Ion current surface for a double focusing mass spectrometer of reversed geometry

Ion currents obtained for fragmentations in a mass spectrometer of reversed geometry have been represented as three-dimensional surfaces, which are termed ‘ion current surfaces’. In addition to ion current, useful dimensions of the ion current surfaces are a parameter ln(|ρ|) where ρ = (V₀/V)(E/E₀) and a parameter ln(|m*|) where m* = (V₀/V)m_B. Each ion reaction occurring in the source and flight path gives rise to a pattern of peaks and ridges on the surface. If the major features of the surface corresponding to each ion reaction are projected onto the zero ion current plane, they are disposed in a characteristic trapezoidal pattern. All simple and linked modes of scanning correspond to cross-sections of the surfaces, and representing the scanning modes in this light facilitates the identification of ‘cross-talk’.