Laser scanning measurement of the density distribution of confined 6Li+ ions

Publisher Website
Google Scholar
Abstract
The density distribution of metastable 1s2s 3S1 Li+ ions confined in a radio‐frequency quadrupole ion trap has been studied using a laser scanning technique. The laser beam, resonant with the 5485‐Å 1s2s 3S1–1s2p 3P1 transition, is scanned in a plane normal to the trap z axis. Intercombination photons, 1s2 1S0–1s 2p 3P1 at 202 Å, are counted and stored as a function of laser‐beam position. Application of the Abel transform to the data gives the density profile in the plane of the scan. In all cases, the density profiles were consistent with a Gaussian distribution of ions. The radial and axial widths of the distribution were measured as a function of the number of ions and potential well depth and shape. The results are discussed in terms of a model in which the ions are in thermal equilibrium at a temperature of several thousand degrees Kelvin.