Sector-field Spectrometer Research Articles

Emergence and impact of alternative sources and mass analyzers in plasma source mass spectrometry

Inductively coupled plasma mass spectrometry (ICPMS) has become an invaluable tool for the measurement of elemental concentrations in samples of all kinds. However, the ICP was by far not the first source employed for elemental mass spectrometry, and arguments can be made that it is not the best, especially in specific situations. Chemical flames, arcs, sparks, microwave plasmas, glow discharges, electrospray sources, thermal-ionization sources, and novel atmospheric-pressure plasmas have all been explored and many, such as the thermal-ionization source, occupy a niche in the analytical arsenal that is unlikely to be occupied by an ICP of the present form. Similarly, quadrupole mass filters and sector-field spectrometers that are now the most commonly used are not the only ones that have been coupled with plasma sources for elemental determinations. Others, such as Fourier-transform mass spectrometers, ion traps, time-of-flight mass spectrometers, and multi-channel detector systems have all been joined with ICPs and other sources to yield improved capabilities in targeted applications. In this manuscript, these alternative sources and mass analyzers will be examined; greatest emphasis will be placed on mass analyzers, for brevity. This historical walk through instrumental developments will be a somewhat subjective one, taken from the author's viewpoint and including a number of personal experiences and those involving his research group. It will be shown that exciting opportunities exist for even greater capabilities from future instrumentation for plasma source mass spectrometry.

Untersuchung der Elektronenempfindlichkeit von Si-oberflächensperrschichtzählern mit Hilfe eines magnetischen Sektorfeldspektrometers: 1. Das Sektorfeldspektrometer

This first part of the paper describes the calculation and design of a symmetric, double focusing 75° sector field spectrometer which is used for response measurements of solid state detectors given in part 2. The design feature was derived from the use as a versatile laboratory instrument for generating a monochromatic parallel beam of electrons of energies up to 3 MeV. The specific data of the instrument are: Radius of curvature: ϱ = 6.62 cm , Distance effective-field-boundary to radioactive source: l = 17.25 cm , Resolution: Δp/p = 1.5%, Solid angle: Ω = 0.1%, Pole-piece gap: k = 2.0 cm .

Finite solid angle correction factors in directional correlation measurements with beta-ray spectrometers

Correction factors have been calculated for the attenuation of directional correlation due to finite solid angle of lens-spectrometers and sector field spectrometers. The factors have been tabulated for angles from 90° to 180° and for entrance diaphragms of different size. The P 2 and P 4 Legendre polynomials are also given for these angles in order to facilitate possible interpolations.