Technique for Simultaneously Measuring Ion Densities, Metastable Atom Densities, and Light Emission in Decaying Gaseous Plasmas

Abstract

An apparatus for simultaneously measuring the time dependence of (a) ion densities, (b) metastable atom densities, and (c) the intensities of spectral lines and bands during the decay period of a gaseous plasma is described. It is comprised of a quadrupole mass spectrometer for the ion density measurements and a light spectrometer for light emission and fractional light absorption studies. The reliability of the results obtained by mass spectrometer probing of a decaying plasma was checked by comparing the results obtained in helium with those obtained by other measuring methods. The data were found to be consistent and showed that this technique can be a significant tool for the study of collision processes occurring in decaying plasmas. Moreover, the simultaneous application of mass and light spectrometric methods gives information about the time dependences of the various plasma constituents at the same plasma region.