High resolution imaging of barium ions and atoms near the sampling cone of an inductively coupled plasma mass spectrometer

Modeling the gas flow upstream and in the sampling nozzle of the inductively coupled plasma mass spectrometer via the Direct Simulation Monte Carlo algorithm

“…This effect is also seen in the behavior of the temperature. This means that when significant changes are seen 2-4 mm upstream from the sampling cone, as has been reported [25][26][27] they must be due to large-scale transport effects such as the diffusion of thermal profiles from the torch and electron temperature effects, not dynamic effects due to neutral gas flow into the sampling cone.…”

“…The dynamics of this flow was first described theoretically by Douglas and French [1] and many authors since have referred to their work [2][3][4][5][6][7][8][9][10][11][12][13]. The fluid dynamics of this process are rather complicated, involving a transition to supersonic flow in the nozzle and an expansion beyond the nozzle to densities low enough to invalidate the Navier-Stokes description of gas dynamics.…”

The effect of the sampling interface on spatial distributions of barium ions and atoms in an inductively coupled plasma ion source

“…The instrumentation for creating PLIF images of the plasma has been described in detail in reference [7]. That instrumentation was modified as follows to facilitate comparisons between the plasma in Spectrochimica Acta Part B 64 (2009) 384-391 the presence and absence of the sampling interface.…”

“…That instrumentation was modified as follows to facilitate comparisons between the plasma in Spectrochimica Acta Part B 64 (2009) 384-391 the presence and absence of the sampling interface. In the original imaging experiments described in reference [7], the CCD camera and the laser excitation optics were mounted on the vacuum chamber in fixed positions with respect to the sampling cone. For the current experiments, the camera and excitation optics were mounted to a massive x-y-z stage that supports the impedance matching network and plasma torch, with positions that were fixed with respect to the ICP load coil.…”

“…Fundamental studies from several research groups have clearly demonstrated the value of collecting a comprehensive spatial picture of the plasma in studies of matrix effects and the effects of changes in plasma operating parameters [5][6][7][8][9][10][11][12][13]. Recent studies from our group have shown the value of planar laser-induced fluorescence (PLIF) as a tool for rapid acquisition of two-dimensional images of relative analyte densities with high spatial resolution [7]. In this paper we report on the use of PLIF to provide comprehensive two-dimensional views of the effect of the sampling interface on analyte atom and ion densities in an ICP used as an ion source for elemental mass spectrometry.…”