Measurement of the Depopulation of the2P0,1,23Levels of Heliumlike Ions by Electron Collisions

Abstract

The collisional depopulation rate of the $2^{3}P_{0,1,2}$ triplet levels of Cv, Nvi, Ovii, Fviii, and Ne ix was determined from measured $2^{3}S\ensuremath{-}2^{3}P$ line intensity ratios. The triplet lines were observed in a hot $\ensuremath{\theta}$-pinch deuterium plasma seeded with a few percent of the element to be examined. The plasma electron temperature and density were known from laser-light-scattering experiments. The total depopulation rate of the $2^{3}P_{0,1,2}$ levels is mainly due to the $2^{3}S\ensuremath{-}2^{3}P$ collisional deexcitation rate. The measured rate agrees well with calculations by Blaha based on the Coulomb---Born approximation. With these depopulation rates known, the electron density of the plasma can be determined just by measuring the triplet-line intensity ratios.