アイテム詳細

要旨

This thesis investigates the interaction of electrons and highly charged ions in thin plasmas with a focus on spectroscopic studies of resonant recombination processes. For this purpose, a new electron beam ion trap (EBIT) was assembled and brought into operation at the Max-Planck Institute for Nuclear Physics. This cryogenic device is also designed for fast charge breeding and serves as a prototype for future devices used at radioactive ion beam facilities. In its first stage electron beam currents of 550mA were reached, and an upgrade to 5A is planned. As an initial scientific application, X-Ray spectra of di- and trielectronic recombination into helium-like to oxygen-like silicon-ions under excitation of an electron from n = 1 -> 2 were studied with the new EBIT. These spectra show an excellent resolution in the projectile electron energy. A comparison with MCDF and CI calculations shows an influence of recombination into ions in longlived, metastable states. The time evolution of the recombination spectra is used to investigate the charge state distribution within the trap. Along with these measurements, spectra in the region between 5nm and 12nm were recorded to diagnose the charge breeding process and to determine the effective electron density in the EBIT plasma.