TRANSIT-TIME METHOD FOR METERING CHARGE AND MASS COMPOSITION OF PLASMA IONS Russian patent published in 2008 - IPC H01J49/40 

FIELD: charged-particle spectrometry; metering plasma charge and mass composition.

SUBSTANCE: proposed method involves immersion of drift tube into plasma followed by acceleration of ions by applying negative-polarity voltage pulse across drift tube, pulse length being shorter than its transit time within drift tube carrying analyzed plasma accelerated ions at highest Z/M_i ratio, where Z is degree of ion charge in plasma; M_i is ion mass; this is followed by separating ions with respect to their mass, charge, and energy as they are conveyed through equipotential space of drift tube, as well as measurement of ion current pulse at drift tube outlet; then second measurement similar to first one is made but for different length of negative-polarity voltage pulse supplied to drift tube; charge and mass composition of plasma ions is evaluated by subtracting results of measuring ion current pulses at outlet of drift tube obtained at different lengths of negative-polarity voltage pulses.

EFFECT: enhanced resolving power and precision of evaluating charge and mass composition of plasma ions.

1 cl, 3 dwg