Electrical And Spectroscopic Characterization Of A Theta-pinch Magnetically Confined Exploding Conductor Analytical Plasma.

Abstract

The studies reported here have shown that the exploding graphite fiber bundle plasma system is well suited for the direct trace elemental analysis of samples in both solution and particulate form. The analytical utility of the exploding graphite fiber bundle plasmas has been demonstrated under a variety of conditions. Linear analytical curves were obtained for several elements. Detection limits in the range of 5-20 ng were obtained for Cr and Mn under a variety of discharge conditions. Detection limits in the low microgram range were obtained for Pb. The cylindrical geometry of the graphite fiber bundle plasma makes it amenable to magnetic field confinement using the theta-pinch configuration. Benefits arising from the use of the magnetic field in conjunction with the plasma include better line radiation reproducibility, reduced particle size effects, lower continuum radiation intensity, and greater linearity for analytical curves. The effect of the magnetic field on the plasma was enhanced by the unidirectional capacitive discharge system. Time resolved photoelectric measurements show a reduction in continuum radiation of over 50% relative to an equivalent oscillatory discharge; neutral and ion line radiation intensities were relatively unchanged. The unidirectional discharge system also demonstrated more efficient spatial confinement of continuum radiation intensity.