The magnetic trapping mode of an electron beam ion trap: New opportunities for highly charged ion research
- Department of Physics and Space Technology, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
- Institut fuer Physik, Johannes Gutenberg Universitaet, D-55099 Mainz (Germany)
Using x-ray spectroscopic techniques, we have investigated the properties of an electron beam ion trap (EBIT) after the electron beam is switched off. In the absence of the electron beam, bare, and hydrogenlike Kr{sup 35+} and Kr{sup 36+} ions remain trapped due to externally applied magnetic and electric fields for at least 5 s; xenon ions with an open {ital L} shell, i.e., Xe{sup 45+}{endash}Xe{sup 52+}, remain trapped at least as long as 20 s. The ion storage time in this {open_quote}{open_quote}magnetic trapping mode{close_quote}{close_quote} depends on the pressure of background atoms as well as on the value of the externally applied trapping potential, and even longer ion storage times appear possible. The magnetic trapping mode enables a variety of new opportunities for atomic physics research involving highly charged ions, which include the study of charge transfer reactions, Doppler-shift-free measurements of the Lamb shift, measurements of radiative lifetimes of long-lived metastable levels, or ion-ion collision studies, by x-ray or laser spectroscopy, and mass spectrometry. Because the trap is filled {ital in} {ital situ} during the electron trapping phase, transfer losses associated with filling the trap from an external source are avoided. We present spectra of the {ital K}-shell emission from heliumlike and hydrogenlike Kr{sup 34+} and Kr{sup 35+} as well as Xe{sup 52+} and Xe{sup 53+} that are produced by charge transfer reactions in collisions between ions and neutral atoms. Marked differences with {ital K}-shell spectra produced by electron-impact excitation are evident. We use the measurements to infer the Lamb shift contribution to the energy of the 1{ital s}{sub 1/2}{endash}2{ital p}{sub 3/2} transition in hydrogenlike Xe{sup 53+} and determine it to be 31276(12) eV. The measurement technique can be applied to any ion produced in an EBIT so that Doppler-shift-free Lamb shift measurements of hydrogenlike U{sup 91+} are within reach.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 392127
- Journal Information:
- Review of Scientific Instruments, Vol. 67, Issue 11; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Recent results from the EBIT and Super EBIT at Lawrence Livermore National Laboratory
Confinement in a cryogenic Penning trap of highest charge state ions from EBIT