Ba–Pb tester for mass spectrometric LTE plasma diagnostics

Abstract A simple method of temperature and electron density measurement in quasi-equilibrium plasma at temperatures below 10 kK from the ratio of mass spectrometric signals of the doubly and singly ionized ions of Ba and Pb has been proposed. High masses of the ions and possibility to select the odd isotopes makes it possible to perform measurements at a low mass resolution and low concentrations of the test elements. For atmospheric pressure plasmas at temperatures from 3500 K to 8000 K the temperature can be determined from the relation T  = 19,443 (log ( N Ba++ / N Ba+ )/( N Pb++ / N Pb+ )) −0.871 . Sources of uncertainty and accuracy of the results have also been discussed.