Gas density measurements with heavy ion beams.

High current discharge channels are a promising option for the final stage of beam transport in a heavy ion fusion reactor. The creation and the properties of the channel are studied at the Gesellschaft fuer Schwerionenforschung accelerator facility. This article discusses a diagnostic technique to determine the neutral gas density channel created by a laser in a neutral gas. The concept is to measure the spreading of an ion beamlet due to collisional scattering with the gas, and thereby deduce the average line-integrated gas density. The results show a density reduction near the axis, which compares favorably with one-dimensional code calculations. [ABSTRACT FROM AUTHOR]