1996 Articles

Overview of the current spectroscopy effort on the Livermore electron beam ion traps

Beiersdorfer, P.; Brown, G. V.; López-Urrutia, J. Crespo; Decaux, V.; Elliott, S. R.; Savin, Daniel Wolf; Smith, A. J.; Stefanelli, G. S.; Widmann, K.; Wong, K. L.

An overview is given of the current spectroscopic effort on the Livermore electron beam ion trap facilities. The effort focuses on four aspects: spectral line position, line intensity, temporal evolution, and line shape. Examples of line position measurements include studies of the K-shell transitions in heliumlike Kr34+ and the 2s-2p intrashell transitions in lithiumlike Th87+ and U89+, which provide benchmark values for testing the theory of relativistic and quantum electrodynamical contributions in high-Z ions. Examples of line intensity measurements are provided by measurements of the electron-impact excitation and dielectronic recombination cross sections of the heliumlike transition-metal ions Ti20+ through Co25+. A discussion of radiative lifetime measurements of metastable levels in heliumlike ions is given to illustrate our time-resolved spectroscopy techniques in the microsecond range. We also present a measurement of the spectral lineshape that illustrates the very low ion temperatures that can be achieved in an EBIT.