Abstract: A plasma mass spectrometer has a plasma ion source (1). The source has associated with it an electromagnetic excitation means (2), which may be one or more induction coils. The excitation means is powered by an RF generator (3). Ions are sampled from the plasma ion source through an interface (15) into a vacuum chamber (16). The stream of ions is directed by an ion optics element (4) through a mass analyser (5) to an ion detector (6). The excitation means may include means (7) for altering the axial component of the electromagnetic field sustaining the plasma. Alternatively or additionally, the spectrometer may include signal detecting means (11,17) to provide feedback enabling optimisation of parameters.

Abstract: In inductively coupled plasma spectroscopy, the use of an induction coil assembly comprising at least two helical coils which are arranged in overlapping relationship. In one practical form, the overlap is achieved by interlacing of the coils so that at least one turn of one coil is interposed between two adjacent turns of the other coil. For that purpose, the two coils will ideally be of the same diameter and will be coaxial. A tubular part of a plasma torch is contained within the space surrounded by the coil assembly, and a RF energy source is connected to an end of each coil. The other ends of the coils may be connected to ground.