processor is used in conjunction with channel switching, errors due to channel mismatch are completely eliminated. In a preferred embodiment, the sensors are beam sensing electrodes and the signal processor is used for estimating the position of a scanned ion beam in a ion implantation system.

Treating workpieces with beams

Abstract: A dose monitoring system for ion implantation devices which employ a moving support element such as a spinning support disk which is moved through an ion beam by a scan motion uses a pick-up plate on the spinning support disk to measure incremental dose and to generate a signal which is used to vary the scan motion of the spinning support disk in order to control dosage.

Evaluation of an ultrasonic nebulizer-membrane separation interface (USN-MEMSEP) with ICP-AES for the determination of trace elements by solvent extraction

Abstract: The introduction of volatile organic solvents and metal organic complexes into an inductively coupled plasma (ICP) is problematic due to overloading and pyrolysis effects. These include carbon built up in the torch and spectral interferences. As a consequence, solvent extraction as a method for preconcentrating trace metals for the determination by ICP has been limited. In this report a commercial ultrasonic nebulizer-membrane separation interface (USN-MEMSEP) for the direct introduction and separation of organic solvents using ICP atomic emission spectrometry (AES) and a sequential spectrometer has been evaluated for solvent extraction of chelated trace metals. The ability of the MEMSEP to separate volatile organic flows from metal aerosols has been demonstrated by determining the recoveries of several transition metals in an oil-based methyl-isobutyl ketone (MIBK) standard relative to an aqueous solution. However, low recoveries of several metal chelates have been found evidently due to the volatilization of the organic metal species at the boiling point of MIBK (160° C). Moreover, the multielement capability and limits of detection have been limited due to sequential atomic emission detection. Advantages of the technique include enhanced limits of detection (LODs) and reduced plasma and spectral interferences.