A Digital Mass Spectrometer

Authors:
  • GCG. L. Cumming
    G. L. Cumming
  • MBM. D. Burke
    M. D. Burke
  • FTF. Tsong
    F. Tsong
  • HMH. McCullough
    H. McCullough
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Abstract
A mass spectrometer control and recording system has been built which utilizes synchronous incremental stepping of the magnet current during the scanning of the mass spectrum with time-locked digitizing of the output, producing successive scans as similar time series and preserving the frequency spectral content of each scan. The digital output is recorded on magnetic tape and processed later on a computer. A new method of fitting polynomials to the reduced peak heights is described, which yields a measuring precision of about 0.06% at one standard deviation on 10–20 scans of the spectrum.Some studies of fractionation are described which illustrate the large errors which may occur from this effect.