Tracking ground state Ba+ ions in an expanding laser–plasma plume using time-resolved vacuum ultraviolet photoionization imaging
We report results from a study of the integrated column density and expansion dynamics of ground-state-selected Ba+ ions in a laser–plasma plume using a new experimental system—VPIF (vacuum-ultraviolet photoabsorption imaging facility). The ions are tracked by recording the attenuation of a pulsed and collimated vacuum ultraviolet beam, tuned to the 5p–6d inner-shell resonance of singly ionized barium, as the expanding plasma plume moves across it. The attenuated beam is allowed to fall on a CCD array where the spatial distribution of the absorption is recorded. Time-resolved ion velocity and integrated column density maps are readily extracted from the photoionization images.(Received November 1 2003)
(Accepted February 17 2004)
Key Words: Barium; Imaging; Laser plasma; Photoabsorption; Vacuum ultraviolet.
c1 Address correspondence and reprint requests to: John T. Costello, National Centre for Plasma Science and Technology (NCPST) and School of Physical Sciences, Dublin City University, Dublin 9, Ireland. E-mail: email@example.com